Synthesis of Antiprotozoal 2-(4-Alkyloxyphenyl)-Imidazolines and Imidazoles and Their Evaluation on Leishmania mexicana and Trypanosoma cruzi.

Twenty 2-(4-alkyloxyphenyl)-imidazolines and 2-(4-alkyloxyphenyl)-imidazoles were synthesized, with the former being synthesized in two steps by using MW and ultrasonication energy, resulting in good to excellent yields. Imidazoles were obtained in moderate yields by oxidizing imidazolines with MnO2 and MW energy. In response to the urgent need to treat neglected tropical diseases, a set of 2-(4-alkyloxyphenyl)- imidazolines and imidazoles was tested in vitro on Leishmania mexicana and Trypanosoma cruzi. The leishmanicidal activity of ten compounds was evaluated, showing an IC50 < 10 µg/mL. Among these compounds, 27-31 were the most active, with IC50 values < 1 µg/mL (similar to the reference drugs). In the evaluation on epimastigotes of T. cruzi, only 30 and 36 reached an IC50 < 1 µg/mL, showing better inhibition than both reference drugs. However, compounds 29, 33, and 35 also demonstrated attractive trypanocidal activities, with IC50 values < 10 µg/mL, similar to the values for benznidazole and nifurtimox.

FeNi-MIL-88B-based electrochemiluminescence immunosensor for ultra-sensitive detection of CD44 protein via dual-quenching strategy.

BACKGROUND: Cluster of Differentiation 44 (CD44) is considered an important biomarker for various cancers, and achieving highly sensitive detection of CD44 is crucial, which plays a significant role in tumor invasion and metastasis, providing essential information for clinical tumor diagnosis. Commonly used methods for analysis include fluorescence spectroscopy (FL), photoelectrochemical analysis (PEC), electrochemical analysis (EC), and commercial ELISA kits. Although these methods offer high sensitivity, they can be relatively complex to perform experimentally. Electrochemiluminescence (ECL) has gained widespread research attention due to its high sensitivity, ease of operation, effective spatiotemporal control, and close to zero background signal. RESULTS: In this work, a sandwich-type ECL immunosensor for detecting CD44 was constructed using luminol as a luminophore. In this sensing platform, bimetallic MOFs (Pd@FeNi-MIL-88B) loaded with palladium nanoparticles (Pd NPs) were used as a novel enzyme mimic, exhibiting excellent catalytic performance towards the electroreduction of H2O2. The hybrids provided a strong support platform for luminol and antibodies, significantly enhancing the initial ECL signal of luminol. Subsequently, core-shell Au@MnO2 nanocomposites were synthesised by gold nanoparticles (Au NPs) encapsulated in manganese dioxide (MnO2) thin layers, as labels. In the luminol/H2O2 system, Au@MnO2 exhibited strong light absorption in the broad UV-vis spectrum, similar to the black body effect, and the scavenging effect of Mn2+ on O2•-, which achieved the dual-quenching of ECL signal. Under the optimal experimental conditions, the immunosensor demonstrated a detection range of 0.1 pg mL-1 - 100 ng mL-1, with a detection limit of 0.069 pg mL-1. SIGNIFICANCE: Based on Pd@FeNi-MIL-88B nanoenzymes and Au@MnO2 nanocomposites, a dual-quenching sandwich-type ECL immunosensor for the detection of CD44 was constructed. The proposed immunosensor exhibited excellent reproducibility, stability, selectivity, and sensitivity, and provided a valuable analytical strategy and technical platform for the accurate detection of disease biomarkers, and opened up potential application prospects for early clinical treatment.

Dual biomarkers-activatable hollow MnO2-Based theranostic nanoplatform for efficient breast cancer-specific multisite fluorescence imaging and synergistic therapy.

BACKGROUND: Theranostic nanoplatforms with integrated diagnostic imaging and multiple therapeutic functions play a vital role in precise diagnosis and efficient treatment for breast cancer, but unfortunately, these nanoplatforms are usually stuck in single-site imaging and single mode of treatment, causing unsatisfactory diagnostic and therapeutic efficiency. Herein, a dual biomarkers-activatable facile hollow mesoporous MnO2 (H-MnO2)-based theranostic nanoplatform, DNAzyme@H-MnO2-MUC1 aptamer (DHMM), was constructed for the simultaneous multi-site diagnosis and multiple treatment of breast cancer. RESULTS: The DHMM acted as an integrated diagnostic and therapeutic nanoplatform that realizes multi-site fluorescence imaging-guided high-efficient photothermal/chemodynamic/gene synergistic therapy (PTT/CDT/GT) for breast cancer. The H-MnO2 exhibits high loading capacity for Cy5-MUC1 aptamer (3.05 pmoL µg-1) and FAM-DNAzyme (3.37 pmoL µg-1), and excellent quenching for the probes. In the presence of MUC1 on the cell membrane and GSH in the cytoplasm, Cy5-MUC1 aptamer and FAM-DNAzyme was activated triggering dual-channel fluorescence imaging at different sites. Moreover, the self-supplied Mn2+ was further supplied as DNAzyme cofactors to catalytic cleavage intracellular EGR-1 mRNA for high-efficient GT and stimulated the Fenton-like reaction for CDT. The H-MnO2 also showcases a favorable photothermal performance with a photothermal conversion efficiency of 44.16%, which ultimately contributes to multi-site fluorescence imaging-guided synergistic treatment with an apoptosis rate of 71.82%. SIGNIFICANCE: This dual biomarker-activatable multiple therapeutic nanoplatform was realized multi-site fluorescence imaging-guided PTT/CDT/GT combination therapy for breast cancer with higher specificity and efficiency, which provides a promising theranostic nanoplatform for the precision and efficiency of breast cancer treatment.

Detection of tumor marker CA72-4 with an electrochemical immunosensor based on MnO2 nanosheets and HNM-AuPtPd nanocomposites.

To accurately detect tumor marker carbohydrate antigen 72-4 (CA72-4) of serum samples is of great significance for the early diagnosis of malignant tumors. In the present study, MnO2/hollow nanobox metal-organic framework (HNM)-AuPtPd nanocomposites were prepared via multi-step synthesis and superposition method and a series of characterizations were carried out. A highly sensitive immunosensor Ab/MnO2/HNM-AuPtPd/GCE based on the composite nanomaterial was further prepared and used to detect the tumor marker CA72-4. The constructed immunosensor achieved signal amplification by increasing the electrocatalytic activity to H2O2 by means of the synergistic effect of MnO2 ultra-thin nanosheets (MnO2 UNs) and HNM-AuPtPd. At the same time, the electrochemical properties of the immunosensor were analyzed using cyclic voltammetry, electrochemical impedance, amperometry (with the test voltage of -0.4 V), and differential pulse voltammetry. The experimental results showed that the MnO2/HNM-AuPtPd nanocomposites were successfully prepared, and the immunosensor Ab/MnO2/HNM-AuPtPd/GCE demonstrated an excellent electrochemical performance. The electrochemical immunosensor had the highest detection sensitivity under the optimal experimental conditions, such as incubation pH of 7.0, incubation time of 60 min, with the addition of 15 µL of H2O2, and in the concentration range 0.001-500 U/mL. It had a low detection limit of 1.78×10-5 U/mL (S/N = 3). Moreover, the serum sample recovery were in the range from 99.38 to 100.52%. This study provides a new method and experimental basis for the detection of tumor markers in clinical practice.

Catalytic oxidation of toluene by manganese oxides: Effect of K+ doping on oxygen vacancy.

Alkali metal potassium was beneficial to the electronic regulation and structural stability of transition metal oxides. Herein, K ions were introduced into manganese oxides by different methods to improve the degradation efficiency of toluene. The results of activity experiments indicated that KMnO4-HT (HT: Hydrothermal method) exhibited outstanding low-temperature catalytic activity, and 90% conversion of toluene can be achieved at 243°C, which was 41°C and 43°C lower than that of KNO3-HT and Mn-HT, respectively. The largest specific surface area was observed on KMnO4-HT, facilitating the adsorption of toluene. The formation of cryptomelane structure over KMnO4-HT could contribute to higher content of Mn3+ and lattice oxygen (Olatt), excellent low-temperature reducibility, and high oxygen mobility, which could increase the catalytic performance. Furthermore, two distinct degradation pathways were inferred. Pathway Ⅰ (KMnO4-HT): toluene → benzyl → benzoic acid → carbonate → CO2 and H2O; Pathway ⅠⅠ (Mn-HT): toluene → benzyl alcohol → benzoic acid → phenol → maleic anhydride → CO2 and H2O. Fewer intermediates were detected on KMnO4-HT, indicating its stronger oxidation capacity of toluene, which was originated from the doping of K+ and the interaction between KOMn. More intermediates were observed on Mn-HT, which can be attributed to the weaker oxidation ability of pure Mn. The results indicated that the doping of K+ can improve the catalytic oxidation capacity of toluene, resulting in promoted degradation of intermediates during the oxidation of toluene.

MnOx-Coffea arabica Husk and Catha edulis Leftover Biochar Nanocomposites for Removal of Methylene Blue from Wastewater.

In this study, we investigated the use of manganese oxide-biochar nanocomposites (MnOx-BNC), synthesized from coffee husk (CH) and khat leftover (KL) for the removal of methylene blue (MB) from wastewater. Pristine biochars of each biomass (CH and KL) as well as their corresponding biochar-based nanocomposites were synthesized by pyrolyzing at 300°C for 1 h. The biochar-based nanocomposites were synthesized by pretreating 25 g of each biomass with 12.5 mmol of KMnO4. To assess the MB removal efficiency, we conducted preliminary tests using 0.2 g of each adsorbent, 20 mL of 20 mg·L-1 MB, pH 7.5, and shaking the mixture at 200 rpm and for 2 h at 25°C. The results showed that the pristine biochar of CH and KL removed 39.08% and 75.26% of MB from aqueous solutions, respectively. However, the MnOx-BNCs removed 99.27% with manganese oxide-coffee husk biochar nanocomposite (MnOx-CHBNC) and 98.20% with manganese oxide-khat leftover biochar nanocomposite (MnOx-KLBNC) of the MB, which are significantly higher than their corresponding pristine biochars. The adsorption process followed the Langmuir isotherm and a pseudo-second-order model, indicating favorable monolayer adsorption. The MnOx-CHBNC and MnOx-KLBNC demonstrated satisfactory removal efficiencies even after three and six cycles of reuse, respectively, indicating their potential effectiveness for alternative use in removing MB from wastewater.

Composite of KLVFF-Transthyretin-Penetratin and Manganese Dioxide Nanoclusters: A Multifunctional Agent against Alzheimer's ß-Amyloid Fibrillogenesis.

Design of amyloid ß-protein (Aß) inhibitors is considered an effective strategy for the prevention and treatment of Alzheimer's disease (AD). However, the limited blood-brain barrier (BBB) penetration and poor Aß-targeting capability restricts the therapeutic efficiency of candidate drugs. Herein, we have proposed to engineer transthyretin (TTR) by fusion of the Aß-targeting peptide KLVFF and cell-penetrating peptide Penetratin to TTR, and derived a fusion protein, KLVFF-TTR-Penetratin (KTP). Moreover, to introduce the scavenging activity for reactive oxygen species (ROS), a nanocomposite of KTP and manganese dioxide nanoclusters (KTP@MnO2) was fabricated by biomineralization. Results revealed that KTP@MnO2 demonstrated significantly enhanced inhibition on Aß aggregation as compared to TTR. The inhibitory effect was increased from 18%, 33%, and 49% (10, 25, and 50 µg/mL TTR, respectively) to 52%, 81%, and 100% (10, 25, and 50 µg/mL KTP@MnO2). In addition, KTP@MnO2 could penetrate the BBB and target amyloid plaques. Moreover, multiple ROS, including hydroxyl radicals, superoxide radicals, hydrogen peroxide, and Aß-induced-ROS, which cannot be scavenged by TTR, were scavenged by KTP@MnO2, thus resulting in the mitigation of cellular oxidative damages. More importantly, cell culture and in vivo experiments with AD nematodes indicated that KTP@MnO2 at 50 µg/mL increased the viability of Aß-treated cells from 66% to more than 95%, and completely cleared amyloid plaques in AD nematodes and extended their lifespan by 7 d. Overall, despite critical aspects such as the stability, metabolic distribution, long-term biotoxicity, and immunogenicity of the nanocomposites in mammalian models remaining to be investigated, this work has demonstrated the multifunctionality of KTP@MnO2 for targeting Aß in vivo, and provided new insights into the design of multifunctional nanocomposites of protein-metal clusters against AD.

Tumor microenvironment activated mussel-inspired hollow mesoporous nanotheranostic for enhanced synergistic photodynamic/chemodynamic therapy.

Anti-tumor therapies reliant on reactive oxygen species (ROS) as primary therapeutic agents face challenges due to a limited oxygen substrate. Photodynamic therapy (PDT) is particularly hindered by inherent hypoxia, while chemodynamic therapy (CDT) encounters obstacles from insufficient endogenous hydrogen peroxide (H2O2) levels. In this study, we engineered biodegradable tumor microenvironment (TME)-activated hollow mesoporous MnO2-based nanotheranostic agents, designated as HAMnO2A. This construct entails loading artemisinin (ART) into the cavity and surface modification with a mussel-inspired polymer ligand, namely hyaluronic acid-linked poly(ethylene glycol)-diethylenetriamine-conjugated (3,4-dihydroxyphenyl) acetic acid, and the photosensitizer Chlorin e6 (mPEG-HA-Dien-(Dhpa/Ce6)), facilitating dual-modal imaging-guided PDT/CDT synergistic therapy. In vitro experimentation revealed that HAMnO2A exhibited ideal physiological stability and enhanced cellular uptake capability via CD44-mediated endocytosis. Additionally, it was demonstrated that accelerated endo-lysosomal escape through the pH-dependent protonation of Dien. Within the acidic and highly glutathione (GSH)-rich TME, the active component of HAMnO2A, MnO2, underwent decomposition, liberating oxygen and releasing both Mn2+ and ART. This process alleviates hypoxia within the tumor region and initiates a Fenton-like reaction through the combination of ART and Mn2+, thereby enhancing the effectiveness of PDT and CDT by generating increased singlet oxygen (1O2) and hydroxyl radicals (•OH). Moreover, the presence of Mn2+ ions enabled the activation of T1-weighted magnetic resonance imaging. In vivo findings further validated that HAMnO2A displayed meaningful tumor-targeting capabilities, prolonged circulation time in the bloodstream, and outstanding efficacy in restraining tumor growth while inducing minimal damage to normal tissues. Hence, this nanoplatform serves as an efficient all-in-one solution by facilitating the integration of multiple functions, ultimately enhancing the effectiveness of tumor theranostics.

Algal Extracellular Organic Matter Induced Photochemical Oxidation of Mn(II) to Solid Mn Oxide: Role of Mn(III)-EOM Complex and Its Ability to Remove 17α-Ethinylestradiol.

Photosensitizer-mediated abiotic oxidation of Mn(II) can yield soluble reactive Mn(III) and solid Mn oxides. In eutrophic water systems, the ubiquitous algal extracellular organic matter (EOM) is a potential photosensitizer and may have a substantial impact on the oxidation of Mn(II). Herein, we focused on investigating the photochemical oxidation process from Mn(II) to solid Mn oxide driven by EOM. The results of irradiation experiments demonstrated that the generation of Mn(III) intermediate was crucial for the successful photo oxidization of Mn(II) to solid Mn oxide mediated by EOM. EOM can serve as both a photosensitizer and a ligand, facilitating the formation of the Mn(III)-EOM complex. The complex exhibited excellent efficiency in removing 17α-ethinylestradiol. Furthermore, the complex underwent decomposition as a result of reactions with reactive intermediates, forming a solid Mn oxide. The presence of nitrate can enhance the photochemical oxidation process, facilitating the conversion of Mn(II) to Mn(III) and then to solid Mn oxide. This study deepens our grasp of Mn(II) geochemical processes in eutrophic water and its impact on organic micropollutant fate.

Reactive Oxygen Species Scavenging Injectable Hydrogel Potentiates the Therapeutic Potential of Mesenchymal Stem Cells in Skin Flap Regeneration.

Cell-based therapies offer tremendous potential for skin flap regeneration. However, the hostile microenvironment of the injured tissue adversely affects the longevity and paracrine effects of the implanted cells, severely reducing their therapeutic effectiveness. Here, an injectable hydrogel (nGk) with reactive oxygen species (ROS) scavenging capability, which can amplify the cell viability and functions of encapsulated mesenchymal stem cells (MSCs), is employed to promote skin flap repair. nGk is formulated by dispersing manganese dioxide nanoparticles (MnO2 NPs) in a gelatin/κ-carrageenan hydrogel, which exhibits satisfactory injectable properties and undergoes a sol-gel phase transition at around 40 °C, leading to the formation of a solid gel at physiological temperature. MnO2 NPs enhance the mechanical properties of the hydrogel and give it the ability to scavenge ROS, thus providing a cell-protective system for MSCs. Cell culture studies show that nGk can mitigate the oxidative stress, improve cell viability, and boost stem cell paracrine function to promote angiogenesis. Furthermore, MSC-loaded nGk (nGk@MSCs) can improve the survival of skin flaps by promoting angiogenesis, reducing inflammatory reactions, and attenuating necrosis, providing an effective approach for tissue regeneration. Collectively, injectable nGk has substantial potential to enhance the therapeutic benefits of MSCs, making it a valuable delivery system for cell-based therapies.

Cascade reaction triggered colorimetric array for identification of organophosphorus pesticides congeners.

A modern agriculture uses alternative pest control methods to boost productivity, leading to an accumulation of organophosphorus (OPPs) congeners. This necessitates an intuitive and quick way to identify OPPs congeners. A colorimetric sensor for detecting OPPs congeners using a double-enzyme cascade reaction has been successfully designed and constructed in this study. The OPPs regulate the color changes induced by manganese dioxide nanoflowers (MnO2 NFs) and specific alkaline phosphatases (ALP) during the etching of gold nanopyramids (Au NBPs). The ascorbic acid (AA) produced by ALP hydrolysis inhibits Au NBPs etching by MnO2 NFs oxidized 3, 3', 5, 5'-tetramethylbenzidine (TMB). By inhibiting ALP catalytic activity, OPPs prevent AA formation. In this process, Au NBPs will undergo further etching, resulting in various colors so they can be analyzed semi-quantitatively with the naked eye. It has been found that different types of OPPs inhibit enzymes differently and therefore result in varying degrees of etching of Au NBPs. Principal Component Analysis (PCA) is performed by smart devices that convert R, G, and B signals into digital signals. This colorimetric array tests various foods (tea, apple, and cabbage). Colorimetric visualization sensors combined with data analysis will be used in real-life product development.

Microneedles loaded with cerium-manganese oxide nanoparticles for targeting macrophages in the treatment of rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis (RA) is a prevalent inflammatory autoimmune disease characterised by persistent inflammation and joint damage with elevated levels of reactive oxygen species (ROS). Current treatment modalities for RA have significant limitations, including poor bioavailability, severe side effects, and inadequate targeting of inflamed joints. Herein, we synthesised cerium/manganese oxide nanoparticles (NPs) as efficient drug carriers with antioxidant and catalytic-like functions that can eliminate ROS to facilitate the polarization of macrophages phenotype from M1 to M2 and alleviate inflammation. Methotrexate (MTX), a first-line RA medication, was loaded into the NPs, which were further modified with bovine serum albumin (BSA) and integrated into dissolving hyaluronic acid-based microneedles (MNs) for transdermal delivery. RESULT: This innovative approach significantly enhanced drug delivery efficiency, reduced RA inflammation, and successfully modulated macrophage polarization toward an anti-inflammatory phenotype. CONCLUSION: This research not only presents a promising drug delivery strategy for RA but also contributes broadly to the field of immune disease treatment by offering an advanced approach for macrophage phenotypic reprogramming.

Bionic nanotheranostic for multimodal imaging-guided NIR-II-photothermal cancer therapy.

In photothermal therapy (PTT), the photothermal conversion of the second near-infrared (NIR-II) window allows deeper penetration and higher laser irradiance and is considered a promising therapeutic strategy for deep tissues. Since cancer remains a leading cause of deaths worldwide, despite the numerous treatment options, we aimed to develop an improved bionic nanotheranostic for combined imaging and photothermal cancer therapy. We combined a gold nanobipyramid (Au NBP) as a photothermal agent and MnO2 as a magnetic resonance enhancer to produce core/shell structures (Au@MnO2; AM) and modified their surfaces with homologous cancer cell plasma membranes (PM) to enable tumour targeting. The performance of the resulting Au@MnO2@PM (AMP) nanotheranostic was evaluated in vitro and in vivo. AMP exhibits photothermal properties under NIR-II laser irradiation and has multimodal in vitro imaging functions. AMP enables the computed tomography (CT), photothermal imaging (PTI), and magnetic resonance imaging (MRI) of tumours. In particular, AMP exhibited a remarkable PTT effect on cancer cells in vitro and inhibited tumour cell growth under 1064 nm laser irradiation in vivo, with no significant systemic toxicity. This study achieved tumour therapy guided by multimodal imaging, thereby demonstrating a novel strategy for the use of bionic gold nanoparticles for tumour PTT under NIR-II laser irradiation.

Enhancing Photothermal/Photodynamic Therapy for Glioblastoma by Tumor Hypoxia Alleviation and Heat Shock Protein Inhibition Using IR820-Conjugated Reduced Graphene Oxide Quantum Dots.

We use low-molecular-weight branched polyethylenimine (PEI) to produce cytocompatible reduced graphene oxide quantum dots (rGOQD) as a photothermal agent and covalently bind it with the photosensitizer IR-820. The rGOQD/IR820 shows high photothermal conversion efficiency and produces reactive oxygen species (ROS) after irradiation with near-infrared (NIR) light for photothermal/photodynamic therapy (PTT/PDT). To improve suspension stability, rGOQD/IR820 was PEGylated by anchoring with the DSPE hydrophobic tails in DSPE-PEG-Mal, leaving the maleimide (Mal) end group for covalent binding with manganese dioxide/bovine serum albumin (MnO2/BSA) and targeting ligand cell-penetrating peptide (CPP) to synthesize rGOQD/IR820/MnO2/CPP. As MnO2 can react with intracellular hydrogen peroxide to produce oxygen for alleviating the hypoxia condition in the acidic tumor microenvironment, the efficacy of PDT could be enhanced by generating more cytotoxic ROS with NIR light. Furthermore, quercetin (Q) was loaded to rGOQD through π-π interaction, which can be released in the endosomes and act as an inhibitor of heat shock protein 70 (HSP70). This sensitizes tumor cells to thermal stress and increases the efficacy of mild-temperature PTT with NIR irradiation. By simultaneously incorporating the HSP70 inhibitor (Q) and the in situ hypoxia alleviating agent (MnO2), the rGOQD/IR820/MnO2/Q/CPP can overcome the limitation of PTT/PDT and enhance the efficacy of targeted phototherapy in vitro. From in vivo study with an orthotopic brain tumor model, rGOQD/IR820/MnO2/Q/CPP administered through tail vein injection can cross the blood-brain barrier and accumulate in the intracranial tumor, after which NIR laser light irradiation can shrink the tumor and prolong the survival times of animals by simultaneously enhancing the efficacy of PTT/PDT to treat glioblastoma.

Three-dimensional DNA biomimetic networks (B-3D Net)-based ratiometric fluorescence platform for cancer-related gene biosensing.

Efficient detection of cancer-related nucleic acids is pivotal for early cancer diagnosis. This study introduces a target induced three-dimensional DNA biomimetic networks (B-3D Net)-based ratiometric fluorescence platform using manganese dioxide nanosheets (MnO2 NS)/o-phenylenediamine in combination with hybridization chain reaction to detect cancer-related genes (p53 gene). The incorporation of multiple signals within the B-3D networks can significantly enhance catalytic activity and amplify the output signals, enabling a high sensitivity. Compared with traditional ratio fluorescence platforms, there is no demand to synthesize fluorescent nanoprobes due to the in-situ formation of fluorescence species, which is simple and cost-effective. The corresponding assay demonstrated exceptional sensitivity (with a detection limit as low as 2 fM), selectivity, reproducibility, and accuracy, which mitigates disturbances caused by instrument errors, an inaccurate probe count, and the microenvironment. Furthermore, the ease and straightforwardness of discerning changes in fluorescent brightness and colour by the naked eye are evident. Using the relevant software, a linear relationship between fluorescent images using a smartphone and target concentration was obtained. Hence, the novel ratiometric sensing system will demonstrate new opportunities on determination of target DNA samples in complex biological environments.

Flexible microfluidic colorimetric detection chip integrated with ABTS·+ and Co@MnO2 nanozyme catalyzed TMB reaction systems for bio-enzyme free detection of sweat uric acid.

BACKGROUND: The development of wearable detection devices that can achieve noninvasive, on-site and real-time monitoring of sweat metabolites is of great demand and practical significance for point-of-care testing and healthcare monitoring. Monitoring uric acid (UA) content in sweat provides a simple and promising way to reduce the risk of gout and hyperuricemia. Traditional bioenzyme based UA assays suffer from high cost, poor stability, inconvenience for storage and easy deactivation of bioenzymes. Wearable microfluidic colorimetric detection device for sweat UA detection has not been reported. The development of novel wearable microfluidic colorimetric detection chip with no requirement of bioenzymes for sweat UA detection is of great importance for health care monitoring. RESULTS: Firstly, Co@MnO2 nanozyme with high oxidase-like activity was synthesized and characterized. Co@MnO2 can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) directly to generate blue-green colored ox-TMB. Green colored 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) radical (ABTS·+) was produced by the oxidation of ABTS by potassium persulfate. UA exhibits distinct quenching effect on Co@MnO2 catalyzed TMB colorimetric reaction system and ABTS·+ based colorimetric system, leading to obvious color fading of the two colorimetric systems. Then, a flexible microfluidic colorimetric detection chip for UA detection was fabricated by assembling Co@MnO2/TMB modified paper chips and ABTS·+ modified paper chips into a polydimethylsiloxane (PDMS) microfluidic chip. The fabricated microfluidic colorimetric detection chip exhibits good linear relationship for sweat UA detection. The linear range is from 20 to 200 µmol/L with detection limit as low as 6.6 µmol/L. Good results were obtained for the detection of UA in actual sweat from three volunteers. SIGNIFICANCE: This work provides two bio-enzyme free colorimetric detection systems for UA detection. Furthermore, a simple, low-cost and selective flexible wearable microfluidic colorimetric detection chip was fabricated for noninvasive and on-site detection of sweat UA, which holds great application potential for personal health monitoring and point-of-care testing.

The influence of steroidal implants and manganese sulfate supplementation on growth performance, trace mineral status, hepatic gene expression, hepatic enzyme activity, and circulating metabolites in feedlot steers.

Angus-cross steers (n = 144; 359 kg ±â€…13.4) were used to assess the effect of dietary Mn and steroidal implants on performance, trace minerals (TM) status, hepatic enzyme activity, hepatic gene expression, and serum metabolites. Steers (n = 6/pen) were stratified by BW in a 3 × 2 factorial. GrowSafe bunks recorded individual feed intake (experimental unit = steer; n = 24/treatment). Dietary treatments included (MANG; 8 pens/treatment; Mn as MnSO4): (1) no supplemental Mn (analyzed 14 mg Mn/kg DM; Mn0); (2) 20 mg supplemental Mn/kg DM (Mn20); (3) 50 mg supplemental Mn/kg DM (Mn50). Within MANG, steers received a steroidal implant treatment (IMP) on day 0: (1) no implant; NO; or (2) combination implant (Revalor-200; REV). Liver biopsies for TM analysis and qPCR, and blood for serum glucose, insulin, non-esterified fatty acids, and urea-N (SUN) analysis were collected on days 0, 20, 40, and 77. Data were analyzed as a randomized complete block with a factorial arrangement of treatments including fixed effects of Mn treatment (MANG) and implant (IMP) using PROC MIXED of SAS 9.4 using initial BW as a covariate. Liver TM, serum metabolite, enzyme activity, and gene expression data were analyzed as repeated measures. No MANG × IMP effects were noted (P ≥ 0.12) for growth performance or carcass characteristic measures. Dietary Mn did not influence final body weight, overall ADG, or overall G:F (P ≥ 0.14). Liver Mn concentration increased with supplemental Mn concentration (MANG; P = 0.01). An IMP × DAY effect was noted for liver Mn (P = 0.01) where NO and REV were similar on day 0 but NO cattle increased liver Mn from days 0 to 20 while REV liver Mn decreased. Relative expression of MnSOD in the liver was greater in REV (P = 0.02) compared to NO and within a MANG × IMP effect (P = 0.01) REV increased liver MnSOD activity. These data indicate current NASEM Mn recommendations are adequate to meet the demands of finishing beef cattle given a steroidal implant. Despite the roles of Mn in metabolic pathways and antioxidant defense, a basal diet containing 14 mg Mn/kg DM was sufficient for the normal growth of finishing steers. This study also provided novel insight into how implants and supplemental Mn influence genes related to arginine metabolism, urea synthesis, antioxidant capacity, and TM homeostasis as well as arginase and MnSOD activity in hepatic tissue of beef steers.

Steroidal implants improve cattle growth and efficiency partially through increased net protein synthesis resulting in increased skeletal muscle hypertrophy. Necessary to support this increased growth are trace minerals (TM). Manganese (Mn) is essential, serving as a cofactor and activator of various enzymes. Manganese plays a crucial role in ruminant animals by supporting nitrogen recycling while also being essential for mitochondrial antioxidant defense. Consulting nutritionists routinely supplement Mn, amongst other TM, at concentrations greater than current recommendations. However, there is limited research on the impact of supplemental Mn in implanted finishing cattle. Our prior work suggests steroidal implants decrease liver Mn concentration. This is of interest as liver Mn concentration is tightly regulated. Therefore, this study evaluated the effects of steroidal implants and manganese sulfate supplementation on cattle growth performance, trace mineral status, expression of relevant hepatic genes, hepatic enzyme activity, and circulating metabolites in feedlot steers. In this study, supplementing Mn at the recommended concentration did not influence the growth of both implanted and non-implanted cattle.

In vivo detection of DNA secondary structures using permanganate/S1 footprinting with direct adapter ligation and sequencing (PDAL-Seq).

DNA secondary structures are essential elements of the genomic landscape, playing a critical role in regulating various cellular processes. These structures refer to G-quadruplexes, cruciforms, Z-DNA or H-DNA structures, amongst others (collectively called 'non-B DNA'), which DNA molecules can adopt beyond the B conformation. DNA secondary structures have significant biological roles, and their landscape is dynamic and can rearrange due to various factors, including changes in cellular conditions, temperature, and DNA-binding proteins. Understanding this dynamic nature is crucial for unraveling their functions in cellular processes. Detecting DNA secondary structures remains a challenge. Conventional methods, such as gel electrophoresis and chemical probing, have limitations in terms of sensitivity and specificity. Emerging techniques, including next-generation sequencing and single-molecule approaches, offer promise but face challenges since these techniques are mostly limited to only one type of secondary structure. Here we describe an updated version of a technique permanganate/S1 nuclease footprinting, which uses potassium permanganate to trap single-stranded DNA regions as found in many non-B structures, in combination with S1 nuclease digest and adapter ligation to detect genome-wide non-B formation. To overcome technical hurdles, we combined this method with direct adapter ligation and sequencing (PDAL-Seq). Furthermore, we established a user-friendly pipeline available on Galaxy to standardize PDAL-Seq data analysis. This optimized method allows the analysis of many types of DNA secondary structures that form in a living cell and will advance our knowledge of their roles in health and disease.

Tumor acidification and GSH depletion by bimetallic composite nanoparticles for enhanced chemodynamic therapy of TNBC.

Chemodynamic therapy (CDT) based on intracellular Fenton reaction to produce highly cytotoxic reactive oxygen species (ROS) has played an essential role in tumor therapy. However, this therapy still needs to be improved by weakly acidic pH and over-expression of glutathione (GSH) in tumor microenvironment (TEM), which hinders its future application. Herein, we reported a multifunctional bimetallic composite nanoparticle MnO2@GA-Fe@CAI based on a metal polyphenol network (MPN) structure, which could reduce intracellular pH and endogenous GSH by remodeling tumor microenvironment to improve Fenton activity. MnO2 nanoparticles were prepared first and MnO2@GA-Fe nanoparticles with Fe3+ as central ion and gallic acid (GA) as surface ligands were prepared by the chelation reaction. Then, carbonic anhydrase inhibitor (CAI) was coupled with GA to form MnO2@GA-Fe@CAI. The properties of the bimetallic composite nanoparticles were studied, and the results showed that CAI could reduce intracellular pH. At the same time, MnO2 could deplete intracellular GSH and produce Mn2+ via redox reactions, which re-established the TME with low pH and GSH. In addition, GA reduced Fe3+ to Fe2+. Mn2+ and Fe2+ catalyzed the endogenous H2O2 to produce high-lever ROS to kill tumor cells. Compared with MnO2, MnO2@GA-Fe@CAI could reduce the tumor weight and volume for the xenograft MDA-MB-231 tumor-bearing mice and the final tumor inhibition rate of 58.09 ± 5.77%, showing the improved therapeutic effect as well as the biological safety. Therefore, this study achieved the high-efficiency CDT effect catalyzed by bimetallic through reshaping the tumor microenvironment.

A Comparative Analysis of the Antibacterial Spectrum of Ultrasmall Manganese Ferrite Nanozymes with Varied Surface Modifications.

Bacterial infectious diseases pose a significant global challenge. However, conventional antibacterial agents exhibit limited therapeutic effectiveness due to the emergence of drug resistance, necessitating the exploration of novel antibacterial strategies. Nanozymes have emerged as a highly promising alternative to antibiotics, owing to their particular catalytic activities against pathogens. Herein, we synthesized ultrasmall-sized MnFe2O4 nanozymes with different charges (MnFe2O4-COOH, MnFe2O4-PEG, MnFe2O4-NH2) and assessed their antibacterial capabilities. It was found that MnFe2O4 nanozymes exhibited both antibacterial and antibiofilm properties attributed to their excellent peroxidase-like activities and small sizes, enabling them to penetrate biofilms and interact with bacteria. Moreover, MnFe2O4 nanozymes effectively expedite wound healing within 12 days and facilitate tissue repair and regeneration while concurrently reducing inflammation. MnFe2O4-COOH displayed favorable antibacterial activity against Gram-positive bacteria, with 80% bacterial removal efficiency against MRSA by interacting with phosphatidylglycerol (PG) and cardiolipin (CL) of the membrane. By interacting with negatively charged bacteria surfaces, MnFe2O4-NH2 demonstrated the most significant and broad-spectrum antibacterial activity, with 95 and 85% removal efficiency against methicillin-resistant Staphylococcus aureus (MRSA) and P. aeruginosa, respectively. MnFe2O4-PEG dissipated membrane potential and reduced ATP levels in MRSA and P. aeruginosa, showing relatively broad-spectrum antibacterial activity. To conclude, MnFe2O4 nanozymes offer a promising therapeutic approach for treating wound infections.