Micro

In this study, we developed polyethylene glycol-4000-based hydrogels for ketorolac tromethamine-controlled delivery systems through a free radical polymerization method. The developed hydrogels were subjected to FTIR, TGA, DSC, XRD, SEM, porosity analysis, dynamic swelling analysis, release studies, etc. The successful crosslinking and stability of the prepared hydrogels were confirmed by FTIR, DSC, and TGA analysis. The surface morphology and the reduction in the crystallinity of the polymer after grafting were shown by SEM and XRD analysis. Similarly, the soluble part of the developed hydrogels was eliminated from their insoluble part by the Soxhlet extraction process. Higher dynamic swelling and drug release were observed at high pH values compared to low pH values. High porosity was perceived with high concentrations of the monomers and polymer and decreased with the high incorporation of a crosslinker. The release mechanism of all formulations followed non-Fickian diffusion. The results demonstrate that the developed polyethylene glycol-4000 hydrogels could serve as promising controlled drug delivery carriers. Full article

Electrospun polymer membranes are regarded as prospective biosensor components due to their large specific surface area and diverse opportunities for chemical modifications. However, their intricate porous structure can impede diffusion and render some analyte-binding sites inaccessible. To overcome these diffusion limitations and improve analyte adsorption onto the polymer, a pressure-driven sample flow through the membrane can be employed. To date, the efficiency of pressure-driven analyte delivery into these membranes has not been quantified. Here, we compare forced flow and passive sample diffusion through poly(dioxanone) electrospun membranes. We examine two model analytes, BSA and interleukin-1 beta (IL1b), to address both non-specific and specific binding. Following exposure of the membranes to the test solutions, we measured the residual concentrations of the analytes using fluorometry and enzyme-linked immunosorbent assay (ELISA) techniques. The pressure-driven sample loading was superior to passive diffusion, with a 2.8–11.5-fold change for physical adsorption and a 2.4–3.4-fold difference for specific binding. Our data can be useful for the development of immunoassays and microfluidic devices. Full article

Starting from the late 1980’s, scanning probe microscopy has progressively diffused in Italy until today. In this paper, we provide a brief account of the main historical events and a current picture of the distribution of the active groups. A survey was prepared by LimeSurvey, made of six sections asking for personal and institutional data, human resources, equipment available, fields of interest, research projects, educational/dissemination activities, and two relevant publications in the last six years. It turns out that the Italian community includes more than seventy groups and two companies. It is widely diffused, although mostly concentrated near large academic and research institutions, often in locations where prominent Italian researchers have operated. This community is active in many scientific fields and can produce research of high international quality. It shows a wide competence, as proven by the list of research works published in journals ranked within the top 20% class. The diffusion of SPM microscopes in industry is still sporadic, possibly due to extensive collaborations between the research institutions and industries themselves. The authors hope that this work might be useful to the community and beyond, and that it might stimulate the formation of a more structured network. Full article

Microfluidics, also known as lab-on-a-chip or micro total analysis systems, can precisely regulate and manipulate micro-sized fluids. They have great potential in biology, chemistry, and medicine, as well as other fields of science. By definition, microfluidic devices operate with small-volume samples and small reactant quantities, which renders them both efficient and affordable. However, such small objects have very demanding requirements for the utilized optical detection system. Due to the specifics of those devices, monitoring the results of experiments is carried out with commercial inverted optical microscopes. Unfortunately, that type of optical device is still expensive. In this article, we present a truly functional, inexpensive, standalone, three-dimensionally printed, and inverted microscope, including the design, engineering, and manufacturing process and some of the experiments that have been conducted with it. Finally, we summarize the advantages of this three-dimensionally printed microscope (including the total fabrication costs) and the future improvements that will be introduced to it. Full article

Our recent development of a wireless humidity sensor system embedded in incontinence products enables new sensor applications to diagnose and supervise geriatric diseases (i.e., age-related diabetes mellitus type II). The measurement of glucose in urine, so-called glucosuria, is an early indicator for an incipient diabetes mellitus disease, whose symptoms are often age-related but misjudged. In this paper, an incontinence glucose sensor is printed with biocompatible ink and Prussian blue as an electron mediator on foil and functionalized with immobilized glucose oxidase. Inkjet printing of multiple layers of Nafion prevents large interference substances from diffusing into the measuring electrode and allows precise adjustment of the linear working range, which is significantly different from blood glucose measurement. Performance tests show the potential to detect minimum glucose values and store the sensor over a prolonged period at room temperature. The printed glucose sensor can be embedded into the absorber material of incontinence products, where capillary forces transport the urine analyte to the detection area. An attached readout module with an integrated potentiostat measures the glucose concentration in urine, which is transmitted wirelessly with incontinence events and stored in a cloud service for further analysis by medical staff and care workers. Full article

Sinapic acid, 3,5-dimethoxyl-4-hydroxycinnamic acid, belonging to the class of hydroxycinnamic acids, shows antioxidant, anti-inflammatory, anticancer, hepatoprotective, cardioprotective, renoprotective, neuroprotective, antidiabetic, anxiolytic, and antibacterial activity. The aim of this work was to incorporate sinapic acid into solid lipid nanoparticles in order to improve its bioavailability. SLNs were prepared using the hot high-speed homogenization method. The pharmaco-technological properties and thermotropic profile of SLNs encapsulated with sinapic acid, as well as their interaction with biomembrane models, were evaluated. SLNs showed promising physicochemical properties and encapsulation efficiency, as well as a desirable release profile; moreover, they facilitated the interaction of sinapic acid with a biomembrane model made of multilamellar vesicles. In conclusion, this formulation can be used in further studies to assess its suitability to improve sinapic acid activity. Full article

This paper aims to study the tensile behavior of a woven [0/90]₇ hemp/Elium composite after three different conditionings: “Ambient storage”, “Saturated at 60 °C” and “15 wet/dry cycles”. Instrumented repeated progressive tensile loading tests were carried out and showed an unexpected increase in the secant modulus for the aged samples at the end of the test. An in-situ micro-CT tensile test was then performed on a “15 wet/dry cycles” aged sample. The analysis of the tomographic images showed the damage development with interfacial debonding and matrix cracks in the specimen volume, and also the decrease in the curvature radius of the warp yarns during tensile loading facilitated by the plasticization of the resin. Finite element calculations were thus performed and demonstrated that the increase in the modulus is directly linked to the straightening of warp yarns, showing that the evolution of the modulus on a macroscopic scale can be explained by the deformations of the yarns on a microscopic level. These results allow us to better understand the mechanical behavior and the damage mechanisms that occur in biocomposites during tensile testing after water aging. Full article

Plastic straws are well-known tools to assist human beings in drinking fluid, but most of them have micro-defects including black spot defects, head problems, pressure tube defects, and sealing wrinkles. The manual detection of these defects has drawbacks such as low efficiency, a high false detection rate, and excessive labor. This paper proposed machine vision-based detection with self-adaption and high-accuracy characteristics. A serial synthesis of algorithms including homomorphic filtering, Nobuyuki Otsu, and morphological opening operations is proposed to obtain plastic straws with binary images with good performance, and it was further found that the convolutional neural network can be designed to realize the real-time recognition of black spot defects, where the corner detection algorithm demonstrates the linear fitting of the edge point of the straw with the effective detection of sealing wrinkle defects. We also demonstrated that the multi-threshold classification algorithm is used to detect defects effectively for head problems and pressure tube defects. The detection system based on machine vision successfully overcomes shortcomings of manual inspection, which has high inspection efficiency and adaptively detects multiple defects with 96.85% accuracy. This research can effectively help straw companies achieve high-quality automated production and promotes the application of machine vision in plastic straw defects with the aid of machine learning. Full article

The dental environment is being polluted with metals from dental materials in many ways, mainly due to aerosol-generating procedures; this could affect the long-term well-being of dentists, dental students, and dental personnel. The current dental pollution incorporates metallic nanoparticles, which are highly reactive and quickly become airborne, especially those particles that become unbound in the bulk composition. In addition, liquid mercury or mercury vapors may be released from dental amalgam, causing concerns in the dental community. In our study, we reviewed the behavior of metallic elements present in dental materials, their routes of exposure, and their potentially toxic effects on the dental team. This review found that skin and lung disorders are the most harmful effects of metallic exposure for dentists, dental students, and dental personnel. Therefore, chronic exposure to low concentrations of metals in the dental environment, especially in nanosized forms, should be further investigated to improve the environmental matrix, material choice, and safety protocols. Full article

In this study, we report the optoelectric and thermoelectric properties of famatinite Cu₃SbS₄ that was mechanochemically synthesized in a planetary mill from powder elements for 120 min in an inert atmosphere. The tetragonal famatinite Cu₃SbS₄ was nanocrystalline with a crystallite size of 14 nm, as endorsed by Rietveld refinement. High-resolution transmission electron microscopy showed several crystallites in the range of 20–50 nm. Raman spectroscopy proved the purity of the synthesized famatinite Cu₃SbS₄ and chemical-state characterization performed by X-ray photoelectron spectroscopy confirmed that the prepared sample was pure. The Cu¹⁺, Sb⁵⁺, and S²⁻ oxidation states in Cu₃SbS₄ sample were approved. The morphology characterization showed homogeneity of the prepared sample. The photoresponse of Cu₃SbS₄ was confirmed from I–V measurements in the dark and under illumination. The photocurrent increase reached 20% compared to the current in the dark at a voltage of 5 V. The achieved results confirm that synthesized famatinite Cu₃SbS₄ can be applied as a suitable absorbent material in solar cells. The performed thermoelectric measurements revealed a figure of merit ZT of 0.05 at 600 K. Full article

The mechanical properties of scaffolds play a vital role in regulating key cellular processes in tissue development and regeneration in the field of tissue engineering. Recently, scaffolding material design strategies leverage viscoelasticity to guide stem cells toward specific tissue regeneration. Herein, we designed and developed a viscoelastic Gel-PEG hybrid hydrogel with anisotropic morphology and mechanical properties using a gelatin and functionalized PEG (as a crosslinker) under a benign condition for tissue engineering application. The chemical crosslinking/grafting reaction was mainly involved between epoxide groups of PEG and available functional groups of gelatin. FTIR spectra revealed the hybrid nature of Gel-PEG hydrogel. The hybrid hydrogel showed good swelling behavior (water content > 600%), high porosity and pore interconnectivity suitable for tissue engineering application. Simple unidirectional freezing followed by a freeze-drying technique allowed the creation of structurally stable 3D anisotropic macroporous architecture that showed tissue-like elasticity and was capable of withstanding high deformation (50% strain) without being damaged. The tensile and compressive modulus of Gel-PEG hybrid hydrogel were found to be 0.863 MPa and 0.330 MPa, respectively, which are within the range of normal human articular cartilage. In-depth mechanical characterizations showed that the Gel-PEG hybrid hydrogel possessed natural-tissue-like mechanics such as non-linear and J-shaped stress-strain curves, stress softening effect, high fatigue resistance and stress relaxation response. A month-long hydrolytic degradation test revealed that the hydrogel gradually degraded in a homogeneous manner over time but maintained its structural stability and anisotropic mechanics. Overall, all these interesting features provide a potential opportunity for Gel-PEG hybrid hydrogel as a scaffold in a wide range of tissue engineering applications. Full article

NMR Relaxation (NMRR) is an extremely useful quantitative technique for material science, particularly for studying polymers and porous materials. NMR Cryoporometry (NMRC) is a powerful technique for the measurement of pore-size distributions and total porosities. This paper discusses the use, capabilities and application of a newly developed compact NMR time-domain relaxation spectrometer suitable for studying both solid and liquid samples (Mk3 NMR Relaxation spectrometer & Cryoporometer, Lab-Tools (nano-science), Ramsgate, Kent, UK. (2019)). This highly compact precision NMR Spectrometer is based on a Field Programmable Gate array (FPGA) module and custom surface mount low-noise NMR receiver and NMR linear transmitter. A high proportion of the RF circuitry is in a digital form, implemented as firmware in the FPGA, which gives the instrument an excellent long-term stability. It also includes an on-chip Linux computer. The FPGA module is credit-card sized, and both the NMR receiver and NMR transmitter are even smaller. The software, including the top-level NMR pulse sequence definitions, are written in an array processing language, Apl. The spectrometer comes complete with a Graphical User Interface (GUI) for control and on- and offline curve fitting and data analysis. The recent development of the Lab-Tools Peltier thermo-electrically cooled NMR variable-temperature (V-T) probe that cools the sample below −60 °C is also discussed. This Peltier cooling gives the precision temperature control and smoothness needed by NMR Cryoporometry (10 mK near the probe liquid bulk melting point). This enables the NMRC measurement of pore-size distributions in porous materials, for the unusually wide pore-size range of sub-nano to over 1 micron-sized pores. The NMR Spectrometer’s unusually small size, ability to measure solids, low noise and high performance make it particularly suitable for material science studies both in the field and in university, research institute, company and even school laboratories. A human portable version now exists. Use of the controlling GUI is described, and results from example NMR Relaxation and NMR Cryoporometric measurements are given. Full article

Quantum dots (QDs) have different properties: high electron density, magnetic moment, phosphorescence, photoluminescence (fluorescence), and strong optical absorption. The layer or ligands on the QDs surface has a vital role because they allow the stabilization and practical uses on different matrixes. Ligand exchange is a commonly carried out methodology to incorporate functional groups that alter the solubility, introduce electron transfer partners, integrate biological receptors, or improve the properties of the QDs surface. CdSSe QDs were synthesized using a microwave system using thioglycolic acid (TGA) as a sulfur source and cover agent. The TGA ligand was interchanged with cysteine (Cys), glutamic acid (GA), glutathione (GTO), glutaraldehyde (GLT), and lysine (Lys). The viability and response of the CYP1A1, CYP1A2, and CYP3A4 isoenzymes were directly measured in HEP-G2 cells after exposure to CdSSe-TGA, CdSSe-Cys, CdSSe-GA, CdSSe-GTO, CdSSe-GLT, and CdSSe-Lys. CdSSe and CdSSe-GTO (10 mg/L) decrease viability by around 65%. The response of the cytochrome isoenzymes is based on the organic ligand on the surface of the CdSSe QDs. Changes in CYP 1A1 could be related to carcinogenic xenobiotics. Fluorescence microscopy shows CdSSe QDs on and inside HEPG2 cells. The results confirm that apoptosis and necrosis are the principal mechanisms of decreased viability. Full article

For the first time AFM (atomic-force microscopy) was used to record significant changes in the geometric parameters of the image of erythrocytes in vitro under conditions of glycolytic starvation (ATP (Adenosine triphosphate) deficiency). The difference in the action of antioxidants, phenosan K, and Ihfan-10 on erythrocytes that we detected with AFM seems to be mainly due to their difference in hydrophobicity. We used the AFM method to research the self-organization of the components of the active center of P450 (Porphyrin-450) metalloenzymes that are part of a class of hemoproteins with functions of affinity to molecular oxygen O₂. Stable supramolecular nanostructures in the form of triangular prisms based on the iron porphyrin complex with amino acids due to self-assembly involving intermolecular hydrogen bonds were received. A possible scheme for the formation of such structures is proposed. Full article

The aim of this study was to investigate the photoactivity of dioxide titanium (TiO₂) nanotube films depending on different structure factors including pore size, tube length, tube wall thickness and crystallinity. Aqueous p-nitroaniline was used as a probe to assess the photocatalytic activity of titanium dioxide nanotube layers under UV irradiations. Self-organized titanium dioxide nanotube thin films were prepared by electrochemical anodization of titanium (Ti) foils and Ti thin films sputtered onto silicon (Si). The amorphous as-formed titanium nanotube layers were then annealed at different temperatures ranging from 450 to 900 °C in order to form crystalline phases. The structure and the morphology of the films were characterized by surface analysis techniques and scanning electron microscopy, respectively. The photocatalytic activity of the resulting TiO₂ thin films was evaluated by monitoring the UV degradation of p-nitroaniline by UV spectrophotometry and by determining nitrification yields of by ion chromatography. The highest photocatalytic activity was exhibited for titanium nanotubes annealed at 450 °C. The presence of rutile -obtained for an annealing temperature of 900 °C—appeared to reduce the photodegradation yield of p-nitroaniline. Finally, the TiO₂ nanotubes obtained from Ti foils revealed the most efficient photocatalytic properties. Full article

Many of the carbon and natural fibres used in composite reinforcement have a non-circular cross section. Recently non-circular, or flat, cross section glass fibre products have become commercially available. This paper explores the potential effects that such non-circular fibre cross section shapes may have on the micromechanics of stress transfer at the composite fibre–matrix interface and the resulting changes in composite strength performance. Analytical modelling is used to show how the critical fibre length in composites with non-circular fibres is always less when compared to circular fibres with an equal cross-sectional area. This can result in significant changes to the strength performance of discontinuous fibre reinforced composites. Additionally, it is shown that the surface roughness found on natural and carbon fibres, many of which are also non-circular in cross section, can decrease the critical fibre length still further. These effects have important consequences for the use of single fibre micromechanical tests used for the characterisation of interfacial strength. Full article

In microfluidics, it is important to confine and transport light as close as possible to the sample by guiding it into a small volume of the microfluidic channel, acquiring the emitted/transmitted radiation. A challenge in this context is the miniaturization of the optical components and their integration into the microfluidic device. Among all of the optical components, a particular role is played by the beam splitter, an important optical device capable of splitting light into several paths. In this paper, a micro-splitter is designed and realized by exploiting low-cost technologies. The micro-splitter consists of a micro-mirror in-between two micro-waveguides. This component was fabricated in different materials: poly-dimethyl-siloxane (PDMS), poly(methyl methacrylate) (PMMA), and VeroClear RGD810. A 3D printing master–slave fabrication protocol was used with PDMS, a direct 3D printing approach with VeroClear, and a laser cutting procedure with PMMA. The experimental results obtained show the high potential of the proposed fabrication protocols, based on low-cost technologies, for the realization of micro-optical components, which could also be easily integrated with microfluidics systems. Full article

Although plastic is ubiquitous in marine systems, our current knowledge of its transport is limited. Recent studies suggest size-selective removal of small plastic particles (<5 mm) from the ocean surface as a result of the formation of a biofilm (the “plastisphere”) on the microplastic particle (MP) surface. This localized microenvironment can isolate the microcosm from the adjacent aqueous medium, and thus protect component alien species from the surrounding physico-chemical conditions. Apart from resulting in specific conditions for the transfer of alien species through the environment, the plastisphere can impact MP hydrodynamics and cause MPs to move through the water column, initially sinking. The importance of this phenomenon has not been previously considered for these particles. The size-dependent vertical movement of MPs through the water column determines their distribution, which will vary with time of exposure and colonization. Some plastisphere organisms have plastic-degrading activities, which could be harnessed in marine depollution strategies. This article seeks to increase our understanding of the role of biofilms in the biological dynamics and diffusion of plastic microparticles. Full article

In the last few years, quantum dots (QDs) have attracted research interest in different fields of science and technology. Despite their applications, it is essential to understand how nanomaterials (with different crystal sizes) are metabolized inside organisms. Thus, the focus of this study was on an evaluation of how crystal sizes of CdSTe QDs affect the viability and response of the cytochrome P450 system in CHO-K1 and HEP-G2 cells. CdSTe QDs were synthesized using a microwave-assisted system at different reaction temperatures (60, 120, 150, and 180 °C) to obtain different crystal sizes. The optical and structural characterization confirmed four crystal sizes from 3 to 8 nm. Fluorescence microscopy confirmed that CdSTe QDs are incorporated into both cell lines. Viability studies suggested that CHO-K1 cells are more sensitive than HEP-G2 cells to CdSTe QDs and Cd⁺² ions. The responsible mechanisms for the toxicity of QDs and Cd⁺² are apoptosis followed by necrosis. The activity of CYP 1A1, 1A2, and 3A4 isoenzymes suggests that the smallest CdSTe crystals are recognized in a manner similar to that of Cd⁺². Furthermore, the largest CdSTe crystals can have different metabolic routes than Cd⁺². Full article