The interface between nanotechnology and life sciences is one of the fastest-growing and most promising areas of material science. This review is following a recent shift toward the engineering of vertically aligned (VA) semiconductor nanowire (NW) arrays for the development of next-generation biodevices. The focus of the review is on porous and non-porous silicon and other semiconductor NWs. We will first cover key aspects of VA-NW array fabrication and chemical functionalization. Then we will concentrate on the interactions between VA-NW elements and mammalian cells. Specifically, we assess the ability of these nanostructures to influence cellular adhesion, morphology, migration, proliferation, and differentiation. We then address the use of vertically aligned NWs as tools for the delivery of biomolecular cargo into mammalian cells. The final sections of the review will be dedicated to examples of vertically aligned silicon nanowire (VA-SiNW) arrays used in drug delivery and for biosensing. (C) 2014 Elsevier Ltd. All rights reserved.