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1.
Sensors (Basel) ; 22(8)2022 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-35458979

RESUMO

Resonating MEMS mass sensors are microdevices with broad applications in fields such as bioscience and biochemistry. Their advantageous surface-to-volume ratio makes their resonant frequency highly sensitive to variations in their mass induced by surface depositions. Recent global challenges, such as water quality monitoring or pandemic containment, have increased the need for low-cost (even disposable), rapidly fabricated microdevices as suitable detectors. Resonant MEMS mass sensors are among the best candidates. This paper introduces a simple and robust fabrication of polymeric piezoelectric resonating MEMS mass sensors. The microfabrication technology replaces the traditional layer-by-layer micromachining techniques with laser micromachining to gain extra simplicity. Membrane-based resonant sensors have been fabricated to test the technology. Their characterization results have proven that the technology is robust with good reproducibility (around 2% batch level variations in the resonant frequency). Initial tests for the MEMS mass sensors' sensitivity have indicated a sensitivity of 340 Hz/ng. The concept could be a starting point for developing low-cost MEMS sensing solutions for pandemic control, health examination, and pollution monitoring.


Assuntos
Sistemas Microeletromecânicos , Microtecnologia , Polímeros , Reprodutibilidade dos Testes
2.
Nat Commun ; 13(1): 2016, 2022 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-35440590

RESUMO

Magnetically driven wireless miniature devices have become promising recently in healthcare, information technology, and many other fields. However, they lack advanced fabrication methods to go down to micrometer length scales with heterogeneous functional materials, complex three-dimensional (3D) geometries, and 3D programmable magnetization profiles. To fill this gap, we propose a molding-integrated direct laser writing-based microfabrication approach in this study and showcase its advanced enabling capabilities with various proof-of-concept functional microdevice prototypes. Unique motions and functionalities, such as metachronal coordinated motion, fluid mixing, function reprogramming, geometrical reconfiguring, multiple degrees-of-freedom rotation, and wireless stiffness tuning are exemplary demonstrations of the versatility of this fabrication method. Such facile fabrication strategy can be applied toward building next-generation smart microsystems in healthcare, robotics, metamaterials, microfluidics, and programmable matter.


Assuntos
Lasers , Magnetismo , Luz , Microtecnologia , Redação
3.
Sci Rep ; 12(1): 6346, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35428793

RESUMO

This study investigates the manufacturing method of oblique patterns in microchannels and the effect of these patterns on mixing performance in microchannels. To fabricate three-dimensional (3D) and oblique patterns in microchannels, 3D printing and replica methods were utilized to mold patterns and microchannels, respectively. The angle and size of the patterns were controlled by the printing angle and resolution, respectively. The mixing efficiency was experimentally characterized, and the mixing principle was analyzed using computational fluid dynamics simulation. The analysis showed that the mixing channel cast from the mold printed with a printing angle of 30° and resolution of 300 µm exhibited the best mixing efficiency with a segregation index of approximately 0.05 at a Reynolds number of 5.4. This was because, as the patterns inside the microchannel were more oblique, "split" and "recombine" behaviors between two fluids were enhanced owing to the geometrical effect. This study supports the use of the 3D printing method to create unique patterns inside microchannels and improve the mixing performance of two laminar flows for various applications such as point-of-care diagnostics, lab-on-a-chip, and chemical synthesis.


Assuntos
Dispositivos Lab-On-A-Chip , Microtecnologia , Simulação por Computador , Desenho de Equipamento , Impressão Tridimensional
4.
J Photochem Photobiol B ; 229: 112424, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35276580

RESUMO

Three dimensional (3D) printing technology has pushed state-of-the-art manufacturing towards more advanced processing methods through its ability to produce complex computer-designed 3D structures in a wide range of materials. Two-photon polymerization applied to the fabrication of ultraprecise 3D microstructures is one of the various innovative approaches to cutting-edge 3D printing. The integration of an ultrashort pulsed laser source and an appropriate photoresist has made it an attractive candidate for advanced photonics and biomedical applications. This paper presents the development of 3D solid microneedle arrays as a novel transdermal drug delivery system via two-photon polymerization in a single manufacturing step. Through a series of experiments, the best fabrication parameters are identified. Finite element simulations are then performed to investigate the interaction between a single microneedle and human skin. The results of this study highlight the influence of fabrication parameters such as laser power, scanning speed, hatch distance and layer height on the structural resolution and fabrication time of microneedles, as well as human skin deformation caused through application of force to a single polymer microneedle.


Assuntos
Microtecnologia , Polímeros , Administração Cutânea , Sistemas de Liberação de Medicamentos/métodos , Humanos , Microtecnologia/métodos , Polimerização
5.
Small Methods ; 6(2): e2101051, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35174985

RESUMO

Electrode microfabrication technologies such as lithography and deposition have been widely applied in wearable electronics to boost interfacial coupling efficiency and device performance. However, a majority of these approaches are restricted by expensive and complicated processing techniques, as well as waste discharge. Here, helium plasma irradiation is employed to yield a molybdenum microstructured electrode, which is constructed into a flexible piezoresistive pressure sensor based on a Ti3 C2 Tx nanosheet-immersed polyurethane sponge. This electrode engineering strategy enables the smooth transition between sponge deformation and MXene interlamellar displacement, giving rise to high sensitivity (1.52 kPa-1 ) and good linearity (r2  = 0.9985) in a wide sensing range (0-100 kPa) with a response time of 226 ms for pressure detection. In addition, both the experimental characterization and finite element simulation confirm that the hierarchical structures modulated by pore size, plasma bias, and MXene concentration play a crucial role in improving the sensing performance. Furthermore, the as-developed flexible pressure sensor is demonstrated to measure human radial pulse, detect finger tapping, foot stomping, and perform object identification, revealing great feasibility in wearable biomonitoring and health assessment.


Assuntos
Desenho de Equipamento/métodos , Determinação da Frequência Cardíaca/instrumentação , Dispositivos Eletrônicos Vestíveis , Análise de Elementos Finitos , Humanos , Microtecnologia , Poliuretanos/química , Titânio/química , Tato
6.
Sensors (Basel) ; 22(3)2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-35161869

RESUMO

Micro free-flow electrophoresis (µFFE) provides a rapid and straightforward route for the high-performance online separation and purification of targeted liquid samples in a mild manner. However, the facile fabrication of a µFFE device with high throughput and high stability remains a challenge due to the technical barriers of electrode integration and structural design for the removal of bubbles for conventional methods. To address this, the design and fabrication of a high-throughput µFFE chip are proposed using laser-assisted chemical etching of glass followed by electrode integration and subsequent low-temperature bonding. The careful design of the height ratio of the separation chamber and electrode channels combined with a high flow rate of buffer solution allows the efficient removal of electrolysis-generated bubbles along the deep electrode channels during continuous-flow separation. The introduction of microchannel arrays further enhances the stability of on-chip high-throughput separation. As a proof-of-concept, high-performance purification of fluorescein sodium solution with a separation purity of ~97.9% at a voltage of 250 V from the mixture sample solution of fluorescein sodium and rhodamine 6G solution is demonstrated.


Assuntos
Vidro , Microtecnologia , Eletroforese , Fluoresceína , Lasers
7.
Biomaterials ; 281: 121367, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35032908

RESUMO

Upon monolayer cultures on flat and rigid plastic dishes, many cells de-differentiate and lose their native phenotype. Technologies able to identify and reconstitute the cell niche factors that best maintain the physiological cellular phenotype in cultures are critical. We have developed a multiphoton microfabrication and micropatterning (MMM) technology, a robust 3D micro-printing platform capable to fabricate protein microstructures and micropatterns with quantitative, spatial and independent control of the mechanical, topological and extracellular matrix properties. Here, using bovine nucleus pulposus cells (bNPCs) as an example, we aim to reconstitute a spectrum of individual cell niche factors (2 mechanical, 9 topological and 4 matrices) in vitro for multiplex cell niche factor screening, and fabricate the optimal combinations of a series of shortlisted cell niche factors that best maintain the bNPC phenotype. Among all factors screened, two topological (micropillar array; fiber-bead structure) and two matrix (laminin; vitronectin) factors were shortlisted and the combinatory cell niche factors reconstituted from the shortlisted factors were found to synergistically augmented the expression of selected bNPC phenotype markers (Col II, SNAP25 and Keratin 8) and maintained their morphology and phenotype. These optimal cell niches can be micro-printed on culture dishes for physiologically relevant cultures and contribute to biomimetic scaffold design for intervertebral disc tissue engineering.


Assuntos
Disco Intervertebral , Núcleo Pulposo , Animais , Bovinos , Células Cultivadas , Matriz Extracelular/metabolismo , Microtecnologia , Fenótipo , Engenharia Tecidual
8.
Mol Microbiol ; 117(3): 569-577, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34592794

RESUMO

Advances in microfabrication technology, and its increasing accessibility, allow us to explore fungal biology as never before. By coupling molecular genetics with fluorescence live-cell imaging in custom-designed chambers, we can now probe single yeast cell responses to changing conditions over a lifetime, characterise population heterogeneity and investigate its underlying causes. By growing filamentous fungi in complex physical environments, we can identify cross-species commonalities, reveal species-specific growth responses and examine physiological differences relevant to diverse fungal lifestyles. As affordability and expertise broadens, microfluidic platforms will become a standard technique for examining the role of fungi in cross-kingdom interactions, ranging from rhizosphere to microbiome to interconnected human organ systems. This review brings together the perspectives already gained from studying fungal biology in microfabricated systems and outlines their potential in understanding the role of fungi in the environment, health and disease.


Assuntos
Fungos , Microtecnologia , Biologia , Fungos/genética , Humanos , Rizosfera , Saccharomyces cerevisiae
9.
J Chromatogr A ; 1661: 462678, 2022 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-34879308

RESUMO

In the last decade, there has been a growing interest in developing microfluidic systems as new scale-down models for accelerated and cost-effective biopharmaceutical process development. Nonetheless, the research in this field is still in its infancy and requires further investigation to simplify and accelerate the microfabrication process. In addition, integration of different label-free sensors into the microcolumn systems has utmost importance to minimize result discrepancies during the scale-up process. In this study, we developed a simple, low-cost integrated microcolumn (26 µl). Micromilling technology was employed to define the geometry and shape of microfluidic structures using poly(methylmethacrylate) (PMMA). The design of PMMA microstructure was transferred to polydimethylsiloxane (PDMS), and interdigitated planar microelectrodes (IDE) were integrated into the system. To evaluate the scalability of the developed microcolumn column, column performance was assessed and compared with a conventional 1-ml prepacked column. Computational Fluid Dynamics (CFD) studies were performed for both columns to understand the differences between theoretical and experimental results regarding retention time and peak broadening. Despite obtaining an acceptable asymmetric factor for the microcolumn (1.03 ± 0.02), the reduced plate height value was still higher than the recommended range with the value of 4.14 ± 0.18. Nevertheless, the consistency and significant improvement of microcolumn efficiency compared to previous studies provide the possibility of developing robust simulation tools for transferring acquired experimental data for larger-scale units.


Assuntos
Hidrodinâmica , Microtecnologia , Simulação por Computador , Impedância Elétrica
10.
Adv Mater ; 34(3): e2104608, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34738258

RESUMO

Solid-state transistor sensors that can detect biomolecules in real time are highly attractive for emerging bioanalytical applications. However, combining upscalable manufacturing with the required performance remains challenging. Here, an alternative biosensor transistor concept is developed, which relies on a solution-processed In2 O3 /ZnO semiconducting heterojunction featuring a geometrically engineered tri-channel architecture for the rapid, real-time detection of important biomolecules. The sensor combines a high electron mobility channel, attributed to the electronic properties of the In2 O3 /ZnO heterointerface, in close proximity to a sensing surface featuring tethered analyte receptors. The unusual tri-channel design enables strong coupling between the buried electron channel and electrostatic perturbations occurring during receptor-analyte interactions allowing for robust, real-time detection of biomolecules down to attomolar (am) concentrations. The experimental findings are corroborated by extensive device simulations, highlighting the unique advantages of the heterojunction tri-channel design. By functionalizing the surface of the geometrically engineered channel with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody receptors, real-time detection of the SARS-CoV-2 spike S1 protein down to am concentrations is demonstrated in under 2 min in physiological relevant conditions.


Assuntos
Técnicas Biossensoriais/instrumentação , COVID-19/virologia , SARS-CoV-2/química , Glicoproteína da Espícula de Coronavírus/análise , Transistores Eletrônicos , Enzima de Conversão de Angiotensina 2/metabolismo , Anticorpos Imobilizados , Anticorpos Antivirais , Bioengenharia , COVID-19/sangue , COVID-19/diagnóstico , Teste para COVID-19/instrumentação , Teste para COVID-19/métodos , Simulação por Computador , Sistemas Computacionais , DNA/análise , Desenho de Equipamento , Humanos , Índio , Microtecnologia , Estudo de Prova de Conceito , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Óxido de Zinco
11.
Biotechnol Bioeng ; 119(2): 523-534, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34741535

RESUMO

Parameter estimation for scale-up of downstream operations from microtiter plates (MTPs) is mostly done empirically because engineering correlations between microplates and stirred tank reactors (STRs) are not yet available. It is challenging to change the operation mode from shaken MTPs to large-scale STRs. For the scale-up of STRs, volumetric power input is well-established although it is unclear whether this parameter can be used to transfer the operations from MTPs. We determine the volumetric power input in MTPs via the temperature increase caused by the motion of the liquid. The hydrodynamics in MTPs are studied with computational fluid dynamics (CFD). Mixing is investigated in 96-, 24-, and 6-well MTPs to cover different geometries, filling volumes, shaking diameters, and shaking frequencies. All CFD simulations are validated by experimental results, which now allows prediction of the volumetric power input and hydrodynamics at various conditions in MTPs without the need for further experiments. We provide a map of the power input achievable in MTPs. Based on this map, from knowing about large-scale conditions, adequate microscale conditions can be adjusted for process development. This enables the direct scale-up of downstream unit operations from MTPs to STRs.


Assuntos
Biotecnologia/métodos , Simulação por Computador , Hidrodinâmica , Calorimetria , Precipitação Química , Microtecnologia , Temperatura
12.
Eur Biophys J ; 51(2): 147-156, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34304293

RESUMO

Single-cell adhesion measured with atomic force microscopy (AFM) offers outstanding time and force resolution and allows the investigation of many important phenomena with unmatched precision. However, this technique suffers from serious practical limitations that hinder its effective application to a broader set of situations. Here we propose a different strategy based on the fabrication of large cantilevers and on the culture of the cells directly on them. Cantilevers are fabricated by standard micromachining, with an active area of 300 × 300 µm. A wedged structure is created so that the cantilever surface lies parallel to the substrate when mounted on an AFM system, so that the adhesion measurement probes the whole surface area at the same time. Thanks to the large area, cells can be seeded and grown on the cantilevers the day before the experiment, and let recover to optimal condition for the experiment. We used Human Embryonic Kidney cells, HEK 293A, to demonstrate the measurement of adhesion forces of up to 100 cells in parallel, and obtain a straightforward measurement of the average single cell adhesion energy. Our approach can improve significantly the cell-cell and cell-substrate adhesion statistics, reduce the experiment time and allow the investigation of the adhesion properties of cells that do not grow well in solution or on low adherent substrates, or that develop their characteristic features only after several hours or days of culture on a solid and adherent substrate.


Assuntos
Fenômenos Mecânicos , Microtecnologia , Adesão Celular , Humanos , Microscopia de Força Atômica/métodos
13.
Methods Mol Biol ; 2373: 39-55, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34520005

RESUMO

Thermoplastic polymers are besides glass the material of choice for the industrialization of microfluidic and organ-on-chip applications. In most cases, however, such devices are developed on the basis standard lithographic clean room technologies and subsequent casting into PDMS. This results in comparably fast progress in the development of functional designs but important aspects with respect to later industrialization are thereby largely neglected. For that reason, it is advisable to switch at a rather early stage of development from PDMS to a thermoplastic polymer such as, for instance, cyclo-olefin (co)polymer (COC, COP). By making this step, additional challenges related to the anticipated manufacturing process can be identified, which is particularly important when aiming at industrialization. We present herein a standard process sequence for mastering of microfluidic devices by two-photon polymerization and final transfer into COC films by hot embossing. In addition, we describe the laser micromanufacturing of polymeric mold inserts and subsequent prototype injection molding of small series of COP samples.


Assuntos
Técnicas Analíticas Microfluídicas , Microfluídica , Dispositivos Lab-On-A-Chip , Microtecnologia , Polímeros
14.
Adv Healthc Mater ; 11(8): e2101532, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34921719

RESUMO

A long-sought goal in tissue engineering (TE) is the development of tissues able to recapitulate the complex architecture of the native counterpart. Microtissues, by resembling the functional units of living structures, can be used to recreate tissues' architecture. Howbeit, microfabrication methodologies fail to reproduce cell-based tissues with uniform shape. At the macroscale, complex tissues are already produced by magnetic-TE using solely magnetized cells as building materials. The enhanced extracellular matrix (ECM) deposition guaranties the conservation of tissues' architecture, leading to a successful cellular engraftment. Following the same rational, now the combination of a versatile microfabrication-platform is proposed with magnetic-TE to generate robust micro-tissues with complex architecture for TE purposes. Small tissue units with circle, square, and fiber-like shapes are designed with high fidelity acting as building blocks for engineering complex tissues. Notably, freestanding microtissues maintain their geometry after 7 days post-culturing, overcoming the challenges of microtissues fabrication. Lastly, the ability of microtissues in invading distinct tissue models while releasing trophic factors is substantiated in methacryloyl laminarin (LAM) and platelet lysates (PLMA) hydrogels. By simply using cells as building units and such microfabrication-platform, the fabrication of complex multiscale and multifunctional tissues with clinical relevance is envisaged, including for therapies or disease models.


Assuntos
Hidrogéis , Engenharia Tecidual , Matriz Extracelular/química , Fenômenos Magnéticos , Microtecnologia , Engenharia Tecidual/métodos
15.
Methods Mol Biol ; 2393: 367-414, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34837190

RESUMO

Optical fibers revolutionized the rate of information reception and transmission in telecommunications. The revolution has now extended to the field of physicochemical sensing. Optical fiber sensors (OFSs) have found a multitude of applications, spanning from structural health monitoring to biomedical and clinical measurements due to their unique physical and functional advantages, such as small dimensions, light weight, immunity to electromagnetic interference, high sensitivity and resolution, multiplexing, and remote operation. OFSs generally rely on the detection of measurand-induced changes in the optical properties of the light propagating in the fiber, where the OFS essentially functions as the conduit and physical link between the probing light waves and the physicochemical parameters under investigation. Several advanced micromachining techniques have been developed to optimize the structure of OFSs, thus improving their sensing performance. These techniques include fusion splicing, tapering, polishing, and more complicated femtosecond laser micromachining methods. This chapter discusses and reviews the most recent developments in micromachined OFSs specifically for biomedical applications. Step-by-step procedures for several optical fiber micromachining techniques are detailed.


Assuntos
Fibras Ópticas , Lasers , Microtecnologia
16.
Lab Chip ; 22(1): 148-155, 2021 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-34870665

RESUMO

3D microparticles have promising applications in self-assembly, biomedical engineering, mechanical engineering, etc. The shape of microparticles plays a significant role in their functionalities. Although numerous investigations have been conducted to tailor the shape of microparticles, the diversity is still limited, and it remains a challenge to fabricate 3D microparticles with sharp edges. Here, we present a facile approach that combines a folded PDMS channel and orthogonal projection lithography for shaping sharp-edged 3D microparticles. By adjusting the number and the length of channel sides, both regular and irregular polyhedral cross-sections of the folded channel can be obtained. UV light with diverse patterns is applied vertically as the second shape controlling factor. A variety of 3D microparticles are obtained with sharp edges, which are potential templates for micromachining tools and abrasives. Some sharp-edged microparticles are assembled into 2D and 3D mesoscale structures, which demonstrates their prospective applications in self-assembly, tissue engineering, etc.


Assuntos
Técnicas Analíticas Microfluídicas , Microfluídica , Microtecnologia , Impressão , Engenharia Tecidual
17.
J Vis Exp ; (177)2021 11 20.
Artigo em Inglês | MEDLINE | ID: mdl-34866622

RESUMO

Today, cryo-electron tomography (cryo-ET) is the only technique that can provide near-atomic resolution structural data on macromolecular complexes in situ. Owing to the strong interaction of an electron with the matter, high-resolution cryo-ET studies are limited to specimens with a thickness of less than 200 nm, which restricts the applicability of cryo-ET only to the peripheral regions of a cell. A complex workflow that comprises the preparation of thin cellular cross-sections by cryo-focused ion beam micromachining (cryo-FIBM) was introduced during the last decade to enable the acquisition of cryo-ET data from the interior of larger cells. We present a protocol for the preparation of cellular lamellae from a sample vitrified by plunge freezing utilizing Saccharomyces cerevisiae as a prototypical example of a eukaryotic cell with wide utilization in cellular and molecular biology research. We describe protocols for vitrification of S. cerevisiae into isolated patches of a few cells or a continuous monolayer of the cells on a TEM grid and provide a protocol for lamella preparation by cryo-FIB for these two samples.


Assuntos
Tomografia com Microscopia Eletrônica , Saccharomyces cerevisiae , Microscopia Crioeletrônica/métodos , Tomografia com Microscopia Eletrônica/métodos , Substâncias Macromoleculares , Microtecnologia
18.
Comput Math Methods Med ; 2021: 9949328, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34938362

RESUMO

Developing new treatments for emerging infectious diseases in infectious and noninfectious diseases has attracted a particular attention. The emergence of viral diseases is expected to accelerate; these data indicate the need for a proactive approach to develop widely active family specific and cross family therapies for future disease outbreaks. Viral disease such as pneumonia, severe acute respiratory syndrome type 2, HIV infection, and Hepatitis-C virus can cause directly and indirectly cardiovascular disease (CVD). Emphasis should be placed not only on the development of broad-spectrum molecules and antibodies but also on host factor therapy, including the reutilization of previously approved or developing drugs. Another new class of therapeutics with great antiviral therapeutic potential is molecular communication networks using deep learning autoencoder (DL-AEs). The use of DL-AEs for diagnosis and prognosis prediction of infectious and noninfectious diseases has attracted a particular attention. MCN is map to molecular signaling and communication that are found inside and outside the human body where the goal is to develop a new black box mechanism that can serve the future robust healthcare industry (HCI). MCN has the ability to characterize the signaling process between cells and infectious disease locations at various levels of the human body called point-to-point MCN through DL-AE and provide targeted drug delivery (TDD) environment. Through MCN, and DL-AE healthcare provider can remotely measure biological signals and control certain processes in the required organism for the maintenance of the patient's health state. We use biomicrodevices to promote the real-time monitoring of human health and storage of the gathered data in the cloud. In this paper, we use the DL-based AE approach to design and implement a new drug source and target for the MCN under white Gaussian noise. Simulation results show that transceiver executions for a given medium model that reduces the bit error rate which can be learned. Then, next development of molecular diagnosis such as heart sounds is classified. Furthermore, biohealth interface for the inside and outside human body mechanism is presented, comparative perspective with up-to-date current situation about MCN.


Assuntos
Doenças Transmissíveis Emergentes/tratamento farmacológico , Aprendizado Profundo , Viroses/tratamento farmacológico , Antivirais/uso terapêutico , Doenças Transmissíveis Emergentes/epidemiologia , Biologia Computacional , Simulação por Computador , Sistemas de Liberação de Medicamentos , Descoberta de Drogas/métodos , Descoberta de Drogas/estatística & dados numéricos , Epidemias , Humanos , Microtecnologia , Redes Neurais de Computação , Biologia Sintética , Viroses/epidemiologia
19.
Small Methods ; 5(12): e2100638, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34928031

RESUMO

Biocomposite structures are difficult to characterize by bulk approaches due to their morphological complexity and compositional heterogeneity. Therefore, a versatile method is required to assess, for example, the mechanical properties of geometrically simple parts of biocomposites at the relevant length scales. Here, it is demonstrated how a combination of Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) and micromanipulators can be used to isolate, transfer, and determine the mechanical properties of frustule constituents of diatom Thalassiosira pseudonana (T.p.). Specifically, two parts of the diatom frustule, girdle bands and valves, are separated by FIB milling and manipulated using a sharp tungsten tip without compromising their physical or chemical integrity. In situ mechanical studies on isolated girdle bands combined with Finite Element Method (FEM) simulations, enables the quantitative assessment of the Young's modulus of this biosilica; E = 40.0 GPa. In addition, the mechanical strength of isolated valves could be measured by transferring and mounting them on top of premilled holes in the sample support. This approach may be extended to any hierarchical biocomposite material, regardless of its chemical composition, to isolate, transfer, and investigate the mechanical properties of selected constituents or specific regions.


Assuntos
Diatomáceas/ultraestrutura , Microtecnologia/instrumentação , Fenômenos Biomecânicos , Módulo de Elasticidade , Análise de Elementos Finitos , Microscopia Eletrônica de Varredura , Nanoestruturas , Espectrometria por Raios X
20.
ACS Appl Mater Interfaces ; 13(51): 61723-61732, 2021 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-34913686

RESUMO

Tunable and reconfigurable materials with autonomic shape transformation in response to the environment have emerged as one of the most promising approaches for a variety of biomedical applications, such as tissue engineering, biosensing, and in vivo biomedical devices. Currently, it is still quite challenging to fabricate soft, microscaled 3D shape-reconfigurable structures due to either complicated microfabrication or limited microscale photopolymerization-based printing approaches to enable adaptive shape transformation. Here, a one-step photo-cross-linking approach has been demonstrated to obtain a 3D-to-3D morphological transformable microhelix from a self-rolled hydrogel microsheet, resulting in chirality conversion. It was enabled by a custom-designed "hard" stripe/"soft" groove topography on the microsheets for introducing, which introduced both in-planar and out-of-planar anisotropies. Both experiment and simulation confirmed that a stripe/groove geometry can effectively control the 3D transformation by activating in-planar or/and out-of-planar mismatch stress within the microsheets, resulting in switching of the rolling direction between perpendicular/parallel to the length of the stripe. Furthermore, versatile 3D microconstructs with the ability to transform between two distinct 3D configurations have been achieved based on controlled rolling of microhelices, demonstrated as "windmill"-to-"T-cross" and "cylinder"-to-"scroll" transformations and dynamic blossoming of biomimetic orchids. In contrast to conventional 2D-to-3D micro-origami, we have successfully demonstrated an approach for fabricating microscale, all-soft-material-based constructs with autonomic 3D-to-3D structural transformation, which presents an opportunity for designing more complex hydrogel-based microrobotics.


Assuntos
Materiais Biocompatíveis/química , Hidrogéis/química , Impressão Tridimensional , Tecidos Suporte/química , Materiais Biocompatíveis/síntese química , Hidrogéis/síntese química , Teste de Materiais , Microtecnologia
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