Graphene Decorated Zinc Oxide and Curcumin to Disinfect the Methicillin-Resistant Staphylococcus aureus.

Sometimes, life-threatening infections are initiated by the biofilm formation facilitated at the infection site by the drug-resistant bacteria Staphylococcus aureus. The aggregation of the same type of bacteria leads to biofilm formation on the delicate tissue, dental plaque, and skin. In the present investigation, a Graphene (Gr)-based nano-formulation containing Curcumin (C.C.M.) and Zinc oxide nanoparticles (ZnO-NPs) showed a wide range of anti-microbial activity against Methicillin-resistant Staphylococcus aureus (MRSA) biofilm and demonstrated the anti-microbial mechanism of action. The anti-microbial effect of GrZnO nanocomposites, i.e., GrZnO-NCs, suggests that the integrated graphene-based nanocomposites effectively suppressed both sensitive as well as MRSA ATCC 43300 and BAA-1708 isolates. The S. aureus inhibitory effect of GrZnO-NCs improved >5-fold when combined with C.C.M., and demonstrated a M.I.C. of 31.25 µg/mL contrasting with the GrZnO-NCs or C.C.M. alone having M.I.C. value of 125 µg/mL each. The combination treatment of GrZnO-NCs or C.C.M. inhibited the M.R.S.A. topical dermatitis infection in a mice model with a significant decrease in the CFU count to ~64%. Interestingly, the combination of C.C.M. and GrZnO-NCs damaged the bacterial cell wall structure, resulting in cytoplasm spillage, thereby diminishing their metabolism. Thus, owing to the ease of synthesis and highly efficient anti-microbial properties, the present graphene-based curcumin nano-formulations can cater to a new treatment methodology against M.R.S.A.

Enhanced photoelectrochemical water splitting activity of carbon nanotubes@TiO2 nanoribbons in different electrolytes.

Hydrogen production from water splitting by a photocatalytic process is one way that can be used to solve global problems related to energy depletion and environmental pollution. This work aims to design and characterize a novel photocatalyst nanohybrid carbon nanotubes@TiO2 nanoribbons (CNTs@TNRs) for enhanced photoelectrochemical (PEC) water splitting in different electrolytes under visible light irradiance. Here, hydrothermal and chemical vapor deposition (HT-CVD) were combined to grow CNTs @ the nanopits of TNRs producing network of nanohybrid CNTs@TNRs. The structural, morphological, optical, and photocatylatic properties of the TNRs and CNTs@TNRs nanohybrid were characterized by different techniques. The crystallite size is increased from 14.86 nm for TNRs to 21.61 nm for CNTs@TNRs nanohybrid. The CNTs@TNRs nanohybrid has well-resolved nanopits on the surface of the TNRs with an average diameter of 10 nm. The absorption edge of CNTs@TNRs relative to TNRs was strongly shifted to the visible light region. The band gap values are 3.78 and 2.07 eV for TNRs and CNTs@TNRs, respectively. The TNRs and CNTs@TNRs were used for the photocatalytic water splitting under visible light irradiance in Na2S2O3, HCl and KOH electrolytes of different concentrations. The calculated incident photon-to-current conversion efficiency (IPCE) was 97% at 510 nm. These values are higher than those previously reported for different photoelectrodes. The number of hydrogen moles was calculated to be 300 µmol h-1 cm-2. Therefore, our work demonstrates a feasible route for efficient PEC water splitting under sunlight irradiation utilizing the novel CNTs@TNRs photocatalyst.