Rapid, ultrasensitive, and highly specific identification of Brucella abortus utilizing multiple cross displacement amplification combined with a gold nanoparticles-based lateral flow biosensor

Loop-mediated isothermal amplification linked a nanoparticles-based biosensor for detecting Epstein-Barr virus

Epstein-Barr virus (EBV) is a ubiquitous gamma herpesvirus that maintains a lifelong latent association with B lymphocytes. Here, a rapid and reliable diagnosis platform for detecting EBV infection, employing loop-mediated isothermal amplification (LAMP) combined with a gold nanoparticles-based lateral flow biosensors (AuNPs-LFB) (termed LAMP Amplification Mediated AuNPs-LFB Detection, LAMAD), was developed in the current study. A set of specific LAMP primers targeting the Epstein-Barr nuclear antigen (EBNA) leader protein (EBNA-LP) gene was designed and synthesized. Subsequently, these templates extracted from various pathogens and whole blood samples were used to optimize and evaluate the EBV-LAMAD assay. As a result, the limit of detection (LoD) of the EBV-LAMAD assay was 45 copies/reaction. The EBV-LAMAD assay can detect all representative EBV pathogens used in the study, and of note, no cross-reactions were observed with other non-EBV organisms. Moreover, the whole workflow of the EBV-LAMAD assay can be completed within 70 min, including rapid EBV template preparation, EBV-LAMP amplification, and AuNPs-LFB-mediated detection. Taken together, the EBV-LAMAD assay targeting the EBNA-LP gene is a rapid, simplified, sensitive, reliable, and easy-to-use detection protocol that can be used as a competitive potential diagnostic/screening tool for EBV infection in clinical settings, especially in basic laboratories in resource-limited regions. KEY POINTS: • A novel, simplified, and easy-to-use AuNPs-LFB biosensor was designed and prepared. • LAMP combined with an AuNPs-LFB targeting the novel EBNA-LP gene was established. • EBV-LAMAD is a rapid, sensitive, and reliable detection protocol for EBV infection.

Ultra-rapid and sensitive detection of African swine fever virus using multiple cross displacement amplification combined with nanoparticle-based lateral flow biosensor

African swine fever (ASF) is a devastating disease that can kill almost all infected pigs, causing great damage to the pig industry and destabilizing the global economy. Here, we developed a specific assay that combined multiple cross-displacement amplification (MCDA) with a nanoparticle-based lateral flow biosensor (LFB) for early and rapid identification of the African swine fever virus (ASFV-MCDA-LFB). We first designed a set of MCDA primers to recognize 10 different regions of the target ASFV B646L gene. Subsequently, the MCDA reaction was monitored with various methods: MG chromogenic reagents, agarose gel electrophoresis, real-time turbidity, and LFB. The ASFV-MCDA-LFB assay was optimized and evaluated with target nucleic acid templates extracted from various pathogens and simulated whole blood samples. As a result, the detection of limit (LOD) of the ASFV assay was 200 copies/reaction within 30 min, and no cross-reaction were observed with other non-ASFV viruses and common pathogens in this study. The evaluation assays demonstrated that the ASFV-MCDA-LFB method here is rapid, objective, easy-to-use, and low-cost detection method which can be used as a diagnostic or screening tool with competitive potential for point-of-care testing (POCT) of ASFV.

Enhanced diagnostic accuracy of combined serological and bacteriological tests for brucella infection

OBJECTIVE

To analyze the effects and value of combining serological and bacteriological tests in diagnosing Brucella infection.

METHODS

In this retrospective study, patients suspected of having Brucella infection admitted to Lishui Second People's Hospital from January 2019 to December 2022 were assessed using serological, bacteriological, and combined (serological + bacteriological) tests. The diagnostic performance of each test was compared using previous clinical results as the gold standard. We also compared the acceptance rate and satisfaction with clinical diagnostic results for the different testing modalities.

RESULTS

The combined examination (serological + bacteriological test) showed higher diagnostic efficiency for Brucella infection compared to single serological and single bacteriological tests (P < 0.05). Similarly, the satisfaction rate for the clinical diagnostic effects of the combined examination was higher than for the serological and bacteriological tests alone (P < 0.05).

CONCLUSION

The combination of serological and bacteriological tests provides superior diagnostic value for Brucella infection, with high diagnostic accuracy, sensitivity, and specificity. It is recommended as the preferred method for clinical diagnosis.

A modified multiple cross displacement amplification linked with a gold nanoparticle biosensor for the detection of Epstein-Barr virus in clinical applications

Epstein-Barr virus (EBV), a double-stranded DNA virus belonging to the family Herpesviridae, infects more than 95% of healthy adults by attacking the host immune system. Here, a novel detection protocol, utilizing the modified multiple cross displacement amplification (MCDA) technique combined with a gold nanoparticles-based lateral flow biosensors (AuNPs-LFB), was devised and developed to detect EBV infection (termed EBV-MCDA-LFB assay). Ten MCDA primers targeting the EBNA-LP gene were designed, including CP1* primers modified with 6-carboxyfluorescein (FAM) and D1* primers modified with biotin. Then, nucleic acid templates extracted from various pathogens and whole blood samples were used to optimize and evaluate the EBV-MCDA-LFB assay. As a result, the lowest concentration of EBNA-plasmids, which can be detected by MCDA-LFB assay with an optimal reaction condition of 67°C for 30 min, was 10 copies/reaction. Here, the MCDA-LFB assay can detect all EBV pathogens used in the study, and no cross-reactions with non-EBV organisms were observed. Meanwhile, the entire detection workflow of the EBV-MCDA-LFB assay for whole blood samples, including DNA template preparation (25 min), EBV-MCDA amplification (30 min), and AuNPs-LFB-mediated validation (2-5 min), can be completed within 1 h. Taken together, the EBV-MCDA-LFB assay established in the current study is a rapid, simplified, sensitive, specific, and easy-to-obtain technique that can be used as a screening or diagnostic tool for EBV infection in clinical applications, especially in resource-poor regions.