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1.
ACS Appl Mater Interfaces ; 11(17): 15411-15416, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30924633

RESUMO

A two-step synthesis is described for activating the surface of a fully hydrated hydrogel that is of interest as a possible scaffold for neural regeneration devices. The first step exploits the water content of the hydrogel and the hydrophobicity of the reaction solvent to create a thin oxide layer on the hydrogel surface using a common titanium or zirconium alkoxide. This layer serves as a reactive interface that enables rapid transformation of the hydrophilic, cell-nonadhesive hydrogel into either a highly hydrophobic surface by reaction with an alkylphosphonic acid, or into a cell-adhesive one using a (α,ω-diphosphono)alkane. Physically imprinting a mask ("debossing") into the hydrogel, followed by a two-step surface modification with a phosphonate, allows for patterning its surface to create spatially defined, cell-adhesive regions.


Assuntos
Adesão Celular , Hidrogéis/química , Animais , Adesão Celular/efeitos dos fármacos , Fumaratos/química , Hidrogéis/farmacologia , Interações Hidrofóbicas e Hidrofílicas , Camundongos , Microscopia , Células NIH 3T3 , Polietilenoglicóis/química , Propriedades de Superfície , Titânio/química , Zircônio/química
2.
Light Sci Appl ; 7: 17181, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30839516

RESUMO

High-throughput laser micro-machining demands precise control of the laser beam position to achieve optimal efficiency, but existing methods can be both time-consuming and cost-prohibitive. In this paper, we demonstrate a new high-throughput micro-machining technique based on rapidly scanning the laser focal point along the optical axis using an acoustically driven variable focal length lens. Our results show that this scanning method enables higher machining rates over a range of defocus distances and that the effect becomes more significant as the laser energy is increased. In a specific example of silicon, we achieve a nearly threefold increase in the machining rate, while maintaining sharp side walls and a small spot size. This method has great potential for improving the micro-machining efficiency of conventional systems and also opens the door to applying laser machining to workpieces with uneven topography that have been traditionally difficult to process.

3.
ACS Appl Mater Interfaces ; 9(22): 18911-18917, 2017 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-28485911

RESUMO

Embedding metallic and semiconductor nanoparticles in a chalcogenide glass matrix effectively modifies the photonic properties. Such nanostructured materials could play an important role in optoelectronic devices, catalysis, and imaging applications. In this work, we fabricate and characterize germanium nanocrystals (Ge NCs) embedded in arsenic sulfide thin films by pulsed laser ablation in aliphatic amine solutions. Unstable surface termination of aliphatic groups and stable termination by amine on Ge NCs are indicated by Raman and Fourier-transform infrared spectroscopy measurements. A broad-band photoluminescence in the visible range is observed for the amine functionalized Ge NCs. A noticeable enhancement of fluorescence is observed for Ge NCs in arsenic sulfide, after annealing to remove the residual solvent of the glass matrix.

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