Temperature-responsive poly(N-isopropylacrylamide)-grafted microcarriers for large-scale non-invasive harvest of anchorage-dependent cells

Cell cultivation on the surface of microcarriers in stirred suspension is an essential method for the large-scale culture of anchorage-dependent cells. For applying this method to the field of cell therapy and for obtaining a large number of intact cells, non-invasive cell harvest without proteolytic enzyme treatment is an advantageous method. In this regard, temperature-responsive microcarriers that bearing poly(N-isopropylacrylamide) (PIPAAm)-grafted chains on the outermost surface were developed for harvesting cultured cells by temperature alteration. PIPAAm-grafted beads with the various grafted amount of PIPAAm and various bead diameters were synthesized for optimizing cell proliferation and thermally-induced detachment on the surface. The chinese hamster ovary (CHO-K1) cells adhered on the surface of all PIPAAm-grafted beads at 37 °C, while the adhering cells were found to detach themselves from the surfaces at 20 °C. The efficiency of thermally-induced cell detachment increased with increasing the grafted amount of PIPAAm and the diameter of bead. An efficient cell proliferation on bead surfaces in stirred suspension culture and subsequent thermally-induced cell detachment were achieved by the precise regulation of both the grafted amount of PIPAAm and diameter of bead. The temperature-responsive microcarriers exhibiting temperature-dependent cell adhesion and detachment will be an attractive candidate for the large-scale cell culture of therapeutic cells.