Nanocellulose aerogels from banana pseudo-stem as a wound dressing

Wound dressings with natural antimicrobial, moisturizing and swelling properties have received increasing attention. However, many natural materials used as wound dressings require chemical cross-linking agents or acidic and alkaline environments and have problems such as poor stability and uneven distribution. In this study, banana nanocellulose (BCNF) with a diameter of less than 70 nm was extracted from banana pseudo-stem through benzyl alcohol extraction, sodium chlorite bleaching, potassium hydroxide alkaline treating, and ultrasonic crushing treatment. There was an addition of konjac glucomannan (KGM) to 0.8 wt% nanocellulose suspension and freeze-drying to form composite aerogel (BCNK) by freeze-drying. Different ratios of BCNF and KGM were used to regulate the performance of aerogels such as swelling, water retention, water vapor transmission rate, and mechanical property. It was evident that the aerogel with an 8/2 mass ratio of BCNF to KGM (BCNK2) exhibited better performance, with a 2981% swelling rate, 97.71% porosity, and 810 g·m−2·d−1 water vapor transmission rate, and also showed the applicable mechanical properties. According to the results of antibacterial and biocompatibility, the composite aerogel had commendable inhibitory effects on E. coli and S. aureus. The hemolysis rate of BCNK2 was 3.38% and the cell survival rate was over 90%, which proved that BCNK2 had good hemolysis and no cytotoxicity. Therefore, the nanocellulose composite aerogel prepared from banana pseudo-stem has the potential to be applied to wound dressings.