Research

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16 pages, 4154 KiB

Open AccessArticle

Network Bursts in 3D Neuron Clusters Cultured on Microcontact-Printed Substrates

by Qian Liang, Zhe Chen, Xie Chen, Qiang Huang and Tao Sun

Micromachines 2023, 14(9), 1703; https://doi.org/10.3390/mi14091703 - 31 Aug 2023

Viewed by 890

Microcontact printing (CP) is widely used to guide neurons to form 2D networks for neuroscience research. However, it is still difficult to establish 3D neuronal cultures on the CP substrate even though 3D neuronal structures are able to recapitulate critical aspects of native [...] Read more.

Microcontact printing (CP) is widely used to guide neurons to form 2D networks for neuroscience research. However, it is still difficult to establish 3D neuronal cultures on the CP substrate even though 3D neuronal structures are able to recapitulate critical aspects of native tissue. Here, we demonstrate that the reduced cell-substrate adhesion caused by the CP substrate could conveniently facilitate the aggregate formation of large-scale 3D neuron cluster networks. Furthermore, based on the quantitative analysis of the calcium activity of the resulting cluster networks, the effect of cell seeding density and local restriction of the CP substrate on network dynamics was investigated in detail. The results revealed that cell aggregation degree, rather than cell number, could take on the main role of the generation of synchronized network-wide calcium oscillation (network bursts) in the 3D neuron cluster networks. This finding may provide new insights for easy and cell-saving construction of in vitro 3D pathological models of epilepsy, and into deciphering the onset and evolution of network bursts in developmental nerve systems. Full article

(This article belongs to the Special Issue 3D Bioprinting and Biofabrication for the Future of Tissue Engineering)

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12 pages, 3197 KiB

Open AccessArticle

Uniaxial Cyclic Cell Stretching Device for Accelerating Cellular Studies

by Sharda Yadav, Pradip Singha, Nhat-Khuong Nguyen, Chin Hong Ooi, Navid Kashaninejad and Nam-Trung Nguyen

Micromachines 2023, 14(8), 1537; https://doi.org/10.3390/mi14081537 - 31 Jul 2023

Cited by 1 | Viewed by 1377

Abstract

Cellular response to mechanical stimuli is a crucial factor for maintaining cell homeostasis. The interaction between the extracellular matrix and mechanical stress plays a significant role in organizing the cytoskeleton and aligning cells. Tools that apply mechanical forces to cells and tissues, as [...] Read more.

Cellular response to mechanical stimuli is a crucial factor for maintaining cell homeostasis. The interaction between the extracellular matrix and mechanical stress plays a significant role in organizing the cytoskeleton and aligning cells. Tools that apply mechanical forces to cells and tissues, as well as those capable of measuring the mechanical properties of biological cells, have greatly contributed to our understanding of fundamental mechanobiology. These tools have been extensively employed to unveil the substantial influence of mechanical cues on the development and progression of various diseases. In this report, we present an economical and high-performance uniaxial cell stretching device. This paper reports the detailed operation concept of the device, experimental design, and characterization. The device was tested with MDA-MB-231 breast cancer cells. The experimental results agree well with previously documented morphological changes resulting from stretching forces on cancer cells. Remarkably, our new device demonstrates comparable cellular changes within 30 min compared with the previous 2 h stretching duration. This third-generation device significantly improved the stretching capabilities compared with its previous counterparts, resulting in a remarkable reduction in stretching time and a substantial increase in overall efficiency. Moreover, the device design incorporates an open-source software interface, facilitating convenient parameter adjustments such as strain, stretching speed, frequency, and duration. Its versatility enables seamless integration with various optical microscopes, thereby yielding novel insights into the realm of mechanobiology. Full article

(This article belongs to the Special Issue 3D Bioprinting and Biofabrication for the Future of Tissue Engineering)

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15 pages, 7678 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Low-Cost Light-Based GelMA 3D Bioprinting via Retrofitting: Manufacturability Test and Cell Culture Assessment

by Juan Enrique Pérez-Cortez, Víctor Hugo Sánchez-Rodríguez, Salvador Gallegos-Martínez, Cristina Chuck-Hernández, Ciro A. Rodriguez, Mario Moises Álvarez, Grissel Trujillo-de Santiago, Elisa Vázquez-Lepe and J. Israel Martínez-López

Micromachines 2023, 14(1), 55; https://doi.org/10.3390/mi14010055 - 25 Dec 2022

Cited by 6 | Viewed by 2448

Abstract

Light-based bioprinter manufacturing technology is still prohibitively expensive for organizations that rely on accessing three-dimensional biological constructs for research and tissue engineering endeavors. Currently, most of the bioprinting systems are based on commercial-grade-based systems or modified DIY (do it yourself) extrusion apparatuses. However, [...] Read more.

Light-based bioprinter manufacturing technology is still prohibitively expensive for organizations that rely on accessing three-dimensional biological constructs for research and tissue engineering endeavors. Currently, most of the bioprinting systems are based on commercial-grade-based systems or modified DIY (do it yourself) extrusion apparatuses. However, to date, few examples of the adoption of low-cost equipment have been found for light-based bioprinters. The requirement of large volumes of bioinks, their associated cost, and the lack of information regarding the parameter selection have undermined the adoption of this technology. This paper showcases the retrofitting and assessing of a low-cost Light-Based 3D printing system for tissue engineering. To evaluate the potential of a proposed design, a manufacturability test for different features, machine parameters, and Gelatin Methacryloyl (GelMA) concentrations for 7.5% and 10% was performed. Furthermore, a case study of a previously seeded hydrogel with C2C12 cells was successfully implemented as a proof of concept. On the manufacturability test, deviational errors were found between 0.7% to 13.3% for layer exposure times of 15 and 20 s. Live/Dead and Actin-Dapi fluorescence assays after 5 days of culture showed promising results in the cell viability, elongation, and alignment of 3D bioprinted structures. The retrofitting of low-cost equipment has the potential to enable researchers to create high-resolution structures and three-dimensional in vitro models. Full article

(This article belongs to the Special Issue 3D Bioprinting and Biofabrication for the Future of Tissue Engineering)

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14 pages, 2344 KiB

Open AccessArticle

A Stretching Force Control-Based Cyclic Loading Method for the Evaluation of Mechanical Properties of Gelation Methacrylate (GelMA) Microfibers

by Qian Liang, Xiao Yu, Xie Chen, Qiang Huang and Tao Sun

Micromachines 2022, 13(10), 1703; https://doi.org/10.3390/mi13101703 - 10 Oct 2022

Cited by 1 | Viewed by 1292

Abstract

Microfluidic spun gelation mechacrylate (GelMA) microfiber has been widely utilized as a promising bioink for 3D bioprinting. However, its weak and easily tuned mechanical properties are still difficult to precisely evaluate, due to the lack of an effective stretching method. In this paper, [...] Read more.

Microfluidic spun gelation mechacrylate (GelMA) microfiber has been widely utilized as a promising bioink for 3D bioprinting. However, its weak and easily tuned mechanical properties are still difficult to precisely evaluate, due to the lack of an effective stretching method. In this paper, we propose a force-control-based cyclic loading method for rapidly evaluating the elastic modulus: the E of the microfibers with different GelMA concentrations. A two-tube manipulation system is used to stretch microfiber with a non-destructive process. Based on the model reference adaptive control strategy, the stress response can be fitted into a sinusoidal wave when a small sinusoidal strain is automatically applied onto the microfiber. Afterwards, the maximum tensile stress and tensile stain is obtained to determine the E. Moreover, different stress amplitudes and frequencies are applied to form different stress-strain loops with almost same E. Compared with a frequently-used constant force loading method, the proposed method shows an obvious advantage in measurement accuracy, especially for low-concentration GelMA microfiber. Furthermore, the reasonableness of the measured E for different GelMA concentrations is confirmed by 3D cell culture experiments, and the results show the proposed method has great application potential to investigate the interaction between cell and fibrous bioink substrate. Full article

(This article belongs to the Special Issue 3D Bioprinting and Biofabrication for the Future of Tissue Engineering)

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12 pages, 3667 KiB

Open AccessArticle

Optimization of Complete Rat Heart Decellularization Using Artificial Neural Networks

by Greta Ionela Barbulescu, Taddeus Paul Buica, Iacob Daniel Goje, Florina Maria Bojin, Valentin Laurentiu Ordodi, Gheorghe Emilian Olteanu, Rodica Elena Heredea and Virgil Paunescu

Micromachines 2022, 13(1), 79; https://doi.org/10.3390/mi13010079 - 02 Jan 2022

Cited by 3 | Viewed by 1841

Abstract

Whole organ decellularization techniques have facilitated the fabrication of extracellular matrices (ECMs) for engineering new organs. Unfortunately, there is no objective gold standard evaluation of the scaffold without applying a destructive method such as histological analysis or DNA removal quantification of the dry [...] Read more.

Whole organ decellularization techniques have facilitated the fabrication of extracellular matrices (ECMs) for engineering new organs. Unfortunately, there is no objective gold standard evaluation of the scaffold without applying a destructive method such as histological analysis or DNA removal quantification of the dry tissue. Our proposal is a software application using deep convolutional neural networks (DCNN) to distinguish between different stages of decellularization, determining the exact moment of completion. Hearts from male Sprague Dawley rats (n = 10) were decellularized using 1% sodium dodecyl sulfate (SDS) in a modified Langendorff device in the presence of an alternating rectangular electric field. Spectrophotometric measurements of deoxyribonucleic acid (DNA) and total proteins concentration from the decellularization solution were taken every 30 min. A monitoring system supervised the sessions, collecting a large number of photos saved in corresponding folders. This system aimed to prove a strong correlation between the data gathered by spectrophotometry and the state of the heart that could be visualized with an OpenCV-based spectrometer. A decellularization completion metric was built using a DCNN based classifier model trained using an image set comprising thousands of photos. Optimizing the decellularization process using a machine learning approach launches exponential progress in tissue bioengineering research. Full article

(This article belongs to the Special Issue 3D Bioprinting and Biofabrication for the Future of Tissue Engineering)

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23 pages, 9835 KiB

Open AccessArticle

Design and Mechanical Properties Verification of Gradient Voronoi Scaffold for Bone Tissue Engineering

by Haiyuan Zhao, Yafeng Han, Chen Pan, Ding Yang, Haotian Wang, Tingyu Wang, Xinyun Zeng and Penglei Su

Micromachines 2021, 12(6), 664; https://doi.org/10.3390/mi12060664 - 05 Jun 2021

Cited by 22 | Viewed by 3591

Abstract

In order to obtain scaffold that can meet the therapeutic effect, researchers have carried out research on irregular porous structures. However, there are deficiencies in the design method of accurately controlling the apparent elastic modulus of the structure at present. Natural bone has [...] Read more.

In order to obtain scaffold that can meet the therapeutic effect, researchers have carried out research on irregular porous structures. However, there are deficiencies in the design method of accurately controlling the apparent elastic modulus of the structure at present. Natural bone has a gradient porous structure. However, there are few studies on the mechanical property advantages of gradient bionic bone scaffold. In this paper, an improved method based on Voronoi-tessellation is proposed. The method can get controllable gradient scaffolds to fit the modulus of natural bone, and accurately control the apparent elastic modulus of porous structure, which is conducive to improving the stress shielding. To verify the designed structure can be fabricated by additive manufacturing, several designed models are obtained by SLM and EBM. Through finite element analysis (FEA), it is verified that the irregular porous structure based on Voronoi-tessellation is more stable than the traditional regular porous structure of the same structure volume, the same pore number and the same material. Furthermore, it is verified that the gradient irregular structure has a better stability than the non-gradient structure. An experiment is conducted successfully to verify the stability performance got by FEA. In addition, a dynamic impact FEA is also performed to simulate impact resistance. The result shows that the impact resistance of the regular porous structure, the irregular porous structure and the gradient irregular porous structure becomes better in turn. The mechanical property verification provides a theoretical basis for the structural design of gradient irregular porous bone tissue engineering scaffolds. Full article

(This article belongs to the Special Issue 3D Bioprinting and Biofabrication for the Future of Tissue Engineering)

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Review

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32 pages, 32677 KiB

Open AccessReview

Fabrication of Concave Microwells and Their Applications in Micro-Tissue Engineering: A Review

by Weijin Guo, Zejingqiu Chen, Zitao Feng, Haonan Li, Muyang Zhang, Huiru Zhang and Xin Cui

Micromachines 2022, 13(9), 1555; https://doi.org/10.3390/mi13091555 - 19 Sep 2022

Cited by 10 | Viewed by 2832

Abstract

At present, there is an increasing need to mimic the in vivo micro-environment in the culture of cells and tissues in micro-tissue engineering. Concave microwells are becoming increasingly popular since they can provide a micro-environment that is closer to the in vivo environment [...] Read more.

At present, there is an increasing need to mimic the in vivo micro-environment in the culture of cells and tissues in micro-tissue engineering. Concave microwells are becoming increasingly popular since they can provide a micro-environment that is closer to the in vivo environment compared to traditional microwells, which can facilitate the culture of cells and tissues. Here, we will summarize the fabrication methods of concave microwells, as well as their applications in micro-tissue engineering. The fabrication methods of concave microwells include traditional methods, such as lithography and etching, thermal reflow of photoresist, laser ablation, precision-computerized numerical control (CNC) milling, and emerging technologies, such as surface tension methods, the deformation of soft membranes, 3D printing, the molding of microbeads, air bubbles, and frozen droplets. The fabrication of concave microwells is transferring from professional microfabrication labs to common biochemical labs to facilitate their applications and provide convenience for users. Concave microwells have mostly been used in organ-on-a-chip models, including the formation and culture of 3D cell aggregates (spheroids, organoids, and embryoids). Researchers have also used microwells to study the influence of substrate topology on cellular behaviors. We will briefly review their applications in different aspects of micro-tissue engineering and discuss the further applications of concave microwells. We believe that building multiorgan-on-a-chip by 3D cell aggregates of different cell lines will be a popular application of concave microwells, while integrating physiologically relevant molecular analyses with the 3D culture platform will be another popular application in the near future. Furthermore, 3D cell aggregates from these biosystems will find more applications in drug screening and xenogeneic implantation. Full article

(This article belongs to the Special Issue 3D Bioprinting and Biofabrication for the Future of Tissue Engineering)

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31 pages, 3634 KiB

Open AccessReview

The Biofabrication of Diseased Artery In Vitro Models

by Chen Pan, Qiqi Gao, Byoung-Soo Kim, Yafeng Han and Ge Gao

Micromachines 2022, 13(2), 326; https://doi.org/10.3390/mi13020326 - 19 Feb 2022

Cited by 4 | Viewed by 5548

Abstract

As the leading causes of global death, cardiovascular diseases are generally initiated by artery-related disorders such as atherosclerosis, thrombosis, and aneurysm. Although clinical treatments have been developed to rescue patients suffering from artery-related disorders, the underlying pathologies of these arterial abnormalities are not [...] Read more.

As the leading causes of global death, cardiovascular diseases are generally initiated by artery-related disorders such as atherosclerosis, thrombosis, and aneurysm. Although clinical treatments have been developed to rescue patients suffering from artery-related disorders, the underlying pathologies of these arterial abnormalities are not fully understood. Biofabrication techniques pave the way to constructing diseased artery in vitro models using human vascular cells, biomaterials, and biomolecules, which are capable of recapitulating arterial pathophysiology with superior performance compared with conventional planar cell culture and experimental animal models. This review discusses the critical elements in the arterial microenvironment which are important considerations for recreating biomimetic human arteries with the desired disorders in vitro. Afterward, conventionally biofabricated platforms for the investigation of arterial diseases are summarized, along with their merits and shortcomings, followed by a comprehensive review of advanced biofabrication techniques and the progress of their applications in establishing diseased artery models. Full article

(This article belongs to the Special Issue 3D Bioprinting and Biofabrication for the Future of Tissue Engineering)

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25 pages, 6786 KiB

Open AccessReview

Applications of 3D Bioprinting Technology in Induced Pluripotent Stem Cells-Based Tissue Engineering

by Arvind Kumar Shukla, Ge Gao and Byoung Soo Kim

Micromachines 2022, 13(2), 155; https://doi.org/10.3390/mi13020155 - 20 Jan 2022

Cited by 8 | Viewed by 4629

Abstract

Induced pluripotent stem cells (iPSCs) are essentially produced by the genetic reprogramming of adult cells. Moreover, iPSC technology prevents the genetic manipulation of embryos. Hence, with the ensured element of safety, they rarely cause ethical concerns when utilized in tissue engineering. Several cumulative [...] Read more.

Induced pluripotent stem cells (iPSCs) are essentially produced by the genetic reprogramming of adult cells. Moreover, iPSC technology prevents the genetic manipulation of embryos. Hence, with the ensured element of safety, they rarely cause ethical concerns when utilized in tissue engineering. Several cumulative outcomes have demonstrated the functional superiority and potency of iPSCs in advanced regenerative medicine. Recently, an emerging trend in 3D bioprinting technology has been a more comprehensive approach to iPSC-based tissue engineering. The principal aim of this review is to provide an understanding of the applications of 3D bioprinting in iPSC-based tissue engineering. This review discusses the generation of iPSCs based on their distinct purpose, divided into two categories: (1) undifferentiated iPSCs applied with 3D bioprinting; (2) differentiated iPSCs applied with 3D bioprinting. Their significant potential is analyzed. Lastly, various applications for engineering tissues and organs have been introduced and discussed in detail. Full article

(This article belongs to the Special Issue 3D Bioprinting and Biofabrication for the Future of Tissue Engineering)

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21 pages, 2129 KiB

Open AccessReview

The Development of Design and Manufacture Techniques for Bioresorbable Coronary Artery Stents

by Liang Wang, Li Jiao, Shuoshuo Pang, Pei Yan, Xibin Wang and Tianyang Qiu

Micromachines 2021, 12(8), 990; https://doi.org/10.3390/mi12080990 - 20 Aug 2021

Cited by 14 | Viewed by 5185

Abstract

Coronary artery disease (CAD) is the leading killer of humans worldwide. Bioresorbable polymeric stents have attracted a great deal of interest because they can treat CAD without producing long-term complications. Bioresorbable polymeric stents (BMSs) have undergone a sustainable revolution in terms of material [...] Read more.

Coronary artery disease (CAD) is the leading killer of humans worldwide. Bioresorbable polymeric stents have attracted a great deal of interest because they can treat CAD without producing long-term complications. Bioresorbable polymeric stents (BMSs) have undergone a sustainable revolution in terms of material processing, mechanical performance, biodegradability and manufacture techniques. Biodegradable polymers and copolymers have been widely studied as potential material candidates for bioresorbable stents. It is a great challenge to find a reasonable balance between the mechanical properties and degradation behavior of bioresorbable polymeric stents. Surface modification and drug-coating methods are generally used to improve biocompatibility and drug loading performance, which are decisive factors for the safety and efficacy of bioresorbable stents. Traditional stent manufacture techniques include etching, micro-electro discharge machining, electroforming, die-casting and laser cutting. The rapid development of 3D printing has brought continuous innovation and the wide application of biodegradable materials, which provides a novel technique for the additive manufacture of bioresorbable stents. This review aims to describe the problems regarding and the achievements of biodegradable stents from their birth to the present and discuss potential difficulties and challenges in the future. Full article

(This article belongs to the Special Issue 3D Bioprinting and Biofabrication for the Future of Tissue Engineering)

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21 pages, 937 KiB

Open AccessReview

Cancer Cell Direct Bioprinting: A Focused Review

by David Angelats Lobo, Paola Ginestra, Elisabetta Ceretti, Teresa Puig Miquel and Joaquim Ciurana

Micromachines 2021, 12(7), 764; https://doi.org/10.3390/mi12070764 - 28 Jun 2021

Cited by 6 | Viewed by 3140

Abstract

Three-dimensional printing technologies allow for the fabrication of complex parts with accurate geometry and less production time. When applied to biomedical applications, two different approaches, known as direct or indirect bioprinting, may be performed. The classical way is to print a support structure, [...] Read more.

Three-dimensional printing technologies allow for the fabrication of complex parts with accurate geometry and less production time. When applied to biomedical applications, two different approaches, known as direct or indirect bioprinting, may be performed. The classical way is to print a support structure, the scaffold, and then culture the cells. Due to the low efficiency of this method, direct bioprinting has been proposed, with or without the use of scaffolds. Scaffolds are the most common technology to culture cells, but bioassembly of cells may be an interesting methodology to mimic the native microenvironment, the extracellular matrix, where the cells interact between themselves. The purpose of this review is to give an updated report about the materials, the bioprinting technologies, and the cells used in cancer research for breast, brain, lung, liver, reproductive, gastric, skin, and bladder associated cancers, to help the development of possible treatments to lower the mortality rates, increasing the effectiveness of guided therapies. This work introduces direct bioprinting to be considered as a key factor above the main tissue engineering technologies. Full article

(This article belongs to the Special Issue 3D Bioprinting and Biofabrication for the Future of Tissue Engineering)

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