Photoactive polymer coatings for antibacterial applications

Because bacteria can readily induce illnesses in the human body, research into new bactericidal approaches remains relevant to the global community. Photoactive materials (e.g., photocatalysts) provide an environmentally-friendly method for killing bacteria with light. By means of light-mediated reactive oxygen generation, photocatalysts are capable of disrupting bacterial membranes. Much research on antibacterial surfaces has focused on planar substrates or physisorbed coatings, which often provide small active surface areas and limited surface-to-volume ratios, and thereby create a need for new design strategies to incorporate photocatalysts onto more scalable supports. To this end, this contribution describes the synthesis of particle-tethered polymer brush coatings, crosslinked with the organic photocatalyst tetrakis(4-carboxyphenyl)porphyrin (TCPP). Successful engineering on SiO₂ surfaces was confirmed using X-ray photoelectron spectroscopy, tensiometry, and ellipsometry. Singlet oxygen (¹O₂) generation was confirmed through dimethyl sulfoxide oxidation experiments under visible (blue) light and bactericidal activity against Escherichia coli was verified through live/dead assays and cell viability tests.