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, 1h, 10mL/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±21.31nm, respectively; while cellulose nanocrystal II has a mean thickness and length of 15.58±2.85 and 78.09±18.22nm, 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.

Mussel-Inspired Electrospun Nanofibers Functionalized with Size-Controlled Silver Nanoparticles for Wound Dressing Application.

Electrospun nanofibers that contain silver nanoparticles (AgNPs) have a strong antibacterial activity that is beneficial to wound healing. However, most of the literature available on the bactericidal effects of this material is based on the use of AgNPs with uncontrolled size, shape, surface properties, and degree of aggregation. In this study, we report the first versatile synthesis of novel catechol moieties presenting electrospun nanofibers functionalized with AgNPs through catechol redox chemistry. The synthetic strategy allows control of the size and amount of AgNPs on the surface of nanofibers with the minimum degree of aggregation. We also evaluated the rate of release of the AgNPs, the biocompatibility of the nanofibers, the antibacterial activity in vitro, and the wound healing capacity in vivo. Our results suggest that these silver-releasing nanofibers have great potential for use in wound healing applications.