Development of Nanoporous Ultrathin Membranes For Implantable Drug Delivery

Eric E Nuxoll; Marc A Hillmyer; Ronald A Siegel

doi:10.1115/1.2927432

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Development of Nanoporous Ultrathin Membranes For Implantable Drug Delivery

Journal article

Open access

Peer reviewed

Development of Nanoporous Ultrathin Membranes For Implantable Drug Delivery

Eric E Nuxoll, Marc A Hillmyer and Ronald A Siegel

Journal of medical devices, Vol.2(2), pp.1-1

06/01/2008

DOI: 10.1115/1.2927432

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Abstract

For drug release or physiological sensing with advanced functionality, an implanted device must have an interface that permits passage of drugs or analytes while blocking immunoproteins and other physiological fouling agents. To this end, we have developed a composite membrane which integrates the nanoscale size selectivity of block-copolymers with the mechanical strength and order of micromachined silicon. A silicon wafer was coated with low-stress silicon nitride (LSN) and patterned with 20μm squares on the bottom side by photolithography. These squares were etched through the underlying silicon, using the LSN on the top side as an etch-stop. Poly(styrene)-poly(isoprene)-poly(lactide) (PS-PI-PLA) triblock terpolymer was spin-coated onto the top-side LSN surface and annealed under vacuum. The PLA domains self-assembled into cylinders perpendicular to the coating, nearly spanning it. The PLA was etched away, leaving 40nm pores in the polymer film. The device was subjected to hydrofluoric acid to remove the LSN capping the microscale pores and a final, brief oxygen plasma etch removed any PS capping the nanoscale pores. The resulting composite membrane consists of a 80nm thick PS layer with 40nm wide pores overlaying a 100μm thick silicon support with 20μm wide pores. Preliminary mechanical tests have demonstrated the membrane’s robustness. Such membranes should provide immuno-isolation without retarding small molecule transport and should integrate well with the burgeoning number of BioMEMS devices under development.

drug delivery systems

polymer blends

polymer films

nanobiotechnology

annealing

sputter etching

nanocomposites

spin coating

mechanical strength

nanoporous materials

photolithography

self-assembly

prosthetics

biomedical materials

Details

Title: Subtitle: Development of Nanoporous Ultrathin Membranes For Implantable Drug Delivery
Creators: Eric E Nuxoll - University of Minnesota
Marc A Hillmyer - University of Minnesota
Ronald A Siegel - University of Minnesota
Resource Type: Journal article
Publication Details: Journal of medical devices, Vol.2(2), pp.1-1
DOI: 10.1115/1.2927432
ISSN: 1932-6181
eISSN: 1932-619X
Publisher: ASME
Language: English
Date published: 06/01/2008
Academic Unit: Pharmaceutical Sciences and Experimental Therapeutics; Chemical and Biochemical Engineering
Record Identifier: 9984197524802771

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