Hierarchical Micro/Mesoporous Copper Structure with Enhanced Antimicrobial Property via Laser Surface Texturing

Copper (Cu) and its alloys have been shown to eradicate a wide range of multidrug-resistant microbes upon direct contact. In this study, a facile one-step laser texturing (LT) process is demonstrated to effectively enhance the bactericidal properties of copper surfaces via concurrent selective modification of surface topography and chemistry of laser textured copper (LT-Cu). Surface morphology and elemental composition are analyzed via field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), and Raman spectroscopy. Surface area and pore size of LT-Cu is determined by Barrett-Joyner-Halenda (BJH) and Brunauer-Emmett-Teller (BET) analysis. It reveals direct formation of mesoporous structures with higher surface oxide (Cu2O and CuO), which provide a highly stable superhydrophilic property to the LT-Cu surfaces. The antibacterial properties of LT-Cu are tested against pathogenic bacterial strains with different concentrations including Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus (MRSA USA300) at 10(5) CFU mL(-1), and Escherichia coli and Staphylococcus aureus at high bacterial concentrations of 10(8) CFU mL(-1) using standard contact killing tests. The analysis shows that LT-Cu needs 40, 90, 60, and 120 min to completely eradicate the respective bacterial strain. The LT-Cu causes membrane damage to the bacterial cells immediately after exposure. Furthermore, the biocompatibility of LT-Cu is investigated by in vitro immune-staining assays with mammary stromal fibroblasts and T4-2 cells.