Development of bioactive cellulose nanocrystals derived from dominant cellulose polymorphs I and II from Capsosiphon Fulvescens for biomedical applications

Cellulose I and II polymorphs were isolated from Capsosiphon fulvescens (CF) using the conventional method of extraction and direct mercerization of raw sample, respectively. The morphological and structural differences between the isolated polymorphs were studied by FTIR, FESEM and XRD. Direct mercerization of raw CF yielded the transformation of highly crystalline cellulose I (81.3%) to II (63.7%) as observed in the shifting of XRD patterns. The derived cellulose I and II were hydrolyzed (60% w/w H₂SO₄, 55 °C, 1 h, 10 mL/g) to obtain the spindle-shaped cellulose nanocrystals. Cellulose nanocrystal I was observed to have a mean thickness and length of 12.67 ± 2.69 and 92.31 ± 21.31 nm, respectively; while cellulose nanocrystal II has a mean thickness and length of 15.58 ± 2.85 and 78.09 ± 18.22 nm, respectively. Furthermore, a fiber-like mat assembly, which could be used as supplement support structure for tissue engineering, was obtained after subjecting the aqueous cellulose nanocrystal suspensions to freeze-drying. A possible application of this material can be as a biocompatible and biodegradable composite for tissue engineering and other biomedical applications.