Suppressed DNA base pair stacking assembly of gold nanoparticles in an alcoholic solvent for enhanced ochratoxin A detection in Baijiu

Naked-Eye LAMP Assay of M. tuberculosis in Sputum by In Situ Au Nanoprobe Identification: For the In Vitro Diagnostics of Tuberculosis

In spite of the development of diagnostic tests for Mycobacterium tuberculosis (M. tuberculosis), the etiological agent of tuberculosis, there has remained a gap between the established methods and an easily accessible diagnostic test, particularly in developing and resource-poor areas. By combining isothermal amplification of IS6110 as the target gene and recognition by DNA-functionalized Au nanoparticles (DNA-AuNPs), we develop a colorimetric LAMP assay for convenient in vitro diagnostics of tuberculosis with a quick (≤50 min) "yes" or "no" readout. The DNA-AuNPs not only tolerate the interference in the complex LAMP system but also afford in situ identification of the amplicon, allowing for colloidal dispersion via steric effect depending on DNA grafting density. The target-induced stabilization and red appearance of the DNA-AuNPs contrast with the occurrence of gray aggregates in a negative sample. Furthermore, the DNA-AuNPs demonstrate excellent performance after long-term (≥7 months) storage while preserving the unsacrificed sensitivity. The high specificity of the DNA-AuNPs is further demonstrated in the naked-eye LAMP assay of M. tuberculosis in patients' sputum samples. Given the rapidity, cost-effectiveness, and instrument-free characteristics, the naked-eye LAMP assay is particularly beneficial for tuberculosis diagnosis in urgent situations and resource-limited settings and can potentially expedite patient care and treatment initiation.

Nanotechnology-based optical sensors for Baijiu quality and safety control

Baijiu quality and safety have received considerable attention owing to the gradual increase in its consumption. However, owing to the unique and complex process of Baijiu production, issues leading to quality and safety concerns may occur during the manufacturing process. Therefore, establishing appropriate analytical methods is necessary for Baijiu quality assurance and process control. Nanomaterial (NM)-based optical sensing techniques have garnered widespread interest because of their unique advantages. However, comprehensive studies on nano-optical sensing technology for quality and safety control of Baijiu are lacking. In this review, we systematically summarize NM-based optical sensor applications for the accurate detection and quantification of analytes closely related to Baijiu quality and safety. Furthermore, we evaluate the sensing mechanisms for each application. Finally, we discuss the challenges nanotechnology poses for Baijiu analysis and future trends. Overall, nanotechnological approaches provide a potentially useful alternative for simplifying Baijiu analysis and improving final product quality and safety.

MNAzyme catalyzed signal amplification-mediated lateral flow biosensor for portable and sensitive detection of mycotoxin in food samples

Here, an enzyme-free lateral flow aptasensor was designed by target-induced strand-displacement effect and followed by the activation of multi-component nucleic acid enzyme (MNAzyme)-mediated cleavage to enable rapid and portable ochratoxin A (OTA) detection. The substrate was prepared as an oligonucleotide strand modified with magnetic beads (MB) and human chorionic gonadotropin (hCG). The interaction of OTA with the aptamer induces the release of blocking DNA, which hybridized with three separated subunits of DNA, forming a sequence-specific MNAzyme catalytic core. This core subsequently initiated an enzyme-free MNAzyme cleavage reaction in the presence of the Mg2+ cofactor, cleaving a special substrate and releasing both the incomplete MNAzyme catalytic core and hCG-DNA probe. The incomplete MNAzyme catalytic core was then recognized by substrates once again, triggering a cascade recycling cleavage and resulting in the generation of a larger number of hCG-DNA probes. After magnetic enrichment, the free hCG-DNA probes flow through the pregnancy test strip (PTS) to the T line, generating a colorimetric readout that unequivocally confirms the presence of the target OTA. This work leverages the efficient enzyme-free cleavage amplification of MNAzyme and the PTS-based portable detection device, presenting a biosensing strategy with significant potential for sensitive and portable OTA detection. This method exhibited remarkable sensitivity and selectivity for OTA detection, boasting a detection limit of 5 nM. The present study successfully demonstrated the practical application of this method on real samples, offering a viable alternative for rapid and portable detection of mycotoxins.

Nanoscale Materials Applying for the Detection of Mycotoxins in Foods

Trace amounts of mycotoxins in food matrices have caused a very serious problem of food safety and have attracted widespread attention. Developing accurate, sensitive, rapid mycotoxin detection and control strategies adapted to the complex matrices of food is crucial for in safeguarding public health. With the continuous development of nanotechnology and materials science, various nanoscale materials have been developed for the purification of complex food matrices or for providing response signals to achieve the accurate and rapid detection of various mycotoxins in food products. This article reviews and summarizes recent research (from 2018 to 2023) on new strategies and methods for the accurate or rapid detection of mold toxins in food samples using nanoscale materials. It places particular emphasis on outlining the characteristics of various nanoscale or nanostructural materials and their roles in the process of detecting mycotoxins. The aim of this paper is to promote the in-depth research and application of various nanoscale or structured materials and to provide guidance and reference for the development of strategies for the detection and control of mycotoxin contamination in complex matrices of food.