RESUMO
Commercially available permeable supports with microporous membranes have led to significant improvements in the culture of polarized cells because they permit them to feed basolaterally and thus carry out metabolism in a more in vivo-like setting. The porous nature of these membranes enables permeability measurements of drugs or biomolecules across the cellular barrier. However, current porous membranes have a high flow resistance due to great thickness (20-40 µm), low porosity, and a wide pore size distribution with tortuous diffusion paths, which make them low-throughput for permeability studies. Here we describe an alternate platform that is more flexible, allows for more control over physical parameters of the membranes, and is high-throughput. This study reports on the synthesis, nanofabrication, and surface characterization of a 3-µm-thick transparent membrane based on poly(4-hydroxy styrene) (PHOST). The membranes are nanofabricated using electron beam lithography and deep ion plasma etching to achieve an organized array of straight pores from 50 to 800 nm in diameter, with at least 23 times less flow resistance. It also shows for the first time the potential utility of PHOST as a cell culture substrate without cytotoxicity, and suitability for nanofabrication processes due to temperature stability.
Assuntos
Poliestirenos/química , Engenharia Tecidual/instrumentação , Animais , Astrócitos/citologia , Técnicas de Cultura de Células/métodos , Sobrevivência Celular , Difusão , Imuno-Histoquímica/métodos , Espectroscopia de Ressonância Magnética/métodos , Membranas Artificiais , Modelos Químicos , Nanoestruturas/química , Nanotecnologia/métodos , Permeabilidade , Polímeros/química , Porosidade , Ratos , Ratos Wistar , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Temperatura , Engenharia Tecidual/métodosRESUMO
Photoresists based on molecular glasses are gaining more and more importance as resist material to replace polymer based photoresist. In addition environmental issues have to be considered in the long-term. Therefore the paper describes novel negative photoresists containing a ternary mixture of a glassy low molecular functional polyphenol where the film preparation is possible by solvent-free physical vapor deposition. After UV light exposure and a thermal annealing process to enable acid catalyzed crosslinking between the molecular glass and the crosslinker, the photoresist was developed using only water to give well-defined patterns. In order to experimentally study efficiently the multiple parameters such as composition, exposure dose, and development times combinatorial PVD techniques were utilized.
