Cellulose-chitosan beads crosslinked by dialdehyde cellulose

Crosslinked cellulose-chitosan beads were obtained via dissolution-regeneration of cellulose and chitosan by a LiOH/urea aqueous solution, followed by the crosslinking of chitosan via dialdehyde cellulose (DAC). This crosslinking reaction involved the Schiff base formation between the aldehyde groups of DAC and the amino groups of chitosan and subsequent reduction. DAC was prepared through periodate oxidation of cellulose and solubilization in hot water at 100 °C for 1 h. Four grades of DAC-crosslinked cellulose-chitosan were prepared by controlling the amount of cellulose and chitosan. The DAC-crosslinked cellulose-chitosan showed higher stability in the pH range of 2–9 over a long-term 21-day test. Additionally, the DAC-crosslinked chitosan showed a higher bovine serum albumin adsorption capacity as a result of the increased amino group content due to the crosslinking between DAC and chitosan, which occurred at multiple points in spite of a lower degree in crosslinking.