Xiaoqing Zhang,Ye Feng,Shaoyun Duan,Lingling Su,Jialin Zhang,Fengjiao He
The accurate and rapid detection of Mycobacterium tuberculosis (M. tuberculosis) is essential for the effective treatment of tuberculosis. In this article, we propose an electrochemical sensor to detect M. tuberculosis reference strain H37Rv. The sensor contains an H37Rv aptamer and oligonucleotides modified with gold nanoparticles (AuNPs–DNA). An H37Rv aptamer screened by our laboratory was used as the recognition probe. The change in frequency shift mediated by AuNPs–DNA in the presence of H37Rv was detected using a multichannel series piezoelectric quartz crystal (MSPQC) system. Three oligonucleotides modified with gold nanoparticles were designed. These oligonucleotides contained 12, 12, and 13 bases that hybridized with the 37-nt H37Rv aptamer. H37Rv aptamer was immobilized on the gold electrode surface by Au–S bonds. A conductive-layer was then formed by sequential hybridization of the aptamer with the three designed AuNPs–DNAs. When H37Rv was present, it specifically bound to the aptamer, resulting in the detachment of AuNPs–DNA from the electrode. The conductive layer was thereby replaced by a nonconductive complex of aptamer and bacteria. These changes were monitored by the MSPQC system. The proposed sensor is rapid, specific and sensitive, the detection time was 2 h. The detection limit was 100 cfu/mL. This sensor would be of great benefit for the early clinical diagnosis of tuberculosis.
The accurate and rapid detection of Mycobacterium tuberculosis ( M . tuberculosis ) is essential for the effective treatment of tuberculosis. In this work, perovskite/silica nanocomposites CsPbBr 3 @MSNs-PbBrOH (DP-CPB) were synthesized via a dual in situ-coating strategy, encapsulating CsPbBr 3 nanocrystals with mesoporous silica and PbBrOH. The resulting nanocomposites exhibited excellent stability in physiological media. The nanocomposites’ surface was conjugated with the MS10-Trunc aptamer specific for Mtb malate synthase ( MtbMS ). Leveraging the aptamer’s high affinity, we developed two fluorescent aptasensors: one based on a 96-well plate for MtbMS detection, and another employing magnetic nanoparticles for the detection of Mtb bacterial strains ( Mtb H37Rv). The sensors demonstrate dynamic ranges of 50-750 nM for MtbMS and 10 2 -10⁷ CFU/mL for Mtb H37Rv, with low limits of detection (LOD) of 1.17 nM and 3 CFU/mL, respectively. The aptasensors possess the comprehensive advantages of the highly efficient photoluminescence of DP-CPB, high specificity, and fast detection of MtbMS and H37Rv. The aptasensor was successfully applied for the determination of Mtb H37Rv, revealing the vast potential of perovskites in biosensing.
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