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17 pages, 5925 KiB

Open AccessArticle

Design and Analysis of XY Large Travel Micro Stage Based on Secondary Symmetric Lever Amplification

by Tao Zhang, Liuguang Xiong, Zequan Pan, Chunhua Zhang, Wen Qu, Yuhang Wang and Chunmei Yang

Micromachines 2023, 14(9), 1805; https://doi.org/10.3390/mi14091805 - 21 Sep 2023

Viewed by 892

Abstract

This study presents a newly developed piezoelectric drive mechanism for the purpose of designing, analyzing, and testing a micro-positioning platform driven by piezoelectric actuators. The platform incorporates a piezoelectric ceramic actuator and a flexible hinge drive and features a symmetrical two-stage lever (STSL) [...] Read more.

This study presents a newly developed piezoelectric drive mechanism for the purpose of designing, analyzing, and testing a micro-positioning platform driven by piezoelectric actuators. The platform incorporates a piezoelectric ceramic actuator and a flexible hinge drive and features a symmetrical two-stage lever (STSL) amplification mechanism and a parallelogram output structure. The implementation of this design has led to notable enhancements in the dynamic properties of the platform, thereby eliminating the undesired parasitic displacement of the mechanism. An analytical model describing the fully elastic deformation of the platform is established, which is further verified by finite element simulation. Finally, the static and dynamic performances of the platform are comprehensively evaluated through experiments. A closed-loop control strategy is adopted to eliminate the nonlinear hysteresis phenomenon of the piezoceramic actuator (PEA). The experimental results show that the piezoelectric micro-actuator platform has a motion range of 97.84 μm

\times

98.03 μm; the output coupling displacement error is less than 1%; the resolutions of the two axes are 8.1 nm and 8 nm, respectively; and the x-axis and y-axis trajectory tracking errors are both 0.6%. The piezoelectric micromotion platform has good dynamic properties, precision, and stability. The design has a wide application potential in the field of micro-positioning. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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23 pages, 6103 KiB

Open AccessArticle

Precision Motion Control of a Piezoelectric Actuator via a Modified Preisach Hysteresis Model and Two-Degree-of-Freedom H-Infinity Robust Control

by Ayad G. Baziyad, Irfan Ahmad and Yasser Bin Salamah

Micromachines 2023, 14(6), 1208; https://doi.org/10.3390/mi14061208 - 07 Jun 2023

Cited by 2 | Viewed by 1360

Abstract

The nonlinear hysteresis phenomenon can occur in piezoelectric-driven nanopositioning systems and can lead to reduced positioning accuracy or result in a serious deterioration of motion control. The Preisach method is widely used for hysteresis modeling; however, for the modeling of rate-dependent hysteresis, where [...] Read more.

The nonlinear hysteresis phenomenon can occur in piezoelectric-driven nanopositioning systems and can lead to reduced positioning accuracy or result in a serious deterioration of motion control. The Preisach method is widely used for hysteresis modeling; however, for the modeling of rate-dependent hysteresis, where the output displacement of the piezoelectric actuator depends on the amplitude and frequency of the input reference signal, the desired accuracy cannot be achieved with the classical Preisach method. In this paper, the Preisach model is improved using least-squares support vector machines (LSSVMs) to deal with the rate-dependent properties. The control part is then designed and consists of an inverse Preisach model to compensate for the hysteresis nonlinearity and a two-degree-of-freedom (2-DOF) H-infinity feedback controller to enhance the overall tracking performance with robustness. The main idea of the proposed 2-DOF H-infinity feedback controller is to find two optimal controllers that properly shape the closed-loop sensitivity functions by imposing some templates in terms of weighting functions in order to achieve the desired tracking performance with robustness. The achieved results with the suggested control strategy show that both hysteresis modeling accuracy and tracking performance are significantly improved with average root-mean-square error (RMSE) values of 0.0107 μm and 0.0212 μm, respectively. In addition, the suggested methodology can achieve better performance than comparative methods in terms of generalization and precision. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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14 pages, 3693 KiB

Open AccessArticle

Label-Free Sensing of Cell Viability Using a Low-Cost Impedance Cytometry Device

by Bowen Yang, Chao Wang, Xinyi Liang, Jinchao Li, Shanshan Li, Jie Jayne Wu, Tanbin Su and Junwei Li

Micromachines 2023, 14(2), 407; https://doi.org/10.3390/mi14020407 - 09 Feb 2023

Cited by 2 | Viewed by 1462

Abstract

Cell viability is an essential physiological status for drug screening. While cell staining is a conventional cell viability analysis method, dye staining is usually cytotoxic. Alternatively, impedance cytometry provides a straightforward and label-free sensing approach for the assessment of cell viability. A key [...] Read more.

Cell viability is an essential physiological status for drug screening. While cell staining is a conventional cell viability analysis method, dye staining is usually cytotoxic. Alternatively, impedance cytometry provides a straightforward and label-free sensing approach for the assessment of cell viability. A key element of impedance cytometry is its sensing electrodes. Most state-of-the-art electrodes are made of expensive metals, microfabricated by lithography, with a typical size of ten microns. In this work, we proposed a low-cost microfluidic impedance cytometry device with 100-micron wide indium tin oxide (ITO) electrodes to achieve a comparable performance to the 10-micron wide Au electrodes. The effectiveness was experimentally verified as 7 μm beads can be distinguished from 10 μm beads. To the best of our knowledge, this is the lowest geometry ratio of the target to the sensing unit in the impedance cytometry technology. Furthermore, a cell viability test was performed on MCF-7 cells. The proposed double differential impedance cytometry device has successfully differentiated the living and dead MCF-7 cells with a throughput of ~1000 cells/s. The label-free and low-cost, high-throughput impedance cytometry could benefit drug screening, fundamental biological research and other biomedical applications. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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12 pages, 2816 KiB

Open AccessArticle

Portable Multi-Channel Electrochemical Device with Good Interaction and Wireless Connection for On-Site Testing

by Yifei Xu, Haohao Ning, Shixin Yu, Shikun Liu, Yan Zhang, Chunyan Niu, Yongzhuo Zhang, Sze Shin Low and Jingjing Liu

Micromachines 2023, 14(1), 142; https://doi.org/10.3390/mi14010142 - 05 Jan 2023

Cited by 1 | Viewed by 1299

Abstract

It is very important to rapidly test the key indicators of water in the field to fully evaluate the quality of the regional water environment. However, a high-resolution measuring device that can generate small currents for low-concentration analytes in water samples is often [...] Read more.

It is very important to rapidly test the key indicators of water in the field to fully evaluate the quality of the regional water environment. However, a high-resolution measuring device that can generate small currents for low-concentration analytes in water samples is often bulky, complex to operate, and difficult for data sharing. This work introduces a portable multi-channel electrochemical device with a small volume, good interaction, and data-sharing capabilities called PMCED. The PMCED provides an easy-to-operate graphical interactive interface to conveniently set the parameters for cyclic voltammetry or a differential pulse method performed by the four electrode channels. At the same time, the device, with a current sensitivity of 100 nA V⁻¹, was applied to the detection of water samples with high background current and achieved a high-resolution measurement at low current levels. The PMCED uses the Narrow Band Internet of Things (NB-IoT) to meet the needs for uploading data to the cloud in remote areas. The electrochemical signal preprocessing and chemometrics models run in the cloud, and the final results are visualized on a web page, providing a remote access channel for on-site testing results. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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16 pages, 5674 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Magnetically Driven Manipulation of Nonmagnetic Liquid Marbles: Billiards with Liquid Marbles

by Parnian Azizian, Mahbod Mohammadrashidi, Ali Abbas Azimi, Mohamad Ali Bijarchi, Mohammad Behshad Shafii and Rohollah Nasiri

Micromachines 2023, 14(1), 49; https://doi.org/10.3390/mi14010049 - 25 Dec 2022

Cited by 9 | Viewed by 2527

Abstract

Liquid marbles are droplets encapsulated by a layer of hydrophobic nanoparticles and have been extensively employed in digital microfluidics and lab-on-a-chip systems in recent years. In this study, magnetic liquid marbles were used to manipulate nonmagnetic liquid marbles. To achieve this purpose, a [...] Read more.

Liquid marbles are droplets encapsulated by a layer of hydrophobic nanoparticles and have been extensively employed in digital microfluidics and lab-on-a-chip systems in recent years. In this study, magnetic liquid marbles were used to manipulate nonmagnetic liquid marbles. To achieve this purpose, a ferrofluid liquid marble (FLM) was employed and attracted toward an electromagnet, resulting in an impulse to a water liquid marble (WLM) on its way to the electromagnet. It was observed that the manipulation of the WLM by the FLM was similar to the collision of billiard balls except that the liquid marbles exhibited an inelastic collision. Taking the FLM as the projectile ball and the WLM as the other target balls, one can adjust the displacement and direction of the WLM precisely, similar to an expert billiard player. Firstly, the WLM displacement can be adjusted by altering the liquid marble volumes, the initial distances from the electromagnet, and the coil current. Secondly, the WLM direction can be adjusted by changing the position of the WLM relative to the connecting line between the FLM center and the electromagnet. Results show that when the FLM or WLM volume increases by five times, the WLM shooting distance approximately increases by 200% and decreases by 75%, respectively. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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20 pages, 7829 KiB

Open AccessArticle

2D Magnetic Manipulation of a Micro-Robot in Glycerin Using Six Pairs of Magnetic Coils

by Qigao Fan, Jiawei Lu, Jie Jia and Juntian Qu

Micromachines 2022, 13(12), 2144; https://doi.org/10.3390/mi13122144 - 04 Dec 2022

Cited by 1 | Viewed by 1865

Abstract

This paper demonstrates the control system of a single magnetic micro-robot driven by combined coils. The combined coils consist of three pairs of Helmholtz coils and three pairs of Maxwell coils. The rotating magnetic field, gradient magnetic field, and combined magnetic field model [...] Read more.

This paper demonstrates the control system of a single magnetic micro-robot driven by combined coils. The combined coils consist of three pairs of Helmholtz coils and three pairs of Maxwell coils. The rotating magnetic field, gradient magnetic field, and combined magnetic field model of the combined coils were analyzed. To make the output magnetic field quickly converge to the reference point without steady-state error, the discrete-time optimal controller was designed based on the auto disturbance rejection technology. We have designed a closed-loop controller based on a position servo. The control system includes the position control and direction control of the micro-robot. To address problems with slow sampling frequency in visual feedback and inability to feed real-time position back to the control system, a Kalman filter algorithm was used to predict the position of the micro-robot in two-dimensional space. Simulations and experiments were carried out based on the proposed structure of combined coils and control scheme. The experimental results demonstrated the uniformity and excellent dynamic performance of the generated magnetic field. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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16 pages, 5555 KiB

Open AccessArticle

Nonsingular Integral Terminal Sliding Mode Control for Resonant Frequency Tracking of Electromagnetic Acoustic Transducers (EMATs) Based on Fixed-Time Strategy

by Haichao Yuan, Qi Li, Ran Peng, Chuan Wang, Peng Xu, Xinxiang Pan and Minyi Xu

Micromachines 2022, 13(11), 2005; https://doi.org/10.3390/mi13112005 - 17 Nov 2022

Viewed by 1125

Abstract

Resonant frequency tracking control of electromagnetic acoustic transducers (EMATs) remains a challenge in terms of drifting working frequency and reduced conversion efficiency caused by working environment changes. This paper presents a fixed-time nonsingular integral terminal sliding mode (FT-NITSM) control strategy for resonant frequency [...] Read more.

Resonant frequency tracking control of electromagnetic acoustic transducers (EMATs) remains a challenge in terms of drifting working frequency and reduced conversion efficiency caused by working environment changes. This paper presents a fixed-time nonsingular integral terminal sliding mode (FT-NITSM) control strategy for resonant frequency tracking of EMATs to realize precise and high robustness resonant frequency tracking performance. Specifically, a FT-NITSM control method with fast convergence feature is developed and a resonant frequency tracking controller for EMATs is further designed to improve the convergence speed and tracking accuracy. Fixed time stability of the proposed frequency tracking control system is proved through Lyapunov function analysis. Moreover, numerical simulations demonstrate that the FT-NITSM control strategy can ensure precise tracking of the system’s operating frequency to its natural resonant frequency in less than 3 s with a tracking error of less than 0.01 × 10⁴ Hz. With the maximum overshoot variation between −20 and 20 and error range in −5 and 5° at the steady state, the FT-NITSM control strategy can ensure the control system impedance angle

θ

being consistent and eventually bounded. This study provides a toolbox for the resonant frequency tracking control and performance improvement of EMATs. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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10 pages, 1773 KiB

Open AccessArticle

A Hydrogel-Based Self-Sensing Underwater Actuator

by Shuyu Wang, Zhaojia Sun, Shuaiyang Duan, Yuliang Zhao, Xiaopeng Sha, Shifeng Yu and Lei Zuo

Micromachines 2022, 13(10), 1779; https://doi.org/10.3390/mi13101779 - 19 Oct 2022

Viewed by 1955

Abstract

Soft robots made of hydrogels are suited for underwater exploration due to their biocompatibility and compliancy. Yet, reaching high dexterity and actuation force for hydrogel-based actuators is challenging. Meanwhile, real-time proprioception is critical for feedback control. Moreover, sensor integration to mimic living organisms [...] Read more.

Soft robots made of hydrogels are suited for underwater exploration due to their biocompatibility and compliancy. Yet, reaching high dexterity and actuation force for hydrogel-based actuators is challenging. Meanwhile, real-time proprioception is critical for feedback control. Moreover, sensor integration to mimic living organisms remains problematic. To address these challenges, we introduce a hydrogel actuator driven by hydraulic force with a fast response (time constant 0.83 s). The highly stretchable and conductive hydrogel (1400% strain) is molded into the PneuNet shape, and two of them are further assembled symmetrically to actuate bi-directionally. Then, we demonstrate its bionic application for underwater swimming, showing 2 cm/s (0.19 BL/s) speed. Inspired by biological neuromuscular systems’ sensory motion, which unifies the sensing and actuation in a single unit, we explore the hydrogel actuator’s self-sensing capacity utilizing strain-induced resistance change. The results show that the soft actuator’s proprioception can monitor the undulation in real-time with a sensitivity of 0.2%/degree. Furthermore, we take a finite-element method and first-order differential equations to model the actuator’s bending in response to pressure. We show that such a model can precisely predict the robot’s bending response over a range of pressures. With the self-sensing actuator and the proposed model, we expect the new approach can lead to future soft robots for underwater exploration with feedback control, and the underlying mechanism of the undulation control might offer significant insights for biomimetic research. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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20 pages, 1506 KiB

Open AccessArticle

Activation and Switching of Supramolecular Chemical Signals in Multi-Output Microfluidic Devices

by Artem Bezrukov and Yury Galyametdinov

Micromachines 2022, 13(10), 1778; https://doi.org/10.3390/mi13101778 - 19 Oct 2022

Cited by 4 | Viewed by 1642

Abstract

In this study, we report on the developing of a continuous microfluidic reaction device that allows selective activation of polyelectrolyte-surfactant chemical signals in microflows and switches them between multiple outputs. A numerical model was developed for convection-diffusion reaction processes in reactive polymer-colloid microfluidic [...] Read more.

In this study, we report on the developing of a continuous microfluidic reaction device that allows selective activation of polyelectrolyte-surfactant chemical signals in microflows and switches them between multiple outputs. A numerical model was developed for convection-diffusion reaction processes in reactive polymer-colloid microfluidic flows. Matlab scripts and scaling laws were developed for this model to predict reaction initiation and completion conditions in microfluidic devices and the location of the reaction front. The model allows the optimization of microfluidic device geometry and the setting of operation modes that provide release of the reaction product through specific outputs. Representing a chemical signal, polyelectrolyte-surfactant reaction products create various logic gate states at microfluidic chip outputs. Such systems may have potential as biochemical signal transmitters in organ-on-chip applications or chemical logic gates in cascaded microfluidic devices. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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11 pages, 4616 KiB

Open AccessArticle

Adaptive Fiber-Ring Lasers Based on Isopropanol Filled Microfiber Coupler for High-Sensitivity Temperature Sensing

by Weihao Lin, Jie Hu, Fang Zhao, Siming Sun, Yuhui Liu, Shuaiqi Liu, Feihong Yu, Peng-Un Mak, Sio-Hang Pun, Perry-Ping Shum, Mang-I Vai and Liyang Shao

Micromachines 2022, 13(10), 1697; https://doi.org/10.3390/mi13101697 - 09 Oct 2022

Cited by 2 | Viewed by 1383

Abstract

We demonstrated a new method for temperature measurement inside a fiber ring laser (FRL) cavity. Different from traditional FRL temperature sensing system which need additional filter working as a sensor, a micro-fiber coupler (MFC) was designed as a beam splitter, filter, and temperature [...] Read more.

We demonstrated a new method for temperature measurement inside a fiber ring laser (FRL) cavity. Different from traditional FRL temperature sensing system which need additional filter working as a sensor, a micro-fiber coupler (MFC) was designed as a beam splitter, filter, and temperature sensor. In addition, isopropanol, a liquid with very high photothermal coefficient, is selectively filled in the MFC in order to improve the sensitivity of the system on temperature. In the dynamic range of 20–40 °C, we obtained a good temperature sensitivity of −1.29 nm/°C, with linear fitting up to 0.998. Benefiting from the advantages of laser sensing, the acquired laser has a 3 – dB bandwidth of less than 0.2 nm and a signal-to-noise ratio (SNR) of up to 40 dB. The proposed sensor has a low cost and high sensitivity, which is expected to be used in biomedical health detection, real-time monitoring of ocean temperature, and other application scenarios. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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19 pages, 4522 KiB

Open AccessArticle

Vertical Graphene-Based Biosensor for Tumor Cell Dielectric Signature Evaluation

by Bianca Tincu, Tiberiu Burinaru, Ana-Maria Enciu, Petruta Preda, Eugen Chiriac, Catalin Marculescu, Marioara Avram and Andrei Avram

Micromachines 2022, 13(10), 1671; https://doi.org/10.3390/mi13101671 - 04 Oct 2022

Cited by 4 | Viewed by 1667

Abstract

The selective and rapid detection of tumor cells is of critical consequence for the theragnostic field of tumorigenesis; conventional methods, such as histopathological diagnostic methods, often require a long analysis time, excessive analytical costs, complex operations, qualified personnel and deliver many false-positive results. [...] Read more.

The selective and rapid detection of tumor cells is of critical consequence for the theragnostic field of tumorigenesis; conventional methods, such as histopathological diagnostic methods, often require a long analysis time, excessive analytical costs, complex operations, qualified personnel and deliver many false-positive results. We are considering a new approach of an electrochemical biosensor based on graphene, which is evidenced to be a revolutionary nanomaterial enabling the specific and selective capture of tumor cells. In this paper, we report a biosensor fabricated by growing vertically aligned graphene nanosheets on the conductive surface of interdigitated electrodes which is functionalized with anti-EpCAM antibodies. The dielectric signature of the three types of tumor cells is determined by correlating the values from the Nyquist and Bode diagram: charge transfer resistance, electrical double layer capacity, Debye length, characteristic relaxation times of mobile charges, diffusion/adsorption coefficients, and variation in the electrical permittivity complex and of the phase shift with frequency. These characteristics are strongly dependent on the type of membrane molecules and the electromagnetic resonance frequency. We were able to use the fabricated sensor to differentiate between three types of tumor cell lines, HT-29, SW403 and MCF-7, by dielectric signature. The proposed evaluation method showed the permittivity at 1 MHz to be 3.63 nF for SW403 cells, 4.97 nF for HT 29 cells and 6.9 nF for MCF-7 cells. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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14 pages, 1976 KiB

Open AccessArticle

Low-Cost High-Resolution Potentiostat for Electrochemical Detection of Nucleic Acids and Biomolecular Interactions

by Alper Demirhan, Ece Eksin, Yalin Kilic and Arzum Erdem

Micromachines 2022, 13(10), 1610; https://doi.org/10.3390/mi13101610 - 27 Sep 2022

Cited by 2 | Viewed by 2852

Abstract

A handheld USB-powered instrument developed for the electrochemical detection of nucleic acids and biomolecular interactions is presented. The proposed instrument is capable of scanning ± 2.25 V while measuring currents up to ±10 mA, with a minimum current resolution of 6.87 pA. Therefore, [...] Read more.

A handheld USB-powered instrument developed for the electrochemical detection of nucleic acids and biomolecular interactions is presented. The proposed instrument is capable of scanning ± 2.25 V while measuring currents up to ±10 mA, with a minimum current resolution of 6.87 pA. Therefore, it is suitable for nucleic acid sensors, which have high background currents. A low-cost microcontroller with an on-chip 16-bit analog-to-digital converter, 12-bit digital-to-analog converter, and a built-in USB controller were used to miniaturize the system. The offset voltages and gain errors of the analog peripherals were calibrated to obtain a superior performance. Thus, a similar performance to those of the market-leader potentiostats was achieved, but at a fraction of their cost and size. The performance of the application of this proposed architecture was tested successfully and was found to be similar to a leading commercial device through a clinical application in the aspects of the detection of nucleic acids, such as calf thymus ssDNA and dsDNA, and their interactions with a protein (BSA) by using single-use graphite electrodes in combination with the differential pulse voltammetry technique. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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18 pages, 4357 KiB

Open AccessArticle

A Parametric Study on a Paper-Based Bi-Material Cantilever Valve

by Hojat Heidari-Bafroui, Ashutosh Kumar, Amer Charbaji, Winfield Smith, Nassim Rahmani, Constantine Anagnostopoulos and Mohammad Faghri

Micromachines 2022, 13(9), 1502; https://doi.org/10.3390/mi13091502 - 09 Sep 2022

Cited by 5 | Viewed by 2224

Abstract

The novel paper-based Bi-Material Cantilever (B-MaC) valve allows the autonomous loading and control of multiple fluid reagents which contributes to the accurate operation of paper-based microfluidic devices utilized for biological and chemical sensing applications. In this paper, an extensive parametric study is presented [...] Read more.

The novel paper-based Bi-Material Cantilever (B-MaC) valve allows the autonomous loading and control of multiple fluid reagents which contributes to the accurate operation of paper-based microfluidic devices utilized for biological and chemical sensing applications. In this paper, an extensive parametric study is presented to evaluate the effects of key geometric parameters of the valve, such as paper direction, cantilever width, paper type, tape type, and sample volume, in addition to the effects of relative humidity and temperature on the functionality of the B-MaC and to provide a better understanding of the rate of fluid flow and resulting deflection of the cantilever. Machine direction, cantilever width, paper type, and tape type were found to be important parameters that affect the B-MAC’s activation time. It was also observed that the rate of fluid imbibition in the B-MaC is considerably affected by change in humidity for high (55 °C) and low (25 °C) temperatures, while humidity levels have no significant effect during imbibition in the B-MaC at an ambient temperature of 45 °C. It was also found that a minimum distance of 4 mm is required between the B-MaC and the stationary component to prevent accidental activation of the B-MaC prior to sample insertion when relative humidity is higher than 90% and temperature is lower than 35 °C. The rate of fluid imbibition that determines the wetted length of the B-MaC and the final deflection of the cantilever are critical in designing and fabricating point-of-care microfluidic paper-based devices. The B-MaC valve can be utilized in a fluidic circuit to sequentially load several reagents, in addition to the sample to the detection area. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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14 pages, 7916 KiB

Open AccessArticle

Fluid Viscosity Measurement by Means of Secondary Flow in a Curved Channel

by Maxim I. Pryazhnikov, Anton S. Yakimov, Ivan A. Denisov, Andrey I. Pryazhnikov, Andrey V. Minakov and Peter I. Belobrov

Micromachines 2022, 13(9), 1452; https://doi.org/10.3390/mi13091452 - 02 Sep 2022

Cited by 2 | Viewed by 1790

Abstract

This article presents a new approach to determining the viscosity of Newtonian fluid. The approach is based on the analysis of the secondary Dean flow in a curved channel. The study of the flow patterns of water and aqueous solutions of glycerin in [...] Read more.

This article presents a new approach to determining the viscosity of Newtonian fluid. The approach is based on the analysis of the secondary Dean flow in a curved channel. The study of the flow patterns of water and aqueous solutions of glycerin in a microfluidic chip with a U-microchannel was carried out. The advantages of a microfluidic viscometer based on a secondary Dean flow are its simplicity, quickness, and high accuracy in determining the viscosity coefficient of a liquid. A viscosity image in a short movie represents fluid properties. It is revealed that the viscosity coefficient can be determined by the dependence of the recirculation angle of the secondary Dean flow. The article provides a correlation between the Dean number and the flow recirculation angle. The results of the field experiment, presented in the article, correlate with the data obtained using computational fluid dynamics and allow for selecting parameters to create microfluidic viscometers with a U-shaped microchannel. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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10 pages, 1996 KiB

Open AccessArticle

Experiment—Simulation Comparison in Liquid Filling Process Driven by Capillarity

by Wei Hua, Wei Wang, Weidong Zhou, Ruige Wu and Zhenfeng Wang

Micromachines 2022, 13(7), 1098; https://doi.org/10.3390/mi13071098 - 12 Jul 2022

Viewed by 1243

Abstract

This paper studies modifications made to the Bosanquet equation in order to fit the experimental observations of the liquid filling process in circular tubes that occurs by capillary force. It is reported that there is a significant difference between experimental observations and the [...] Read more.

This paper studies modifications made to the Bosanquet equation in order to fit the experimental observations of the liquid filling process in circular tubes that occurs by capillary force. It is reported that there is a significant difference between experimental observations and the results predicted by the Bosanquet equation; hence, it is reasonable to investigate these differences intensively. Here, we modified the Bosanquet equation such that it could consider more factors that contribute to the filling process. First, we introduced the air flowing out of the tube as the liquid inflow. Next, we considered the increase in hydraulic resistance due to the surface roughness of the inner tube. Finally, we further considered the advancing contact angle, which varies during the filling process. When these three factors were included, the modified Bosanquet equation was well correlated with the experimental results, and the R square—which indicates the fitting quality between the simulation and the experiment—significantly increased to above 0.99. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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18 pages, 4795 KiB

Open AccessArticle

Mechanical Characterization and Modelling of Subcellular Components of Oocytes

by Yue Du, Yizhe Chen, Shuai Zhang, Dai Cheng, Yaowei Liu, Qili Zhao, Mingzhu Sun, Maosheng Cui and Xin Zhao

Micromachines 2022, 13(7), 1087; https://doi.org/10.3390/mi13071087 - 08 Jul 2022

Cited by 2 | Viewed by 1835

Abstract

The early steps of embryogenesis are controlled exclusively by the quality of oocyte that linked closely to its mechanical properties. The mechanical properties of an oocyte were commonly characterized by assuming it was homogeneous such that the result deviated significantly from the true [...] Read more.

The early steps of embryogenesis are controlled exclusively by the quality of oocyte that linked closely to its mechanical properties. The mechanical properties of an oocyte were commonly characterized by assuming it was homogeneous such that the result deviated significantly from the true fact that it was composed of subcellular components. In this work, we accessed and characterized the subcellular components of the oocytes and developed a layered high-fidelity finite element model for describing the viscoelastic responses of an oocyte under loading. The zona pellucida (ZP) and cytoplasm were isolated from an oocyte using an in-house robotic micromanipulation platform and placed on AFM to separately characterizing their mechanical profiling by analyzing the creep behavior with the force clamping technique. The spring and damping parameters of a Kelvin–Voigt model were derived by fitting the creeping curve to the model, which were used to define the shear relaxation modulus and relaxation time of ZP or cytoplasm in the ZP and cytoplasm model. In the micropipette aspiration experiment, the model was accurate sufficiently to deliver the time-varying aspiration depth of the oocytes under the step negative pressure of a micropipette. In the micropipette microinjection experiment, the model accurately described the intracellular strain introduced by the penetration. The developed oocyte FEM model has implications for further investigating the viscoelastic responses of the oocytes under different loading settings. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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14 pages, 2607 KiB

Open AccessArticle

Fast Electrochemical Actuator with Ti Electrodes in the Current Stabilization Regime

by Ilia V. Uvarov, Artem E. Melenev and Vitaly B. Svetovoy

Micromachines 2022, 13(2), 283; https://doi.org/10.3390/mi13020283 - 10 Feb 2022

Cited by 1 | Viewed by 1505

Abstract

The actuators needed for autonomous microfluidic devices have to be compact, low-power-consuming, and compatible with microtechnology. The electrochemical actuators could be good candidates, but they suffer from a long response time due to slow gas termination. An actuator in which the gas is [...] Read more.

The actuators needed for autonomous microfluidic devices have to be compact, low-power-consuming, and compatible with microtechnology. The electrochemical actuators could be good candidates, but they suffer from a long response time due to slow gas termination. An actuator in which the gas is terminated orders of magnitude faster has been demonstrated recently. It uses water electrolysis performed by short voltage pulses of alternating polarity (AP). However, oxidation of Ti electrodes leads to a rapid decrease in the performance. In this paper, we demonstrate a special driving regime of the actuator, which is able to support a constant stroke for at least 10

^{5}

cycles. The result is achieved using a new driving regime when a series of AP pulses are interspersed with a series of single-polarity (SP) pulses. The new regime is realized by a special pulse generator that automatically adjusts the amplitude of the SP pulses to keep the current flowing through the electrodes at a fixed level. The SP pulses increase the power consumption by 15–60% compared to the normal AP operation and make the membrane oscillate in a slightly lifted position. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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10 pages, 6337 KiB

Open AccessArticle

Investigation of the Contact Characteristics of Silicon–Gold in an Anodic Bonding Structure

by Lin Zhang, Kaicong Cao, Longqi Ran, Huijun Yu and Wu Zhou

Micromachines 2022, 13(2), 264; https://doi.org/10.3390/mi13020264 - 06 Feb 2022

Cited by 1 | Viewed by 2154

Abstract

Anodic bonding is broadly utilized to realize the structure support and electrical connection in the process of fabrication and packaging of MEMS devices, and the mechanical and electrical characteristics of the bonded interface of structure exhibit a significant impact on the stability and [...] Read more.

Anodic bonding is broadly utilized to realize the structure support and electrical connection in the process of fabrication and packaging of MEMS devices, and the mechanical and electrical characteristics of the bonded interface of structure exhibit a significant impact on the stability and reliability of devices. For the anodic bonding structure, including the gold electrode of micro accelerometers, the elastic/plastic contact model of a gold–silicon rough surface is established based on Hertz contact theory to gain the contact area and force of Gauss surface bonding. The trans-scale finite element model of a silicon–gold glass structure is built in Workbench through the reconstruction of Gauss surface net by the reverse engineering technique. The translation load is added to mimic the process of contact to acquire the contact behaviors through the coupling of mechanical and electrical fields, and then the change law of contact resistance is obtained. Finally, the measurement shows a good agreement between the experimental results, theoretical analysis and simulation, which indicates there is almost no change of resistance when the surface gap is less than 20 nm and the resistance is less than 5Ω, while the resistance changes rapidly after the gap exceeds 20 nm. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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9 pages, 9445 KiB

Open AccessArticle

Outer Acoustic Streaming Flow Driven by Asymmetric Acoustic Resonances

by Junjun Lei, Gaokun Zheng, Zhen Yao and Zhigang Huang

Micromachines 2022, 13(1), 65; https://doi.org/10.3390/mi13010065 - 30 Dec 2021

Cited by 2 | Viewed by 8237

Abstract

While boundary-driven acoustic streaming resulting from the interaction of sound, fluids and walls in symmetric acoustic resonances have been intensively studied in the literature, the acoustic streaming fields driven by asymmetric acoustic resonances remain largely unexplored. Here, we present a theoretical and numerical [...] Read more.

While boundary-driven acoustic streaming resulting from the interaction of sound, fluids and walls in symmetric acoustic resonances have been intensively studied in the literature, the acoustic streaming fields driven by asymmetric acoustic resonances remain largely unexplored. Here, we present a theoretical and numerical analysis of outer acoustic streaming flows generated over a fluid–solid interface above which a symmetric or asymmetric acoustic standing wave is established. The asymmetric standing wave is defined by a shift of acoustic pressure in its magnitude, i.e.,

S_{0}

, and the resulting outer acoustic streaming is analyzed using the limiting velocity method. We show that, in symmetric acoustic resonances (

S_{0} = 0

), on a slip-velocity boundary, the limiting velocities always drive fluids from the acoustic pressure node towards adjacent antinodes. In confined geometry where a slip-velocity condition is applied to two parallel walls, the characteristics of the obtained outer acoustic streaming replicates that of Rayleigh streaming. In an asymmetric standing wave where

S_{0} \neq 0

, however, it is found that the resulting limiting velocity node (i.e., the dividing point of limiting velocities) on the slip-velocity boundary locates at a different position to acoustic pressure node and, more importantly, is shown to be independent of

S_{0}

, enabling spatial separation of acoustic radiation force and acoustic streaming flows. The results show the richness of boundary-driven acoustic streaming pattern variations that arise in standing wave fields and have potentials in many microfluidics applications such as acoustic streaming flow control and particle manipulation. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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12 pages, 3332 KiB

Open AccessCommunication

Wafer-Level 3D Integration Based on Poly (Diallyl Phthalate) Adhesive Bonding

by Zhong Fang, Peng You, Yijie Jia, Xuchao Pan, Yunlei Shi, Junjie Jiao and Yong He

Micromachines 2021, 12(12), 1586; https://doi.org/10.3390/mi12121586 - 20 Dec 2021

Cited by 1 | Viewed by 2443

Abstract

Three-dimensional integration technology provides a promising total solution that can be used to achieve system-level integration with high function density and low cost. In this study, a wafer-level 3D integration technology using PDAP as an intermediate bonding polymer was applied effectively for integration [...] Read more.

Three-dimensional integration technology provides a promising total solution that can be used to achieve system-level integration with high function density and low cost. In this study, a wafer-level 3D integration technology using PDAP as an intermediate bonding polymer was applied effectively for integration with an SOI wafer and dummy a CMOS wafer. The influences of the procedure parameters on the adhesive bonding effects were determined by Si–Glass adhesive bonding tests. It was found that the bonding pressure, pre-curing conditions, spin coating conditions, and cleanliness have a significant influence on the bonding results. The optimal procedure parameters for PDAP adhesive bonding were obtained through analysis and comparison. The 3D integration tests were conducted according to these optimal parameters. In the tests, process optimization was focused on Si handle-layer etching, PDAP layer etching, and Au pillar electroplating. After that, the optimal process conditions for the 3D integration process were achieved. The 3D integration applications of the micro-bolometer array and the micro-bridge resistor array were presented. It was confirmed that 3D integration based on PDAP adhesive bonding is suitable for the fabrication of system-on-chip when using MEMS and IC integration and that it is especially useful for the fabrication of low-cost suspended-microstructure on-CMOS-chip systems. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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14 pages, 5788 KiB

Open AccessArticle

Development of Cell-Carrying Magnetic Microrobots with Bioactive Nanostructured Titanate Surface for Enhanced Cell Adhesion

by Junyang Li, Lei Fan, Yanfang Li, Tanyong Wei, Cheng Wang, Feng Li, Hua Tian and Dong Sun

Micromachines 2021, 12(12), 1572; https://doi.org/10.3390/mi12121572 - 17 Dec 2021

Cited by 4 | Viewed by 2703

Abstract

Cell-carrying magnet-driven microrobots are easily affected by blood flow or body fluids during transportation in the body, and thus cells often fall off from the microrobots. To reduce the loss of loaded cells, we developed a microrobot with a bioactive nanostructured titanate surface [...] Read more.

Cell-carrying magnet-driven microrobots are easily affected by blood flow or body fluids during transportation in the body, and thus cells often fall off from the microrobots. To reduce the loss of loaded cells, we developed a microrobot with a bioactive nanostructured titanate surface (NTS), which enhances cell adhesion. The microrobot was fabricated using 3D laser lithography and coated with nickel for magnetic actuation. Then, the microrobot was coated with titanium for the external generation of an NTS through reactions in NaOH solution. Enhanced cell adhesion may be attributed to the changes in the surface wettability of the microrobot and in the morphology of the loaded cells. An experiment was performed on a microfluidic chip for the simulation of blood flow environment, and result revealed that the cells adhered closely to the microrobot with NTS and were not obviously affected by flow. The cell viability and protein absorption test and alkaline phosphatase activity assay indicated that NTS can provide a regulatory means for improving cell proliferation and early osteogenic differentiation. This research provided a novel microrobotic platform that can positively influence the behaviour of cells loaded on microrobots through surface nanotopography, thereby opening up a new route for microrobot cell delivery. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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12 pages, 19448 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

SiGe/Si Multi-Quantum-Well Micro-Bolometer Array Design and Fabrication with Heterogeneous Integration

by Zhong Fang, Yong He, Zhequan Chen, Yunlei Shi, Junjie Jiao and Xuchao Pan

Micromachines 2021, 12(12), 1553; https://doi.org/10.3390/mi12121553 - 13 Dec 2021

Cited by 1 | Viewed by 2223

Abstract

The micro-bolometer is important in the field of infrared imaging, although improvements in its performance have been limited by traditional materials. SiGe/Si multi-quantum-well materials (SiGe/Si MQWs) are novelty thermal-sensitive materials with a significantly high TCR and a comparably low 1/f noise. The application [...] Read more.

The micro-bolometer is important in the field of infrared imaging, although improvements in its performance have been limited by traditional materials. SiGe/Si multi-quantum-well materials (SiGe/Si MQWs) are novelty thermal-sensitive materials with a significantly high TCR and a comparably low 1/f noise. The application of such high-performance monocrystalline films in a micro-bolometer has been limited by film integration technology. This paper reports a SiGe/Si MQWs micro-bolometer fabrication with heterogeneous integration. The integration with the SiGe/Si MQWs handle wafer and dummy read-out circuit wafer was achieved based on adhesive wafer bonding. The SiGe/Si MQWs infrared-absorption structure and thermal bridge were calculated and designed. The SiGe/Si MQWs wafer and a 320 × 240 micro-bolometer array of 40 µm pitch L-type pixels were fabricated. The test results for the average absorption efficiency were more than 90% at the wavelength of 8–14 µm. The test pixel was measured to have a thermal capacity of 1.043 × 10⁻⁹ J/K, a thermal conductivity of 1.645 × 10⁻⁷ W/K, and a thermal time constant of 7.25 ms. Furthermore, the total TCR value of the text pixel was measured as 2.91%/K with a bias voltage of 0.3 V. The SiGe/Si MQWs micro-bolometer can be widely applied in commercial fields, especially in early medical diagnosis and biological detection. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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10 pages, 2927 KiB

Open AccessArticle

A DIY Fabrication Approach for Ultra-Thin Focus-Tunable Liquid Lens Using Electrohydrodynamic Pump

by Taichi Murakami, Yu Kuwajima, Ardi Wiranata, Ayato Minaminosono, Hiroki Shigemune, Zebing Mao and Shingo Maeda

Micromachines 2021, 12(12), 1452; https://doi.org/10.3390/mi12121452 - 26 Nov 2021

Cited by 5 | Viewed by 2180

Abstract

Demand for variable focus lens is increasing these days due to the rapid development of smart mobile devices and drones. However, conventional mechanical systems for lenses are generally complex, cumbersome, and rigid (e.g., for motors and gears). This research proposes a simple and [...] Read more.

Demand for variable focus lens is increasing these days due to the rapid development of smart mobile devices and drones. However, conventional mechanical systems for lenses are generally complex, cumbersome, and rigid (e.g., for motors and gears). This research proposes a simple and compact liquid lens controlled by an electro hydro dynamics (EHD) pump. In our study, we propose a do-it-yourself (DIY) method to fabricate the low-cost EHD lens. The EHD lens consists of a polypropylene (PP) sheet for the exterior, a copper sheet for the electrodes, and an acrylic elastomer for the fluidic channel where dielectric fluid and pure water are filled. We controlled the lens magnification by changing the curvature of the liquid interface between the dielectric fluid and pure water. We evaluated the magnification performance of the lens. Moreover, we also established a numerical model to characterize the lens performance. We expect to contribute to the miniaturization of focus-tunable lenses. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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Review

Jump to: Research

29 pages, 12157 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Recent State and Challenges in Spectroelectrochemistry with Its Applications in Microfluidics

by Zhenglong Li, Charmi Chande, Yu-Hsuan Cheng and Sagnik Basuray

Micromachines 2023, 14(3), 667; https://doi.org/10.3390/mi14030667 - 17 Mar 2023

Viewed by 1891

Abstract

This review paper presents the recent developments in spectroelectrochemical (SEC) technologies. The coupling of spectroscopy and electrochemistry enables SEC to do a detailed and comprehensive study of the electron transfer kinetics and vibrational spectroscopic fingerprint of analytes during electrochemical reactions. Though SEC is [...] Read more.

This review paper presents the recent developments in spectroelectrochemical (SEC) technologies. The coupling of spectroscopy and electrochemistry enables SEC to do a detailed and comprehensive study of the electron transfer kinetics and vibrational spectroscopic fingerprint of analytes during electrochemical reactions. Though SEC is a promising technique, the usage of SEC techniques is still limited. Therefore, enough publicity for SEC is required, considering the promising potential in the analysis fields. Unlike previously published review papers primarily focused on the relatively frequently used SEC techniques (ultraviolet-visible SEC and surface-enhanced Raman spectroscopy SEC), the two not-frequently used but promising techniques (nuclear magnetic resonance SEC and dark-field microscopy SEC) have also been studied in detail. This review paper not only focuses on the applications of each SEC method but also details their primary working mechanism. In short, this paper summarizes each SEC technique’s working principles, current applications, challenges encountered, and future development directions. In addition, each SEC technique’s applicative research directions are detailed and compared in this review work. Furthermore, integrating SEC techniques into microfluidics is becoming a trend in minimized analysis devices. Therefore, the usage of SEC techniques in microfluidics is discussed. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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26 pages, 4364 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Microfluidic Gas Sensors: Detection Principle and Applications

by Sreerag Kaaliveetil, Juliana Yang, Saud Alssaidy, Zhenglong Li, Yu-Hsuan Cheng, Niranjan Haridas Menon, Charmi Chande and Sagnik Basuray

Micromachines 2022, 13(10), 1716; https://doi.org/10.3390/mi13101716 - 11 Oct 2022

Cited by 12 | Viewed by 3984

Abstract

With the rapid growth of emerging point-of-use (POU)/point-of-care (POC) detection technologies, miniaturized sensors for the real-time detection of gases and airborne pathogens have become essential to fight pollution, emerging contaminants, and pandemics. However, the low-cost development of miniaturized gas sensors without compromising selectivity, [...] Read more.

With the rapid growth of emerging point-of-use (POU)/point-of-care (POC) detection technologies, miniaturized sensors for the real-time detection of gases and airborne pathogens have become essential to fight pollution, emerging contaminants, and pandemics. However, the low-cost development of miniaturized gas sensors without compromising selectivity, sensitivity, and response time remains challenging. Microfluidics is a promising technology that has been exploited for decades to overcome such limitations, making it an excellent candidate for POU/POC. However, microfluidic-based gas sensors remain a nascent field. In this review, the evolution of microfluidic gas sensors from basic electronic techniques to more advanced optical techniques such as surface-enhanced Raman spectroscopy to detect analytes is documented in detail. This paper focuses on the various detection methodologies used in microfluidic-based devices for detecting gases and airborne pathogens. Non-continuous microfluidic devices such as bubble/droplet-based microfluidics technology that have been employed to detect gases and airborne pathogens are also discussed. The selectivity, sensitivity, advantages/disadvantages vis-a-vis response time, and fabrication costs for all the microfluidic sensors are tabulated. The microfluidic sensors are grouped based on the target moiety, such as air pollutants such as carbon monoxide and nitrogen oxides, and airborne pathogens such as E. coli and SARS-CoV-2. The possible application scenarios for the various microfluidic devices are critically examined. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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25 pages, 5618 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Ultrasound-Responsive Nanocarriers for Breast Cancer Chemotherapy

by Gelan Ayana, Jaemyung Ryu and Se-woon Choe

Micromachines 2022, 13(9), 1508; https://doi.org/10.3390/mi13091508 - 11 Sep 2022

Cited by 12 | Viewed by 4710

Abstract

Breast cancer is the most common type of cancer and it is treated with surgical intervention, radiotherapy, chemotherapy, or a combination of these regimens. Despite chemotherapy’s ample use, it has limitations such as bioavailability, adverse side effects, high-dose requirements, low therapeutic indices, multiple [...] Read more.

Breast cancer is the most common type of cancer and it is treated with surgical intervention, radiotherapy, chemotherapy, or a combination of these regimens. Despite chemotherapy’s ample use, it has limitations such as bioavailability, adverse side effects, high-dose requirements, low therapeutic indices, multiple drug resistance development, and non-specific targeting. Drug delivery vehicles or carriers, of which nanocarriers are prominent, have been introduced to overcome chemotherapy limitations. Nanocarriers have been preferentially used in breast cancer chemotherapy because of their role in protecting therapeutic agents from degradation, enabling efficient drug concentration in target cells or tissues, overcoming drug resistance, and their relatively small size. However, nanocarriers are affected by physiological barriers, bioavailability of transported drugs, and other factors. To resolve these issues, the use of external stimuli has been introduced, such as ultrasound, infrared light, thermal stimulation, microwaves, and X-rays. Recently, ultrasound-responsive nanocarriers have become popular because they are cost-effective, non-invasive, specific, tissue-penetrating, and deliver high drug concentrations to their target. In this paper, we review recent developments in ultrasound-guided nanocarriers for breast cancer chemotherapy, discuss the relevant challenges, and provide insights into future directions. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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31 pages, 5935 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Review of Bubble Applications in Microrobotics: Propulsion, Manipulation, and Assembly

by Yuting Zhou, Liguo Dai and Niandong Jiao

Micromachines 2022, 13(7), 1068; https://doi.org/10.3390/mi13071068 - 04 Jul 2022

Cited by 13 | Viewed by 4438

Abstract

In recent years, microbubbles have been widely used in the field of microrobots due to their unique properties. Microbubbles can be easily produced and used as power sources or tools of microrobots, and the bubbles can even serve as microrobots themselves. As a [...] Read more.

In recent years, microbubbles have been widely used in the field of microrobots due to their unique properties. Microbubbles can be easily produced and used as power sources or tools of microrobots, and the bubbles can even serve as microrobots themselves. As a power source, bubbles can propel microrobots to swim in liquid under low-Reynolds-number conditions. As a manipulation tool, microbubbles can act as the micromanipulators of microrobots, allowing them to operate upon particles, cells, and organisms. As a microrobot, microbubbles can operate and assemble complex microparts in two- or three-dimensional spaces. This review provides a comprehensive overview of bubble applications in microrobotics including propulsion, micromanipulation, and microassembly. First, we introduce the diverse bubble generation and control methods. Then, we review and discuss how bubbles can play a role in microrobotics via three functions: propulsion, manipulation, and assembly. Finally, by highlighting the advantages and current challenges of this progress, we discuss the prospects of microbubbles in microrobotics. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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18 pages, 4006 KiB

Open AccessReview

Architecture of Computing System based on Chiplet

by Guangbao Shan, Yanwen Zheng, Chaoyang Xing, Dongdong Chen, Guoliang Li and Yintang Yang

Micromachines 2022, 13(2), 205; https://doi.org/10.3390/mi13020205 - 28 Jan 2022

Cited by 15 | Viewed by 7750

Abstract

Computing systems are widely used in medical diagnosis, climate prediction, autonomous vehicles, etc. As the key part of electronics, the performance of computing systems is crucial in the intellectualization of the equipment. The conflict between performance, efficiency, and cost can be solved by [...] Read more.

Computing systems are widely used in medical diagnosis, climate prediction, autonomous vehicles, etc. As the key part of electronics, the performance of computing systems is crucial in the intellectualization of the equipment. The conflict between performance, efficiency, and cost can be solved by choosing an appropriate computing system architecture. In order to provide useful advice and instructions for the designers to fabricate high-performance computing systems, this paper reviews the Chiplet-based computing system architectures, including computing architecture and memory architecture. Firstly, the computing architecture used for high-performance computing, mobile, and PC is presented and summarized. Secondly, the memory architecture based on mainstream memory and emerging non-volatile memory used for data storing and processing are introduced, and the key parameters of memory are compared and discussed. Finally, this paper is concluded, and the future perspectives of computing system architecture based on Chiplet are presented. Full article

(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)

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