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1.
Science ; 373(6552): 337-342, 2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-34437153

RESUMO

Piezoelectric biomaterials are intrinsically suitable for coupling mechanical and electrical energy in biological systems to achieve in vivo real-time sensing, actuation, and electricity generation. However, the inability to synthesize and align the piezoelectric phase at a large scale remains a roadblock toward practical applications. We present a wafer-scale approach to creating piezoelectric biomaterial thin films based on γ-glycine crystals. The thin film has a sandwich structure, where a crystalline glycine layer self-assembles and automatically aligns between two polyvinyl alcohol (PVA) thin films. The heterostructured glycine-PVA films exhibit piezoelectric coefficients of 5.3 picocoulombs per newton or 157.5 × 10-3 volt meters per newton and nearly an order of magnitude enhancement of the mechanical flexibility compared with pure glycine crystals. With its natural compatibility and degradability in physiological environments, glycine-PVA films may enable the development of transient implantable electromechanical devices.


Assuntos
Materiais Biocompatíveis/química , Eletricidade , Glicina/química , Álcool de Polivinil/química , Animais , Sobrevivência Celular , Células Cultivadas , Cristalização , Teoria da Densidade Funcional , Elasticidade , Humanos , Ligação de Hidrogênio , Próteses e Implantes , Ratos , Ratos Sprague-Dawley , Estresse Mecânico
2.
SLAS Technol ; 25(5): 446-454, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32406795

RESUMO

High-throughput enzyme screening for desired functionality is highly demanded. This paper utilizes a newly developed microfluidic pneumatic printing platform for high-throughput enzyme screening applications. The novel printing platform can achieve distinct features including a disposable cartridge, which avoids crosstalk; a flexible cartridge design, allowing for integration of multiple channels; and fast printing speed with submicroliter spot size. Moreover, a polydimethylsiloxane (PDMS)-based sandwich structure has been proposed and used during the printing and imaging, which can lead to better results, including reduced evaporation as well as a uniform light path during imaging. Using this microfluidic pneumatic printed PDMS sandwiched microdroplet array platform, we have demonstrated the capability of high-throughput generation of a combinatorial droplet array with concentration and volume gradients. Furthermore, the potential for enzymatic study has been validated by quantified cellulose reaction implemented with the printing platform.


Assuntos
Celulase/metabolismo , Ensaios de Triagem em Larga Escala/métodos , Microfluídica/métodos , Impressão , Celulose/metabolismo , Luz , Software
3.
Theranostics ; 10(4): 1590-1603, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32042324

RESUMO

Autologous nerve transplantation, which is the gold standard for clinical treatment of peripheral nerve injury, still has many limitations. In this study, aligned chitosan fiber hydrogel (ACG) grafted with a bioactive peptide mixture consisting of RGI (Ac-RGIDKRHWNSQGG) and KLT (Ac-KLTWQELYQLKYKGIGG), designated as ACG-RGI/KLT, was used as nerve conduit filler to repair sciatic nerve defects in rats. Methods: Chitosan nanofiber hydrogel was prepared by a combination of electrospinning and mechanical stretching methods, and was then grafted with RGI and KLT, which are peptides mimicking brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF), respectively. The physicochemical properties of ACG-RGI/KLT were fully characterized. In vitro, the distribution, proliferation, and secretory activity of Schwann cells were analyzed. Next, the in vivo repair potential for 15-mm rat sciatic nerve defects was examined. The recovery of regenerated nerve, muscle, and motor function was evaluated by neuromuscular histology, electrophysiology, and catwalk gait analysis. Results: We first constructed directionally aligned chitosan nanofiber hydrogel grafted with RGI/KLT peptide mixture (ACG-RGI/KLT). ACG-RGI/KLT oriented the Schwann cells, and promoted the proliferation and secretion of neurotrophic factors by Schwann cells. At an early injury stage, ACG-RGI/KLT not only enhanced nerve regeneration, but also promoted vascular penetration. At 12 weeks, ACG-RGI/KLT facilitated nerve regeneration and functional recovery in rats. Conclusions: Aligned chitosan nanofiber hydrogel grafted with RGI/KLT peptide provides an effective means of repairing sciatic nerve defects and shows great potential for clinical application.


Assuntos
Quitosana/farmacologia , Hidrogéis/farmacologia , Nanofibras/uso terapêutico , Tecido Nervoso/transplante , Nervo Isquiático/patologia , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Quitosana/química , Hidrogéis/química , Nanofibras/química , Regeneração Nervosa/efeitos dos fármacos , Peptídeos/metabolismo , Traumatismos dos Nervos Periféricos , Ratos , Recuperação de Função Fisiológica/efeitos dos fármacos , Células de Schwann/efeitos dos fármacos , Células de Schwann/metabolismo , Células de Schwann/patologia , Nervo Isquiático/efeitos dos fármacos , Estresse Mecânico , Fator A de Crescimento do Endotélio Vascular/metabolismo
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