Photodegradable hydrogels for selective capture and release of Mammalian cells

This paper describes the fabrication of capture surfaces for the specific capture and selective release of rare mammalian cells using photodegradable poly(ethylene glyocol) (PEG) hydrogels in microfluidic devices. Microfluidic devices have been shown to capture rare cells from complex fluids, such as blood, with better yield and purity than alternative methods. A current limitation to the use of microfluidic devices for the capture of rare cells is the inability to release cells from the capture surface. Recent methods developed to help improve on this downfall utilized bulk release of the entire capture surface including all the viable cells caught on the surface. The problems associated with this method are the lack of purity and the inability to mold complex geometries. By using photodegradable PEG hydrogels the ability to mold complex structures is introduced along with the selective release of rare cells via local UV exposure to increase the purity of the released cells. Herringbone patterned devices, designed to increase fluid mixing and capture area, have been fabricated from photodegradable PEG. These surfaces show high capture yield and purity while enabling specific release of target cells for diagnostic and prognostic applications.