title: Label-free capacitive immunosensor for microcystin-LR using self-assembled thiourea monolayer incorporated with Ag nanoparticles on gold electrode.
abstract: A label-free immunosensor based on a modified gold electrode incorporated with silver (Ag) nanoparticles (NPs) to enhance the capacitive response to microcystin-LR (MCLR) has been developed. Anti-microcystin-LR (anti-MCLR) was immobilized on silver nanoparticles bound to a self-assembled thiourea monolayer. Interaction of anti-MCLR and MCLR were directly detected by capacitance measurement. Under optimum conditions, MCLR could be determined with a detection limit of 7.0 pgl(-1) and linearity between 10 pgl(-1) and 1 microgl(-1). The immobilized anti-MCLR on self-assembled thiourea monolayer incorporated with silver nanoparticles was stable and good reproducibility of the signal could be obtained up to 43 times with an R.S.D. of 2.1%. Comparing to the modified electrode without silver nanoparticles it gave 1.7-fold higher sensitivity and lower limit of detection. The developed immunosensor was applied to analyze MCLR in water samples and the results were in good agreement with those obtained by high-performance liquid chromatography (HPLC) (P < 0.05).
authors.affiliation: Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
authors.forename: Suchera
authors.initials: S
authors.lastname: Loyprasert
authors.forename: Panote
authors.initials: P
authors.lastname: Thavarungkul
authors.forename: Punnee
authors.initials: P
authors.lastname: Asawatreratanakul
authors.forename: Booncharoen
authors.initials: B
authors.lastname: Wongkittisuksa
authors.forename: Chusak
authors.initials: C
authors.lastname: Limsakul
authors.forename: Proespichaya
authors.initials: P
authors.lastname: Kanatharana
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D004566:Electrodes; D017022:Flow Injection Analysis; D006046:Gold; D007118:Immunoassay / Q000379:methods*; D008387:Marine Toxins; D053768:Metal Nanoparticles / Q000737:chemistry*; D052998:Microcystins / Q000032:analysis*; D015203:Reproducibility of Results; D012834:Silver; D013890:Thiourea / Q000737:chemistry*
chemical_list: D008387:Marine Toxins; D052998:Microcystins; D012834:Silver; D006046:Gold; C057862:cyanoginosin LR; D013890:Thiourea