Nanostructured Superhydrophobic Coatings with Antibacterial and SERS Activity

Bacteria infect millions of people every year, and thousands ofpeople die from these infections. With the increasing antibioticresistance of bacteria, traditional treatment methods are insufficient and the threat is growing day by day. Therefore, the bestway to fight harmful bacteria is to fight them outside before theyinfect the human body. Here, we present nanostructured coatings that can combine anti-biofouling, bactericidal and bacteriadetection-identification properties in a single platform.In the study, end-functional polyethylene glycol brushes weregrafted onto glass surfaces, and then hydrophobic silica nanoparticles were deposited on the surface, leading to transparent superhydrophobic coatings. This coating was further modified byphysical vapor deposition of silver, which had a broad-spectrumantibacterial activity. After the deposition of 10 nm film of silver, the coating has a static contact angle of 169° and sliding angle of 3°. This superhydrophobicity has given the platform theability to prevent initial attack, adhesion and contamination bybacteria. Moreover, the platform exhibited over 99.9% bactericidal activity against Gram-positive S. aureus and Gram-negative E. coli bacteria through silver nanostructures. In addition,the platform exhibited high surface-enhanced Raman scattering(SERS) activity with the plasmonic surface resonance of silver,enabling label-free and sensitive detection of bacteria at low cellcounts (1000 CFU/mL). Finally, the platform was coupled withmachine learning algorithms for bacterial species identificationand 5 different species of bacteria were automatically identifiedfrom SERS spectra with over 90% accuracy using support vectormachines. With all these features, the platform can be a widelyeffective solution to prevent material and moral losses caused bybacterial contamination.Keywords: Anti-biofouling, Bactericidal, SERS, Bacteria Detection, Machine Learning, Bacteria Identification