Antibacterial efficiency assessment of polymer-nanoparticle composites using a high-throughput microfluidic platform

Over the past decades, inorganic nanoparticles (NPs), particularly metal oxide NPs, have attracted great attention due to their strong bactericidal effects. Researchers have used NPs to fabricate nanocomposite materials which have innate antibacterial capability. Herein, we present a straightforward method to fabricate antibacterial nanocomposites. Ag, TiO₂, and ZnO NPs were dispersed within liquid silicone rubber (LSR) structure in four concentrations. Three different methods were used to evaluate the antibacterial efficiency of the NPs forming the nanocomposite materials: (I) the diffusion method, (II) agar counting plate, and (III) a live/dead assay of E. coli. The mechanical properties and hydrophobicity of the nanocomposites were characterized and correlated to the antibacterial efficiency of the NPs. In order to test the antibacterial efficiency in a high-throughput, cost-effective and efficient manner, a microfluidic device fabricated by 3D printing and soft-lithography methods was used. The LSR-15 wt% TiO₂ nanocomposites showed the best antibacterial efficiency. In addition, TiO₂ NPs formed the stiffest nanocomposites with very fine, even surface which increased the hydrophobicity of the surface where bacteria attach to grow, preventing bacteria from further growth.