A Green Polymer Biomaterial Functionalized With Waste Coffee Grounds for Anti-Hemolytic and Antibacterial Applications

Abstract

This study presents the development of a sustainable and biocompatible polymer biomaterial by incorporating waste coffee grounds (WCG) into polyvinyl alcohol (PVA) films for antibacterial and anti-hemolytic applications. Composite films with 1%, 3%, and 5% WCG were prepared via solvent casting. The films were characterized using SEM-EDX, FTIR, XRD, GC-MS, swelling ratio, hemolysis, and antibacterial activity tests, including MIC and MBC. The SEM-EDX and FTIR results revealed good dispersion of WCG and strong intermolecular bonding within the PVA matrix. GC-MS analysis identified 84 phenolic compounds in WCG, supporting its antibacterial potential. MIC tests showed that PC3 inhibited S. aureus at 400 ppm and PC5 at 200 ppm, while PC5 inhibited E. coli even at 25 ppm. MBC results further demonstrated that PC3 was bactericidal at 1200 ppm and PC5 at 800 ppm for both bacteria, confirming the more substantial antibacterial efficiency of PC5. Disk diffusion tests showed inhibition zones of 7 mm for E. coli and 8 mm for S. aureus in the PC5 film. Hemolysis rates were below 2% in all samples, indicating excellent blood compatibility. Swelling tests revealed enhanced water absorption, especially in PC3 and PC5, making them promising for wound healing. The zeta potential and microhardness measurements confirmed the films' colloidal stability and improved mechanical strength. The films have been proven to be highly biodegradable by soil burial testing. This study highlights the potential of waste coffee grounds as a natural, low-cost filler for producing green, functional biomaterials suitable for medical and environmental applications.