Ta. Desai et al., Characterization of micromachined silicon membranes for immunoisolation and bioseparation applications, J MEMBR SCI, 159(1-2), 1999, pp. 221-231
The application of microfabrication technology to create precise separation
and isolation membranes for biomedical applications is described. By utili
zing fabrication techniques commonly employed in the microelectronics indus
try (MEMS), membranes can be fabricated with well-controlled and uniform po
re sizes, allowing the optimization of membrane parameters for biomedical a
pplications in cell immunoisolation and viral filtration. Using bulk and su
rface micromachining to create diffusion membranes, pore sizes down to 18 n
m have been attained through deposition and subsequent etching of sacrifici
al layers on silicon. Membranes were shown to be sufficiently permeable to
small biomolecules such as oxygen, glucose, and insulin, while excluding th
e passage of larger proteins such as immunoglobulin G (IgG). The semipermea
bility of microfabricated membranes, their biocompatibility, ease in steril
ization, along with their thermal and chemical stability, may provide a sig
nificant advantages for biomedical applications. Microfabrication technolog
y may also be applied to other materials of interest for the development of
highly controlled membranes. (C) 1999 Elsevier Science B.V. All rights res
erved.