White Light-Activated Antimicrobial Paint using Crystal Violet

Abstract

Crystal violet (CV) was incorporated into acrylic latex to produce white light activated antimicrobial paint (WLAAP). Measurement of the water contact angle of the WLAAP showed that the water contact angle increased with increasing CV concentration. In a leaching test over 120 h, the amount of CV which leached from the WLAAPs was close to the detection limit (<0.03 %). The WLAAPs were used to coat samples of polyurethane and these showed bactericidal activity against E. coli which is a key causative agent of healthcare-associated infections (HAIs). A reduction in the numbers of viable bacteria was observed on the painted coated polyurethane after 6 h in the dark and the bactericidal activity increased with increasing CV concentration (P <0.1). After 6 h of white light exposure, all of coated polyurethanes demonstrated a potent photobactericidal activity and it was statistically confirmed that the WLAAP showed better activity in white light than in the dark (P <0.05). At the highest CV concentration, the numbers of viable bacteria fell below the detection limit (<10 3 CFU/mL) after 6h of white light exposure. The difference in antimicrobial activity between the materials in the light and dark was 0.48 log at CV 250 ppm and it increased by 0.43 log at each increment of CV 250 ppm. The difference was the highest (>1.8 log) at the highest CV concentration (1000 ppm).These WLAAPs are promising candidates for use in healthcare facilities to reduceHAIs.

Photobactericidal activity activated by thiolated gold nanoclusters at low flux levels of white light

“…It is known that the photobactericidal mechanism of CV starts with the absorption of light, resulting in an excited singlet state which has paired electron spin 22,28 . This either returns to the ground state or transforms to a triplet state, which has unpaired electron spin 22,28 . Molecules in the triplet state undergo two photochemical reaction processes known as Type-І and -ІІ.…”

“…Molecules in the triplet state undergo two photochemical reaction processes known as Type-І and -ІІ. For Type-І, redox reactions occur with their environment resulting in ROS generation 22,28 . For Type-ІІ, the energy is transferred to ground state molecular oxygen, resulting in the transformation from triplet oxygen ( 3 O 2 ) to singlet oxygen ( 1 O 2 ) 22,28 .…”

“…It has been shown that zinc oxide (ZnO), silver (Ag), and gold (Au) nanoparticles (NPs) in combination with TBO, CV, and MB produce a synergistic bactericidal effect. This effect was most pronounced using intense light sources such as lasers or bright light of white light source (1000-10000 lux; 0.15-1.5 mW cm −2 ) [23][24][25][26][27][28] . For gold NPs, there is a size effect, where the smallest NPs tested (2-20 nm) showed the greatest promotion of the dyes' bactericidal properties [23][24][25][26][27][28][29] .…”

Impacts of indoor surface finishes on bacterial viability

“…Moreover, innovations in engineering “self‐decontaminating” surfaces not only aim to prevent biological deterioration of products but also work toward killing microbes on contact with surfaces. Various antimicrobial agents have been used in the fabrication of “self‐decontaminating” surfaces for both medical device coatings and latex paint formulations . Antimicrobial ingredients such as silver nanoparticles; crystal violet; a combination of crystal violet, methylene blue, safranin O, and gold nanoparticles; and cationic quaternary ammonium salts (QAS) have been successfully integrated into latex paints.…”

“…Various antimicrobial agents have been used in the fabrication of "self-decontaminating" surfaces 5 for both medical device coatings and latex paint formulations. [6][7][8][9] Antimicrobial ingredients such as silver nanoparticles 6,7 ; crystal violet 9 ; a combination of crystal violet, methylene blue, safranin O, and gold nanoparticles 8 ; and cationic quaternary ammonium salts (QAS) 10 have been successfully integrated into latex paints. To assess their antimicrobial performance, researchers often follow the Japanese Industrial Standard (JIS) Z 2801 as a mainstream antimicrobial efficacy testing, utilizing laboratory test strains, mainly Staphylococcus aureus and Escherichia coli, which is a poor representation of the tremendous diversity of Gram-positive and Gram-negative bacteria.…”