ß-Galactosidase-guided self-assembled 68Ga nanofibers probe for micro-PET tumor imaging.

ß-galactosidase (ß-gal) has high activity in various malignancies, which is suitable for targeted positron emission tomography (PET) imaging. Meanwhile, ß-gal can successfully guide the formation of nanofibers, which enhances the intensity of imaging and extends the imaging time. Herein, we designed a ß-galactosidase-guided self-assembled PET imaging probe [68Ga]Nap-NOTA-1Gal. We envisage that ß-gal could recognize and cleave the target site, bringing about self-assembling to form nanofibers, thereby enhancing the PET imaging effect. The targeting specificity of [68Ga]Nap-NOTA-1Gal for detecting ß-gal activity was examined using the control probe [68Ga]Nap-NOTA-1. Micro-PET imaging showed that tumor regions of [68Ga]Nap-NOTA-1Gal were visible after injection. And the tumor uptake of [68Ga]Nap-NOTA-1Gal was higher than [68Ga]Nap-NOTA-1 at all-time points. Our results demonstrated that the [68Ga]Nap-NOTA-1Gal can be used for the purpose of a new promising PET probe for helping diagnose cancer with high levels of ß-gal activity.

Targeting vulnerable microcircuits in the ventral hippocampus of male transgenic mice to rescue Alzheimer-like social memory loss.

BACKGROUND: Episodic memory loss is a prominent clinical manifestation of Alzheimer's disease (AD), which is closely related to tau pathology and hippocampal impairment. Due to the heterogeneity of brain neurons, the specific roles of different brain neurons in terms of their sensitivity to tau accumulation and their contribution to AD-like social memory loss remain unclear. Therefore, further investigation is necessary. METHODS: We investigated the effects of AD-like tau pathology by Tandem mass tag proteomic and phosphoproteomic analysis, social behavioural tests, hippocampal electrophysiology, immunofluorescence staining and in vivo optical fibre recording of GCaMP6f and iGABASnFR. Additionally, we utilized optogenetics and administered ursolic acid (UA) via oral gavage to examine the effects of these agents on social memory in mice. RESULTS: The results of proteomic and phosphoproteomic analyses revealed the characteristics of ventral hippocampal CA1 (vCA1) under both physiological conditions and AD-like tau pathology. As tau progressively accumulated, vCA1, especially its excitatory and parvalbumin (PV) neurons, were fully filled with mislocated and phosphorylated tau (p-Tau). This finding was not observed for dorsal hippocampal CA1 (dCA1). The overexpression of human tau (hTau) in excitatory and PV neurons mimicked AD-like tau accumulation, significantly inhibited neuronal excitability and suppressed distinct discrimination-associated firings of these neurons within vCA1. Photoactivating excitatory and PV neurons in vCA1 at specific rhythms and time windows efficiently ameliorated tau-impaired social memory. Notably, 1 month of UA administration efficiently decreased tau accumulation via autophagy in a transcription factor EB (TFEB)-dependent manner and restored the vCA1 microcircuit to ameliorate tau-impaired social memory. CONCLUSION: This study elucidated distinct protein and phosphoprotein networks between dCA1 and vCA1 and highlighted the susceptibility of the vCA1 microcircuit to AD-like tau accumulation. Notably, our novel findings regarding the efficacy of UA in reducing tau load and targeting the vCA1 microcircuit may provide a promising strategy for treating AD in the future.

ß-Galactosidase-Activated and Red Light-Induced RNA Modification Strategy for Prolonged NIR Fluorescence/PET Bimodality Imaging.

Improving the retention of small-molecule-based therapeutic agents in tumors is crucial to achieve precise diagnosis and effective therapy of cancer. Herein, we propose a ß-galactosidase (ß-Gal)-activated and red light-induced RNA modification (GALIRM) strategy for prolonged tumor imaging. A ß-Gal-activatable near-infrared (NIR) fluorescence (FL) and positron emission tomography (PET) bimodal probe 68Ga-NOTA-FCG consists of a triaaza triacetic acid chelator NOTA for 68Ga-labeling, a ß-Gal-activated photosensitizer CyGal, and a singlet oxygen (1O2)-susceptible furan group for RNA modification. Studies have demonstrated that the probe emits an activated NIR FL signal upon cleavage by endogenous ß-Gal overexpressed in the lysosomes, which is combined with the PET imaging signal of 68Ga allowing for highly sensitive imaging of ovarian cancer. Moreover, the capability of 68Ga-NOTA-FCG generating 1O2 under 690 nm illumination could be simultaneously unlocked, which can trigger the covalent cross-linking between furan and nucleotides of cytoplasmic RNAs. The formation of the probe-RNA conjugate can effectively prevent exocytosis and prolong retention of the probe in tumors. We thus believe that this GALIRM strategy may provide entirely new insights into long-term tumor imaging and efficient tumor treatment.

The Efficacy of Magnesium Sulfate (MgSO4) Wet Dressing in Reducing Eyelid Swelling and Bruising after Blepharoplasty: A Randomized, Controlled, and Observer-Blinded Assessment Study.

The purpose of this study was to evaluate the effects of wet dressing with 50% magnesium sulfate (MgSO4) solution on decreasing eyelid swelling and bruising after blepharoplasty. Fifty-eight patients (23 male and 35 female) who underwent bilateral blepharoplasty were enrolled in our randomized clinical trial. One side of the periorbital area (upper and lower eyelids) per patient received a wet dressing with 50% MgSO4 solution randomly, and the other side was cooled with an ice pack from the first postoperative day for two consecutive days (30 minutes per time and twice a day). The eyelid edema and ecchymosis were evaluated and classified using respective graded scales. Degrees of eyelid edema were similar after surgery in both groups (p > 0.05) and were significantly decreased with time. Compared with the cooled ones, less swelling was observed in the eyelids treated by MgSO4 wet compress on postoperative day 5 (p < 0.01). Both the incidence and area of ecchymosis were lower in the MgSO4 group than those in the cooling group (p < 0.01 and p < 0.05, respectively). Moreover, the majority of patients (39/58, 67.2%) indicated a preference for MgSO4 wet dressing over ice cooling. MgSO4 wet dressing can be conveniently applied to alleviate eyelid swelling and reduce recovery time after blepharoplasty.

Synthesis and preliminary biological evaluation of a novel 99mTc-labeled small molecule for PD-L1 imaging.

In recent years, PD-1/PD-L1 checkpoint blockade immunotherapy with remarkable efficacy has set off a heat wave. The expression level of PD-L1, which plays a predictive role in anti-PD-1/PD-L1 therapy, could be quantified by noninvasive imaging with radiotracers. Herein, we introduced the synthesis and preliminary biological evaluation of a novel 99mTc-labeled small molecule radiotracer [99mTc]G3C-CBM for PD-L1 imaging. [99mTc]G3C-CBM was achieved with high radiochemical purity (>96 %) and remained good stability in PBS and FBS. In competitive combination experiment, [99mTc]G3C-CBM was displaced by increasing concentrations of unlabeled G3C-CBM, resulting in an IC50 value of 41.25±2.23 nM for G3C-CBM. The uptake of [99mTc]G3C-CBM in A375-hPD-L1 cells (17.51±2.08 %) was approximately 6.47 folds of that in A375 cells (2.71±0.36 %) after co-incubation for 2 h. The biodistribution results showed that the radioactivity uptake in A375-hPD-L1 tumor reached the maximum (0.35±0.01 %ID/g) at 2 h post injection, and the optimum tumor/muscle ratio of 2.94±0.29 occurred at the same time. In addition, [99mTc]G3C-CBM was quickly cleared from the blood with a clearance half-life of just 119.25 min. These results indicate that [99mTc]G3C-CBM is a potential SPECT PD-L1 imaging agent and is worthy of further study.

Eradication rates of Helicobacter pylori in treatment-naive patients following 14-day vonoprazan-amoxicillin dual therapy: A multicenter randomized controlled trial in China.

BACKGROUND: Potassium-competitive acid blockers (P-CAB) are recommended for the treatment of Helicobacter pylori infections, but dual therapy of P-CAB with amoxicillin has been poorly studied. The current study compared the efficacy, adverse reactions, compliance, and effects on gut microbiota of 14-day vonoprazan-amoxicillin (VA) dual therapy with esomeprazole, bismuth potassium citrate, amoxicillin, and metronidazole (EBAM) quadruple therapy in treatment-naive patients with H. pylori. MATERIALS AND METHODS: This was a multicenter, open-label, randomized, and controlled, non-inferiority study. Patients (n = 194) enrolled from six centers were randomly divided into either the VA or EBAM group. H. pylori eradication was determined using 13 C urea breath tests (UBT) 4-6 weeks post-treatment. Fecal samples were collected, and gut microbial populations were analyzed by 16S rDNA and metagenomic sequencing technology. RESULTS: Eradication rates of H. pylori in the VA and EBAM groups were 88.7% and 91.8%, respectively, according to intention-to-treat (ITT) analysis; 95.6% and 96.7% with per-protocol (PP) analysis; and 94.5% and 96.7% with modified ITT (mITT) analysis (all p > 0.05). The incidence of adverse reactions in the VA group was significantly lower compared to the EBAM group, and compliance within both groups was good. There was no difference in α-diversity or microbial composition in the VA and EBAM groups at one-month post-treatment compared to baseline, except for a markedly reduced abundance of Bacteroides in the EBAM group. CONCLUSION: VA therapy achieved excellent eradication rates with low adverse reactions, good compliance, and little impact on gut microbiota. VA therapy should be recommended as a first-line treatment against H. pylori.

Prediction of Esophageal Stricture after Endoscopic Submucosal Dissection in Patients with Early Esophageal Cancer.

BACKGROUND: Endoscopic submucosal dissection (ESD) treatment of early esophageal cancer is effective and safe. It is currently the first-line treatment for early esophageal cancer. However, a common side effect is the development of esophageal strictures after ESD. This study was designed to identify the risk factors for esophageal stricture development and to predict its occurrence after ESD. METHODS: In this retrospective study, 150 consecutive patients with early esophageal cancer treated with ESD at Daping Hospital, Chongqing, were enrolled between January 2016 and December 2020. Data on patient demographics, esophageal tumor characteristics, procedure-related factors, and postoperative situations were collected. We identified independent risk factors of esophageal stricture formation using univariate analysis and multivariate logistic regression. The predictive probability was obtained after multivariate logistic analysis. In addition, patients were divided into six groups based on these risk factors and the rate of esophageal stricture in each group was analyzed. RESULTS: The postoperative esophageal stricture rate was 14% (21/150). Tumor location (OR = 5.655, 95% CI: 1.245-25.691, P = 0.025) and circumferential resection range (OR = 16.113, 95% CI: 4.294-60.466, P < 0.001) are independent risk factors for the development of esophageal strictures. According to predictive probability analysis and the rates of stricture in six groups, we developed a possible flow chart to predict stricture formation. CONCLUSIONS: Tumor location and circumferential resection range are reliable risk factors to predict the occurrence of esophageal strictures. Our prediction flow chart suggests that tumors with a circumferential resection range of 1/2-3/4 and located above the upper thoracic segment or a circumferential resection range of > 3/4 have a high risk of postoperative stricture. Thus, timely and effective preventive measures should be taken in these patients following ESD.

Conditioned medium from the bone marrow mesenchymal stem cells modulates immune response via signal transduction and activator of transcription 6 signaling pathway in an allergic rhinitis mouse model.

BACKGROUND: Allergic rhinitis (AR) is a common immune disease of the nasal mucosa characterized with immunoglobulin E (IgE)-mediated allergic inflammation after exposure to allergens in susceptible population. Previous reports have demonstrated that the bone marrow mesenchymal stem cells (BMSCs) could reduce allergic inflammation. However, there is little knowledge about whether the culture supernatant of BMSCs (conditioned medium, CM) has similar anti- inflammatory potential in treating AR. OBJECTIVE: The study aimed to evaluate the immunoregulatory effects of conditioned medium derived from BMSCs (BMSC-CM) on allergic inflammation in an AR mouse model. MATERIAL AND METHODS: The AR murine model was induced by repeated sensitization and challenges with ovalbumin (OVA). Subsequently the allergic symptoms of AR mice, cytokine levels, the histopathological features of the nasal mucosa and T helper 1 (Th1) : T helper 2 (Th2) cells ratio were evaluated. RESULTS: Treatment with BMSC-CM was found as effective as BMSCs in reducing allergic symptoms and inhibiting eosinophilic infiltration in the nasal mucosa. After BMSC-CM or BMSCs administration, the OVA-specific IgE and interleukin 4 levels in serum decreased and interferon gamma level increased compared with AR mice treated with uncultured fresh medium. Flow cytometry analysis revealed a decrease in Th1:Th2 cells ratio after OVA-sensitization and the ratio was reversed by BMSC-CM and BMSCs treatments. Furthermore, the data revealed that BMSC-CM suppressed the production of signal transduction and activator of transcription 6 (STAT6) at messenger RNA and protein levels in the nasal mucosa. CONCLUSION: BMSC-CM could ameliorate allergic inflammation and regulate the balance of Th cells, and the underlying mechanism was closely related to STAT6 signaling pathway. The immunoregulatory effects of BMSCs could be achieved through paracrine function, and nasal dripping of BMSC-CM might be a novel approach for the treatment of AR.

Recent advances in the synthesis of 2,3-fused quinazolinones.

As one of the most important structural units in pharmaceuticals and medicinal chemistry, quinazolinone and its derivatives exhibit a wide range of biological and pharmacological activities, including anti-inflammatory, antitubercular, antiviral, and anticancer activities, etc. In particular, 2,3-fused quinazolinones have attracted much attention because the rings fused to the 2,3-positions of quinazolinones improve their rigidity and planarity. Their synthetic strategies have made great advances in recent years. Therefore, this review focuses on novel strategies for the synthesis of 2,3-fused quinazolinone derivatives from 2017 to 2022, such as the difunctionalization of alkenes, the ring-opening of easily available small rings, dehydrogenative cross-coupling reactions, transition-metal catalyzed cyclizations, cycloadditions, and other cascade reactions.

Clinical Evaluation of Antiphospholipase A2 Receptor IgG4 level and Its IgG4-to-IgG Ratio Based on Quantitative Immunoassays in Idiopathic Membranous Nephropathy.

Background: Phospholipase A2 receptor (PLA2R), located at the membrane of glomerular podocyte, is the major autoantigen of idiopathic membranous nephropathy (IMN), and its antibodies with a predominant IgG4 subclass lead to pathological lesions. Further studies could be performed to validate the clinical values of PLA2R-IgG, PLA2R-IgG4, and PLA2R-IgG4-to-IgG ratios, as ultrasensitive and quantitative immunoassays for PLA2R antibodies have been well established in our previous work. Methods: A cohort of 58 IMN patients, 30 of whom were followed from 3 to 42 months, was assessed for serum PLA2R-IgG and -IgG4 levels, and the ratio of PLA2R-IgG4/-IgG combined with relative clinicopathological indicators. Results: Serum PLA2R-IgG4 level was significantly correlated with glomerular PLA2R staining. In addition, it was strongly correlated with PLA2R-IgG and its ratio. PLA2R-IgG and -IgG4 levels were both correlated with high-density lipoprotein and erythrocyte sedimentation rates. The ratio at the first diagnosis can predict the remission, and its efficacy overmatched PLA2R-IgG4. In the survival curves, negative results for the ratio or PLA2R-IgG4 at the first diagnosis demonstrated higher remission rates. Conclusion: Serum PLA2R-IgG4 concentration may replace renal PLA2R immunohistochemistry in IMN diagnosis. We propose that the PLA2R-IgG4-to-IgG ratio and PLA2R-IgG4 could be novel indicators for remission prediction in clinical practice.

Pre-fermentation of rice flour for improving the cooking quality of extruded instant rice.

Extruded instant rice (EIR) could not maintain an intact grain morphology during cooking, which seriously affected its cooking quality. The problem was solved by pre-fermentation of rice flour for 5-10 days. Consequently, the cooking loss was significantly reduced, while the hardness, stickiness and water absorption of EIR were significantly increased. The mechanism was that the gel network of EIR was strengthened by the following ways: (1) pre-fermentation significantly increased the total starch and amylose contents of rice flour due to the dissolution or leaching of lipids, ash and soluble proteins into the fermentation broth; (2) pre-fermentation degraded the amorphous region of starch granules by enzymes and organic acids, resulting in a molecular structure with lower polydispersity index and molecular weight, and higher proportion of long- and ultra-long branched chains of amylopectin. This kind of molecular structure was conducive to the formation of ordered double helix structures and strong gel network.

Synthesis of spiroindolenine-3,3'-pyrrolo[2,1-b]quinazolinones through gold(I)-catalyzed dearomative cyclization of N-alkynyl quinazolinone-tethered indoles.

A variety of functionalized spiroindolenine-3,3'-pyrrolo[2,1-b]quinazolinones were prepared in good to excellent yields through a gold(I)-catalyzed dearomative cyclization of N-alkynyl quinazolinone-tethered C2-substituted indoles. This reaction features a broad substrate scope, good functional group tolerance, and easy gram-scale preparation and transformations. Furthermore, biological activity studies showed that most of the obtained spiroindolenine-3,3'-pyrrolo[2,1-b]quinazolinone scaffolds showed potential as good anti-inflammatory agents.

Palladacycle-Catalyzed Regioselective Heck Reaction Using Diaryliodonium Triflates and Aryl Iodides.

We describe a P-containing palladacycle-catalyzed regioselective Heck reaction of 2,3-dihydrofuran with diaryliodonium salts and aryl iodides to afford 2-aryl-2,5-dihydrofurans and 2-aryl-2,3-dihydrofurans, respectively, in good yields. Mechanistic studies revealed that the oxidative addition of diaryliodonium salts to palladacycles to form Pd(IV) species showed high chemoselectivity and that electron-rich aryl moieties were preferentially transferred to the Heck product. DFT calculations indicated that the regioselectivity-determining step is the reductive elimination reaction rather than the isomerization and reinsertion of Pd(IV)-hydride intermediates into the double bond.

High-dose dual therapy versus culture-based susceptibility-guided therapy as a rescue regimen for Helicobacter pylori infection: a randomized controlled trial.

Background: Although the Maastricht VI/Florence consensus report recommended high-dose proton pump inhibitor-amoxicillin dual therapy as possible rescue therapy for Helicobacter pylori infection, clinical evidence of its efficacy was lacking. Objectives: To compare the efficacy, safety, patient compliance, and cost between high-dose dual therapy (HDDT) and culture-based susceptibility-guided therapy (CB-SGT) as a rescue regimen for H. pylori infection. Design: A single-center, open-label, randomized controlled clinical trial. Methods: In all, 146 patients with a history of eradication failure were enrolled and randomly assigned to receive HDDT or CB-SGT. HDDT consisted of esomeprazole 20 mg and amoxicillin 750 mg, both given four times per day (qid). CB-SGT consisted of esomeprazole 20 mg twice daily (bid), amoxicillin 1000 mg bid plus clarithromycin 500 mg bid, metronidazole 400 mg bid, or levofloxacin 500 mg daily (qd) for sensitive patients, in that order. For patients with triple resistance, a bismuth-containing regimen with a high dose of metronidazole was chosen, including esomeprazole 20 mg bid, bismuth 220 mg bid, amoxicillin 1000 mg bid, and metronidazole 400 mg qid. All regimens were given for 14 days. Results: The eradication H. pylori rates achieved with HDDT in the intention-to-treat (ITT), per-protocol, and modified ITT analyses were all 84.9% [62/73, 95% confidence interval (CI): 76.5-93.9%], compared with 83.6% (61/73, 95% CI: 74.9-92.3%), 84.7% (61/72, 95% CI: 76.2-93.2%), and 84.7% (61/72, 95% CI: 76.2-93.2%) with CB-SGT, respectively. For patients with CYP2C19 polymorphisms of intermediate/poor metabolizers, the eradication rates of HDDT and CB-SGT were 90.70% (39/43, 95% CI: 77.86-97.41%) and 84.21% (32/38, 95% CI: 68.75-93.98%), respectively. The difference between groups was 6.49% (95% CI: -8.00% to 20.97%), and the non-inferiority p value was 0.0128. For patients with a treatment interval of more than 3 months, the eradication rates of the two regimens reached 88.71% (95% CI: 78.11-95.34%) and 71.97% (95% CI: 70.02-90.64%). The difference between groups was 6.74% (95% CI: -5.71% to 19.20%), with a non-inferiority p value of 0.0042. Patient adherence was high in both groups. The HDDT had a lower cost and rate of side effects (p < 0.001) compared with CB-SGT. Conclusions: HDDT can reach an eradication rate of 85% in treatment-experienced patients of H. pylori infection and 91% in patients with CYP2C19 polymorphisms of intermediate/poor metabolizers, with good compliance, lower side effects and costs, and less use of antibiotics. In conclusion, HDDT offers an effective rescue regimen for H. pylori infection. Registration: This clinical trial was registered at the Chinese Clinical Trail Registry (trail registration number: ChiCTR1900025044).

10-Day and 14-day high-dose dual therapy for the treatment of Helicobacter pylori: A propensity score matching analysis.

BACKGROUND: Inconsistent eradication rates for Helicobacter pylori have been reported worldwide with dual therapy, perhaps owing to the difference in dose administration and treatment duration. This retrospective study aimed to determine whether high-dose dual therapy (HDDT) with different regimens leads to different eradication rates. The study compares the efficacy and safety of HDDT 10-day vs 14-day and investigates the factors that might affect the eradication rates. MATERIALS AND METHODS: Two comparable treatment groups were based on propensity score matching (PSM). Patients were divided into two groups based on the therapy they underwent: 10-day HDDT and 14-day HDDT (20 mg esomeprazole and 750 mg amoxicillin, administered four times daily). The eradication rates, adverse events (AEs), patient compliance, CYP2C19 gene polymorphisms, and antibiotic resistance rates of the two groups were compared. RESULTS: The intention to treat (ITT) analysis showed that the eradication rates for 10-day and 14-day groups were 78.4% (95% CI 69.6%-87.2%) and 89.7% (95% CI 83.3%-96.2%; p = .039), respectively, while the per-protocol (PP) eradication rates were 80.0% (95% CI 71.3%-88.7%) and 92.9% (95% CI 87.4%-98.5%; p = .014), respectively. The corresponding drug-related AEs were 6.8% (6/88) and 5.7% (5/88; p = .755). No significant differences were observed between the compliance rates of the two groups. The CYP2C19 gene polymorphism had no effect on the eradication rates of the two groups. CONCLUSION: The results showed that the 14-day HDDT affords a higher H. pylori eradication rate than the 10-day HDDT.

Intracellular Synthesis of Hybrid Gallium-68 Nanoparticle Enhances MicroPET Tumor Imaging.

Positron-emission tomography (PET) imaging enables cancer diagnosis at an early stage and to determine its pathological degree. However, tumor uptake efficiency of traditional PET radiotracers is usually low. Herein, we rationally designed a precursor CBT-NODA, the cold analogue CBT-NODA-Ga, and its corresponding radiotracer CBT-NODA-68Ga. Using these three compounds, we verified that coinjection of CBT-NODA-68Ga with CBT-NODA or CBT-NODA-Ga could lead to the synthesis of hybrid gallium-68 nanoparticles in furin-overexpressing cancer cells and enhance microPET tumor imaging in mice. In vivo experiments showed that coinjection of CBT-NODA-68Ga with CBT-NODA-Ga had the most prolonged retention of the radiotracer in blood, the highest radioactivity in tumor regions, and the most enhanced microPET tumor imaging in mice. We anticipate that, by combining the coinjection strategy with our CBT-Cys click condensation reaction, more radiotracers are developed for microPET imaging of more tumors in clinical settings in the future.

A novel fluorescent aptasensor based on exonuclease-assisted triple recycling amplification for sensitive and label-free detection of aflatoxin B1.

Aflatoxins are the most toxic type of mycotoxins, which may cause serious carcinogenesis, teratogenesis, and mutagenesis to humans and animals. In this work, we demonstrate a novel label-free fluorescent aptasensor based on exonuclease-assisted triple recycling amplification for the sensitive detection of aflatoxin B1 (AFB1). With the close cooperation of T7 exonuclease and three elaborately designed hairpin probes, the target AFB1 can perform three consecutive cycles of amplification reactions. In this process, each hairpin probe is fully utilized, and the target AFB1, the secondary target and the tertiary target are recycled, thereby achieving a high amplification. Interestingly and importantly, the secondary and tertiary targets generated by amplification are also excellent DNA template sequences for silver nanoclusters (AgNCs). In the presence of NaBH4 and AgNO3, a great number of DNA-AgNCs are synthesized, thereby producing a strong fluorescent signal. Under optimal conditions, the developed aptasensor exhibited high sensitivity to AFB1 with a low detection limit of 0.19 pg mL-1 and a wide dynamic range of 1 × 10-6-1 µg mL-1. In addition, the aptasensor also performed well in the determination of AFB1 in real samples.

Sensitive and label-free chemiluminescence detection of malathion using exonuclease-assisted dual signal amplification and G-quadruplex/hemin DNAzyme.

Malathion is one of the most commonly used organophosphorus pesticides that can cause serious harm to the ecological environment and human health. Herein, we demonstrated a label-free chemiluminescent aptasensor for the sensitive detection of malathion based on exonuclease-assisted dual signal amplification and G-quadruplex/hemin DNAzyme. Upon the addition of malathion, the aptamer probe specifically bound to the target to form a complex malathion-S3, leaving a duplex S1-S2. The complex malathion-S3 was digested by exonuclease I and the target was released. The released target was recycled to perform exonuclease I-assisted signal amplification. Furthermore, after treatment with exonuclease III, the duplex S1-S2 was converted into the secondary target ST. The secondary target ST interacted with the hairpin H1 to form a complex H1-ST, which was further digested by exonuclease III and released the secondary target. The released secondary target was recycled to perform exonuclease III-assisted signal amplification. After complete amplification, large numbers of G-quadruplex/hemin DNAzymes were generated. Under the optimal experimental conditions, the prepared aptasensor showed an excellent linear response to malathion with a detection limit of 0.47 pM. The relative standard deviations were in the range of 4.2-6.9%. Moreover, the aptasensor was successfully applied to detect malathion in spiked food and traditional Chinese medicine samples.

Silver nanoclusters-based fluorescent biosensing strategy for determination of mucin 1: Combination of exonuclease I-assisted target recycling and graphene oxide-assisted hybridization chain reaction.

A novel label-free fluorescent biosensing strategy was described for the sensitive detection of mucin 1 (MUC1). It consisted of an M-shaped aptamer probe for exonuclease I (Exo I)-assisted target recycling (EATR) amplification, and two AgNCs-hairpin probes for graphene oxide (GO)-assisted hybridization chain reaction (HCR) amplification. Based on the specificity of aptamer-target recognition, the addition of MUC1 caused a conformational change in the M-shaped aptamer probe, which was split into a MUC1-P3 complex and a P1-P2 duplex. Exo I then catalyzed the cleavage of aptamer sequence P3 from the MUC1-P3 complex and released the target MUC1. The released target MUC1 was free to bind with a new M-shaped probe to perform EATR amplification. Furthermore, the P1-P2 duplex with three single-stranded arms can act as a primer to initiate HCR between hairpin probes AgNCs-H1 and AgNCs-H2. In the process of HCR, two AgNCs-hairpins were autonomously cross-opened, generating long linear double-stranded nanowires containing large numbers of AgNCs. These nanowires cannot be quenched by GO due to the weak affinity between the long double-stranded DNA and GO, thereby retaining a strong fluorescent signal indicative of the concentration of MUC1. With these designs, in addition to an extremely low detection limit of 0.36 fg mL-1, the method exhibited an acceptable linear response to detect MUC1 from 1 fg mL-1 to 1 ng mL-1. Additionally, this method could be exerted with a high degree of success to detect MUC1 in diluted human serum with satisfactory results.

Development of a cost-efficient micro-detection slide system for the detection of multiple shrimp pathogens.

In view of the current demand for rapid detection and identification of pathogens, point-of-care testing (POCT) with fast portability, low consumption, and increased sensitivity and specificity has become more and more popular. The emerging nucleic acid isothermal amplification technology (NAIAT) has shown potential advantages in the development of rapid microbial detection. In this study, a micro-detection slide system was developed based on the NAIAT of various nucleic acids of shrimp pathogens. The system included a micro-detection slide with 48 identical detecting cells precoated with all detection reagents, except the sample template. The process of producing the micro-detection slides mainly combined super-hydrophobic/super-oleophobic and super-hydrophilic materials to obtain separated spaces for detection, and aerosol pollution was eliminated in the form of water-in-oil. The micro-detection slide system was capable of simultaneously detecting 4 groups of samples and 8 important shrimp pathogens and is a relatively low-cost, portable, and high-throughput nucleic acid (RNA and DNA) detection technology. The establishment of this technology will provide key technical support for the construction of biosecurity systems for healthy shrimp culture.