title: Electrochemical immunosensor for prostate-specific antigens using a label-free second antibody based on silica nanoparticles and polymer brush.
abstract: In this paper, we propose a sensitive electrochemical immunosensor synthesized using a surface-initiated atom transfer radical polymerization process for the detection of prostate-specific antigen (PSA). Electrochemical immunosensors based on polymer brush [oligo(ethylene glycol)methacrylate-co-glycidyl methacrylate] (OEGMA-co-GMA) were grown on plane Au and nanostructured (NS) Au electrodes, characterized and compared for their sensitivity to detect PSA. Due to a large capacity for antibody loading and high resistance to nonspecific antibody adsorption of POEGMA-co-GMA brush, the Au-NS immunosensor exhibited detection in a wide dynamic range of five orders of magnitude with an improved lower limit of detection of 2pgml(-1), which was better than the synthesized immunosensor with the polymer brush grown on plane Au electrode. The Au-NS electrode showed improved detection sensitivity of 4.9μAng(-1)ml for PSA detection, which was almost 2 times better than the plane Au electrode. Finally, the use of silica nanoparticles (Si-NPs) conjugated with polyclonal antibody enhanced the response of the immunosensor. The proposed electrochemical immunosensor would be an exciting addition in medical diagnostics for the early detection of cancer biomarkers, e.g., PSA due to improved limit of detection (LOD); eventually helpful in circumventing cancer metastasis.
authors.affiliation: Centre for Micro and Nano Devices, Department of Physics, Faculty of Science, Park Road Campus, COMSATS Institute of Information Technology, Islamabad, 44000. Pakistan.
authors.forename: Saima
authors.initials: S
authors.lastname: Rafique
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637457, Singapore.
authors.forename: Wang
authors.initials: W
authors.lastname: Bin
authors.affiliation: Centre for Micro and Nano Devices, Department of Physics, Faculty of Science, Park Road Campus, COMSATS Institute of Information Technology, Islamabad, 44000. Pakistan. Electronic address: asbhatti@comsats.edu.pk.
authors.forename: Arshad S
authors.initials: AS
authors.lastname: Bhatti
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry* / Q000276:immunology; D002138:Calibration; D058266:Dielectric Spectroscopy; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004867:Equipment Design; D006046:Gold / Q000737:chemistry; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods*; D057230:Limit of Detection; D008689:Methacrylates / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D011095:Polyethylenes / Q000737:chemistry; D017430:Prostate-Specific Antigen / Q000032:analysis* / Q000276:immunology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: D055910:Antibodies, Immobilized; D008689:Methacrylates; D011095:Polyethylenes; C542536:poly(ethylene-co-glycidyl methacrylate); D006046:Gold; D012822:Silicon Dioxide; D017430:Prostate-Specific Antigen
keywords: Electrochemical immunosensor; Prostate-specific antigen; Silica nanoparticles; Surface-initiated atom radical polymerization