Stretchable bacterial cellulose–based nanocomposites with outstanding mechanical strength for potential biomedical applications

The development of stretchable bacterial cellulose (BC)–based nanocomposites with enhanced mechanical strength holds significant potential for biomedical applications. The study utilized the cost-effectively produced BC by using coconut waste as the carbon source and utilized an ex situ approach to synthesize BC-based composites by incorporating cactus gel (BC-C) and multiwalled carbon nanotubes (BC-MWCNT) alone and together (BC-C-MWCNT). Field emission scanning electron microscopy (FE-SEM) revealed porous and fibrous morphology of BC and successful impregnation of cactus gel and MWCNTs into its matrix. Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analyses confirmed successful additives integration, with thermogravimetric analysis (TGA) demonstrating improved thermal stability. Mechanical behavior analysis via tensile testing demonstrated significant improvements in both tensile strength and elongation properties with the addition of cactus gel and MWCNTs. While cactus gel enhanced elongation to 17.03%, MWCNTs primarily increased tensile strength to 146.30 MPa, resulting in a balanced enhancement in BC-C-MWCNT nanocomposite. Full-field strain analysis using the three-dimensional digital image correction (3D-DIC) method provided insights into the failure mechanisms and strain localization. BC-C-MWCNT nanocomposite exhibited a combination of ductile and brittle failure modes, with enhanced strength and elongation compared to pristine BC. The BC-C-MWCNT nanocomposites demonstrated notable antibacterial activity against Escherichia coli and Staphylococcus aureus. In vitro biocompatibility assessments with NIH 3T3 cells showed superior cell proliferation and spreading for BC-C and BC-C-MWCNT composites. In conclusion, the incorporation of cactus gel and MWCNTs into the BC matrix significantly enhanced its structural, mechanical, antibacterial, and biocompatible properties, making it a promising biomaterial for advanced biomedical applications.