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Fe3O4@PDA immune probe-based signal amplification in surface plasmon resonance (SPR) biosensing of human cardiac troponin I
摘要： This work reports immunomagnetic separation technology-assisted surface plasmon resonance (SPR) biosensing for human cardiac troponin-I (cTnI), a well-known diagnostic marker for myocardial damage. Au film modified by Au nanoparticles (AuNPs) and polydopamine (PDA) was employed as the platforms for immobilizing capture antibody (cAb) and SPR sensing. Magnetic immune probe was prepared by attaching detection antibody (dAb) on the surface of Fe3O4 nanoparticles (Fe3O4 NPs) coated by PDA for precise capture, magnetic separation and enrichment of target analyte (cTnI) from samples. This extraction process greatly improves the sensitivity and effectively reduces the nonspecific interference from complex matrixes. The analyte cTnI collected via Fe3O4@PDA-dAb immune probe can be specially recognized by cAb immobilized on the sensing platform. By introducing secondary antibody (Ab2) conjugated with multi-walled carbon nanotube-PDA-AgNPs (MWCNTs-PDA-AgNPs/Ab2) to the sensing system, the residual binding sites of cTnI were occupied, and the SPR response signals were further amplified. The obtained detection limit for cTnI is 3.75 ng mL-1, which is 320-folds lower than that achieved by PDA-based sensing strategy. The present method was applied to the examination of serum samples spiked with cTnI, and the good recoveries demonstrate its future applicability in clinical diagnosis.
关键词： Polydopamine,Human cardiac troponin-I (cTnI),Immune probe,Surface plasmon resonance (SPR),Magnetic separation
更新于2025-09-19 17:15:36
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Sensitive and Quantitative Determination of Cardiac Troponin I Based on Silica-Encapsulated CdSe/ZnS Quantum Dots and a Fluorescence Lateral Flow Immunoassay
摘要： Cardiac troponin I is generally used as a biomarker of myocardial infarction or acute myocardial infarction. A timely and rapid diagnosis method for cardiac troponin I is of great importance. In this paper, a novel CdSe/ZnS quantum dot (QD) based fluorescence lateral flow immunoassay (QD-LFIA) is reported for the rapid and quantitative detection of cardiac troponin I in human serum. The water-soluble silica-encapsulated QDs (QDs@SiO2) serve as a new fluorescent probe and an economical, portable, quantitative instrument was used for the first time to detect cardiac troponin I antigen. By using the optimized immunoassay procedure with clinical samples, cardiac troponin I was determined in 10 min with high sensitivity (as low as 5.6 × 10?3 ng/mL), broad linear range (0.8–200 ng/mL), and good precision (the coefficient of variation was less than 10%). The comparison of this new QD-LFIA and a standard direct chemiluminescence assay demonstrated that the former platform was rapid, low-cost, and sensitive. It may be further applied to the quantitative determination and monitoring of cardiac troponin I levels in clinical use.
关键词： Cardiac troponin I,quantum dots,QD-based lateral flow immunoassays
更新于2025-09-16 10:30:52
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SERS-based lateral flow immunoassay of troponin I by using gap-enhanced Raman tags
摘要： The lateral flow immunoassay (LFIA) has emerged as a powerful tool for rapid screening owing to its simplicity and flexibility for detection of various biomarkers. However, conventional LFIA strips have several disadvantages, including limits in quantitative analysis and low sensitivity. Here we developed a novel surface-enhanced Raman scattering LFIA based on nonspherical gap-enhanced Raman tags (GERTs), with Raman molecules (RMs) embedded in a 1-nm gap between Au nanorod core and Au shell. Such tags have a strong and uniform SERS response, an order of magnitude higher than that of other common SERS tags such as Au nanorods, nanostars, Au nanoshells with surface-adsorbed RMs, or spherical GERTs with embedded RMs. The feasibility of the tags was demonstrated by the semiquantitative and sensitive detection of the heart disease biomarker cardiac troponin I (cTnI). GERTs were conjugated with monoclonal antibodies and used for LFIA in the same way as ordinary functionalized colloidal gold. The presence of the target antigen, cTnI, was identified by Raman microscopy mapping of the test zone. With the SERS-based LFIA, the limit of cTnI detection was about 0.1 ng/mL. This value is within the diagnostic range of cTnI in the blood serum of patients with heart infarction and is 30 times lower than that of the colorimetric LFIA test using the same antibodies and either GERTs or colloidal gold as labels.
关键词： gap-enhanced Raman tags,lateral flow immunoassay,SERS,cardiac Troponin I,Au core/shell nanorods
更新于2025-09-10 09:29:36
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Dual?Wavelength Ratiometric Electrochemiluminescence Immunosensor for Cardiac Troponin I Detection
摘要： Ratiometric electrochemiluminescence (ECL) has attracted special focus in biological analysis field because it could eliminate the environmental interference to gain precise measurement. Herein, a dual?wavelength ratiometric ECL biosensor was designed for detection of cardiac troponin I (cTnI), where (4,4’?dicarboxylicacid?2,2’?bipyridyl) ruthenium(II) (Ru(dcbpy)3 2+) and Au nanoparticles loaded graphene oxide/polyethyleneimine (GPRu?Au) nanomaterial acts as an acceptor, and Au nanoparticles modified graphitic phase carbon nitride nanosheets composite (Au?CNN) acts as donor. Au?CNN shows high and steady ECL signal centered at 455 nm, which is well matched with the adsorption of GPRu?Au, thereby a high efficient electrochemiluminescent resonance energy transfer (ECL?RET) sensing platform is designed. AuNPs facilitate the immobilization of antibody on the nanomaterials through Au?N bond. The high surface area of graphene oxide/polyethyleneimine allows a large number of Ru(dcbpy)3 2+ to be loaded, which immensely amplify the ECL signal. This sensing platform exhibits outstanding analytical performance toward cTnI with a detection limit of 3.94 fg/mL (S/N=3). The high reliability, selectivity and sensitivity of this ratiometric ECL biosensor provides a versatile sensing platform for the bioanalysis.
关键词： carbon nitride nanosheets,ECL biosensor,graphene oxide,Ratiometric electrochemiluminescence,cardiac troponin I,Au nanoparticles
更新于2025-09-04 15:30:14