Development of Antimicrobial Coatings by Incorporating Curcumin and Silver-Based Additive into a Commercial Water-Based Paint.

Antibacterial coatings are essential for preventing infections and maintaining adequate hygiene standards in high-density and high-risk environments, such as public spaces, public transportation systems, schools, and healthcare facilities. In this context, it is essential that such coatings are easy to apply and compatible with large-scale production processes. Among the various strategies for developing antimicrobial surfaces, the incorporation of antibacterial agents into paints represents a particularly practical and versatile approach. In this work, antimicrobial coatings were developed by incorporating curcumin, a naturally derived antibacterial compound, into a commercially available water-based paint. For comparison, coatings were also developed by incorporating a commercially available silver-ion-based additive, a well-established antibacterial agent, into the same paint. Antimicrobial dispersions were deposited onto polycarbonate (PC) and polymethyl methacrylate (PMMA) substrates using a spray coating technique. The produced coatings were evaluated in terms of adhesion and hardness according to the ASTM D3359 and ASTM D3363 standards, respectively, achieving ratings of 4B for adhesion and 4B/5B for hardness. Moreover, after five days of continuous water immersion, no visible signs of cracking, delamination, or discoloration were observed. The resulting curcumin- and silver-based coatings, under the tested surface-contact assay conditions, markedly reduced viable bacterial recovery against both S. aureus and E. coli, with no colonies recovered at the dilution range used for comparison with the Paint-Blank control. These results support the potential of curcumin as a naturally derived antibacterial additive for the development of water-based antibacterial coatings and provide a basis for further investigation of their long-term stability, durability, and practical applicability.