Thermal Reversal Surface with “Sticky Tentacle” for Modulating Initial Cell Adhesion and Detachment

Abstract

Thermal responsive polymers were introduced for effectively cell detachment from the extracellular matrix (ECM), where the poor cell adhesive capacity was improved by the immobilized biodhesion molecules (most are proteins) at the termini of grafted polymer. However, this protein-mediated adhesion makes it hard to be precisely controlled and takes longer time to start initial cell attachment. Here we describe a choline phosphate(CP) modified thermal responsive surface with enhanced initial cell adhesion based on multivalent CP-PC (phosphatidyl choline, the head-group of phospholipids in all the eukaryotic cell membranes) interaction. The well-defined functional surfaces were constructed using surface-initiated ATRP and click reaction, where the initial cell attachment reach saturation in 10 min and can be regulated by CP density on the surface. Consequently, the fast cell adhesion significantly accelerates cell spreading and proliferation. The facile cell harvest, as opposed to the original mechanism of thermally-induced cell detachment, is to take advantage of the thermal contraction of the polymer above the LCST, which release the adherent cell by reducing the accessibility of the CP groups to cell membrane PC lipids. Si-CP is expected to provide a promising universal structural model for modulating cell attachment and detachment in tissue engineering and regenerative medicine field.