Antimicrobial Activity of Photocatalytic Coatings on Surfaces: A Systematic Review and Meta-Analysis

Photocatalytic technologies represent an innovative method to reduce microbial load on surfaces, even considering recent public health emergencies involving coronaviruses and other microorganisms, whose presence has been detected on surfaces. In this review paper, the antimicrobial efficacy of various photocatalysts applied by different coating methods on different surfaces has been compared and critically discussed. Publications reviewing the use of photocatalytic coatings on surfaces for antimicrobial effectiveness have been examined. Clear search parameters were employed to analyze the PubMed, Scopus, and WOS databases, resulting in 45 papers published between 2006 to 2023 that met the inclusion criteria. The paper assessed various types of photocatalytic coatings that targeted different microbial objectives. Based on the pooled data analysis, the TiO2 coating exhibited a substantial effect in decreasing bacteria strains, both Gram-positive and -negative (99.4%). Although the diversity of these technologies poses significant obstacles to obtaining a comprehensive final assessment of their effectiveness and feasibility for surface application, subgroup analysis indicated significant variations in the removal efficiency of Gram-positive strains based on different surface types (p = 0.005) and time of exposure (p = 0.05). Photocatalytic coatings provide a promising approach to combating the spread of microorganisms on surfaces. Further "in-field" investigations are necessary in the foreseeable future to explore and optimize this novel and exciting health technology.