Novel peptidylated surfaces for interference-free electrochemical detection of cardiac troponin I

Sameer Dhawan, Sandhya Sadanandan, V. Haridas, Nicolas H. Voelcker, Beatriz Prieto-Simón

Research output: Contribution to journalArticleResearchpeer-review

25 Citations (Scopus)

Abstract

Novel peptidylated surfaces were designed to minimise interferences when electrochemically detecting cardiac troponin I in complex biological samples. Disulfide-cored peptide dendrons featuring carbomethoxy groups were self-assembled on gold electrodes. The carbomethoxy groups were deprotected to obtain carboxylic groups used to immobilise antibodies for cardiac troponin I marker. The chemisorption of two types of peptides, one containing triazole and the other with native peptide bonds, on a gold substrate was studied by quartz crystal microbalance (QCM), surface plasmon resonance (SPR) and X-ray photoelectron spectroscopy (XPS). Peptides formed ordered self-assembled monolayers, contributing to a more efficient display of the subsequently immobilised antibodies towards their binding to the antigen. As a result, electrochemical immunosensors prepared by self-assembly of peptides afforded higher sensitivities for cardiac troponin I than those prepared by the chemisorption of alkane thiolated compounds. Triazolic peptide-modified immunosensors showed extraordinary sensitivity towards cardiac troponin I [1.7 µA/(ng/mL) in phosphate buffer], but suffered from surface fouling in 10% serum. Modification with non-triazolic peptides gave rise to anti-fouling properties and still enabled the detection of cardiac troponin I at pg/mL concentrations in 10% serum without significant matrix effects.

Original languageEnglish
Pages (from-to)486-492
Number of pages7
JournalBiosensors and Bioelectronics
Volume99
DOIs
Publication statusPublished - 15 Jan 2018

Keywords

  • Cardiac troponin I
  • Electrochemical immunosensor
  • Interference free
  • Peptides
  • Self-assembly

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