Hyperbranching enhanced antibacterial and antibiofouling performance of peptide dendrimers on aluminum surfaces

Marine biofouling poses a persistent challenge to engineering materials, necessitating environmentally benign antifouling strategies. In this work, peptide dendrimers with different degrees of hyperbranching were rationally designed and immobilized onto marine aluminum alloy surfaces via catechol-mediated adhesion to construct antibacterial and antibiofouling surfaces. Linear peptide (HL), dibranched (K 2 HL), and tetrabranched (K 4 HL) peptide dendrimers were systematically investigated to elucidate the influence of hyperbranching architecture on antibacterial performance and membrane-disruptive mechanisms. Experimental results demonstrated that moderate hyperbranching significantly enhanced antibacterial activity. K 2 HL exhibited the lowest minimum inhibitory concentration values (32 mg/mL against Bacillus sp. and 16 mg/mL against Vibrio natriegens ), outperforming both HL and K 4 HL. Coarse-grained molecular dynamics simulations further revealed that peptide dendrimers induced membrane deformation through curvature amplification and thickness heterogeneity, with K 2 HL producing the most pronounced membrane destabilization at equivalent concentrations. Antibacterial and antibiofouling evaluations showed that all peptide-modified surfaces effectively reduced bacterial viability and adhesion. Among them, Al-DK 2 HL surfaces exhibited superior performance, achieving antibacterial rates of 61.4% and 75.1%, and antifouling efficiencies of 87.9% and 93.0% against Bacillus sp. and Vibrio natriegens , respectively. Overall, this study demonstrates that moderate peptide hyperbranching optimally balances peptide aggregation behavior and membrane interaction efficiency, offering a promising, green strategy for designing high-performance antibacterial and antibiofouling surfaces for marine applications.