(701b) Use of Naturally-Occurring Halloysite Nanotubes for Enhanced Capture of Cancer Cells From Blood

The development of individualized treatments for cancer can be facilitated by more efficient methods for separating cancer cells from patient blood in such a way that they remain viable for live cell assays. We have previously shown that immobilized P-selectin protein can be used on the inner surface of a microscale flow system to induce leukemic cells and leukocytes to roll at different velocities and relative fluxes, thereby creating a means for rapid cell fractionation without inflicting cellular damage [Charles et al., Biotechnol. Prog. 23:1463-72 (2007)]. In this study we explored a method to more efficiently select for circulating cancer cells by altering the nanoscale topography of the inner surface of selectin-coated microtubes. This functionalized topography is achieved by attaching naturally occurring halloysite nanotubes to the microtube surface via a monolayer of poly L-lysine, followed by functionalization with recombinant human selectin protein. We have found that halloysite nanotube coatings promote increased capture of circulating cancer cells over a range of selectin surface density while preserving the macroscopic fluid mechanics. Interestingly, at the nano- to micro-scale, the halloysite is found to alter the separation distance between flowing cells and the microtube surface in a predictable way. Ultimately, selectin-functionalized nanotube coatings provide a means for enhanced cancer cell isolation from whole blood.