Nanoporous silicon particles for drug delivery
C. Chiappini, E. Tasciotti, X. Liu, D. Fine, M. Ferrari
The University of Texas at Austin, US
Keywords: porous silicon, microparticle, multi stage, delivery vector, nanoparticle, porosity, morphology
Abstract:Porous silicon (pSi) biodegradability and cytocompatibility suggest its use for drug delivery applications. Our group recently engineered, developed and tested a multi-stage drug delivery system capable of improving its therapeutic index by negotiating with the biological barriers of the patient in a sequential fashion. The first stage of this system is a nanoporous silicon microparticle. The size, shape and morphology of the vectors control the delivery system ability to navigate blood vessels, its cellular uptake, degradation kinetics and biodistribution. To date, porous silicon particles are produced in size and shape polydisperse powders lacking necessary controlled features. Combining semiconductor technology and electrochemical etch we manufactured porous silicon particles with high reproducibility and throughput. We controlled the size, shape and aspect ratio of the particle, its pore size in the range from 5 to 150 nm and its porosity in the range from 30% to 80%. We loaded and directly visualized second stage nanoparticles within the porous silicon matrix and observed the existence of an optimal pore size to particle size conducive to uniform, close packed penetration of the nanoparticles demonstrating the aptness of pSi microparticles as first stage delivery vectors.