title: Binding of chloroquine-conjugated gold nanoparticles with bovine serum albumin.
abstract: We have conjugated chloroquine, an anti-malarial, antiviral and anti-tumor drug, with thiol-functionalized gold nanoparticles and studied their binding interaction with bovine serum albumin (BSA) protein. Gold nanoparticles have been synthesized using sodium borohydride as reducing agent and 11-mercaptoundecanoic acid as thiol functionalizing ligand in aqueous medium. The formation of gold nanoparticles was confirmed from the characteristic surface plasmon absorption band at 522 nm and transmission electron microscopy revealed the average particle size to be ~7 nm. Chloroquine was conjugated to thiolated gold nanoparticles by using EDC/NHS chemistry and the binding was analyzed using optical density measurement and Fourier transform infrared spectroscopy. The chloroquine-conjugated gold nanoparticles (GNP-Chl) were found to interact efficiently with BSA. Thermodynamic parameters suggest that the binding is driven by both enthalpy and entropy, accompanied with only a minor alteration in protein's structure. Competitive drug binding assay revealed that the GNP-Chl bind at warfarin binding site I in subdomain IIA of BSA and was further supported by Trp212 fluorescence quenching measurements. Unraveling the nature of interactions of GNP-Chl with BSA would pave the way for the design of nanotherapeutic agents with improved functionality, enriching the field of nanomedicine.
authors.affiliation: National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110 012, India.
authors.forename: Prachi
authors.initials: P
authors.lastname: Joshi
authors.forename: Soumyananda
authors.initials: S
authors.lastname: Chakraborty
authors.forename: Sucharita
authors.initials: S
authors.lastname: Dey
authors.forename: Virendra
authors.initials: V
authors.lastname: Shanker
authors.forename: Z A
authors.initials: ZA
authors.lastname: Ansari
authors.forename: Surinder P
authors.initials: SP
authors.lastname: Singh
authors.forename: Pinak
authors.initials: P
authors.lastname: Chakrabarti
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D001894:Borohydrides / Q000737:chemistry; D002417:Cattle; D002738:Chloroquine / Q000737:chemistry* / Q000378:metabolism; D005227:Fatty Acids / Q000737:chemistry; D006046:Gold / Q000737:chemistry* / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012710:Serum Albumin, Bovine / Q000378:metabolism*; D017550:Spectroscopy, Fourier Transform Infrared; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013816:Thermodynamics; D014364:Tryptophan / Q000737:chemistry; D014859:Warfarin / Q000737:chemistry / Q000378:metabolism
chemical_list: C505222:11-mercaptoundecanoic acid; D000962:Antimalarials; D001894:Borohydrides; D005227:Fatty Acids; D013438:Sulfhydryl Compounds; D012710:Serum Albumin, Bovine; D014859:Warfarin; D006046:Gold; C025364:sodium borohydride; D002738:Chloroquine; D014364:Tryptophan