Biofunctional chemically modified pectin for cell delivery

To modulate cell adhesion and to improve the biodegradability of pectin for cell immobilization, two possible approaches of functionalization were investigated: oxidation with sodium periodate (oxi-pectin) and coupling with a RGD-containing oligopeptide (RGD-pectin). Modified pectin was characterized in terms of degree of esterification (DE), intrinsic viscosity, molecular weight, rheological properties, biological behaviour and structure. Pectin microspheres were prepared using these modified pectins and their swelling and stability were evaluated. A new method to determine the DE, based on colorimetry, is here proposed, showing a high correlation with the traditional method based on titration. Partial oxidation and RGD grafting were effective in modulating pectin microspheres degradation and cytocompatibility: RGD-pectin microspheres showed highest cytocompatibility, whereas oxi-pectin microspheres provided accelerated dissolution, which may be associated with faster in vivo release of cells. These biomaterials were proven to have potential interest as injectable cell delivery systems for tissue engineering and, in general, for regenerative medicine applications.