Advanced antimicrobial strategies for masonry heritage: Mechanisms, applications and prospects

Microbial colonization and biodeterioration pose persistent threats to the integrity and aesthetics of brick and stone cultural heritage. To address these challenges, this review provides a comprehensive synthesis of antimicrobial strategies, ranging from conventional nanomaterials and natural products to emerging frontier approaches such as composite systems, superhydrophobic antimicrobial coatings, ionic liquid-based treatments, and green synthetic formulations. The study systematically integrates diverse antimicrobial mechanisms and emphasizes the translation gap between laboratory efficacy and real-world conservation practice. Special attention is given to multifunctional and environmentally responsive systems, which offer the potential to combine antibacterial activity with self-cleaning, controlled release, and durability enhancement. We further identify critical limitations, such as short-lived efficacy, ecological risks, and challenges in large-scale application—and highlight innovative solutions including encapsulation technologies, material hybridization, and sustainable synthesis routes. The study not only provides theoretical guidance but also proposes technical pathways for the sustainable protection of masonry heritage.