Logic Signal Amplification System for Sensitive Electrochemiluminescence Detection and Subtype Identification of Cancer Cells.

Achieving sensitive detection and accurate identification of cancer cells is vital for diagnosing and treating the disease. Here, we developed a logic signal amplification system using DNA tetrahedron-mediated three-dimensional (3D) DNA nanonetworks for sensitive electrochemiluminescence (ECL) detection and subtype identification of cancer cells. Specially designed hairpins were integrated into DNA tetrahedral nanostructures (DTNs) to perform a catalytic hairpin assembly (CHA) reaction in the presence of target microRNA, forming hyperbranched 3D nanonetworks. Benefiting from the "spatial confinement effect," the DNA tetrahedron-mediated catalytic hairpin assembly (DTCHA) reaction displayed significantly faster kinetics and greater cycle conversion efficiency than traditional CHA. The resulting 3D nanonetworks could load a large amount of Ru(phen)32+, significantly enhancing its ECL signal, and exhibit detection limits for both miR-21 and miR-141 at the femtomolar level. The biosensor based on modular logic gates facilitated the distinction and quantification of cancer cells and normal cells based on miR-21 levels, combined with miR-141 levels, to further identify different subtypes of breast cancer cells. Overall, this study provides potential applications in miRNA-related clinical diagnostics.

Endogenous AND Logic DNA Nanomachine for Highly Specific Cancer Cell Imaging.

Intracellular cancer-related biomarker imaging strategy has been used for specific identification of cancer cells, which was of great importance to accurate cancer clinical diagnosis and prognosis studies. Localized DNA circuits with improved sensitivity showed great potential for intracellular biomarkers imaging. However, the ability of localized DNA circuits to specifically image cancer cells is limited by off-site signal leakage associated with a single-biomarker sensing strategy. Herein, we integrated the endogenous enzyme-powered strategy with logic-responsive and localized signal amplifying capability to construct a self-assembled endogenously AND logic DNA nanomachine (EDN) for highly specific cancer cell imaging. When the EDN encountered a cancer cell, the overexpressed DNA repairing enzyme apurinic/apyrimidinic endonuclease 1 (APE1) and miR-21 could synergistically activate a DNA circuit via cascaded localized toehold-mediated strand displacement (TMSD) reactions, resulting in amplified fluorescence resonance energy transfer (FRET) signal. In this strategy, both endogenous APE1 and miR-21, served as two "keys" to activate the AND logic operation in cancer cells to reduce off-tumor signal leakage. Such a multiplied molecular recognition/activation nanomachine as a powerful toolbox realized specific capture and reliable imaging of biomolecules in living cancer cells.

Simulation-Assisted DNA Nanodevice Serve as a General Optical Platform for Multiplexed Analysis of Micrornas.

Small frame nucleic acids (FNAs) serve as excellent carrier materials for various functional nucleic acid molecules, showcasing extensive potential applications in biomedicine development. The carrier module and function module combination is crucial for probe design, where an improper combination can significantly impede the functionality of sensing platforms. This study explores the effect of various combinations on the sensing performance of nanodevices through simulations and experimental approaches. Variances in response velocities, sensitivities, and cell uptake efficiencies across different structures are observed. Factors such as the number of functional molecules loaded, loading positions, and intermodular distances affect the rigidity and stability of the nanostructure. The findings reveal that the structures with full loads and moderate distances between modules have the lowest potential energy. Based on these insights, a multisignal detection platform that offers optimal sensitivity and response speed is developed. This research offers valuable insights for designing FNAs-based probes and presents a streamlined method for the conceptualization and optimization of DNA nanodevices.

DNAzyme-Mediated Cascade Nanoreactor for Cuproptosis-Promoted Pancreatic Cancer Synergistic Therapy.

Cuproptosis, a kind of newly recognized cell death modality, shows enormous prospect in cancer treatment. The inducer of cuproptosis has more advantages in tumor therapy, especially that can trigger cuproptosis and chemodynamic therapy (CDT) simultaneously. However, cuproptosis is restricted to the deficiency of intracellular copper ions and the nonspecific delivery of copper-based ionophores. Therefore, high level delivery, responsive release, and utilizing synergistic-function of inducer become the key on cuproptosis-based oncotherapy. In this work, a cascade nanosystem is constructed for enhanced cuproptosis and CDT. In the weak acidic environment of tumor cells, DNA, zinc ions, and Cu+ can release from the nanosystem. Since Cu+ having superior performance in mediating both Fenton-like reaction and cuproptosis, the released Cu+ induces cuproptosis and CDT efficiently, accompanied by Cu2+ generation. Then Cu2+ can be converted into Cu+ partially by glutathione (GSH) to from a Cu+ supply loop and ensure the synergistic action. Meanwhile, the consumption of GSH also contributes to cuproptosis and CDT in return. Finally, DNA and Zn2+ form DNAzyme to shear catalase-related RNA, resulting in the accumulation of hydrogen peroxide and further enhancing combination therapy. These results provide a promising nanotherapeutic platform and may inspire the design for potential cancer treatment based on cuproptosis.

An intelligent DNA nanomachine for amplified MicroRNA imaging and MicroRNA-Guided efficient gene silencing.

The DNA nanomachines as excellent synthetic biological tools have been widely used for the sensitive detection of intracellular microRNA (miRNA) and DNAzyme-involved gene silencing. However, intelligent DNA nanomachines which have the ability to sense intracellular specific biomolecules and respond to external information in complex environments still remain challenging. Herein, we develop a miRNA-responsive DNAzyme cascaded catalytic (MDCC) nanomachine to perform multilayer cascade reactions, enabling the amplified intracellular miRNA imaging and miRNA-guided efficient gene silencing. The intelligent MDCC nanomachine is designed based on multiple DNAzyme subunit-encoded catalyzed hairpin assembly (CHA) reactants sustained by the pH-responsive Zeolitic imidazolate framework-8 (ZIF-8) nanoparticles. After cellular uptake, the MDCC nanomachine degrades in acidic endosome and releases three hairpin DNA reactants and Zn2+, and the latter can act as an effective cofactor for DNAzyme. In the presence of miRNA-21, a catalytic hairpin assembly (CHA) reaction is triggered, which produces a large number of Y-shaped fluorescent DNA constructs containing three DNAzyme modules for gene silencing. The construction of Y-shaped DNA modified with multisite fluorescence and the circular reaction realizes ultrasensitive miRNA-21 imaging of cancer cells. Moreover, miRNA-guided gene silencing inhibits the cancer cell proliferation through the DNAzyme-specific recognition and cleavage of target EGR-1 (Early Growth Response-1) mRNA, which is one key tumor-involved mRNA. The strategy may provide a promising platform for highly sensitive determination of biomolecules and accurate gene therapy of cancer cells.

Near-infrared photothermally activated DNA nanotweezers for imaging ATP in living cells.

By assembling nanotweezers with ATP-splitting aptamers on gold nanorods (AuT123L), we constructed a near-infrared-activated ATP sensing device that could time-controllably image ATP levels in living cells. By replacing the aptamers on the nanotweezers, the nanoplatform can be applied to other important biomolecules, opening up more possibilities for the study of time controllable nanodevices.

Association between bone mineral density and benign paroxysmal positional vertigo: a meta-analysis.

BACKGROUND: The association between bone mineral density (BMD) and benign paroxysmal positional vertigo (BPPV) has been investigated by multiple studies, but the conclusions are controversial. This meta-analysis was conducted to evaluate whether the bone mineral density is associated with BPPV. METHODS: The relevant studies were identified by searching PubMed, EMBASE, Cochrane Library, ScienceDirect, Web of Science database up to June 2018. Statas14.0 software was used for meta-analysis. We used the pooled odds ratio (OR) and 95% confidence interval (CI) to assess the incidence of osteoporosis and osteopenia in patients with BPPV and controls (free of BPPV disease). The standardized mean difference (SMD) and 95% confidence interval (CI) were used to assess the T score in BPPV patients and controls. This meta-analysis has been registered at International Prospective Register of Systematic Reviews (PROSPERO) (number CRD42018082271). RESULTS: A total of 11 studies were eligible for meta-analysis, including 1982 subjects. When compared with the controls, the total incidence of osteoporosis and osteopenia was significantly higher in BPPV patients (OR 3.27, 95% CI 2.66-4.03, p < 0.0001). Further analysis was conducted by separate discussion about the incidence of osteoporosis and osteopenia in BPPV patients, the result of which shows that both the incidence of osteoporosis (OR 3.48, 95% CI 1.86-6.51, p < 0.0001) and the incidence of osteopenia (OR 1.75, 95% CI 1.01-3.04, p < 0.0001) were higher in BPPV patients than that in controls. There was an significant reduction in T scores of BPPV patients (SMD - 0.82, 95% CI -1.18 to - 0.46, p < 0.0001). Publication bias for each analysis was evaluated by Egger's test and Begg's indicating that no publication bias existed. Sensitivity analysis was conducted for each analysis demonstrating that the results were robust. CONCLUSIONS: Our meta-analysis provided stronger evidence that patients with BPPV were associated with a lower T score and a higher risk of osteoporosis and osteopenia. The results demonstrated that lower bone mineral density may be a risk factor for BPPV. However, large-scare, multicenter clinical studies need to be carried out to explore the precise risk of osteoporosis and osteopenia in patients with BPPV in future.

Crosslinked and Dyed Chitosan Fiber Presenting Enhanced Acid Resistance and Bioactivities.

The application of biodegradable chitosan fiber for healthy and hygienic textiles is limited due to its poor acid resistance in wet processing and poor antioxidant activity. In order to prepare chitosan fiber with good acid resistance and high antioxidant activity, chitosan fiber was first crosslinked by a water-soluble aziridine crosslinker, and then dyed with natural lac dye consisting of polyphenolic anthraquinone compounds. The main application conditions and crosslinking mechanism of the aziridine crosslinker, the adsorption mechanism and building-up property of lac dye on the crosslinked fiber, and the effects of crosslinking and dyeing on the antioxidant and antibacterial activities of chitosan fiber were studied. The crosslinked fiber exhibited greatly reduced weight loss in acidic solution, and possessed excellent acid resistance. Lac dye displayed a very high adsorption capability on the crosslinked fiber and a high utilization rate under weakly acidic medium. The Langmuir⁻Nernst isotherm was the best model to describe the adsorption behavior of lac dye, and Langmuir adsorption had great contribution to total adsorption. Lac dyeing imparted good antioxidant activity to chitosan fiber. Crosslinking and dyeing had no impact on the good inherent antibacterial activity of chitosan fiber.

Risks associated with high-dose Lactobacillus rhamnosus in an Escherichia coli model of piglet diarrhoea: intestinal microbiota and immune imbalances.

Probiotic could be a promising alternative to antibiotics for the prevention of enteric infections; however, further information on the dose effects is required. In this study, weanling piglets were orally administered low- or high-dose Lactobacillus rhamnosus ACTT 7469 (10(10) CFU/d or 10(12) CFU/d) for 1 week before F4 (K88)-positive Escherichia coli challenge. The compositions of faecal and gastrointestinal microbiota were recorded; gene expression in the intestines was assessed by real-time PCR; serum tumour necrosis factor-α (TNF-α) concentrations and intestinal Toll-like receptor 4 (TLR4) were detected by ELISA and immunohistochemistry, respectively. Unexpectedly, high-dose administration increased the incidence of diarrhoea before F4(+)ETEC challenge, despite the fact that both doses ameliorated F4(+)ETEC-induced diarrhoea with increased Lactobacillus and Bifidobacterium counts accompanied by reduced coliform shedding in faeces. Interestingly, L. rhamnosus administration reduced Lactobacillus and Bifidobacterium counts in the colonic contents, and the high-dose piglets also had lower Lactobacillius and Bacteroides counts in the ileal contents. An increase in the concentration of serum TNF-α induced by F4(+)ETEC was observed, but the increase was delayed by L. rhamnosus. In piglets exposed to F4(+)ETEC, jejunal TLR4 expression increased at the mRNA and protein levels, while jejunal interleukin (IL)-8 and ileal porcine ß-defensins 2 (pBD2) mRNA expression increased; however, these increases were attenuated by administration of L. rhamnosus. Notably, expression of jejunal TLR2, ileal TLR9, Nod-like receptor NOD1 and TNF-α mRNA was upregulated in the low-dose piglets after F4(+)ETEC challenge, but not in the high-dose piglets. These findings indicate that pretreatment with a low dose of L. rhamnosus might be more effective than a high dose at ameliorating diarrhoea. There is a risk that high-dose L. rhamnosus pretreatment may negate the preventative effects, thus decreasing the prophylactic benefits against potential enteric pathogens. Our data suggest a safe threshold for preventative use of probiotics in clinical practice.