Liquid crystal and gold nanoparticles applied to electrochemical immunosensor for cardiac biomarker.
A label-free electrochemical immunosensor based on the ionic liquid crystal (E)-1-decyl-4-[(4-decyloxyphenyl)diazenyl]pyridinium bromide (Br-Py) coated on a glassy carbon electrode (GCE) for the quantitative detection of myoglobin (Mb), a cardiac marker for acute myocardial infarction, is reported herein for the first time. The monoclonal anti-myoglobin antibody (ab-Mb) was covalently immobilized using glyoxal on a film of polyethyleneimine-coated gold nanoparticles (AuNP-PEI). The proposed method for Mb detection is based on voltammetric suppression of the Br-Py signal when the immunosensor was incubated with Mb antigen. The electrochemical performance of the Mb immunosensor was studied by electrochemical impedance spectroscopy, and cyclic and square-wave voltammetry. Under the optimal conditions, the proposed immunosensor shows a good linear relationship between the electrochemical inhibition response and the concentration of Mb over the range of 9.96-72.8 ng mL(-1) with a detection limit of 6.29 ng mL(-1). The results obtained indicate that the proposed immunosensor provides good sensitivity and simple operation for detecting acute myocardial infarction with Mb as a biomarker.
Laboratory of Biosensors, Department of Chemistry, Federal University of Santa Catarina, 88040-900 Florianópolis, Santa Catarina, Brazil. Electronic address: zapp.edu@gmail.com.
Eduardo
E
Zapp
Laboratory of Synthesis of Liquid Crystals, Department of Chemistry, Federal University of Santa Catarina, 88040-900 Florianópolis, Santa Catarina, Brazil.
Eduard
E
Westphal
Laboratory of Synthesis of Liquid Crystals, Department of Chemistry, Federal University of Santa Catarina, 88040-900 Florianópolis, Santa Catarina, Brazil.
Hugo
H
Gallardo
Bioinorganic and Crystallography Laboratory, Department of Chemistry, Federal University of Santa Catarina, 88040-900 Florianópolis, Santa Catarina, Brazil.
Bernardo
B
de Souza
Laboratory of Biosensors, Department of Chemistry, Federal University of Santa Catarina, 88040-900 Florianópolis, Santa Catarina, Brazil. Electronic address: iolanda.vieira@ufsc.br.
Iolanda
I
Cruz Vieira
D055910:Antibodies, Immobilized / Q000737:chemistry; D055664:Electrochemical Techniques / Q000295:instrumentation*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D057230:Limit of Detection; D050866:Liquid Crystals / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008958:Models, Molecular; D009211:Myoglobin / Q000032:analysis / Q000097:blood*; D011094:Polyethyleneimine / Q000737:chemistry
D055910:Antibodies, Immobilized; D009211:Myoglobin; D006046:Gold; D011094:Polyethyleneimine
Gold nanoparticles; Immunosensor; Liquid crystal; Myoglobin