Green extraction and isolation of cellulose nanofibrils from orchid (Dendrobium sonia earsakul) stem for wound dressing application

This study explored agricultural waste orchid (Dendrobium sonia earsakul) stem as a sustainable material to extract nanocellulose with its extract for wound dressing applications. Cellulose isolation was performed using a green method involving synergistic pretreatment with xylanase and laccase enzymes. This was followed by isolation of cellulose nanofibers (CNF) using mechanical process. The green pretreatment demonstrated high efficiency in delignification, reduced chemical usage, and increased whiteness index to 90.84 %. The fiber showed a high crystallinity index of 72.85 %, which was confirmed by wide-angle X-ray scattering (WAXS) analysis. Transmission electron microscopy (TEM) revealed CNF with an average diameter of 10.51 ± 2.41 nm. The crude extract showed anti-inflammatory effect and antimicrobial activities against S. aureus and E. coli with minimum bactericide concentration (MBC) of 51.6 mg/mL. The cytotoxicity of the extract was evaluated using MC3T3-E1 cell line. A novel multi-layered wound dressing was developed using the CNF and the extract. The chemical composition of the membrane was confirmed by Fourier transform infrared spectroscopy. The 3D structure of the membrane was established using Synchrotron radiation X-ray tomographic microscopy. The membrane is biodegradable, non-toxic against MC3T3-E1 cells and biocompatible with 78.52 % cell viability. These findings suggest the possibility of extracting valuable chemicals from agricultural wastes such as orchid stem using green pretreatment to create an eco-friendly wound dressing.