A novel controlled release system Au-CuONP/P(MMAcoMAA)/chitosan nanocomposites: Synthesis, characterization,...

The aim of the study is to synthesize antibacterial nanocomposites containing green synthesized bimetal nanoparticles, which offers a low-cost and environmentally friendly application opportunity in order to employ in drug delivery. In the study, cotoneaster (Cotoneaster horizontalis) fruits, laurel (Laurus nobilis) and sage (Salvia officinalis) leaves grown in the natural flora of Turkey were used for the synthesis of Au-CuO nanoparticles. Chitosan/nanochitosan and P(MMAcoMAA) containing nanocomposite material was synthesized with the obtained bimetallic nanoparticles. Characterization of the prepared nanocomposite was performed by FT-IR, XRD, SEM, UV-Vis and DLS. Antibacterial activities against E. coli and S. aureus and antifungal activities against A. niger were investigated. The usability of the developed nanocomposite in controlled release systems was tested in the BSA model. The binding affinities of Au-CuO nanoparticles to E. coli β-lactamase, S. aureus TMK and A. niger Fdc1 enzymes were also determined and possible antibacterial and antifungal mechanisms were simulated by molecular docking analysis. Au-CuO NPs showed absorbance peaks between 273-276 and 542-552 nm corresponding to CuO and Au, respectively in UV-Vis analysis evaluating the presence of bimetallic NPs. The peaks observed between 567 and 602 cm^-1 in all samples in FT-IR analysis proves the presence of metal-oxides. In SEM images, it was seen that Au-CuO NPs are between 10 and 90 nm and nanocomposites were homogeneously distributed porous matrix structures. 2θ values in XRD patterns of Au-CuO NPs were 38.2°, 44.5°, 64.7° and 77.7° and corresponded to Au and CuO phases, and peaks from both phases represented successful nanoparticle and nanocomposite formation containing bimetal structure. All synthesized materials showed strong antimicrobial activity, close to commercial antibiotics. Inhibition zone of nanocomposite was measured as 25 mm against E. coli, 26 mm against S. aureus and 28 mm against A. niger. MIC and MBC values of nanoparticles and nanocomposites were higher against Gram (-) bacteria. Controlled drug release was studied on the BSA model for 7 days and while the release of the chitosan-containing nanocomposite was 91 % at the end of the period, the nanochitosan sample released 88 %. The binding energies of the synthesized Au-CuO NPs to β-lactamase, TMK and Fdc1 obtained in the molecular docking analysis, were -1.68, -1.60 and -2.16 kcal/mol, respectively. The results showed that a nanomaterial with controlled release capability, antibacterial and antifungal properties that can contain proteins was produced.