Effect of adhesive ligand on cell deadhesion kinetics on poly(N-isopropylacrylamide)

Thermo-responsive poly(N-isopropylacrylamide) (PIPAAm) with a particular lower critical solution temperature (LCST) have been applied for the non-invasive harvesting of confluent cell layer. Until now, the effect of adhesive ligand on the biophysical responses of cells during cell layer harvesting from PIPAAm has not been elucidated. In this study, the deadhesion kinetics of smooth muscle cells (SMC) on various adhesive ligands immobilized on PIPAAm were investigated. Firstly, the formation of elastin (EL), laminin (LA), hyaluronic acid (HA) and collagen (CL) coating on PIPAAm surfaces were validated with XPS, microBCA assay and AFM. It was shown that EL was most effective in driving cell retraction on PIPAAm surface. Moreover, the highest rate of initial SMC deadhesion on EL-PIPAAm was driven by the formation of stress fibers. Interestingly, HA was most effective in preventing initial SMC detachment from PIPAAm surface in comparison with EL, LA and CL. Also, the adhesion energy of SMC on HA-PIPAAm remained constant, which was two times and six times higher than that on CL-PIPAAm and EL-PIPAAm, respectively from 20 min onward. Overall, the results reported herein pave the way for the engineering of the invasive regeneration/recovery of cells/tissue with adhesive ligand.