Bio-nanocomposite Eri silk fibroin/zinc oxide for antibacterial and anticancer applications

Abstract

The increasing prevalence of multidrug-resistant (MDR) bacteria and aggressive breast cancers such as triple-negative breast cancer (TNBC) poses a significant challenge to current therapeutic strategies, necessitating the development of novel, biocompatible and multifunctional materials. In this study, a bio-nanocomposite matrix of Eri silk fibroin–zinc oxide (ESF@ZnO) has been successfully synthesized and characterized to explore its potential for antibacterial and anticancer applications. XRD, FTIR, UV-vis, FESEM and TEM demonstrated the successful integration of ZnO within the ESF matrix. FESEM of the ESF@ZnO composite revealed a heterogeneous surface morphology with ZnO nanoflakes embedded within the silk fibroin matrix. TEM further confirmed the incorporation of crystalline ZnO structures into the amorphous network, while SAED patterns displayed both sharp diffraction rings from ZnO and diffuse halos from ESF, validating the formation of a hybrid organic–inorganic nanocomposite. The antibacterial activity of ESF@ZnO was evaluated against Escherichia coli and Bacillus subtilis with an inhibition zone of 14.8 ± 0.15 mm and 13.2 ± 0.14 mm, respectively. Furthermore, ESF@ZnO exhibited significant anticancer activity against 4T1 (mouse breast cancer) and MDA-MB-231 (human triple-negative breast cancer) cell lines, with IC₅₀ values of 84.06 ± 21.13 and 29.76 ± 13.46 μg mL⁻¹, respectively. A dose-dependent reduction in cell viability and statistically significant cytotoxic effects (p < 0.001) were observed, confirming its effectiveness in inducing cancer cell death. These results highlight ESF@ZnO as a promising bio-nanocomposite for future antibacterial and anticancer applications.