(321a) Capture and Release of Cardiac Fibroblasts in Microfluidic Devices Using Peptide-Functionalized Alginate Gels

Microfluidic devices with surface-immobilized ligands have recently emerged as an attractive tool for cell separation by positive selection with applications ranging from cancer diagnostics and clinical genomics to tissue engineering. A critical unmet need in these applications, however, is the ability to detach the captured cells non-destructively. We describe the application of peptide functionalized alginic acid via carbodiimide chemistry as a methodology for cell capture and release in microfluidic channels. An alginate-peptide complex was adsorbed on the surface of the channels and rinsing with Ca2+ ionic solutions results in a thin hydrogel layer on the channel surface. Primary rat cardiac fibroblasts were injected into the device and subsequently captured from the flow stream by the adsorbed ligand. The conjugation of Arg-Gly-Asp-Ser (RGDS), a tetrapeptide to the alginate backbone showed a two-fold and four-fold increase in fibroblast adhesion compared to unconjugated alginate and bare glass controls, respectively. Rinsing with EDTA solution resulted in over 95% cell release within the device. The detached fibroblasts had the same viability and spreading characteristics as freshly harvested cells. This method is simple and amendable to all micro-scale devices that operate at low fluid shear stresses. In addition, the conjugation chemistry utilized in this work can be applied to a wide range of molecules containing primary amines and cellular release requires no application of external forces such as heat, electrical potential, or photo-activation.