title: Novel voltammetric and impedimetric sensor for femtomolar determination of lysozyme based on metal-chelate affinity immobilized onto gold nanoparticles.
abstract: In this study, we reported iminodiacetic acid-copper ion complex (IDA-Cu) immobilized onto gold nanoparticles (GNPs)-modified glassy carbon electrode as a novel electrochemical platform for selective and sensitive determination of lysozyme (Lys). IDA-Cu complex acted as an efficient recognition element capable of capturing Lys molecules. GNPs acts as a substrate to immobilize IDA-Cu coordinative complex and its interaction with Lys leds to a great signal amplification through measuring changes in differential pulse voltammetric (DPV) peak current of [Fe(CN)6](3-/4-) redox probe. Upon the recognition of the Lys to the IDA-Cu, the peak current decreased due to the hindered electron transfer reaction on the electrode surface. Under optimum condition, it was found that the proposed method could detect Lys at wide linear concentration range (0.1 pM to 0.10 mM) with detection limit of 60 fM. Furthermore, electrochemical impedance spectroscopy (EIS) detection of Lys was demonstrated as a simple and rapid alternative analytical technique with detection limit of 80 fM at concentration range up to 0.1mM. In addition, the proposed sensor was satisfactorily applied to the determination of Lys in real samples such as hen egg white. The proposed modified electrode showing the high selectivity, good sensitivity and stability toward Lys detection may hold a great promise in developing other electrochemical sensors based on metal-chelate affinity complexes.
authors.affiliation: Department of Chemistry, University of Kurdistan, 66177-15175 Sanandaj, Iran.
authors.forename: Abbas
authors.initials: A
authors.lastname: Arabzadeh
authors.affiliation: Department of Chemistry, University of Kurdistan, 66177-15175 Sanandaj, Iran; Research Center for Nanotechnology, University of Kurdistan, 66177-15175 Sanandaj, Iran. Electronic address: absalimi@uok.ac.ir.
authors.forename: Abdollah
authors.initials: A
authors.lastname: Salimi
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation; D002614:Chelating Agents / Q000737:chemistry; D002645:Chickens; D003300:Copper / Q000737:chemistry*; D004529:Egg White / Q000032:analysis*; D055664:Electrochemical Techniques / Q000295:instrumentation; D004566:Electrodes; D004867:Equipment Design; D006046:Gold / Q000737:chemistry*; D007098:Imino Acids / Q000737:chemistry*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D008958:Models, Molecular; D009113:Muramidase / Q000032:analysis*
chemical_list: D002614:Chelating Agents; D007098:Imino Acids; D006046:Gold; D003300:Copper; D009113:Muramidase; C008109:iminodiacetic acid
keywords: Electrochemical sensor; Gold nanoparticles; Lysozyme detection; Metal–chelate affinity complex; Voltammetric and impedimetric