Culture Conditions can Counterbalance the Thermosensitive Properties of Poly (N-Isopropylacrylamide) during Cell Harvesting

Abstract

Poly (N-isopropylacrylamide) (PNIPAM) has been widely referenced as an alternative solution for proteolyticenzyme- based cell harvesting. However, the reversibility (i.e., consecutive attachment-detachment cycles) of PNIPAM for cell harvesting has not been studied. In this work, we synthesized PNIPAM-grafted glass surfaces to study the efficiency of fibroblastic cell detachment after iterative use. For robust quantification of thermally triggered cell detachment, an innovative wide-field lens free video microscope was introduced. The cell detachment efficiency was shown to decrease significantly after each cell culture experiment due to the loss of polymer brush thermosensitivity. The influence of the temperature variation rate on cell detachment from the re-used PNIPAM-grafted surfaces was further characterized. The cell detachment behavior on these substrates was shown to be quite similar to that on bare glass substrates. Furthermore, it was demonstrated that non-negligible cell detachment occurs and is modulated according to the temperature variation rate. This study aims to inform scientists using PNIPAM-grafted substrates for cell detachment about possible issues, to help scientists to more carefully monitor culture experiments, and to aid scientists in the interpretation of results obtained from cell detachment experiments performed on PNIPAM-grafted surfaces.