Deformable Smart DNA Nanomachine for Synergistic Intracellular Cancer-Related miRNAs Imaging and Chemo-Gene Therapy of Drug-Resistant Tumors.

Diagnosis and treatment of tumor especially drug-resistant tumor remains a huge challenge, which requires intelligent nanomedicines with low toxic side effects and high efficacy. Herein, deformable smart DNA nanomachines are developed for synergistic intracellular cancer-related miRNAs imaging and chemo-gene therapy of drug-resistant tumors. The tetrahedral DNA framework (MA-TDNA) with fluorescence quenched component and five antennas is self-assembled first, and then DOX molecules are loaded on the MA-TDNAs followed by linking MUC1-aptamer and Mcl-1 siRNA to the antennas of MA-TDNA, so that the apt-MA-TDNA@DOX-siRNA (DNA nanomachines) is constructed. The DNA nanomachine can respond to two tumor-related miRNAs in vitro and in vivo, which can undergo intelligent miRNA-triggered opening of the framework, resulting in the "turn on" of the fluorescence for sensitively and specifically sensing intracellular miRNAs. Meanwhile, both miRNA-responded rapid release and pH-responded release of DOX are achieved for chemotherapy of tumor. In addition, the gene therapy of the DNA nanomachines is achieved due to the miRNA-specific capture and the RNase H triggered release of Mcl-1 siRNA. The DNA nanomachines intergrading both tumor imaging and chemo-gene therapy in single nanostructures realized efficient tumor-targeted, image-guided, and microenvironment-responsive tumor diagnosis and treatment, which provides a synergetic antitumor effect on drug-resistant tumor.

Pd Nanoparticle-Modified BiOBr/CdS S-Scheme Photocatalyst for Enhanced Conversion of CO2.

S-scheme heterojunction photocatalyst-coupled plasma-resonance effect can enhance the response range and absorption of light and charge transfer, and, at the same time, obtain strong redox ability, which is an effective way to improve CO2 conversion. In this work, plasma S-scheme heterojunctions of Pd/BiOBr/CdS with heterogeneous interfaces have been successfully constructed by a simple hydrothermal method. The possible reaction mechanism was proposed by in situ infrared, ultraviolet-visible spectroscopy (UV-vis), electron paramagnetic resonance (ESR), density functional theory (DFT), and electrochemical techniques. It was proved that the plasma S-scheme heterojunction can enhance the charge separation efficiency and improve the photocatalytic activity. When the loading ratio is Pd0.6-10%-BiOBr/CdS, it has the best performance, and the CO yield is 30.24 µmol/g, which is 15 and 30 times that of pure BiOBr and CdS, respectively. The results show that with the strong absorption of photon energy and the special electron transfer mode of S-scheme heterojunction, the charge can be effectively separated and transferred, and the photocatalytic activity is significantly improved. This study provides a useful strategy for charge transfer kinetics of plasma S-scheme heterojunction photocatalysts.

Reclassification of Sabulilitoribacter multivorans and Sabulilitoribacter arenilitoris as Flaviramulus multivorans comb. nov. and Wocania arenilitoris comb. nov., respectively, based on genome sequence analysis.

Rapid advancements in DNA sequencing technologies are providing new approaches for bacterial taxonomy. The genus Sabulilitoribacter is a member of the family Flavobacteriaceae, which consists of more than 150 genera. In this study, genome sequence analysis was conducted to revisit the taxonomic status of Sabulilitoribacter arenilitoris and Sabulilitoribacter multivorans, the only two species of this genus. Genome sequence based phylogeny analysis showed that the genus Sabulilitoribacter was non-monophyletic: S. multivorans, the type species of genus Sabulilitoribacter, was clustered with the type species of the genus Flaviramulus, whereas S. arenilitoris formed a robust cluster with the only two species of the genus Wocania. The values of average amino acid identity, genome-wide average nucleotide identity, alignment fractions and some phenotypic features showed that S. multivorans was more closely related with the type species of the genus Flaviramulus than with S. arenilitoris, and S. arenilitoris was more closely related with the only two species of the genus Wocania than with S. multivorans. Based on these results, we consequently propose that S. multivorans and S. arenilitoris should be reclassified as Flaviramulus multivorans comb. nov. and Wocania arenilitoris comb. nov. respectively.

Rapid and accurate SERS assay of disease-related nucleic acids based on isothermal cascade signal amplifications of CRISPR/Cas13a system and catalytic hairpin assembly.

Developing rapid, accurate and convenient nucleic acid diagnostic techniques is essential for the prevention and control of contagious diseases that are prone to gene mutations and may have homologous sequences, especially emerging infectious diseases such as the SARS-CoV-2 pandemic. Herein, a one-pot SERS assay integrating isothermal cascade signal amplification strategy (i.e., CRISPR/Cas13a system (Cas13a) and catalytic hairpin assembly (CHA), Cas13a-CHA) and SERS-active silver nanorods (AgNRs) sensing chips was proposed for rapid and accurate detection of disease-related nucleic acids. Taking SARS-CoV-2 RNA assay as a model, the Cas13a-CHA based SERS sensing strategy can achieve ultra-high sensitivity low to 5.18 × 102 copies·mL-1 within 60 min, and excellent specificity, i.e., not only the ability to identify SARS-CoV-2 RNA from gene mutations, but also incompatibility with coronaviruses such as severe acute respiratory syndrome (SARS-CoV), Middle East respiratory syndrome (MERS-CoV), and other respiratory viruses. The proposed Cas13a-CHA based SERS assay for SARS-CoV-2 RNA has satisfactory sensitivity, specificity, uniformity, and repeatability, and can be easily expanded and universalized for screening different viruses, which is expected to promise as a crucial role for diagnosis of disease-related nucleic acids in various medical application scenarios.

Branched hybridization chain reaction and tetrahedral DNA-based trivalent aptamer powered SERS sensor for ultra-highly sensitive detection of cancer-derived exosomes.

Exosomes have emerged as a promising noninvasive biomarker for early cancer diagnosis due to their ability to carry specific bioinformation related to cancer cells. However, accurate detection of trace amount of cancer-derived exosomes in complex blood remains a significant challenge. Herein, an ultra-highly sensitive SERS sensor, powered by the branched hybridization chain reaction (bHCR) and tetrahedral DNA-based trivalent aptamer (triApt-TDN), has been proposed for precise detection of cancer-derived exosomes. Taking gastric cancer SGC-7901 cells-derived exosomes as a test model, the triApt-TDNs were constructed by conjugating aptamers specific to mucin 1 (MUC1) protein with tetrahedral DNAs and subsequently immobilized on the surface of silver nanorods (AgNRs) arrays to create SERS-active sensing chips capable of specifically capturing exosomes overexpressing MUC1 proteins. The bHCR was further initiated by the trigger aptamers (tgApts) bound to exosomes, and as a result the SERS tags were assembled into AuNP network structures with abundant SERS hotspots. By optimizing the sensing conditions, the SERS sensor showed good performance in ultra-highly sensitive detection of target exosomes within 60 min detection time, with a broad response ranging of 1.44 to 1.44 × 104 particles·µL-1 and an ultralow limit of detection capable of detecting a single exosome in 2 µL sample. Furthermore, the SERS sensor exhibited good uniformity, repeatability and specificity, and capability to distinguish between gastric cancer (GC) patients and healthy controls (HC) through the detection of exosomes in clinical human serums, indicating its promising clinical potential for early diagnosis of gastric cancer.