Bio-nanomechanical Detection of Diabetic Marker HbA1c
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We report the development of an ultrasensitive immunosensor system for the detection of specific diabetic biomarker glycated hemoglobin (HbA1c) using specific antibody functionalized micromechanical cantilever chips. The biomolecules-induced deflection of the cantilever beam reflects the interplay between the strain energy increase of the cantilever and the free energy reduction of the interaction, providing a unique system for investigating the connection between the nanomechanics and the chemistry of antibody–antigen interaction at very low concentration. Cantilevers were functionalized with specific antibodies using site-directed antibody immobilization technique which was adopted to attach antibody on to the gold substrate. The antibody immobilized cantilevers were used to detect the level of the expressed biomarker in standard samples by adopting direct immunoassay format without using any labels. The assay exhibited an excellent sensitivity for HbA1c in the dynamic range from 0.147 to 1.47 pM. This label-free detection method could be used for fast, high-throughput screening of specific biomarkers for the therapeutic management of diabetes mellitus in clinical diagnostic at a very low cost.
KeywordsCantilever Flow assembly Antibodies HbA1c
University Grant Commission India is gratefully acknowledged for the financial support for awarding Senior Research fellowship to PS and AC. Authors greatly acknowledge Dr. G Shekhawat for optical detection measurements and Dr. Gina Mustata for AFM imaging at NUANCE, Northwestern University.
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