Revolutionizing Antibacterial Surfaces: 3D Printed Nanoscale and Microscale Topographies through Two-Photon Polymerization

The evolving bacteria defense mechanism against antimicrobial agents due to the overuse and misuse of antimicrobial chemicals has led to a catastrophic problem - antimicrobial resistance, this has spurred the quest for innovative antibacterial approach to inhibit bacterial growth effectively without using any chemicals. Tailored nano- and microstructured architecture, inspired by natural nanotopography such as those found on cicada wings, hold great promise in antibacterial activity due to their unique mechano-antibacterial properties. Among the various nano-/microfabrication techniques, the two-photon polymerisation (TPP) stands out as a versatile and precise approach to fabricate arbitrarily functional three-dimensional structures with sub-micrometre resolution. The process involves the use of femtosecond laser pulses to induce polymerization of a biocompatible acrylate-based photoresin in a precise spatial pattern to generate the nano-/microarchitecture. In this study, we investigated the influence of key fabrication parameters, such as laser power, exposure time, and interface value to achieve the final pre-defined nano-/microarchitecture. Microscopy analysis showed that nanostructure of heights between 350-650 nm; 300-400 nm diameter; and increasing center-to-center distances of 700-2000 nm were successfully fabricated. The mechano-antibacterial feasibility of the two photon-designed nanoarchitecture were tested against P. aeruginosa pathogenic bacteria commonly encountered in healthcare settings. Our results showed that the TPP nano-/microarchitecture demonstrated intriguing antibacterial activity through physico-mechanical interactions between the nano-/microarchitectures and bacteria, creating surfaces that exhibit bactericidal activity. This study paves the way for advanced antibacterial applications in the field of nanotechnology and biomedicine, making a significant contribution to the ongoing efforts in combating antimicrobial resistance and promoting global health.