Magnetic Rolling Circle Amplification-Assisted Single-Particle Collision Immunosensor for Ultrasensitive Detection of Cardiac Troponin I

Abstract

Owing to its simplicity, high throughput, and ultrasensitivity, single-particle collision electrochemistry (SPCE) has attracted great attention in biosensing, especially labeled SPCE. However, the low signal conversion efficiency and much interference from complex samples limit its wide application. Here, a new and robust SPCE immunosensor was proposed for ultrasensitive cardiac troponin I (cTnI) detection by combining target-driven rolling circle amplification (RCA) with magnetic beads (MBs). Antibody-modified MBs have good stability, dispersity, and magnetic response capacity in complex samples, enabling efficient capture and separation of cTnI with high specificity and anti-interference ability. The presence of cTnI could specifically drive the formation of magnetic immunocomplexes followed by triggering RCA and enzyme digestion reaction. By using Pt nanoparticles (Pt NPs)-modified ssDNA as signal probes, one cTnI molecule could induce the release of 4.5 × 10 4 Pt NPs for collision experiments, greatly enhancing signal conversion efficiency and detection sensitivity. Based on the integration of MBs with RCA, the SPCE immunosensor realized 0.57 fg/mL cTnI detection with a wide linear range of 1 fg/mL to 50 ng/mL. Furthermore, cTnI detection in serum samples of myocardial infarction patients was successfully performed, demonstrating great application prospect of the SPCE immunosensor in clinical diagnosis.

Enhanced Single-Particle Collision Electrochemistry at Polysulfide-Functionalized Microelectrodes for SARS-CoV-2 Detection

“…In addition to sensitivity, the detection accuracy of SPCE biosensors in complex media also needs to be considered. Aiming at the low target content and many interfering substances in complex samples, magnetic beads (MBs) modified with biorecognition molecules are widely used as a powerful tool to capture low-concentration targets and reduce non-specific interference. , Introducing MBs can improve the specificity of SPCE sensors and minimize interference from complex media. So far, there are few reports on applying MBs in SPCE sensors.…”

Impact electrochemistry for biosensing: advances and future directions

“…1a). 74 The presence of cTnI prompted the specific formation of magnetic immunocomplexes, initiating RCA and enzyme digestion reactions that subsequently led to the release of PtNPs for collision experiments. As a result, the LOD can then be lowered to 0.57 fg mL −1 .…”

Chemical–Chemical Redox Cycle Signal Amplification Strategy Combined with Dual Ratiometric Immunoassay for Surface-Enhanced Raman Spectroscopic Detection of Cardiac Troponin I

“…Cardiovascular disease has been threatening human life and health. , Among them, acute myocardial infarction (AMI) is one of the most directly life-threatening acute coronary syndromes, which causes the most serious adverse cardiac events. , Currently, creatine kinase-MB, myoglobin (Myo), troponin T, and cardiac troponin I (cTnI) , are valuable diagnostic biomarkers for AMI. In particular, cTnI is usually produced only in the myocardium and has a high specificity for cardiac injury, so it has been shown to be an important biomarker for the detection of acute AMI. , Over the past few decades, researchers have detected cTnI by colorimetric methods, fluorescence, electrochemistry, and photoelectrochemical studies . These methods provide favorable conditions for obtaining qualitative and quantitative information on bioactive molecules, but the lack of fingerprinting cannot provide detailed information about the molecules.…”

“…In particular, cTnI is usually produced only in the myocardium and has a high specificity for cardiac injury, so it has been shown to be an important biomarker for the detection of acute AMI. 10,11 Over the past few decades, researchers have detected cTnI by colorimetric methods, 12 fluorescence, 13 electrochemistry, 14 and photoelectrochemical studies. 15 These methods provide favorable conditions for obtaining qualitative and quantitative information on bioactive molecules, but the lack of fingerprinting cannot provide detailed information about the molecules.…”