In this study, a novel hybrid CY-HA/PEI-CQ biomaterial was developed by integrating hydroxyapatite (HA) derived from Coturnix ypsilophora (CY) eggshells, Cissus quadrangularis (CQ), and cross-linked polyethyleneimine (PEI). The CY-HA/PEI-CQ biomaterial enhances the lifespan of AISI 316L implants. Biowaste derived CY-HA/PEI-CQ composite were electrophoretically coated over the AISI 316L for enhanced biomedical applications. The XRD revealed that CY-HA exhibited a highly crystalline hexagonal phase, with PEI-CQ incorporating minor lattice distortions without compromising structural integrity. The FT-IR confirmed successful functional group integration, and FESEM and EDX demonstrated a uniform, dense coating with effective elemental incorporation. The CY-HA/PEI-CQ coating demonstrated improved corrosion resistance and mechanical strength, as confirmed by potentiodynamic polarization and compression modulus analyses. The biomaterial effectively inhibited the growth of Escherichia coli and Staphylococcus aureus, with inhibition zones of 26.1 ± 0.3 and 24.5 ± 0.3 mm, respectively. In vitro studies utilizing MG63 osteoblast cells demonstrated high biocompatibility, with cell viability surpassing 97 after seven days, alongside notable proliferation and attachment. Swelling studies in Simulated Body Fluid (SBF) confirmed the composite fluid absorption capacity while maintaining mechanical integrity, which is crucial for orthopedic and tissue engineering applications. These outcomes show that CY-HA/PEI-CQ is a promising biomaterial for biomedical applications. © 2025 Elsevier B.V., All rights reserved.