Efficient dye degradation, antimicrobial behavior and molecular docking analysis of gold (Au) and cellulose nanocrystals (CNC)-doped strontium oxide nanocomposites

Novel Au and cellulose nanocrystals (CNC)-doped SrO nanocomposites have been fabricated using simple and cost-effective chemical co-precipitation technique. Various concentrations of Au were doped into fixed amounts of CNC and SrO nanocomposites. The objective of this triplex nanocomposite was to examine the effect of incorporating dopants in SrO on the efficient elimination of organic contaminants from water and their antibacterial potential with molecular docking study. Adequate experimental conditions such as temperature, suitable volume ratio of reactants and pH were generated during the synthesis. For comparative studies, nanocomposites were evaluated through a number of characterization tools. The structural and morphological analysis through XRD and HR-TEM revealed the cubic crystalline structure of aggregated SrO quantum dots (QDs). Furthermore, an interconnected chain-like structure of nanoclusters was observed upon CNC and Au incorporation in SrO lattice. The size of nanoclusters/nanoparticles was calculated to be approximately 30 nm which matched well with the reported literature. Reduction in crystallinity and bandgap from 4.12 eV (for pristine SrO) to 3.8 eV was observed upon co-doping with CNC and Au in SrO lattice. Furthermore, pH-based catalytic analysis of prepared nanocomposites revealed 98% dye degradation (in acidic media) against methylene blue ciprofloxacin (MBCF) dye along with good bactericidal activities against Gram-positive/negative bacteria, respectively. In silico molecular docking analysis for enzyme targets belonging to cell wall synthesis (penicillin-binding protein 4) and fatty acid synthesis (enoyl-[acyl-carrier-protein] reductase) suggested Au–CNC and Au/CNC-doped SrO nanostructures as possible inhibitors of these enzymes owing to their good binding scores and binding interactions with active site residues. Graphic abstract: (a) Preparation of cellulose nanocrystals (CNC) by acid hydrolysis. (b) Schematic synthesis route to fabricate Au/CNC–SrO nanocomposites. [Figure not available: see fulltext.].