title: General Signal Amplification Strategy for Nonfaradic Impedimetric Sensing: Trastuzumab Detection Employing a Peptide Immunosensor.
abstract: A label-free and reagent-free peptide mimotope capacitive biosensor has been developed for cancer drug (trastuzumab) quantification based on nonfaradic readout. The low sensitivity issue of capacitive biosensors was overcome with two innovations: peptide mimotope mixed self-assembled monolayer (SAM) biointerface and dilution of the analysis buffer. Signal amplification was achieved through dilution of phosphate-buffered saline (PBS) to tune Cdlto dominate the overall capacitance change upon target binding, which contribution is often negligible without dilution. After 1000× dilution, the limit of detection was lowered 500-fold (0.22 μg/mL) and the sensitivity was increased 20-fold [0.04192 (μg/mL)-1] in comparison with undiluted PBS. The proposed signal amplification strategy is more straightforward and practical compared to biorecognition element engineering and other strategies. The proposed method was further applied to planar electrodes for optimizing sensing response time to less than 1 min.
authors.affiliation: Department of Chemistry, Oakland University , Rochester, Michigan 48309, United States.
authors.forename: Juan
authors.initials: J
authors.lastname: Liu
authors.affiliation: Karmanos Cancer Institute , Detroit, Michigan 48201, United States.
authors.forename: Mohammad Muhsin
authors.initials: MM
authors.lastname: Chisti
authors.affiliation: Department of Chemistry, Oakland University , Rochester, Michigan 48309, United States.
authors.forename: Xiangqun
authors.identifier: 0000-0003-3867-226X
authors.initials: X
authors.lastname: Zeng
mesh_terms: D015374:Biosensing Techniques; D055664:Electrochemical Techniques; D007118:Immunoassay; D010455:Peptides / Q000737:chemistry*; D000068878:Trastuzumab / Q000032:analysis*
chemical_list: D010455:Peptides; D000068878:Trastuzumab