Antimicrobial, Mechanical and Thermal Studies of Silver Particle-Loaded Polyurethane

Abstract

Silver-particle-incorporated polyurethane films were evaluated for antimicrobial activity towards two different bacteria: Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Distributed silver particles sourced from silver nitrate, silver lactate and preformed silver nanoparticles were mixed with polyurethane (PU) and variously characterized by field emission scanning electron microscopy (FESEM), fourier transform infra-red (FTIR) spectroscopy, X-ray diffraction (XRD) and contact angle measurement. Antibacterial activity against E.coli was confirmed for films loaded with 10% (w/w) AgNO3, 1% and 10% (w/w) Ag lactate and preformed Ag nanoparticles. All were active against S. aureus, but Ag nanoparticles loaded with PU had a minor effect. The apparent antibacterial performance of Ag lactate-loaded PU is better than other Ag ion-loaded films, revealed from the zone of inhibition study. The better performance of silver lactate-loaded PU was the likely result of a porous PU structure. FESEM and FTIR indicated direct interaction of silver with the PU backbone, and XRD patterns confirmed that face-centred cubic-type silver, representative of Ag metal, was present. Young’s modulus, tensile strength and the hardness of silver containing PU films were not adversely affected and possibly marginally increased with silver incorporation. Dynamic mechanical analysis (DMA) indicated greater thermal stability.

Mitigation of membrane biofouling through surface modification with different forms of nanosilver

“…Of the three membranes tested, the silver-modified nanofibre membrane displayed lowest hydrophilicity due to the hydrophobic nature of the polyurethane nanofibres used during modification. While Paul et al [32] have shown that silver nanoparticles can increase the hydrophilicity of polyurethane nanofibre layers; the silver nanoparticles used in this study had no discernible effect and hydrophilicity was always higher than that of the reference ( Table 3). …”

Fabrication and Characterization of Antibacterial Polyurethane Acrylate-based Materials

“…An adequate amount of free silver ions is required, and while water soluble silver salts can give the necessary high concentrations, this is countered by sequestration by protein and other macromolecules. Loss through insoluble AgCl and chelating to microbial products is an important problem as well 5 . The antimicrobial properties of Ag hold significant promise; the development of bacterial resistance 1,3 , the mechanism of action 6,7 , toxicology 8,9 and clinical utility has been studied greatly for medical applications 10,11 .…”

“…Wet chemistry reduction method of Ag + ion is rapidly and effectively using reducing agent such as Sodium borohydride, Citrate, cellulose, D-glucose etc 3,5,21 . However, one of the disadvantages of these methods is that they are not reduced silver from ions to metallic form at all pH level.…”

Enhanced stability and antibacterial efficacy of a traditional Chinese medicine-mediated silver nanoparticle delivery system

“…In past decades, the approach most commonly used to address this problem involved modification of citrate on the surface of the nanosilver to obtain acceptable stability. 8,9 Recently, van der Zande reported that the stability of nanosilver appeared to be greatly improved after modification with polyvinylpyrrolidone in comparison with citrate coating, remaining stable for up to 5 months. 10 Further, Paredes et al found that certain amino acids could be used as reducing agents in the preparation of nanosilver.…”