Horseradish peroxidase-triggered direct in situ fluorescent immunoassay platform for sensing cardiac troponin I and SARS-CoV-2 nucleocapsid protein in serum

Jinhua Liu, Guotong Ruan, Wenlin Ma, Yujie Sun, Haidong Yu, Zhihui Xu, Changmin Yu, Hai Li, Cheng wu Zhang, Lin Li

Research output: Contribution to journalArticlepeer-review

44 Scopus citations

Abstract

Direct in situ fluorescent enzyme-linked immunosorbent assay (ELISA) is rarely investigated and reported. Herein, a direct in situ high-performance HRP-labeled fluorescent immunoassay platform was constructed. The platform was developed based on a rapid in situ fluorogenic reaction between Polyethyleneimine (PEI) and p-Phenylenediamine (PPD) analogues to generate fluorescent copolymer nanoparticles (FCNPs). The formation mechanism of FCNPs was found to be the oxidation of •OH radicals, which was further proved by nitrogen protection and scavenger of •OH radicals. Meantime, the fluorescence wavelength of FCNPs could be adjusted from 471 to 512 nm by introducing various substitution groups into the PPD structure. Using cardiac troponin I (cTnI) and SARS-CoV-2 nucleocapsid protein (N-protein) as the model antigens, the proposed fluorescent ELISA exhibited a wide dynamic range of 5–180 ng/mL and a low limit of detection (LOD) of 0.19 ng/mL for cTnI, and dynamic range of 0–120 ng/mL and a LOD of 0.33 ng/mL for SARS-CoV-2 N protein, respectively. Noteworthy, the proposed method was successful applied to evaluate the cTnI and SARS-CoV-2 N protein levels in serum with satisfied results. Therefore, the proposed platform paved ways for developing novel fluorescence-based HRP-labeled ELISA technologies and broadening biomarker related clinical diagnostics.

Original languageEnglish
Article number113823
JournalBiosensors and Bioelectronics
Volume198
DOIs
StatePublished - 15 Feb 2022

Keywords

  • Cardiac troponin I
  • Fluorescent immunoassay
  • Horseradish peroxidase
  • SARS-CoV-2 nucleocapsid protein
  • Wavelength-tunable

Fingerprint

Dive into the research topics of 'Horseradish peroxidase-triggered direct in situ fluorescent immunoassay platform for sensing cardiac troponin I and SARS-CoV-2 nucleocapsid protein in serum'. Together they form a unique fingerprint.

Cite this