Poly(ethylene glycol)-crosslinked N-methylene phosphonic chitosan. Preparation and characterization

N-Methylene phosphonic chitosan (NMPC) was modified with poly(ethyleneglycol)-aldehyde (PEG-CHO) with different molecular weight (200, 2000 and 8000) by reductive amination. The degree of substitution (DS) was determined by elemental analysis. Its chemical identity was characterized by FT-IR, 1H NMR and 13C NMR spectrometry. The crosslinking with PEG-COH chains in NMPC increased the water swelling and hygroscopicity. The modification with high molecular weight PEG produced swelling in alkaline pH and remains soluble in acidic medium. No dissolution took place with lysozyme. We performed some preliminary studies to evaluate in vitro, the behavior of this derivatives with the C2C12 cell line. We noticed that NMPC-PEG-CHO 8000 film leads to cell attachment and proliferation. The film forming capacity and swelling properties made these crosslinked NMPC derivatives suitable for medical material item.