Ion Track Technology

PhysicsConsult

Reimar Spohr

PostHeaderIcon Abstract

Thermal control of drug release by a responsive ion track membrane observed by radio tracer flow dialysis. Reimar Spohr, Nicole Reber, Glenn M. Alder, Vincent Ang, C. Lindsay Bashford, Charles A. Pasternak, Hideki Omichi, Masaru Yoshida. Journal Controlled Release 50 (1998) 1-11

The combination of a responsive hydrogel with a rigid porous supporting structure yields a membrane with high mechanical strength and high on-off-permeability ratio. A membrane consisting of an ion track filter with a thermally responsive lining was prepared by penetrating a 19 µm thick foil of poly(ethylene terephthalate) (PET) with swift heavy ions at a fluence of 5·105 ions/cm2, followed by etching of the ion tracks to generate an ion track filter with 2.9 µm pore diameter, onto which a thin layer of poly(N-isopropylacrylamide) (NIPAAm) hydrogel was grafted. It was revealed that the mass flow of various molecules (water, chloride-, choline+, insulin, and albumin) through the membrane could be thermally controlled. The on-off-permeability ratio ranged between 3 and 10 increasing with molecular weight. Over a storage time of 5 months the permeabilities varied up to a factor of 2.6, while the on-off-permeability ratio and temperature sensitivity remained practically constant.