Sub-micron poly(N-isopropylacrylamide) particles as temperature responsive vehicles for the detachment and delivery of human cells

Abstract

We describe the first example of particulate materials that can detach cultured cells and then release them intact in a temperature controlled manner. Topologically open microgels composed of water swollen highly branched polymers prepared from poly(N-isopropylacrylamide) (PNIPAM) were modified with a cell-adhesive peptide (GRGDS) to produce particles for gently detaching and then transferring cultured cells to new substrates. The particles bind to cell surface integrins on both dermal fibroblasts and endothelial cells and at temperatures above the lower critical solution temperature (34 C) remove cells from their normal culture substrates. Brief (45 min) cooling of the resultant particle-cell dispersion to beneath 34 C releases the cells to grow on new substrates. This avoids the need for trypsinisation to detach cells or centrifugation to collect cells post-detachment and offers a flexible approach to cell detachment and transport which is compatible with normal cell culture methodologies.

Thermally reversible colloidal gels for three-dimensional chondrocyte culture

“…Cooling such substrates below the LCST results in cell detachment, thus, providing a non-enzymatic process for cell recovery. In addition, Hopkins et al [17] showed that highly branched PNIPAM with glycine-arginine-glycine-aspartic acidserine (GRGDS) peptide end-groups could lift cells from TCPS surfaces. However, truly reversible threedimensional systems are rare.…”

Modifying biomaterial surfaces to control stem cell growth and differentiation

“…Here particulates are able to bind to and lift cells off adherent surfaces above an LCST of 34 ëC, followed by a temperature-dependent release of cells below 34 ëC (Hopkins, 2009). Pluronic F127 is a triblock co-polymer of poly(ethylene glycol) and poly(propylene glycol) (PEO-PPO-PEO).…”

Functional Microgels for the Decoration of Biointerfaces

“…In a similar manner, peptide‐microgel conjugates were utilized by Hopkins et al. to bring about detachment of cells from polystyrene surfaces, in a viable state . This could be achieved due to the preferential binding of the cells to the GRGDS sequence on the polymer chains.…”