Spatial control over cell attachment by partial solvent entrapment of poly lysine in microfluidic channels

Nicki K Baman¹, Galen B Schneider², Treniece L Terry³, Rebecca Zaharias², Aliasger K Salem^1,3,4

¹Department of Biomedical Engineering, College of Engineering, ²Department of Prosthodontics and Dows Institute for Dental Research, College of Dentistry, ³Department of Chemical and Biochemical Engineering, College of Engineering, ⁴Division of Pharmaceutics, College of Pharmacy, University of Iowa, Iowa City, IA, USA

Abstract:  We demonstrate spatial control over cell attachment on biodegradable surfaces by flowing cell adhesive poly (D-lysine) (PDL) in a trifluoroethanol (TFE)–water mixture through microfluidic channels placed on a biodegradable poly (lactic acid)–poly (ethylene glycol) (PLA–PEG) substrate. The partial solvent mixture swells the PLA–PEG within the confines of the microfluidic channels allowing PDL to diffuse on to the surface gel layer. When excess water is flowed through the channels substituting the TFE–water mixture, the swollen PLA surface collapses, entrapping PDL polymer. Results using preosteoblast human palatal mesenchymal cells (HEPM) indicate that this new procedure can be used for facile attachment of cells in localized regions. The PEG component of the PLA–PEG copolymer prevents cells from binding to the nonpatterned regions.

Keywords: microfluidic, cell binding, tissue engineering, solvent entrapment