A novel recovery system for cultured cells using plasma‐treated polystyrene dishes grafted with poly(N‐isopropylacrylamide)

TLDR

Poly(N‑isopropylacrylamide) (PIPAAm) adopts an expanded chain conformation below 32 °C and a collapsed, compact conformation at higher temperatures. The authors grafted PIPAAm onto commercial polystyrene dishes to create temperature‑responsive surfaces that become hydrophilic below 32 °C and hydrophobic above, allowing bovine endothelial cells and rat hepatocytes to attach and grow at 37 °C similarly to conventional culture dishes. Lowering the temperature below 32 °C causes cells to detach from the PIPAAm‑grafted dishes, and the recovered cells retain adhesion, growth, and secretion comparable to primary cultures, demonstrating that the polymer switch reversibly controls attachment without damaging cell function.

Abstract

Poly(N-isopropyl acrylamide) (PIPAAm) demonstrated a fully expanded chain conformation below 32 degrees C and a collapsed, compact conformation at high temperatures. This unique temperature responsive polymer was grafted onto surfaces of commercial polystyrene dishes and used as temperature switches for creating hydrophilic surfaces below 32 degrees C and hydrophobic surfaces above 32 degrees C. Cell attachment and the growth of bovine endothelial cells and rat hepatocytes on PIPAAm-grafted surfaces at 37 degrees C demonstrated similar behavior to the commercialized culture dishes. Both cell types were observed to detach from the PIPAAm-grafted surface simply by reducing the temperature below the polymer transition temperature (collapse). Cells recovered by this method maintained substrate adhesivity, growth, and secretion activities nearly identical to those found in primary cultured cells in contrast to the compromised function found in cultured cells damaged by trypsinization. These results provide strong evidence that PIPAAm-grafted surfaces, as thermal switches are very effective for reversing cell attachment and detachment without cell damage. Properties of cell culture surfaces can be readily transformed by this technique reversibly into hydrophilic and hydrophobic coatings of PIPAAm-grafted polymers.