title: Surface plasmon resonance based spectrophotometric determination of medicinally important thiol compounds using unmodified silver nanoparticles.
abstract: The determination of thiol based biological molecules and drugs, such as cysteine (Cys) (I), α-lipoic acid (II), and sodium 2-sulfanylethane sulphonate (Mesna (III)) in human plasma are becoming progressively more important due to the growing body of knowledge about their essential role in numerous biological pathways. Herein we demonstrate a sensitive colorimetric sensor for the determination of medicinally important thiol drugs based on aggregation of the citrate capped silver nanoparticles (Ag NPs). This approach exploited the high affinity of thiols towards the Ag NPs surface which could tempt replacement of the citrate shell by the thiolate shell of target molecules, resulting in aggregation of the NPs through intermolecular electrostatic interaction or hydrogen-bonding. Because of aggregation, the plasmon band at around 400nm decreases gradually, along with the appearance of a new band connoting a red shift. The calibration curves are derived from the intensity ratios of A530/A400, which display a linear relation in the range of 1μM-150μM, 5μM-200μM and 10μM-130μM, respectively. The obtained detection limits (3σ) were found to be 1.5μM, 5.6μM and 10.2μM for compound I-III, respectively. The proposed method has been successfully applied for the detection of thiol compounds in real samples.
authors.affiliation: School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur, C.G. 492010, India; State Forensic Science Laboratory, Tikra Para, Raipur, C.G. 492013, India.
authors.forename: Sandeep K
authors.initials: SK
authors.lastname: Vaishnav
authors.affiliation: School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur, C.G. 492010, India.
authors.forename: Kuleshwar
authors.initials: K
authors.lastname: Patel
authors.affiliation: School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur, C.G. 492010, India.
authors.forename: Kumudini
authors.initials: K
authors.lastname: Chandraker
authors.affiliation: School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur, C.G. 492010, India.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Korram
authors.affiliation: Department of Chemistry, Govt. Madhav Science P. G. College, Ujjain, M.P. 456010, India.
authors.forename: Rekha
authors.initials: R
authors.lastname: Nagwanshi
authors.affiliation: School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur, C.G. 492010, India.
authors.forename: Kallol K
authors.initials: KK
authors.lastname: Ghosh
authors.affiliation: School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur, C.G. 492010, India. Electronic address: manmohan@prsu.ac.in.
authors.forename: Manmohan L
authors.initials: ML
authors.lastname: Satnami
mesh_terms: D002138:Calibration; D006801:Humans; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009994:Osmolar Concentration; D012834:Silver / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared; D013438:Sulfhydryl Compounds / Q000737:chemistry* / Q000652:urine; D020349:Surface Plasmon Resonance; D014867:Water / Q000737:chemistry
chemical_list: D013438:Sulfhydryl Compounds; D014867:Water; D012834:Silver
keywords: Detection limits; Electrostatic interaction; Plasmon band; Silver nanoparticles; Thiol compounds