A new antimicrobial PVC-based polymeric material incorporating bisacylthiourea complexes

A new antimicrobial material incorporating Cu(I) and Cd(II) complexes of bisacylthiourea derivatives in a PVC film was successfully synthesized and characterized by IR, UV, NMR, SEM, and thermal analyses. The results revealed that on coordination, the electronic structure change of the ligand affects practically all their spectral vibrational pattern; however, within the complex pattern, some vibrations indicated that the thiourea derivative behaves as a neutral ligand, which coordinates the metal ion through the sulfur atom of the thiocarbonyl group. The greater affinity of the S atom for Cu+ 1 played a role in Cu(II)→Cu(I) reduction, and the intramolecular hydrogen bonds of the type of (NH···Cl) further stabilized the obtained Cu(I) complex in dioxane. The antimicrobial activity shows that all investigated compounds exhibit excellent activity compared to standard antibiotics. The antibacterial power of the PVC/Cd composite is significantly superior against the most resistant species to both disinfectants and antibiotics compared to its PVC/Cu analogue; nevertheless, the latter exhibited activity equal to an average halo diameter of 29 ± 0.33 mm against pathogenic E. coli ATCC 25,922, indicating excellent G (-) activity. Interestingly, the PVC/Cd composite exhibited excellent activity against pathogenic C. albicans RCMB 005003 (1) ATCC 10,231, while its PVC/Cu analogue was inactive. These materials may be used to reduce infection in wounds either as a composite film or coated barrier dressings, and in addition, the results should open a new direction in antimicrobial surface engineering within the biomedical field. Further challenges are the development of reusable and broad-range antimicrobial polymers.