Dual Immunomagnetic Nanobeads-Based Lateral Flow Test Strip for Simultaneous Quantitative Detection of Carcinoembryonic Antigen and Neuron Specific Enolase

Abstract

A novel immunomagnetic nanobeads -based lateral flow test strip was developed for the simultaneous quantitative detection of neuron specific enolase (NSE) and carcinoembryonic antigen (CEA), which are sensitive and specific in the clinical diagnosis of small cell lung cancer. Using this nanoscale method, high saturation magnetization, carboxyl-modified magnetic nanobeads were successfully synthesized. To obtain the immunomagnetic probes, a covalent bioconjugation of the magnetic nanobeads with the antibody of NSE and CEA was carried out. The detection area contained test line 1 and test line 2 which captured the immune complexes sensitively and formed sandwich complexes. In this assay, cross-reactivity results were negative and both NSE and CEA were detected simultaneously with no obvious influence on each other. The magnetic signal intensity of the nitrocellulose membrane was measured by a magnetic assay reader. For quantitative analysis, the calculated limit of detection was 0.094 ng/mL for NSE and 0.045 ng/mL for CEA. One hundred thirty clinical samples were used to validate the test strip which exhibited high sensitivity and specificity. This dual lateral flow test strip not only provided an easy, rapid, simultaneous quantitative detection strategy for NSE and CEA, but may also be valuable in automated and portable diagnostic applications.

High performance immunochromatographic assay for simultaneous quantitative detection of multiplex cardiac markers based on magnetic nanobeads

“…Most ICTs use colloidal gold or fluorescent dyes as probes—they only detect optical signal from the top 10 μm of the NC membrane. Using MNB as probes for ICT can collect the entire magnetic signal from the 100 μm-thick strips to improve sensitivity 10- to 1000-fold 19. In our previous studies and other relevant reports 20, there are some adverse factors that restrict the application of MNBs, including self-aggregation after antibody coupling, high background noise due to nonspecific reaction, and the need for special magnetic signal detection tools.…”

Developing Gold Nanoparticles-Conjugated Aflatoxin B1 Antifungal Strips

“…The visual detection limit of the LFIAs is 10 ng/g. Additionally, we employed a portable smartphone strip reader with multiple image processing to analyse strips in 3 s [19,21]. The LOD is 0.3 ng/g.…”

“…A fluorescence detection apparatus that was coupled to a desktop computer or laptop, enabling rapid processing speeds and stable performances, recorded the fluorescence intensity of the dot. However, these bulky and heavy devices limit their widespread application in the field of family and personal care [19][20][21]. Alternatively, a mobile device-based strip reader could satisfy the requirement of high portability and feature-rich testing.…”

Multiplex Lateral Flow Immunoassay: An Overview of Strategies Towards High-Throughput Point-of-Need Testing

“…Multiplex LFIA realized through the spatial separation of lines in one strip has been combined also with the exploitation of innovative labels, such as up-converting phosphor reporter particles [36][37], magnetic nanobeads [38][39], enzymes triggering chemiluminescence [40] and near-infrared fluorescence label [41]. In the last paper, the detection of three classes of antimicrobial agents in a single run was achieved by combining the use of three broad-specific antibodies and the spatial separation of three lines in one strip.…”

“…The immuno-magnetic probes were included in a dual LFD also comprising a single strip with two spatially separated Test lines. The LFD permitted the simultaneous detection of the two biomarkers with high diagnostic sensitivity and specificity [38]. An original quantification of MNP by non-linear magnetization proposed by Nikitin at al.…”