New evidence for hybrid acrylic/TiO2 films inducing bacterial inactivation under low intensity simulated sunlight

Abstract

a b s t r a c tThis study addresses the preparation and characterization of hybrid films prepared from Titanium dioxide (TiO 2 ) Pickering stabilized acrylic polymeric dispersion as well as their bacterial inactivation efficiency under sunlight irradiation. Complete bacterial inactivation under low intensity simulated solar light irradiation (55 mW/cm 2 ) was observed within 240 min for the films containing 10 weight based on monomers (wbm) % of TiO 2 , whereas 360 min were needed for the films containing 20 wbm% of TiO 2. The hybrid films showed repetitive Escherichia coli (E. coli) inactivation under light irradiation. TiO 2 released from the films surfaces was measured by inductively coupled plasma mass spectrometry (IPC-MS), obtaining values of ∼0.5 and 1 ppb/cm 2 for the films containing 10 wbm% and 20 wbm% of TiO 2 , respectively, far below the allowed cytotoxicity level for TiO 2 (200 ppb). Transmission electron microscopy (TEM) of the hybrid films showed that TiO 2 nanoparticles (NPs) were located at the polymer particle's surface forming a continuous inorganic network inside the film matrix. Atomic force microscopy (AFM) images showed differences in the TiO 2 dispersion between the air-film and film-substrate interfaces. Films containing 10 wbm% of TiO 2 had higher roughness (Rg) at both interfaces than the one containing 20 wbm% of TiO 2 inducing an increase in the bacterial adhesion as well as the bacterial inactivation kinetics. The highly oxidative OH• -radicals participating in the bacterial inactivation were determined by fluorescence.

Optimization of Injection Molding Parameters for HDPE/TiO2 Nanocomposites Fabrication with Multiple Performance Characteristics Using the Taguchi Method and Grey Relational Analysis

“…Among potential polymers, high density polyethylene (HDPE) is a thermoplastic polymer used in biomedical applications, especially in bone tissue engineering and reconstructive dentistry [2,3,4]. Titanium dioxide, on the other hand, is an important bioactive filler that has been studied extensively by researchers and is known to exhibit low cytotoxicity and negligible immune response [5,6,7]; and recent studies [8,9] also show that TiO 2 thin films are effective in inactivating bacteria, such Escherichia coli ( E. coli ) under simulated sunlight. The physiological activity of titania- and polyethylene-based implants has been studied through various in vivo studies [5,10,11,12,13] and has been shown to improve biocompatibility and to elicit low immune response and no damage to the organs surrounding the implant.…”

Nanocomposite materials for photocatalytic degradation of pollutants

“…The evaluation of the E coli inactivation on prepared polymers under simulated solar light demonstrated complete bacterial inactivation within 240 min for the film containing 10 wbm% of TiO 2 (air-film interface), whereas the one containing 20 wbm% of TiO 2 required longer cycles. According authors photogenerated e-and h+ in the 20% TiO 2 sample require a longer diffusion length to reach the surface and initiate the photocatalytic bacteria inactivation [18]. Analogous results were obtained in antibacterial TiO 2 /In 2 O 3 films sputtered on polyester.…”

“…Therefore, the design and implementation of novel TiO 2 -based catalysts deposited onto suitable substrates is a challenging task in order to obtain materials exploitable for environmental applications. A way to reduce the aggregation of the catalysts and increase the mechanical stability of the coatings is their integration in polymer/inorganic hybrids, to achieve a functional nanocomposite [13,14,[17][18][19][20][21]. A nanocomposite is defined as a multiphase solid material where one of the phases has at least one dimension lower than 100 nm.…”

Stable Photocatalytic Paints Prepared from Hybrid Core-Shell Fluorinated/Acrylic/TiO2 Waterborne Dispersions

“…This result is in agreement with the non-homogeneous distribution of the TiO 2 NPs previously observed by SEM ( Figure 1) and XPS ( Table 1). The kinetics of the degradation of Escherichia coli in the substrate-film interface is comparable, but clearly slower than in films produced from TiO 2 nanoparticle Pickering-stabilized (meth)acrylic latexes [20,21].…”

“…The presence of the photocatalytically active TiO 2 NPs at the surface of the paint, together with its higher roughness, are the keys to get a paint with good photocatalytic activity toward pollutant degradation [20,21].…”