Rapid and Sensitive Detection of Cardiac Troponin I for Point-of-Care Tests Based on Red Fluorescent Microspheres

Abstract

A reliable lateral flow immunoassay (LFIA) based on a facile one-step synthesis of single microspheres in combining with immunochromatography technique was developed to establish a new point-of-care test (POCT) for the rapid and early detection of cardiac troponin I (cTnI), a kind of cardiac specific biomarker for acute myocardial infarction (AMI). The double layered microspheres with clear core-shell structures were produced using soap-free emulsion polymerization method with inexpensive compounds (styrene and acrylic acid). The synthetic process was simple, rapid and easy to control due to one-step synthesis without any complicated procedures. The microspheres are nanostructure with high surface area, which have numerous carboxyl groups on the out layer, resulting in high-efficiency coupling between the carrier and antibody via amide bond. Meanwhile, the red fluorescent dye, Nile-red (NR), was wrapped inside the microspheres to improve its stability, as well to reduce the background noise, because of its higher emission wavelength than interference from real plasma samples. The core-shell structures provided different functional areas to separate antibody and dyes, so the immunoassay has highly sensitive, wide working curves in the range of 0–40 ng/mL, low limits of detection (LOD) at 0.016 ng/mL, and limits of quantification (LOQ) at 0.087 ng/mL with coefficient of variations (CV) of 10%. This strategy suggested an outstanding platform for LFIA, with good reproducibility and stability to straightforwardly analyze the plasma samples without washing steps, thereby reducing the operating procedures for non-professionals and promoting detection efficiency. The whole detection process can be completed in less than 15 min. This novel immunoassay offers a reliable and favorable analytical result by detecting the real samples, indicating that it holds great potential as a new alternative for biomolecule detection in complex samples, for the early detection of cardiac specific biomarkers.

Ru(bpy)32+‐Loaded Mesoporous Silica Nanoparticles as Electrochemiluminescent Probes of a Lateral Flow Immunosensor for Highly Sensitive and Quantitative Detection of Troponin I

“…This discrepancy suggests that the detection sensitivity was affected by some interferences, including nonspecific binding reactions caused by the large size of the silica nanoparticle and the two‐step assay sequence. Moreover, compared to other methods for TnI detection using the LFI format, [ 15,53–57 ] ECL‐LFI showed a high degree of sensitivity with a wide dynamic detection range ( Table 1 ), overcoming the limitations of current methods and showing potential efficacy for highly sensitive POCT for biomarker detection. Additionally, we confirmed the good quantitative discrimination of our ECL‐LFI compared to slopes of regression equation under low concentrations of TnI (<1 ng mL −1 ).…”

Point-of-Care Compatibility of Ultra-Sensitive Detection Techniques for the Cardiac Biomarker Troponin I—Challenges and Potential Value

“…There are numerous advantages of using lateral flow assays as they can be fabricated at a low cost, can easily be mass produced, provide a simple and versatile solution, typically do not require pre-treatment and often offer short response times [172,173]. One group have developed core–shell-structured NPs loaded with Nile-red fluorescent dye which are utilised in a cTnI lateral flow assay [174]. The Nile-red fluorescent dye had been specifically selected to reduce the interferential autofluorescence background signal generated by biomolecules in plasma.…”

“…Figure 3 and Figure 4: [37,38,48,49,50,57,58,61,65,66,68,69,70,71,74,84,85,86,87,88,89,93,94,95,96,97,104,105,111,112,115,116,117,120,121,122,123,125,126,127,128,130,132,133,134,136,138,144,145,148,150,151,159,161,174,175,176,184,185,186,187,188,189,190,…”

A Low-Cost, Disposable and Portable Inkjet-Printed Biochip for the Developing World

“…Hua et al developed a DMF platform for automated, multiplexed, real-time polymerase chain reaction (PCR) assays [14]. Sista et al developed a DMF platform for point-of-care detection of cardiac troponin 1, a common cardiac biomarker released during myocardial necrosis [15,16]. solution reduces contact angle hysteresis allowing the droplet movement from one electrode to another.…”