Nanofiber formation of self-crosslinking dialdehyde carboxymethyl cellulose/collagen composites

Self-crosslinking dialdehyde carboxymethyl cellulose (DCMC)/collagen (COL) composites were prepared by blending DCMC and COL at different ratios, and the effect of DCMC amounts on composite nanofiber formation and stability were investigated. The more was the DCMC amount, the higher became the cross-linking degree, thus demonstrating that self-crosslinking system was successfully constructed. At low amount of DCMC, self-assembled DCMC/COL composite exhibited typical nanofiber structure similar to COL nanofibers, and the mean diameter of nanofibers increased from 68 +/- 12 to 84 +/- 15 nm; additionally, the final turbidity of DCMC/COL composite was higher than that of COL, reflecting more nanofibers formed. We conjectured that nanofiber formation was promoted via adding a small amount of DCMC. However, the inhibition of nanofiber formation was detected by reductions in turbidity at 0.3:1 < DCMC/COL <= 2.5:1, and the mean diameter of nanofibers decreased to 54 +/- 13 nm at a DCMC/COL ratio of 2.5:1. Meanwhile, crosslinking occurred again between adjacent nanofibers during self-assembly process; therefore, partial nanofibers presented in pairs. At a DCMC/COL ratio of 5:1, nanofiber formation was completely inhibited and DCMC/COL composite consisted of aggregates. In summary, nanofiber formation was first promoted and then inhibited with increased DCMC amounts. Furthermore, low- and high-temperature stability of DCMC/COL nanofibers was better than those of COL nanofibers due to the formation of crosslinks.