title: Label-free immunosensor based on graphene/polyaniline nanocomposite for neutrophil gelatinase-associated lipocalin detection.
abstract: A novel label-free electrochemical immunosensor for neutrophil gelatinase-associated lipocalin (NGAL) detection has been developed. The immunosensor has been constructed by immobilization of NGAL capture antibodies to electropolymerized aniline deposited on top of an electrosprayed graphene/polyaniline (G/PANI) modified screen printed carbon electrode. Electrospraying of G/PANI increases the electrode surface area while electropolymerization of aniline increases the number of amino groups (-NH2) for antibody immobilization. The factors affecting the sensor sensitivity (i.e. aniline concentration, scan number and scan rate of electropolymerization) have been optimized. In a prior report, Kannan et al. reported a broad oxidation peak in cyclic voltammetry upon the binding between NGAL with its antibody. In this study, a dramatic increase (58-fold) in the oxidation current upon the binding between NGAL and its antibody is obtained when compared to an unmodified electrode, verifying a substantial improvement in the electrochemical sensitivity of this system. Under optimal conditions, this system exhibits high sensitivity with a limit of detection (LOD) of 21.1ngmL-1, wide linearity (50-500ngmL-1) and high specificity toward NGAL detection from small samples (10μL). As an example application, the sensor is tested for the detection of NGAL in human urine, and the results correspond well with the values obtained from a standard ELISA. Compared to the ELISA method, our system requires less analysis time (≤30min/sample), less sample and less operating cost.
authors: Petrochemical and Polymer Science, Faculty of Science, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok, 10330 Thailand.
authors: Jutiporn
authors: J
authors: Yukird
authors: Electrochemistry and Optical Spectroscopy Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok, 10330 Thailand.
authors: Tossapon
authors: T
authors: Wongtangprasert
authors: Metallurgy and Materials Science Research Institute, Chulalongkorn University, Soi Chula 12, Phayathai Road, Patumwan, Bangkok, 10330 Thailand.
authors: Ratthapol
authors: R
authors: Rangkupan
authors: Electrochemistry and Optical Spectroscopy Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok, 10330 Thailand.
authors: Orawon
authors: O
authors: Chailapakul
authors: Chulalongkorn University Systems Biology Center, Faculty of Medicine, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok, 10330 Thailand. Electronic address: trairak@gmail.com.
authors: Trairak
authors: T
authors: Pisitkun
authors: Metallurgy and Materials Science Research Institute, Chulalongkorn University, Soi Chula 12, Phayathai Road, Patumwan, Bangkok, 10330 Thailand. Electronic address: Nadnudda.r@chula.ac.th.
authors: Nadnudda
authors: N
authors: Rodthongkum
mesh_terms: D058186:Acute Kidney Injury / Q000652:urine; D000814:Aniline Compounds / Q000737:chemistry*; D015374:Biosensing Techniques / Q000191:economics / Q000295:instrumentation* / Q000379:methods; D055664:Electrochemical Techniques / Q000191:economics / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004867:Equipment Design; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000191:economics / Q000295:instrumentation / Q000379:methods; D057230:Limit of Detection; D000071068:Lipocalin-2 / Q000652:urine*; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure
chemical_list: D000814:Aniline Compounds; C489506:LCN2 protein, human; D000071068:Lipocalin-2; C416807:polyaniline; D006108:Graphite
keywords: Acute kidney injury (AKI); Electropolymerization; Electrospraying; Graphene; Immunosensor; Neutrophil gelatinase-associated lipocalin (NGAL); Polyaniline