Development of a time-resolved fluorescence immunoassay for Epstein-Barr virus nuclear antigen 1-immunoglobulin A in human serum

Fluorescent detection of emerging virus based on nanoparticles: From synthesis to application

The spread of COVID-19 has caused huge economic losses and irreversible social impact. Therefore, to successfully prevent the spread of the virus and solve public health problems, it is urgent to develop detection methods with high sensitivity and accuracy. However, existing detection methods are time-consuming, rely on instruments, and require skilled operators, making rapid detection challenging to implement. Biosensors based on fluorescent nanoparticles have attracted interest in the field of detection because of their advantages, such as high sensitivity, low detection limit, and simple result readout. In this review, we systematically describe the synthesis, intrinsic advantages, and applications of organic dye-doped fluorescent nanoparticles, metal nanoclusters, up-conversion particles, quantum dots, carbon dots, and others for virus detection. Furthermore, future research initiatives are highlighted, including green production of fluorescent nanoparticles with high quantum yield, speedy signal reading by integrating with intelligent information, and error reduction by coupling with numerous fluorescent nanoparticles.

A New Method for Detection African Swine Fever Virus: Time-resolved Fluorescence Immunoassay

African swine fever (ASF) has severely influenced the swine industry of the whole world. Fast and accurate African swine fever virus (ASFV) antigen detection is very important for ASF prevention. This study aims to establish a new detection method for detection ASFV antigen using time-resolved fluorescence immunoassay (TRFIA) in the nose and mouth discharge. A double antibody sandwich TRFIA method was optimized and established. Recombinant P30 recombinant antigen was captured by its antibodies immobilized on 96-well plate, and then banded together with another detection antibodies labeled with Europium(III) (Eu³⁺) chelates, finally time-resolved analyzer measured the fluorescence intensity. The performance of this TRFIA (sensitivity, specificity and accuracy) was evaluated using the clinical samples and compared with the nucleic acid testing method. The sensitivity of this TRFIA was 0.015 ng/mL (dynamic range 0.24-500 ng/mL) with high specificity. The recovery ranged from 92.00 to 103.62 %, the inter-assay CVs ranged from 5.50 to 11.96 %, and the intra-assay CVs was between 5.20 and 10.53 %. Additionally, the cutoff value was 0.016. TRFIA took only 45 min to generate results, and its detection capability comparable to the nucleic acid detection. This study developed a TRFIA method that could be used for qualitative/quantitative detection of ASFV antigen in pigs nasal discharge, which has high sensitivity, specificity and accuracy. This TRFIA provides a new method for rapidly screening ASFV infection in pigs industry.

Soluble Tim3 detection by time-resolved fluorescence immunoassay and its application in membranous nephropathy

Background

We aimed to develop a time‐resolved fluorescence immunoassay (TRFIA) for detecting soluble T‐cell immunoglobulin and mucin domain 3 (sTim3) in serum samples and to demonstrate a preliminary application of this method in membranous nephropathy (MN).

Methods

sTim3 TRFIA was developed, and the sTim3 concentration in the serum of patients with MN and healthy individuals was detected using a sandwich method.

Results

The sensitivity of the developed sTim3 TRFIA was 0.66 ng/mL, higher than that of an enzyme‐linked immunosorbent assay (ELISA) (1.11 ng/mL). The detection range was 0.66‐40 ng/mL. The intra‐assay coefficient of variation (CV) for sTim3 was 1.64%‐4.68%, and the inter‐assay CV was 5.72%‐9.32%. The cross‐reactivity to interleukin 6 (IL‐6) and kidney injury molecule 1 (KIM‐1) was 0.25% and 0.04%, respectively. The average recovery was 105.26%. The sTim3 concentration in patients with MN was considerably higher than that in healthy individuals (P < .001). The sTim3 concentration in the serum of patients with MN was significantly increased from G1 to G4 based on the Jonckheere‐Terpstra test (P < .001). Thus, we used sTim3 as a diagnostic indicator for distinguishing between healthy individuals and patients with MN as well as between different stages of MN.

Conclusion

We successfully established TRFIA to detect sTim3 in serum. We then applied this method to patients with MN, demonstrating for the first time that TRFIA is a valid diagnostic tool to detect sTim3 in serum.