title: Silver nanoflower-reduced graphene oxide composite based micro-disk electrode for insulin detection in serum.
abstract: Sensitive and selective determination of protein biomarkers remains a significant challenge due to the existence of various biomarkers in human body at a low concentration level. Therefore, new technologies were incessantly steered to detect tiny biomarkers at a low concentration level, yet, it is difficult to develop reliable, stable and sensitive detection methods for disease diagnostics. Therefore, the present study demonstrates a methodology to detect insulin in serum at low levels based on Ag nanoflower (AgNF) decorated reduced graphene oxide (rGO) modified micro-disk electrode arrays (MDEAs). The morphology of AgNF-rGO composite was characterized by scanning electron microscopy, the structure was analyzed using X-ray diffraction patterns and Raman spectra. The hybrid interface exhibited enhanced electrical conductivity when compared with its individual elements and had improved capturing ability for antibody-antigen binding towards insulin detection. In order to measure quantitatively the insulin concentration in PBS and human serum, the change in impedance (ΔZ) from electrochemical impedance spectroscopy was analyzed for various concentrations of insulin in [Fe(CN)6](3-/4-) redox couple. The electrode with adsorbed antibodies showed an increase in ΔZ for the addition of antigen concentrations over a working range of 1-1000 ng mL(-1). The detection limits were 50 and 70 pg mL(-1) in PBS and human serum, respectively.
authors: Department of Biomedical Engineering, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon 21936, Republic of Korea.
authors: Ajay Kumar
authors: AK
authors: Yagati
authors: Department of Biomedical Engineering, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon 21936, Republic of Korea.
authors: Yonghyun
authors: Y
authors: Choi
authors: Department of Biomedical Engineering, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon 21936, Republic of Korea.
authors: Jinsoo
authors: J
authors: Park
authors: Department of Chemical and Biomolecular Engineering, Sogang University, 35 Baekbeom-ro (Sinsu-dong), Mapo-gu, Seoul 04107, Republic of Korea.
authors: Jeong-Woo
authors: JW
authors: Choi
authors: Lee Gil Ya Cancer and Diabetes Institute, Gachon University, 155 Get-Pearl-ro, Yeonsu-gu, Incheon 21999, Republic of Korea.
authors: Hee-Sook
authors: HS
authors: Jun
authors: Department of Biomedical Engineering, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon 21936, Republic of Korea. Electronic address: sbcho@gachon.ac.kr.
authors: Sungbo
authors: S
authors: Cho
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation*; D058266:Dielectric Spectroscopy / Q000295:instrumentation*; D004566:Electrodes; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D007328:Insulin / Q000097:blood*; D057230:Limit of Detection; D008958:Models, Molecular; D049329:Nanostructures / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry; D012834:Silver / Q000737:chemistry*
chemical_list: D055910:Antibodies, Immobilized; D007328:Insulin; D010087:Oxides; D012834:Silver; D006108:Graphite
keywords: Impedance; Indium tin oxide; Insulin; Micro-disk; Reduced graphene oxide; Silver nanoflower