title: γ-Cyclodextrin capped silver nanoparticles for molecular recognition and enhancement of antibacterial activity of chloramphenicol.
abstract: Computational studies were conducted to identify the favourable formation of the inclusion complex of chloramphenicol with cyclodextrins. The results of molecular docking and molecular dynamics predicted the strongest interaction of chloramphenicol with γ-cyclodextrin. Further, the inclusion complex of chloramphenicol with γ-cyclodextrin was experimentally prepared and a phenomenon of inclusion was verified by using different characterization techniques such as thermogravimetric analysis, differential scanning calorimetry, (1)H nuclear magnetic resonance (NMR) and two dimensional nuclear overhauser effect spectroscopy (NOESY) experiments. From these results it was concluded that γ-cyclodextrins could be an appropriate cyclodextrin polymer which can be used to functionalize chloramphenicol on the surface of silver nanoparticles. In addition, γ-cyclodextrin capped silver nanoparticles were synthesized and characterized using UV-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR) and zeta potential analysis. Molecular recognition of chloramphenicol by these cyclodextrin capped silver nanoparticles was confirmed by surface enhanced raman spectroscopy (SERS) experiments. Synergistic antibacterial effect of chloramphenicol with γ-cyclodextrin capped silver nanoparticles was evaluated against Pseudomonas aeruginosa (ATCC 27853), Enterococcus faecalis (ATCC 5129), Klebsiella pneumoniae (ATCC 700603) and Staphylococcus aureus (ATCC 43300). The results from the antibacterial experiment were favourable thus allowing us to conclude that the approach of modifying organic drug molecules with cyclodextrin capped inorganic silver nanoparticles could help to enhance the antibacterial activity of them.
authors.affiliation: Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal (UKZN), Westville, Durban 4000, South Africa.
authors.forename: Ramesh
authors.initials: R
authors.lastname: Gannimani
authors.affiliation: Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal (UKZN), Westville, Durban 4000, South Africa.
authors.forename: Muthusamy
authors.initials: M
authors.lastname: Ramesh
authors.affiliation: Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal (UKZN), Westville, Durban 4000, South Africa.
authors.forename: Sphamandla
authors.initials: S
authors.lastname: Mtambo
authors.affiliation: Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal (UKZN), Westville, Durban 4000, South Africa.
authors.forename: Karen
authors.initials: K
authors.lastname: Pillay
authors.affiliation: Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal (UKZN), Westville, Durban 4000, South Africa.
authors.forename: Mahmoud E
authors.initials: ME
authors.lastname: Soliman
authors.affiliation: Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal (UKZN), Westville, Durban 4000, South Africa. Electronic address: govenderpt@ukzn.ac.za.
authors.forename: Patrick
authors.initials: P
authors.lastname: Govender
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002701:Chloramphenicol / Q000494:pharmacology*; D053768:Metal Nanoparticles; D008855:Microscopy, Electron, Scanning; D056004:Molecular Dynamics Simulation; D012834:Silver / Q000737:chemistry*; D013057:Spectrum Analysis; D047408:gamma-Cyclodextrins / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D047408:gamma-Cyclodextrins; D012834:Silver; D002701:Chloramphenicol; C023792:gamma-cyclodextrin
keywords: Binding free energies; Chloramphenicol; Inclusion complex; Silver nanoparticles; Synergistic antibacterial activity