Electrochemical dealloying of a titanium alloy yields hierarchical surface topography with mechanobactericidal activity

Bioinspired mechanobactericidal structures have emerged as one of the most promising approaches in the era of multidrug-resistant bacteria evolution, particularly for mitigating infections associated with implants. There is a need for a suitable method that can create mechanobactericidal micro-nano structures over a larger region. This study describes the use of an electrochemical dealloying technique to create a combination of micro/nano-structures on biomedically relevant titanium alloy (Ti6Al4V). Electrochemical parameters were varied to yield a range of multiscale topographies on the dealloyed surfaces. Atomic force microscopy revealed that the average roughness (R a ) value for the modified surface is 1.92 ± 0.81 µm, in contrast to R a = 0.02 µm for the smooth surface. Following the dealloying process, the water contact angle on the unmodified surface exhibited a reduction from 62º ± 2º to 37º ± 3º. The antibacterial activity of the surfaces against P. aeruginosa was tested. A micro/nano-structured Ti6Al4V surface effectively markedly reduced bacterial colonization and viability of adhered cells (∼ 82 % reduction) through damage to the bacterial membrane. This dealloying technique can be applied to curved and complex implant surfaces, making it a promising alternative to standard chemical-based antimicrobial approaches for the next generation of titanium alloy implants.