Characterization and Bioactivity of Alginate-Quaternized Chitosan Microcapsules

Poly-L-lysine (PLL) can be replaced successfully by quaternized chitosan to prepare alginate-Ca microcapsules. By changing the compontent of quaternized chitosan mixture, including N-trimethylated chitosan, octadecyl quaternized carboxymethyl chitosan (OQC) and Poly(ethylene glycol) (PEG) modified OQC (PEG-OQC), different alginate-Ca microcapsules as carriers of cell transplantation can be obtained with diverse properties. Compared with alginate-PLL (AP), the mechanical strength of the alginate-quaternized chitosan (AQC) microcapsules was encouraging, and there was no apparent difference between AQC and AP microcapsules (P < 0.05). The permeability of both microcapsules was observed in the presence of fluorescein isothiocyanate (FITC), immunoglobulin and bovine serum albumin (BSA) by fluorescent microscopy. Both microcapsules membranes were permeable to FITC, part-permeable to IgG and impermeable to larger molecule proteins such as BSA. The AQC and AP microcapsules entrapping L929 cells were cultured properly. L929 cells were retrieved from microcapsules and grew well after being recultured for 3 days.