Antimicrobial Coating for Healthcare Settings Based on an Acrylic Binder Modified with Nanosized Hexa[(pyridin-4-yl)amino]cyclotriphosphazene.

Healthcare-associated infections (HAIs) represent a major challenge in medical facilities, necessitating the development of self-disinfecting surfaces. This study investigates the performance of a newly synthesized compound, hexa[( pyridin-4-yl)amino]cyclotriphosphazene (HPP), as a promising modifier for acrylic coatings aimed at reducing microbial surface contamination. HPP was synthesized by grafting six pyridinamine groups onto a hexachlorocyclotriphosphazene core. Its structure was confirmed by NMR spectroscopy and MALDI-TOF mass spectrometry. The potential of HPP as an antimicrobial modifier was evaluated using computational modeling (the SwissADME platform for QSPR/QSAR predictions). Coating compositions were prepared by incorporating HPP (0-5 wt%) into a fast-drying, water-based acrylic paint (Elcon brand). Physicochemical properties (adhesion, water absorption, chemical resistance, abrasion resistance, and UV-aging resistance) and antimicrobial activity against Escherichia coli and Candida albicans were assessed according to ISO standards. HPP is a nanoscale molecule (diameter ~1.25 nm) with a high molecular weight (693.58 g/mol), low water solubility (Log S = -7.31), and moderate lipophilicity (Consensus Log P = 2.94). Compared to unmodified samples, coatings containing HPP demonstrated improved adhesion (score 0 on concrete starting from 1 wt% and on wood starting from 3 wt%), reduced water absorption, increased abrasion resistance, and good chemical resistance to NaOH and H2O2. Antimicrobial activity reached 18.9% inhibition for E. coli and 41.9% for C. albicans at 5 wt% HPP. The predicted low systemic absorption and low skin permeability (Log Kp = -6.69 cm/s) confirm the safety profile of HPP for use in coating formulations. The absence of PAINS alerts indicates stability, while the nanoscale size favors immobilization within the polymer matrix, explaining the improved physicochemical properties and sustained antimicrobial activity. HPP is an effective multifunctional additive for acrylic paints intended for healthcare settings. The resulting modified paint is suitable for application in facilities where a reduction in microbial surface contamination is required.