Poly(N‐isopropylacrylamide) surface‐grafted chitosan membranes as a new substrate for cell sheet engineering and manipulation

Abstract

The immobilization of poly(N-isopropylacrylamide) (PNIPAAm) on chitosan membranes was performed in order to render membranes with thermo-responsive surface properties. The aim was to create membranes suitable for cell culture and in which confluent cell sheets can be recovered by simply lowering the temperature. The chitosan membranes were immersed in a solution of the monomer that was polymerized via radical initiation. The composition of the polymerization reaction solvent, which was a mixture of a chitosan non-solvent (isopropanol) and a solvent (water), provided a tight control over the chitosan membranes swelling capability. The different swelling ratio, obtained at different solvent composition of the reaction mixture, drives simultaneously the monomer solubility and diffusion into the polymeric matrix, the polymerization reaction rate, as well as the eventual chain transfer to the side substituents of the pyranosyl groups of chitosan. A combined analysis of the modified membranes chemistry by proton nuclear magnetic resonance ((1)H-NMR), Fourier transform spectroscopy with attenuated total reflection (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS) showed that it was possible to control the chitosan modification yield and depth in the solvent composition range between 75% and 100% of isopropanol. Plasma treatment was also applied to the original chitosan membranes in order to improve cell adhesion and proliferation. Chitosan membranes, which had been previously subjected to oxygen plasma treatment, were then modified by means of the previously described methodology. A human fetal lung fibroblast cell line was cultured until confluence on the plasma-treated thermo-responsive chitosan membranes and cell sheets were harvested lowering the temperature.

Polysaccharide-based materials for cartilage tissue engineering applications

“…Even so, this appears not to influence its biocompatibility (VandeVord et al , 2002). Chitosan serves different applications and its use ranges from the food industry (Devlieghere et al , 2004) to the biomedical (da Silva et al , 2008) and pharmaceutical fields (Jayakumar et al , 2006; Prabaharan et al , 2007). It has been especially used for cartilage regeneration and the reported studies with this material have been increasing during recent years.…”

Thermoresponsive poly(N‐isopropylacrylamide)‐g‐methylcellulose hydrogel as a three‐dimensional extracellular matrix for cartilage‐engineered applications

“…The poly( N ‐isopropylacrylamide) (PNIPAAm) is a temperature responsive polymer widely used in different biomedical applications 22, 36–38. It presents a lower critical solution temperature (LCST) at around 33°C in which undergoes a reversible coil to compact globe conformational transition in water, changing from a soluble state below this temperature to an insoluble state above it 39.…”

In Situ Characterization of Thermo‐Responsive Poly(N‐Isopropylacrylamide) Films with Sum‐Frequency Generation Spectroscopy

“…The polymer chains exhibit temperature-dependent solvation behaviour in which they become less solvated with increasing temperature. This results in a thermo-responsive behaviour leading to applications in the areas of biointerfaces, [1][2][3][4][5][6] drug delivery systems, [7][8][9][10][11] permeation-controlled filters, [12] and functional composite surfaces. [13][14][15] In addition to bulk applications, pNIPAM films can be attached to a solid support by methods including atom transfer radical polymerization (ATRP), [16][17][18] initiated either by UV light [19] or by electron beam radiation.…”