Transparent and photochromic poly(hydroxyethyl acrylate–acrylamide)/WO3 hydrogel with antibacterial properties against bacterial keratitis in contact lens

There have been numerous challenges in the incorporation of photochromic materials into hydrogel system due to the agglomeration of nanoparticles and non-transparency of the hydrogel material. In this study, WO 3 nanocomposites were prepared and incorporated into poly(hydroxyethyl acrylate) (pHEA) and polyacrylamide (pAAm) to fabricate poly(HEA-AAm)/WO 3 hydrogels with improved coloration efficiency and reversibility. The as-prepared p(HEA-AAm)/WO 3 hydrogel displayed remarkable mechanical properties to sustain compressive and tensile stress up to 15.9 and 58.7 MPa with deformation ratios of 16.2 and 30.8, respectively. The hydrogels exhibited good transmittance (%T) and reflectance (%R) of ~47% and 64% at 829 and 408 nm respectively. The hydrogels also revealed visible spectroscopic absorbance at >781 nm after exposure to UV-lamp and natural sunlight for 5 s and 0.5 h, giving rise to a blue coloration, however, the fading process of the hydrogels was achieved in 20 min and 2.0 h respectively in an open air. More so, the hydrogel solutions displayed a high antibacterial efficacy against bacteria pathogens associated with bacterial keratitis in contact lens care solutions. The observed excellent photochromic and antibacterial properties of the hydrogel show promising potentials for use in the construction of antibacterial contact lenses, optical and intelligent devices.