Graphene Oxide-Based Antifungal Pesticide Delivery System for Tobacco Fungal Disease (Tobacco Target Spot) Control.

In recent years, nanocarrier-based pesticide delivery systems have provided new possibilities for the efficient utilization of pesticides. In this research, we developed a hydroxypropyl-ß-cyclodextrin-modified graphene oxide (GO-HP-ß-CD) nanocarrier for pyraclostrobin (Pyr) delivery and studied its application for tobacco target spot disease control. GO-HP-ß-CD has excellent pesticide-loading performance for Pyr (adsorption capacity of 1562.5 mg/g) and good water dispersibility and stability. Besides, GO-HP-ß-CD shows pH-responsive release performance. In addition, GO-HP-ß-CD also has better leaf affinity than Pyr, and it can effectively adhere to the leaf surface after simulated washing. The results of antifungal experiments indicate that GO-HP-ß-CD-Pyr has a good preventive effect on tobacco target spot disease, and its EC50 value is 0.384 mg/L, which is lower than Pyr. Specifically, this nanopesticide formulation does not contain toxic organic solvent or additive, so it has good environmental friendliness. Therefore, we believe that the GO-HP-ß-CD-Pyr nanopesticide has brilliant potential in the prevention and control of tobacco diseases.

Nanomaterials and Nanotechnology in Agricultural Pesticide Delivery: A Review.

Pesticides play a crucial role in ensuring food production and food security. Conventional pesticide formulations can not meet the current needs of social and economic development, and they also can not meet the requirements of green agriculture. Therefore, there is an urgent need to develop efficient, stable, safe, and environmentally friendly pesticide formulations to gradually replace old formulations which have high pollution and low efficacy. The rise of nanotechnology provides new possibilities for innovation in pesticide formulations. Through reasonable design and construction of an environmentally friendly pesticide delivery system (PDS) based on multifunctional nanocarriers, the drawbacks of conventional pesticides can be effectively solved, realizing a water-based, nanosized, targeted, efficient, and safe pesticide system. In the past five years, researchers in chemistry, materials science, botany, entomology, plant protection, and other fields are paying close attention to the research of nanomaterials based PDSs and nanopesticide formulations and have made certain research achievements. These explorations provide useful references for promoting the innovation of nanopesticides and developing a new generation of green and environmentally friendly pesticide formulations. This Perspective summarizes the recent advances of nanomaterials in PDSs and nanopesticide innovation, aiming to provide useful guidance for carrier selection, surface engineering, controlled release conditions, and application in agriculture.

Estimated bone mineral density and white matter hyperintensities: A bidirectional Mendelian randomization study.

PURPOSE: Greater white matter hyperintensities (WMH) in older adults have been associated with reduced bone mineral density (BMD) and increased fractures and falls. However, it is unclear whether there is a causal relationship between BMD reduction and WMH. In this study, Mendelian randomization (MR) was used to find the causality between WMH and estimated BMD (eBMD). METHODS: We performed a two-sample bidirectional MR analysis using statistical data obtained from publicly available genome-wide association studies (GWAS). The main method of MR analysis is the inverse-variance weighted (IVW) method. To identify and account for the impact of horizontal pleiotropy, we also employed MR-Egger regression, MR pleiotropy residual sum, and outlier (MR-PRESSO). RESULTS: MR analysis found a causal relationship between eBMD and WMH (IVW OR = 0.938, 95 % CI: 0.889-0.990, p = 0.020). Our causal estimates are unlikely to be distorted by horizontal pleiotropy according to heterogeneity test (both p > 0.05) and MR-Egger regression (p > 0.05). However, in the reverse MR analysis, there was no evidence that WMH was causally correlated with eBMD (IVW OR = 0.979, 95 % CI: 0.954-1.005, p = 0.109). CONCLUSION: Our results suggest that low eBMD increased the risk of WMH; conversely, no evidence that WMH causally affects eBMD was found.

Loss of Gucy1a3 causes poor post-stroke recovery by reducing angiogenesis via the HIF-1α/VEGFA signaling pathway in mice.

OBJECTIVES: Ischemic stroke is a common and debilitating disease that can cause permanent neurological damage. Gucy1a3, which encodes the α1 subunit of soluble guanylyl cyclase, has been reported to be associated with functional recovery after ischemic stroke. However, the mechanism is still not well understood. In the present study, we investigated the effects of Gucy1a3 on (i) post-stroke recovery; (ii) vascular endothelial growth factor A (VEGFA) and hypoxia inducible factor 1 alpha (HIF-1α) expression; and (iii) angiogenesis after ischemic stroke. MATERIALS AND METHODS: Wild-type and Gucy1a3 knockout C57BL/6J male mice were respectively used to establish the models of permanent middle cerebral artery occlusion (pMCAO). Neurological deficit scores were evaluated at 24 h and 96 h after pMCAO. Cerebral infarct volume was measured by 2,3,5-triphenyltetrazolium chloride (TTC) staining. For determining microvessel density, immunohistochemical analysis was performed with CD31. The expression of VEGFA and HIF-1α was detected by western blotting. RESULTS: Our results suggest that loss of Gucy1a3 increased the infarct volume and aggravated neurological deficits after pMCAO. In addition, the Gucy1a3 knockout brains exhibited significantly lower microvessel densities and VEGFA and HIF-1α expression levels than the wild-type brains at 96 h post-pMCAO. CONCLUSIONS: Our study indicates that GUCY1A3 might be involved in angiogenesis after ischemic stroke. Further investigation of GUCY1A3 will provide a new therapeutic target for stroke.

Neuronal intranuclear inclusion disease with cortical involvement in left hemisphere: a case report.

BACKGROUND: Neuronal intranuclear inclusion disease (NIID) is a rare highly heterogeneous disease. In this paper, we present a case of NIID featured in cortical involvement in left hemisphere of brain and the imaging changes in the process of the disease. CASE PRESENTATION: A 57-year-old female was hospitalized due to recurrent attacks of headache with cognitive impairment and tremor for 2 years. The symptoms of headache episodes were reversible. The characteristic radiologic change was high intensity signal involving the grey matter-white matter junction on the brain diffusion-weighted imaging (DWI), which existed in the frontal lobe and then extended backwards. Atypical features on fluid-attenuated inversion recovery (FLAIR) sequences showing small patchy high signals in the cerebellar vermis. High signals and edema were detected on FLAIR images along the cortex of the left occipito-parieto-temporal lobes, expanding and gradually shrinking in the follow-up visit. Besides, cerebral atrophy and bilateral symmetrical leukoencephalopathy were also detected. Skin biopsy and genetic testing confirmed the diagnosis of NIID. CONCLUSION: Except for typical radiological change strongly suggesting NIID, it is also necessary to notice the insidious symptoms of NIID combining with some atypical imaging features to make an early diagnosis. Skin biopsies or genetic testing should be carried out early in patients with highly suspected NIID.

Angiotensin-Converting Enzyme Insertion/Deletion Polymorphism and the Risk of Leukoaraiosis in a South Chinese Han Population: A Case-Control Study.

Leukoaraiosis (LA) appears as white matter hyperintensities on T2-weighted brain magnetic resonance imaging scans. Age and hypertension are considered the primary risk factors for LA, but its pathogenesis remains uncertain. This study aims to investigate the correlation between the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism and LA. A total of 140 patients with LA and 136 neuroimaging alteration-free controls were recruited in a case-control study. ACE I/D polymorphism was determined using the polymerase chain reaction method. The allele and genotype distributions of the ACE I/D polymorphism were significantly different between subjects with and without LA. Significant difference was observed in the genotypic distribution between LA patients and controls for recessive and additive models. A statistically significant association remained apparent after adjusting for potential risk factors (D/D vs. I/D + I/I: adjusted OR 3.251, 95% CI 1.185-8.918; D/D vs. I/I: adjusted OR 3.277, 95% CI 1.187-9.047). Our results indicate that the D/D genotype and D allele are important risk factors for LA. Future studies with larger populations are needed to validate our results.

Immunoglobulin A and complement C4 are involved in the progression of liver fibrosis in patients with chronic hepatitis B.

OBJECTIVE: To explore the relationship between immunoglobulin A (IgA), complement C4, and liver fibrosis (L.F.) progression (LFP) in patients with chronic hepatitis B (CHB). METHODS: This is a retrospective cohort study of CHB patients who received liver biopsies. Relevant data, including demographics, clinical serum markers, and immunological results obtained during liver biopsies, were collected and analyzed to assess and verify the relationship between IgA, C4, and LFP. RESULTS: This study included 1,938 CHB patients, of whom 132 received two liver biopsies (group 1). Thirty (22.7%) of these patients were diagnosed with LFP (increase in L.F. stage (Scheuer score F ≥ 1)). IgA (C-IgA) and C4 (C-C4) change values between the first and second biopsies were independent risk factors for LFP. IgA levels increased, and C4 levels decreased during the second liver puncture. The remaining 1,806 patients received one liver puncture (group 2). They were divided into the following subgroups: A (F ≤ 1), B (1 < F ≤ 3), and C (F > 3) to verify whether the same trend was observed by cross-sectional study. IgA levels were highest, and C4 levels were lowest in group C (IgA: C > B > A, p < 0.05; C4: C < B < A, p < 0.05). CONCLUSIONS: The findings of this study suggest that serum IgA and C4 levels are independent risk factors for LFP that could serve as future targets for L.F. management and treatment.

Efficacy and Safety Assessment of Rivaroxaban for the Treatment of Cerebral Venous Sinus Thrombosis in a Chinese Population.

We aimed to investigate the efficacy and safety of rivaroxaban for acute and long-term management of cerebral venous sinus thrombosis (CVST). This study reviewed CVST-diagnosed patients admitted to the First Affiliated Hospital of Guangxi Medical University from January 2015 to December 2020. The primary outcome was a composite of recurrent thrombosis or major bleeding events. The secondary efficacy outcomes included a disease recovery time (DRT) presenting the time from admission to the endpoint as recovery (the modified Rankin scale [mRS] score [0-1]) within 30 and 90 days, and length of hospital stay (LHS). Patients treated with rivaroxaban (38) and warfarin (45) were enrolled in the final analysis. The primary outcome had no significant difference (5.3% vs 11.1%, P = .576) between the 2 groups. The secondary efficacy outcome regarding the median 30-d DRT was 17 days (95% confidence interval [CI], 14.6-19.4) in the rivaroxaban group, compared with 26.0 days (95% CI, 16.8-35.2) in the warfarin group (hazard ratio, 1.806; 95% CI, 1.051-3.103; log-rank P = .026). Two groups have a significant difference in LHS (P = .041). Patients with cerebral edema, intracerebral hemorrhage, and mild/moderate disability (admission mRS score [2-3]) treated with rivaroxaban recovered faster than those with warfarin (log-rank P < .05). Patients with cerebral edema, intracerebral hemorrhage, and mild/moderate disability treated with rivaroxaban had a shorter recovery time than those treated with warfarin within 1 month from admission, indicating that rivaroxaban a promising convenient therapy for CVST, helping them speedily restore social functions.

Enhanced generation of reactive oxygen species by pyrite for As(III) oxidation and immobilization: The vital role of Fe(II).

The migration and conversion of arsenic in the environment usually accompany by the redox of iron-bearing minerals. For instance, the oxidation of pyrite can generate reactive oxygen species (ROS) affecting the species of arsenic, but the types and roles of ROS have been unclear. This paper demonstrated the vital role of Fe(II) in the pyrite for the formation of ROS. Results showed that exogenous addition of Fe(II) significantly enhanced the removal rate of As(III) by pyrite. 2,2'-bipyridine (BPY) decreased the oxidation of As(III) by complexing with Fe2+ in solution, whilst EDTA enhanced the oxidation of As(III) by boosting the autoxidation of Fe2+. In addition, neutral pH is superior for the oxidation of As(III) and removal of total arsenic. Importantly, Methanol, SOD enzyme and PMOS inhibited 54%, 28% and 17.5% of As(III) oxidation, respectively, which indicated O2•- and •OH were the main contributors to As(III) oxidation, and Fe(IV) contributed a small part of As(III) oxidation. The content of As(V) in the FeS2-Fe2+-As(III) system was higher than that in the FeS2-As(III) system, further confirming the vital role of Fe(II) for As(III) oxidation. Lepidocrocite was produced in a single Fe2+ system, which was not detected in the FeS2-As(III) system. Thus, the presence of mineral surfaces changed the oxidation products of Fe2+ and accelerated the oxidation and immobilization of As(III). FA (Fulvic Acid) and HA (Humic Acid) accelerated the oxidation of As(III), but the oxidation of As(III) by pyrite was inhibited to a certain extent, with increasing phenolic hydroxyl groups in phenolic acid. Our findings provide new insight into the oxidative species in the pyrite-Fe(II) system and will help guide the remediation of arsenic pollution in complex environmental systems.

Correction: Gender-Specific Impact of Self-Monitoring and Social Norm Information on Walking Behavior Among Chinese College Students Assessed Using WeChat: Longitudinal Tracking Study.

[This corrects the article DOI: 10.2196/29167.].

Atomically Dispersed Cu Nanozyme with Intensive Ascorbate Peroxidase Mimic Activity Capable of Alleviating ROS-Mediated Oxidation Damage.

Ascorbate peroxidase (APX) as a crucial antioxidant enzyme has drawn attentions for its utilization in preventing cells from oxidative stress responses by efficiently scavenging H2 O2 in plants. For eliminating the specific inactivation of natural APXs and regulating the catalytic activity, single-atom nanozymes are considered as promising classes of alternatives with similar active sites and maximal atomic utilization efficiency to natural APXs. Herein, graphitic carbon nitride (g-C3 N4 ) anchored with isolated single copper atoms (Cu SAs/CN) is designed as an efficient nanozyme with intrinsic APX mimetic behavior. The engineered Cu SAs/CN exhibits comparable specific activity and kinetics to the natural APXs. Based on the density functional theory (DFT), Cu-N4 moieties in the active center of Cu SAs/CN are determined to exert such favorable APX catalytic performance, in which the electron transfer between Cu and coordinated N atoms facilitates the activation and cleavage of the adsorbed H2 O2 molecules and results in fast kinetics. The constructed Cu SAs/CN nanozyme with superior APX-like performance and high biocompatibility can be applied for effectively protecting the H2 O2 -treated cells against oxidative injury in vitro. These findings report the single-atom nanozymes as a successful paradigm for guiding nanozymes to implement APX mimetic performance for reactive oxygen species-related biotherapeutic.

Prognostic Value of Inflammatory Indicators in Chronic Hepatitis B Patients With Significant Liver Fibrosis: A Multicenter Study in China.

Diagnosis of significant liver fibrosis is essential to facilitate the optimal treatment decisions and improve prognosis in patients with chronic hepatitis B (CHB). We aimed to evaluate the value of inflammatory indicators and construct a nomogram that effectively predicts significant liver fibrosis among CHB patients. 563 CHB patients from two centers in China from 2014 to 2019 were divided into three cohorts (development, internal validation, and independent validation cohorts), assigned into cases with significant fibrosis (liver fibrosis stages ≥2) and those without. Multiple biochemical and serological inflammatory indicators were investigated. Inflammatory indicators, Alanine aminotransferase (ALT) and aspartate aminotransferase (AST), were significantly associated with significant liver fibrosis in CHB patients but limited predictive performance, and then we combined them with prothrombin time activity percentage (PTA) and liver stiffness measurement (LSM) were identified by multivariate logistic regression analysis. Based on these factors, we constructed the nomogram with excellent performance. The area under the receiver operating characteristic curve (AUROC) for the nomogram in the development, internal validation, and independent validation cohorts were 0.860, 0.877, and 0.811, respectively. Our nomogram based on ALT and AST that had excellent performance in predicting significant fibrosis of CHB patients were constructed.

Gender-Specific Impact of Self-Monitoring and Social Norm Information on Walking Behavior Among Chinese College Students Assessed Using WeChat: Longitudinal Tracking Study.

BACKGROUND: Walking is a simple but beneficial form of physical activity (PA). Self-monitoring and providing information about social norms are the 2 most widely used "mobile health (mHealth)" strategies to promote walking behavior. However, previous studies have failed to discriminate the effect of self-monitoring from the combination of the 2 strategies, and provide practical evidence within Chinese culture. Some essential moderators, such as gender and group identity, were also overlooked. OBJECTIVE: We aimed to investigate the effectiveness of social norm and self-monitoring interventions for walking behavior and assess the moderating effects of gender and group identity, which could guide optimal mHealth intervention projects in China. METHODS: In 2 longitudinal tracking studies (study 1, 22 days; study 2, 31 days), Chinese college students wore trackers for at least 8 hours per day (MASAI 3D Pedometer and Xiaomi Wristband 2) to record their daily step counts in baseline, intervention, and follow-up stages. In each study, participants (study 1: n=117, 54% female, mean age 25.60 years; study 2: n=180, 51% female, mean age 22.60 years) were randomly allocated to 1 of the following 3 groups: a self-monitoring group and 2 social norm intervention groups. In the 2 intervention groups and during the intervention stage, participants received different social norm information regarding group member step rankings corresponding to their grouping type of social norm information. In study 1, participants were grouped by within-group member PA levels (PA consistent vs PA inconsistent), and in study 2, participants were grouped by their received gender-specific social norm information (gender consistent vs gender inconsistent). Piece-wise linear mixed models were used to compare the difference in walking steps between groups. RESULTS: In study 1, for males in the self-monitoring group, walking steps significantly decreased from the baseline stage to the intervention stage (change in slope=-1422.16; P=.02). However, additional social norm information regardless of group consistency kept their walking unchanged. For females, social norm information did not provide any extra benefit beyond self-monitoring. Females exposed to PA-inconsistent social norm information even walked less (slope during the intervention=-122.18; P=.03). In study 2, for males, a similar pattern was observed, with a decrease in walking steps in the self-monitoring group (change in slope=-151.33; P=.08), but there was no decrease in the 2 social norm intervention groups. However, for females, gender-consistent social norm information decreased walking steps (slope during the intervention=-143.68; P=.03). CONCLUSIONS: Both gender and group identity moderated the effect of social norm information on walking. Among females, social norm information showed no benefit for walking behavior and may have exerted a backfire effect. Among males, while walking behavior decreased with self-monitoring only, the inclusion of social norm information held the level of walking behavior steady.

Ratiometric fluorescent sensor based on 2D MOF nanosheets modified by DNA for sensitive detection of Hg2.

Mercury is highly toxic and can accumulate throughout the food cycle, leading to water contamination and foodstuffs pollution. Therefore, increasing attention has been paid to explore effective detection of Hg2+. Here, we report a sensitive Hg2+sensor based on single-stranded DNA (ssDNA) modified two-dimensional (2D) MOF nanosheets by a ratiometric fluorescent method. The chosen 2D MOF nanosheets possess intrinsic peroxidase-like catalytic ability, ssDNA adsorption and fluorescence quenching. We demonstrate that the adsorption of ssDNA can significantly improve the peroxidase mimetic activity of 2D MOF nanosheets, enhancing the fluorescence of substrate Amplex Red. Taking advantages of the favorable characteristics above, we fabricate an efficient Hg2+sensor. In the presence of Hg2+, the ssDNA is released from 2D MOF nanosheets, which results in a decreasing of peroxidase mimetic activity of 2D MOF nanosheets and a fluorescence enhancement of attached fluorophore. A linear relationship between ratiometric fluorescence of substrate and fluorophore and Hg2+concentrations is obtained. The detection limit is 5 nM, which is much lower than the maximal contamination level in drinking water (30 nM) by Word Health Organization. These findings show 2D MOF based ratiometric fluorescent sensor is a convenient and efficient strategy to detect Hg2+.

Associations between SNP83 of phosphodiesterase 4D gene and carotid atherosclerosis in a southern Chinese Han population: a case-control study.

Atherosclerosis was an important pathophysiological basis of atherothrombotic stroke, and phosphodiesterase 4D (PDE4D) polymorphism (SNP83/rs966221) was reported to be associated with the susceptibility to atherothrombotic stroke. Aim of the present study was to explore the potential association between SNP83 and carotid atherosclerosis (CAS). 204 southern Chinese Han participants were divided into two groups according to the carotid intima-media thickness (IMT) of the carotid artery: CAS group (carotid IMT ≥ 1.0 mm) and non-CAS group (carotid IMT < 1.0 mm). Carotid IMT was measured by color Doppler ultrasound. The PDE4D SNP83 polymorphism was determined by SNaPshot technique. Our study found that SNP83 was associated significantly with CAS susceptibility under the dominant, overdominant and codominant models. After adjusting for age, gender, low-density lipoprotein cholesterol, Hemoglobin A1c, cigarette smoking, hypertension history, and diabetes mellitus history, the association still remained significant (dominant model: crude OR = 2.373, 95% CI: 1.268-4.442, P = 0.007; adjusted OR = 3.129, 95% CI: 1.104-8.866, P = 0.032; overdominant model: crude OR = 1.968, 95% CI: 1.043-3.714, P = 0.037; adjusted OR = 2.854, 95% CI: 1.005-8.108, P = 0.049; codominant: crude OR = 2.102, 95% CI: 1.110-3.979, P = 0.023; adjusted OR = 2.984, 95% CI: 1.047-8.502, P = 0.041). Carotid IMT of carriers with CT + CC genotypes was higher than carriers with TT genotype (P = 0.016). Our results indicated that the SNP83/rs966221 located on PDE4D gene was significantly associated between CAS susceptibility and carotid IMT independently of conventional risk factors in a southern Chinese Han population.

Hot Carriers and Photothermal Effects of Monolayer MoOx for Promoting Sulfite Oxidase Mimetic Activity.

Local surface plasmon resonance (LSPR)-enhanced catalysis has brought a substantial amount of opportunities across various disciplines such as photocatalysis, photodetection, and photothermal therapeutics. Plasmon-induced photothermal and hot carriers effects have also been utilized to activate the enzyme-like reactions. Compared with natural enzymes, the relatively low catalytic performance of nanozymes severely hampered the potential applications in the field of biomedicine. For these issues mentioned above, herein, we demonstrate a highly efficient sulfite oxidase (SuOx) mimetic performance of plasmonic monolayer MoOx (ML-MoOx) upon LSPR excitation. We also established that the considerable photothermal effect and the injection of hot carriers induced by LSPR are responsible for promoting the SuOx activity of ML-MoOx. The high transient local temperature on the surface of ML-MoOx generated by the photothermal effect facilitates to impact the reaction velocity and feed the SuOx-like activity, while the generation of hot carriers which are suggested as predominant effects catalyzes the oxidation of sulfite to sulfate through significantly decreasing the activation energy for the SuOx-like reaction. These investigations present a contribution to the basic understanding of plasmon-enhanced enzyme-like reaction and provided an insight into the optimization of the SuOx mimetic performance of nanomaterials.

Modified Ti3C2 nanosheets as peroxidase mimetics for use in colorimetric detection and immunoassays.

Since being discovered in 2011, a large class of two-dimensional materials, labeled MXenes, has received increased research enthusiasm both theoretically and experimentally due to the unique physical, optical and electrical properties. Here, we prepared few-layered Ti3C2 nanosheets by a facile two-step liquid exfoliation method and, for the first time, demonstrated their intrinsic peroxidase-like activity in a Ti3C2-TMB-H2O2 system. The as-produced Ti3C2 nanosheets, especially after histidine modification, were characterized with excellent water dispersibility, large specific surface area, and high stability, which contribute to their much higher affinity to both substrates when compared to HRP. We have also established the catalytic mechanism whereby Ti3C2 nanosheets, where Ti switched spontaneously from an oxidized to reduced state, promoted the electron transfer from TMB to H2O2. Given the color reaction of Ti3C2 nanosheets, we have fabricated a colorimetric paper-based sensor integrated with a smartphone to detect glucose and an immunoassay to detect IR-ß, enabling Ti3C2 nanosheets to be a powerful tool in the biodetection field.

Identification of prognostic splicing factors and exploration of their potential regulatory mechanisms in pancreatic adenocarcinoma.

Pancreatic adenocarcinoma (PAAD), the most common subtype of pancreatic cancer, is a highly lethal disease. In this study, we integrated the expression profiles of splicing factors (SFs) of PAAD from RNA-sequencing data to provide a comprehensive view of the clinical significance of SFs. A prognostic index (PI) based on SFs was developed using the least absolute shrinkage and selection operator (LASSO) COX analysis. The PI exhibited excellent performance in predicting the status of overall survival of PAAD patients. We also used the percent spliced in (PSI) value obtained from SpliceSeq software to quantify different types of alternative splicing (AS). The prognostic value of AS events was explored using univariate COX and LASSO COX analyses; AS-based PIs were also proposed. The integration of prognosis-associated SFs and AS events suggested the potential regulatory mechanisms of splicing processes in PAAD. This study defined the markedly clinical significance of SFs and provided novel insight into their potential regulatory mechanisms.

Oxygen Vacancy-Engineered PEGylated MoO3-x Nanoparticles with Superior Sulfite Oxidase Mimetic Activity for Vitamin B1 Detection.

Sulfite oxidase (SuOx ) is a molybdenum-dependent enzyme that catalyzes the oxidation of sulfite to sulfate to maintain the intracellular levels of sulfite at an appropriate low level. The deficiency of SuOx would cause severe neurological damage and infant diseases, which makes SuOx of tremendous biomedical importance. Herein, a SuOx mimic nanozyme of PEGylated (polyethylene glycol)-MoO3-x nanoparticles (P-MoO3-x NPs) with abundant oxygen vacancies created by vacancy-engineering is reported. Their level of SuOx -like activity is 12 times higher than that of bulk-MoO3 . It is also established that the superior increased enzyme mimetic activity is due to the introduction of the oxygen vacancies acting as catalytic hotspots, which allows better sulfite capture ability. It is found that vitamin B1 (VB1) inhibits the SuOx mimic activity of P-MoO3-x NPs through the irreversible cleavage by sulfite and the electrostatic interaction with P-MoO3-x NPs. A colorimetric platform is developed for the detection of VB1 with high sensitivity (the low detection limit is 0.46 µg mL-1 ) and good selectivity. These findings pave the way for further investigating the nanozyme which possess intrinsic SuOx mimicing activity and is thus a promising candidate for biomedical detection.

Fullerene-like MoS2 Nanoparticles as Cascade Catalysts Improving Lubricant and Antioxidant Abilities of Artificial Synovial Fluid.

Intraarticular injection of hyaluronic acid (HA) for viscosupplementation is a nonsurgical therapy for osteoarthritis (OA). However, HA fails to lubricate under a significant load and tends to be depolymerized by the overproduction of reactive oxygen species (ROS) in inflammation. Here, we for the first time reported that fullerene-like MoS2 (F-MoS2) nanoparticles are efficient lubricants and antioxidants for artificial synovial fluid. A model of arthrosis was built, to evaluate the tribological behavior of F-MoS2 nanoparticles. The tests showed that they significantly improve the antiwear and friction-reducing abilities of the artificial synovial fluid. More importantly, the F-MoS2 nanoparticles possess intrinsic dual-enzyme-like activity, mimicking superoxide dismutases (SOD) and catalases (CAT) under physiological conditions (pH 7.4, 25 °C). By coupling of these unique properties, a self-organized cascade catalytic system was constructed, which includes the disproportionation of superoxide radicals (O2•-) to hydrogen peroxide (H2O2) and subsequently the disproportionation of H2O2 into oxygen (O2). The effectiveness of the detox system was evaluated by human umbilical vein endothelial cells (HUVEC) models exposed to oxidative stress. After that, F-MoS2 nanoparticles were used to regulate the ROS level in artificial synovial fluid containing HA. Relative viscosity measurements showed the excellent protective effect of F-MoS2 nanoparticles against HA oxidative damage offered by O2•-. These results indicate that F-MoS2 nanoparticles are promising candidates for treatment of OA and other diseases caused by lubrication deficiency or oxidative stress.