Abstract: The present invention relates to the use of porous silicon in the delivery of substances into cells. The porous silicon can be formed into micropiercers, microneedles and biolistic bullets for peenetration of the cell. The control of the pore size and porosity of the porous silicon allows tuning of the bioactivity of the porous silicon. The porous silicon is also resorbable and is therefore resorbed from the cells without leaving any particles or being seen as a foreign body. The present invention also relates to the methods of manufacturing the porous silicon micropiercers, microneedles, microelectrodes, biolistic bullets, and precipitation of calcium phosphate on a bioactive substrate, and their advantages over known methods of delivering materials into cells.

Abstract: Biomaterial, for example bioactive silicon, may be fabricated by anodizing a silicon wafer to produce a wafer having a porous silicon region. In vitro experiments have shown that certain types of porous silicon cause the deposition of apatite deposits both on the porous silicon and neighboring areas of bulk silicon when immersed in a simulated body fluid solution. This deposition of apatite provides an indication that porous silicon of appropriate form is bioactive, and therefore also biocompatible. A form of porous silicon is dissolved in the simulated body fluid solution and this is an indication of a resorbable biomaterial characteristic. In addition to porous silicon, certain types of polycrystalline silicon exhibit bioactive characteristics. Bioactive silicon may be used in the fabrication of biosensors for in vitro or in vivo applications. The bioactivity of the bioactive silicon may be controlled by the application of an electrical potential thereto.

Abstract: Biomaterial, for example bioactive silicon, may be fabricated by anodizing a silicon wafer to produce a wafer having a porous silicon region. In vitro experiments have shown that certain types of porous silicon cause the deposition of apatite deposits both on the porous silicon and neighboring areas of bulk silicon when immersed in a simulated body fluid solution. This deposition of apatite provides an indication that porous silicon of appropriate form is bioactive, and therefore also biocompatible. A form of porous silicon is dissolved in the simulated body fluid solution and this is an indication of a resorbable biomaterial characteristic. In addition to porous silicon, certain types of polycrystalline silicon exhibit bioactive characteristics. Bioactive silicon may be used in the fabrication of biosensors for in vitro or in vivo applications. The bioactivity of the bioactive silicon may be controlled by the application of an electrical potential thereto.