Glucose Oxidation Research Articles

(Invited) Selective Glucose Conversion into Gluconic Acid By Dye-Sensitized Photoelectrochemical Cell

Gluconic acid, one of the valuable products of oxidized glucose projected to soon hit a market value of US$1.9 billion is currently produced using relatively expensive electrochemical, environmentally unsafe chemical or thermal selective oxidation methods to meet market demand. Dye-sensitized photoelectrochemical cells (DSPECs) which has effectively been utilized for selective biomass conversion into other valuable products (alongside hydrogen evolution) is a cheaper, greener and safer alternative unexplored in this field. Herein, we explore this green technology for selective oxidation of glucose into gluconic acid in an aqueous system, employing metal-free organic dye (E)-3-(5-(4-(bis(2',4'-dibutoxy-[1,1'-biphenyl]-4-yl) amino) phenyl) thiophen-2-yl)-2-cyanoacrylic acid (D35) with organic catalyst (4-Acetamido-2,2,6,6-tetramethylpiperidine 1-oxyl) ACT at 0 V vs NHE. Photophysical details revealed the occurrence of intermolecular electron transfer between D35 and ACT under 1 sun illumination (100 mW/cm²). Enhanced generation of the strongly oxidizing reactive oxoammonium species, ACT+, by the photoanode drives the conversion of glucose into gluconic acid. The photoanode assembly employed exhibited remarkable stability, sustaining a continuous operation for 3 days and 88% selectivity for gluconic acid at pH 7. The aqueous phase stability, selectivity, neutral environment and ambient operation of the setup indicates it potential for biomass conversion and hydrogen production towards commercialization purposes.

Enzyme Engineering to Produce SWCNT Nanosensors as a Generalizable Platform for Biochemical Imaging and Sensing

Single-walled carbon nanotubes (SWCNT) stand out as attractive candidates for near-infrared (nIR) fluorescent imaging and chemical sensing. However, to render SWCNT chemically-selective, rational design of the surface corona is required to achieve sufficient sensitivity and selectivity to the target analyte. Recently, we reported on a facile sonication-based generation of glucose oxidase (GOx)-SWCNT conjugate for glucose detection [1]. Notably, we found that the analyte response mechanism does not involve catalytic oxidation of glucose, which motivated us to develop nanosensors using catalytically inactive GOx for enhanced reversibility and biocompatibility. In this study, we study the generalizability of our approach in producing SWCNT-based nanosensors based on 1- facile direct probe tip sonication, and 2- with engineered enzymes, showing the potential applicability of the sonication-based approach as a generalizable strategy for generating rationally designed nanosensors capable of detecting and imaging various analytically-relevant biomolecules.In this work, to test the generalizability of generating enzyme-SWCNT nanosensors, we generated conjugates by facile direct sonication of SWCNT with following enzymes: GOx, choline oxidase (ChOx), horseradish peroxidase (HRP), acetylcholineesterase, tyrosinase, cholesterol oxidase (CholOx), lactate oxidase, alcohol oxidase, xanthine oxidase, and galactose oxidase. Remarkably, six out of nine enzymes yielded stable suspensions of enzyme-SWCNT conjugates following probe-tip sonication, all of which successfully worked as nanosensors to detect their corresponding analytes. These nanosensors, in particular HRP-SWCNT and CholOx-SWCNT, exhibited excellent responses to their targets, with a maximum ΔF/F 0 of up to 300 % and 100 %, respectively. H2O2 is known to quench SWCNT fluorescence, and H2O2 nanosensors previously developed with SWCNT exhibited a negative fluorescence modulation as the sensor output with some challenges towards nanosensor selectivity. We highlight that our approach enables HRP-SWCNT nanosensor generation, which provides a strong ΔF/F 0 = 300 % and instantaneous turn-on response towards H2O2 within 2 s. Next, we sought to show that enzyme inactivation can produce SWCNT-based nanosensors that detect analytes without analyte consumption. To do so, we use ChOx as a model system to show that recombinant enzymes can be used as a generalizable approach to generating catalytically-inactive nanosensors. As expected, nanosensors prepared with mutant-ChOx exhibited responses comparable to those prepared with native ChOx, but without consuming the analyte or producing toxic byproducts such as H2O2. Thus, sonication-based physisorption of engineered enzymes to SWCNTs holds the potential to facilitate rapid nanosensor generation capable of detecting various biologically relevant molecules with reversibility and biocompatibility, thereby motivating their use in in vivo applications.[1] Nishitani, S., Tran, T., Puglise, A., Yang, S. & Landry, M. Engineered Glucose Oxidase-Carbon Nanotube Conjugates for Tissue-Translatable Glucose Nanosensors. Angew. Chem. Int. Ed Engl. e202311476 (2023)

Enhanced Electrohydrogenation of Cis,Cis-Muconic Acid to Trans-3-Hexenedioic Acid Using Hybrid Metal/Carbon Fiber Cathodes

Organic electrosynthesis is a long-known technique for diverse product development and efficient synthesis. With the recent rise of biomass as an alternative carbon and energy source, electrochemistry is further gaining popularity due to its inherently green and environmentally benign operating conditions. Electrochemical hydrogenation (ECH) reactions are particularly attractive for biomass conversion due to their ability to abstract hydrogen from water, tolerate biogenic impurities, and utilize Earth-abundant base metal electrodes. Moreover, the rate and selectivity of the reaction can be tubed by controlling the electrode material, operating potential/current density, and reactor design. However, the implementation of this decarbonized technology for chemical production is still hampered by low productivity and, as a result, unfavorable economics. cis,cis-Muconic acid (ccMA), a bioderived C6 diunsaturated diacid platform molecule, can be converted into commodity chemicals like caprolactam, adipic acid (AA), and terephthalic acid, with AA being of particular interest for the synthesis of nylon 6,6.1 Apart from various drop-in chemicals, ccMA can also be electrochemically upgraded to trans-3-hexenedioic acid (t3HDA), a potential bio-advantaged substitute for AA as the additional C=C bond in t3HDA can be leveraged to synthesize performance-advantaged polyamides.2,3 In this work, we investigated the electrohydrogenation of ccMA to t3HDA over Pb cathodes. We demonstrate that the reaction follows a radical-based pathway involving sequential electron transfer and hydrogen addition in solution to selectively produce t3HDA (100% selectivity). Next, we contacted the cathode with carbon felts (CF) to increase productivity. CF are often used in fuel cells and H2O2 electrolyzers due to their excellent conductivity, porosity for enhanced turbulence, and ability to tune the gas-liquid-solid three-phase interface. Following similar principles, we placed a CF (3mm. thickness) in contact with the Pb cathode to lower the charge transfer resistance (~3Ω) at the interface. The surface functionalities of carbon allowed us to further tune the hydrophobicity/hydrophilicity of our hybrid electrode. Molecular dynamics (MD) calculations provided critical insights into the role of surface functionalities and guided the optimal functionalization of CF’s surface. Combining reactor configuration with fine-tuning of the electrode’s microenvironment, we were able to achieve a 50x increase in t3HDA productivity reaching up to 20 g/cm2/day at a current density of 200 mA/cm2. We further replaced the kinetically sluggish oxygen-evolution reaction with the glucose oxidation reaction at the anode, allowing us to operate the electrolyzer at a lower cell potential.Overall, ECH represents a valuable alternative to thermochemical transformations for biomass upgrading. This work provides critical insights into reactor modifications for the scaled-up synthesis of bio-derived performance monomers via hybrid microbial electrosynthesis (HMES).

The polyunsaturated fatty acid docosahexaenoic affects mitochondrial function in prostate cancer cells

BackgroundProstate cancer (PCa) shows a rewired metabolism featuring increased fatty acid uptake and synthesis via de novo lipogenesis, both sharply related to mitochondrial physiology. The docosahexaenoic acid (DHA) is an omega-3 polyunsaturated fatty acid (PUFA) that exerts its antitumoral properties via different mechanisms, but its specific action on mitochondria in PCa is not clear. Therefore, we investigated whether the DHA modulates mitochondrial function in PCa cell lines.MethodsHere, we evaluated mitochondrial function of non-malignant PNT1A and the castration-resistant (CRPC) prostate 22Rv1 and PC3 cell lines in response to DHA incubation. For this purpose, we used Seahorse extracellular flux assay to assess mitochondria function, [14C]-glucose to evaluate its oxidation as well as its contribution to fatty acid synthesis, 1H-NMR for metabolite profile determination, MitoSOX for superoxide anion production, JC-1 for mitochondrial membrane polarization, mass spectrometry for determination of phosphatidylglycerol levels and composition, staining with MitoTracker dye to assess mitochondrial morphology under super-resolution in addition to Transmission Electron Microscopy, In-Cell ELISA for COX-I and SDH-A protein expression and flow cytometry (Annexin V and 7-AAD) for cell death estimation.ResultsIn all cell lines DHA decreased basal respiratory activity, ATP production, and the spare capacity in mitochondria. Also, the omega-3 induced mitochondrial hyperpolarization, ROS overproduction and changes in membrane phosphatidylglycerol composition. In PNT1A, DHA led to mitochondrial fragmentation and it increased glycolysis while in cancer cells it stimulated glucose oxidation, but decreased de novo lipogenesis specifically in 22Rv1, indicating a metabolic shift. In all cell lines, DHA modulated several metabolites related to energy metabolism and it was incorporated in phosphatidylglycerol, a precursor of cardiolipin, increasing the unsaturation index in the mitochondrial membrane. Accordingly, DHA triggered cell death mainly in PNT1A and 22Rv1.ConclusionIn conclusion, mitochondrial metabolism is significantly affected by the PUFA supplementation to the point that cells are not able to proliferate or survive under DHA-enriched condition. Moreover, combination of DHA supplementation with inhibition of metabolism-related pathways, such as de novo lipogenesis, may be synergistic in castration-resistant prostate cancer.

Two-Dimensional Nanorod-Shaped Co(II) Coordination Polymer on Three-Dimensional Metallic Foam: A Hybrid Platform for Electrochemical Oxidation of Glucose.

This study unveils a novel electrochemical biosensor for monitoring glucose in biological fluids by employing nanorods of a cobalt-bispyridyl/dicarboxylate framework grown in a layer-by-layer manner on a highly porous nickel substrate. The hybrid microporous system has a bicatalytic effect on glucose oxidation due to the synergistic catalytic impact of the nickel and cobalt ions with varying oxidation states as electroactive sites. In addition, the controlled growth of inorganic-organic frameworks changes the mechanism of electron transfer from a diffusion-controlled process to an adsorption-controlled process, thus yielding a low onset oxidation potential (∼0.21 V/Ag-AgCl) and a high current intensity (∼1 mA) for the oxidation of glucose in alkaline media. A fast response time (∼2 s) and a reasonably high sensitivity (0.14 μA μM-1) within a broad linear range (40-360 μM) have determined the suitability and superiority of the hybrid electrode for glucose monitoring compared to many metal-organic-based biosensors. The facile fabrication process of the Co(II) coordination polymer/Ni substrate with a large surface area that benefits from the synergetic catalytic activity of nickel-cobalt hybrids may pave the way for the development of novel hybrid electrodes for biosensors and direct glucose fuel cells.

Novel self-powered sandwich type Aptamer sensor for estrogen detection assisted with peroxidase mimic Cu-MOF

A novel self-powered and flexible enzymatic biofuel cell (EBFC)-based aptasensor was developed for the sensitive and selective detection of 17 β-estradiol (E2). A flexible polyvinyl alcohol (PVA)-tannic acid‑carbon nanotube/reduced graphene oxide (PTCR) substrate was modified with gold nanoparticles (AuNPs) and thiolated aptamer 1 (Apt1) to yield Apt1@AuNPs/PTCR. A copper-based metal-organic framework (Cu-MOF) with peroxidase mimicking activity was employed to anchor glucose oxidase (GOD) and Apt2, forming the Cu-MOF@GOD/Apt2 tag. When E2 was recognized by Apt1, the anchored E2 quantitatively recognized Cu-MOF@GOD/Apt2 to create a Cu-MOF@GOD/Apt2-E2-Apt1 sandwich structure for glucose oxidation to generate electrical power. Increased E2 concentrations enhanced Cu-MOF@GOD/Apt2 capture and amplified the electrical signal. The electrical power increased linearly as the E2 concentration increased from 1.0 pM to 1.0 nM. The sensor was successfully applied to various food samples and blood serum detection. This work promoted the application of novel self-powered biosensors for food safety analysis.

A minimally invasive sensing system based on hydrogel microneedle patches and Au/Cu2O nanospheres modified screen-printed carbon electrode for glucose monitoring in interstitial skin fluid

Glucose monitoring in interstitial skin fluid (ISF) has become a novel approach for diabetes management. In this paper, a minimally invasive sensing system consisted of methacrylated hyaluronic acid (MeHA) based microneedle patches and Au/Cu2O nanospheres modified screen-printed carbon electrode (SPCE) was designed for glucose monitoring in the ISF of living mice. The highly swellable and biocompatible MeHA microneedle patches can effectively extract ISF from the skin, barely cause pain to the living mice. The glucose level in the extracted ISF was detected via an enzyme-free electrochemical sensor using the Au/Cu2O nanospheres as the electrocatalyst. The doping of Au into Cu2O resulted in a highly conductive and active electrocatalyst for glucose oxidation, which improved the sensing performance of glucose sensor. A wide linear range (0.02 – 6 mM), low detection limit (0.018 mM), and high sensitivity (110.38 μA mM−1 cm−2) were obtained under the optimized condition. The obtained results exhibited a comparable trend to those obtained from commercial glucometers. We have combined successfully MeHA patches for ISF extraction with enzyme-free electrochemical glucose sensor. Therefore, this novel sensing system holds great potential for diabetes management in a minimally invasive manner.

An adaptive-conforming biodegradable flexible power supply based on continuous glucose oxidation

This paper reports an adaptive degradable flexible power supply. The power supply is produced using a batch-printed, easy-to-operate screen-printing technique that converts the chemical energy of glucose and oxygen into electricity. The power supply has stable current and voltage outputs in vitro, delivering a consistent open circuit potential of 0.2 V in vitro. Due to the flexibility and degradability of the power supply, the power supply can be implanted anywhere in the tissue. This breaks through the limitation of location, for example, mechanical energy harvesters can only be implanted in places with frequent movements. And due to the degradable nature of the power supply, surgical resection is avoided. Glucose and oxygen are ubiquitous and abundant in interstitial fluid. The in vivo experimental results prove that the power supply can power the light-emitting diode and have a stable current output. Therefore, the power supply is expected to provide internal power for implantable devices, avoiding transmission from external sources such as radio frequency.

Abstract Or123: Increasing ketone supply to the heart has beneficial effects on the source of cardiac ATP production in heart failure with preserved ejection fraction (HFpEF)

Introduction: There is considerable confusion as to what changes in cardiac energy metabolism occur in heart failure with preserved ejection fraction (HFpEF). In HFpEF mice hearts, we found a marked decrease in cardiac glucose oxidation, which is accompanied by an increase in fatty acid oxidation. Ketones have been proposed as an extra source of fuel for the failing, heart, although it remains unclear if ketones may adversely affect glucose and fatty acid oxidation. Methods: 13-month-old C57BL/6N female mice were administered a 60% high-fat diet and L-NAME (0.5g/L/day) for 6 weeks to induce HFpEF. Control mice were fed with regular low-fat diet and regular drinking water. Hearts of the mice were excised and perfused in the isolated working mode aerobically with 5 mM glucose, 0.8 mM palmitate, 100 µU/ml insulin, with either low (0.6 mM) or high (1 mM) levels of β-hydroxybutyrate. Metabolic rates of the hearts were measured with radiolabelled [U- 14 C] glucose, [9,10- 3 H] palmitate, and [3- 14 C] β-hydroxybutyrate. Results: In HFpEF mouse hearts, glucose oxidation was significantly decreased with a parallel increase in fatty acid oxidation. As a result, the HFpEF hearts showed overall preserved ATP production rates (79 ± 12 vs. to 106 ± 13 μmol . g dry wt -1. min -1 control vs. HFpEF). Increasing β-hydroxybutyrate levels from 0.6 mM to 1 mM resulted in a rise in ketone oxidation rates in HFpEF hearts (from 692 ± 47 to 952 ± 90 nmol . g dry wt -1. min -1 ). Interestingly, this increase in ketone oxidation did not further compromise the rates of glucose oxidation in HFpEF hearts, but actually increased glucose oxidation rates (from 95 ± 13 to 190 ± 17 nmol . g dry wt -1. min -1 ), and had minor effects on fatty acid oxidation rates (from 796 ± 123 to 678 ± 92 nmol . g dry wt -1. min -1 ). This resulted in an increase in the contribution of ketone and glucose oxidation to ATP production from 15 % to 28 % in HFpEF hearts. Conclusion: In HFpEF mice hearts overall ATP production is not impaired, but rather the heart switches from glucose oxidation to fatty acid oxidation as the main source of ATP production. Increasing ketone supply to the heart increases ketone oxidation and results in a favourable shift in ATP production in HFpEF.

Abstract Tu126: Unveiling the Role of GRAF1 in Orchestrating Mitophagy and Metabolic Flexibility in Stressed Cardiomyocytes

Mitochondria are essential for cardiomyocyte contraction by generating ATP and orchestrating metabolic pathways. Understanding how mitophagy—selective removal of damaged mitochondria in lysosome—and metabolic flexibility are coordinated is crucial for cardiac function under physiological and pathological conditions. Our study explores the molecular mechanisms behind this coordination in cardiomyocytes. We identify GRAF1(Arhgap26) as a pivotal mediator in PINK1-Parkin dependent mitophagy, facilitating damaged mitochondria clearance and regulating mitochondrial substrate flexibility. Depletion of GRAF1 in neonatal rat ventricular cardiomyocytes (NRVCMs) compromises mitochondrial function, evidenced by reduced membrane potential, impaired oxidative phosphorylation, and elevated cleaved Caspase 3 levels. Moreover, GRAF1 depletion attenuates LC3II activation and increases mitochondrial mass following toxin-induced stress. Using tamoxifen-inducible cardiomyocyte-restricted GRAF1 knockout mice (GRAF1 CKO ), we observe normal cardiac function under basal conditions. However, upon isoproterenol (ISO) treatment, GRAF1 CKO mice display cardiac dysfunction and reduced mitophagy. Metabolomics analysis reveal distinct metabolic signatures between ISO-treated control and GRAF1 CKO mice, with impaired fuel flexibility observed in GRAF1 CKO mice, as highlighted by impaired glucose utilization relative to control mice. Mechanistically, phosphorylation of specific sites (S668, T670, and S671) within the proline-rich region of GRAF1 by PINK1 or PINK1-dependent kinases regulates its dual functions. This phosphorylation event releases the autoinhibitory state of the SH3 domain, enabling it to interact with ABI2 and WAVE2 complex for actin remodeling necessary for efficient mitochondria clearance. Additionally, phosphorylation enhances GRAF1’s affinity for Malonyl-CoA Decarboxylase (MCD), promoting MCD degradation and subsequent elevation of cellular malonyl-CoA levels. This rise in malonyl-CoA inhibits carnitine pamitoyl transferase-I (CPT-I), thereby suppressing fatty acid oxidation while promoting glucose oxidation in mitochondria, contributing to the mitochondrial metabolic flexibility. In summary, our findings elucidate GRAF1's role in orchestrating mitophagy and metabolic flexibility in stressed cardiomyocytes. GRAF1 phosphorylation serves as a molecular switch, ensuring efficient mitochondrial clearance and substrate utilization to maintain cardiac energetics and function.

Bias-free glucose/O2 bio-photoelectrochemical system for multi-energy conversion and phenolic pollutant degradation

Developing a multi-functional green energy device that propels sustainable energy development and concurrently purifies environmental pollutants offers an irresistibly compelling vision for a cleaner future. Herein, we reported a bias-free glucose/O2 bio-photoelectrochemical system (BPECS) for both energy conversion and phenolic pollutants degradation. Coupling a glucose dehydrogenase (GDH) modified self-assembled meso-tetrakis (4-carboxyphenyl)-porphyrin (SA-TCPP)-sensitized TiO2 biophotoanode for glucose oxidation and nitrogen/oxygen doped cobalt single-atom catalyst (CoNOC) cathode for two-electron oxygen reduction, both solar and biochemical energies were converted into electric power in BPECS with a maximum power density of 296.98 μW cm−2 (0.49 V). Working in synergy with horseradish peroxidase (HRP) biocatalysis, the cathode-generated H2O2, a by-product, is effectively redeployed for degrading phenol, attaining an impressive degradation efficiency of approximately 100% within 60 min. Additionally, aiming to scale up this ingenious BPECS approach, peroxidase-mimicking Co3O4 nanozyme were engineered as a substitute for natural HRP. Remarkably, these nanozyme demonstrated a comparable degradation efficiency, achieving the same result in 90 min. In this work, our results demonstrate that this bias-free glucose/O2 BPECS model marks a significant step forward in integrating renewable energy harvesting with environmental remediation, but also opens new avenues for the versatile application of nanozymes.

Artificial-Cofactor-Mediated Hydrogen and Electron Transfer Endows AuFe/Polydopamine Superparticles with Enhanced Glucose Oxidase-Like Activity.

Various applications related to glucose catalysis have led to the development of functional nanozymes with glucose oxidase (GOX)-like activity. However, the unsatisfactory catalytic activity of nanozymes is a major challenge for their practical applications due to their inefficient hydrogen and electron transfer. Herein, we present the synthesis of AuFe/polydopamine (PDA) superparticles that exhibit photothermal-enhanced GOX-like activity. Experimental investigations and theoretical calculations reveal that the glucose oxidation process catalyzed by AuFe/PDA follows an artificial-cofactor-mediated hydrogen atom transfer mechanism, which facilitates the generation of carbon-centered radical intermediates. Rather than depending on charged Au surfaces for thermodynamically unstable hydride transfer, Fe(III)-coordinated PDA with abundant amino and phenolic hydroxyl groups serves as cofactor mimics, facilitating both hydrogen atom and electron transfer in the catalytic process. Finally, leveraging the photothermal-enhanced GOX-like and catalase-like activities of AuFe/PDA, we establish a highly sensitive and accurate point-of-care testing blood glucose determination with exceptional anti-jamming capabilities.

Soybean molasses as a new and low-cost substrate for gluconic acid production by Aspergillus niger

Soybean molasses (SM), a sugar-rich by-product obtained from manufacturing soy protein concentrate, is an interesting source of fermentable sugars for biotechnological processes. For the first time, SM was used as a new and low-cost substrate in Aspergillus niger cultures to produce gluconic acid (GA), a carboxylic acid obtained by the oxidation of glucose and with a wide range of applications. The effect of SM composition and sugar content on GA batch production was studied in a stirred-tank bioreactor using two SM samples with different total sugar concentrations of 46 % and 52 % (w/w) and different sugar profiles. GA productivity improved as the total sugar concentration increased, whereas yield was unaffected. Agitation rate increase positively affected yield and productivity in SM medium with the highest sugar concentration. Under these conditions, the highest GA titer (79 g·L−1) was obtained. Oxalic acid and fructose syrup were other added-value compounds found from the submerged fermentation of SM. This work proved the potential of A. niger in the bioconversion of SM with different compositions into GA, providing a novel strategy for low-cost and eco-friendly GA production from SM.

Deep-sea microorganisms-driven V5+ and Cd2+ removal from vanadium smelting wastewater: Bacterial screening, performance and mechanism

The disorderly discharge of industrial wastewater containing heavy metals has caused serious water pollution and ecological environmental risks, ultimately threatening human life and health. Biological treatment methods have obvious advantages, but the existing microorganisms exhibit issues such as poor resistance, adaptability, colonization ability, and low activity. However, a wide variety of microorganisms in deep-sea hydrothermal vent areas are tolerant to heavy metals, possessing the potential for efficient treatment of heavy metal wastewater. Based on this, the study obtained a group of deep-sea microbial communities dominated by Burkholderia-Caballeronia-Paraburkholderia through shake flask experiments from the sediments of deep-sea hydrothermal vents, which can simultaneously achieve the synchronous removal of vanadium and cadmium heavy metals through bioreduction, biosorption, and biomineralization. Through SEM-EDS, XRD, XPS, and FT-IR analyses, it was found that V(V) was reduced to V(IV) through a reduction process and subsequently precipitated. Glucose oxidation accelerated this process. Cd(II) underwent biomineralization to form precipitates such as cadmium hydroxide and cadmium carbonate. Functional groups on the microbial cell surface, such as -CH2, C=O, N-H, -COOH, phosphate groups, amino groups, and M-O moieties, participated in the bioadsorption processes of V(V) and Cd(II) heavy metals. Under optimal conditions, namely a temperature of 40 °C, pH value of 7.5, inoculation amount of 10%, salinity of 4%, COD concentration of 600 mg/L, V5+ concentration of 300 mg/L, and Cd2+ concentration of 40 mg/L, the OD600 can reach its highest at 72 h, with the removal efficiency of V5+, Cd2+, and COD in simulated vanadium smelting wastewater reaching 86.32%, 59.13%, and 61.63%, respectively. This study provides theoretical insights and practical evidence for understanding the dynamic changes in microbial community structure under heavy metal stress, as well as the resistance mechanisms of microbial treatment of industrial heavy metal wastewater.

The role of acetylation in obesity-induced cardiac metabolic alterations.

Obesity is a growing public health problem, with its prevalence rate having tripled in the last five decades. It has been shown that obesity is associated with alterations in cardiac energy metabolism, which in turn plays a significant role in heart failure development. During obesity, the heart becomes highly dependent on fatty acid oxidation as its primary source of energy (ATP), while the contribution from glucose oxidation significantly decreases. This metabolic inflexibility is associated with reduced cardiac efficiency and contractile dysfunction. Although it is well recognized that alterations in cardiac energy metabolism during obesity are associated with the risk of heart failure development, the molecular mechanisms controlling these metabolic changes are not fully understood. Recently, posttranslational protein modifications of metabolic enzymes have been shown to play a crucial role in cardiac energy metabolic changes seen in obesity. Understanding these novel mechanisms is important in developing new therapeutic options to treat or prevent cardiac metabolic alteration and dysfunction in obese individuals. This review discusses posttranslational acetylation changes during obesity and their roles in mediating cardiac energy metabolic perturbations during obesity as well as its therapeutic potentials.

Self-activated hydrogel cascade reactor integrated with glucose oxidase and silver nanoparticle for enhanced treatment of bacterial infection

The recognition of silver nanoparticles (AgNPs) as a nanozyme with peroxidase-like activity has offered a promising solution to address the challenges of bacterial resistance and argyria risk. However, the catalytic efficacy of AgNPs is limited by the need for a strong acidic environment and high concentrations of hydrogen peroxide (H2O2). In this work, we developed a self-activated hydrogel cascade reactor (AUGP) for enhanced treatment of bacterial infection. The AUGP integrates the properties of glucose oxidase (GOx) and polyacrylamide (pAAm) hydrogel microsphere. The confinement effect of pAAm hydrogel microsphere enables glucose oxidation to occur in a confined space, which creates an acidic environment to activate AgNPs activity, initiating the cascade reaction between GOx and AgNPs. Meanwhile, the confinement effect facilitates the accumulation of a high local concentration of H2O2, allowing AUGP to generate hydroxyl radicals (•OH) without the need for external H2O2. Additionally, the release of Ag+ from AUGP is achieved upon the generation of •OH. The synergistic action of Ag+ and •OH confers exceptional antibacterial efficacy to AUGP. Importantly, the etching effect of H2O2 ensures the absence of any residual AgNPs, reducing the risk of argyria. In vivo studies validated the efficacy of AUGP in wound disinfection with minimal toxicity.

Diffusion-driven height readout analytical device based on gold nanobipyramid-doped supramolecular hydrogel for point-of-care bioanalysis

Point-of-care (POC) diagnostics is crucial for rapid on-site detection in resource-limited settings. However, there are still some challenges in the development of quantitative POC bioassays. Herein, we propose a simple, visual, and instrument-free height readout analytical device injected with target-responsive gold nanobipyramid (AuNBP)-doped guanosine-quartet (G4) supramolecular hydrogel for the quantitative detection of glucose. This sensing platform relies on H2O2 generated by glucose oxidation to induce iodide-mediated etching of AuNBPs, resulting in visualized color-changed hydrogel bar-chart driven by molecular diffusion in a polycarbonate tube. The visual height of the color-changed hydrogel is correlated with the concentration of glucose, and the quantitative determination was achieved simply by using a household ruler or mobile software as a readout. More importantly, this method has been successfully used to detect glucose in human serum samples with high accuracy and reliability. In addition, the AuNBPs are utilized as plasmonic probes to construct two-input logic gates, providing an intelligent strategy to simultaneously detect multiple biomolecules. This height-readout sensing platform demonstrates great promise for applications in POC and intelligent bioanalysis.

Directionally Exfoliated Ni/Co Hydroxide-Organic Framework Nanosheets for Enhanced Wearable Glucose Sensing.

We report two-dimensional (2D) Ni/Co-based metal hydroxide-organic framework nanosheets (Ni/Co-MHOF NSs) for the construction of an efficient electrochemical nonenzymatic glucose sensor. The nanosheet architecture maximizes the exposure of coordinatively unsaturated metal sites, which enables a largely improved electrocatalytic performance toward the glucose oxidation reaction. The as-designed nonenzymatic sensor exhibits a high sensitivity of 235.71 μA·mM-1·cm-2 and a wide linear range of 1-3000 μM. The sensor presents excellent selectivity against several potential interferences and a short response time of 3.0 s. Of interest, a high-performance flexible sensor is developed by depositing the Ni/Co-MHOF NSs on screen-printed electrodes, which reveal decent bending stability. The designed glucose sensor patch can attach to the human body and realize noninvasive glucose monitoring in human sweat. This work may shed light on the application of novel MHOFs in the field of wearable electrochemical sensing.

Ligand effect of PdRu on Pt-enriched surface for glucose complete electro-oxidation to carbon dioxide and abiotic direct glucose fuel cells.

The development of advanced electrocatalysts for the abiotic direct glucose fuel cells (ADGFCs) is critical in the implantable devices in living organisms. The ligand effect in the Pt shell-alloy core nanocatalysts is known to influence the electrocatalytic reaction in interfacial structure. Herein, we reported the synthesis of ternary Pt@PdRu nanoalloy aerogels with ligand effect of PdRu on Pt-enriched surface through electrochemical cycling. Pt@PdRu aerogels with optimized Pt surface electronic structure exhibited high mass activity and specific activity of Pt@PdRu about 450 mA·mgPt-1 and 1.09 mA·cm-2, which were 1.4 and 1.6 times than that of commercial Pt/C. Meanwhile, Pt@PdRu aerogels have higher electrochemical stability comparable to commercial Pt/C. In-situ FTIR spectra results proved that the glucose oxidation reaction on Pt@PdRu aerogels followed the CO-free direct pathway reaction mechanism and part of the products are CO2 by completed oxidation. Furthermore, the ADGFC with Pt@PdRu ultrathin anode catalyst layer showed a much higher power density of 6.2 mW·cm-2 than commercial Pt/C (3.8 mW·cm-2). To simulate the blood fuel cell, the Pt@PdRu integrated membrane electrode assembly was exposed to glucose solution and a steady-state open circuit of approximately 0.6 V was achieved by optimizing the glucose concentration in cell system.

Ultrasensitive self-powered biosensor with facile chemical signal amplification strategy using hydrogen peroxide-triggered silver oxidation reaction

The amplification strategies used for self-powered biosensor based on biofuel cell (BFC-SPB) need to be further developed. Because the currently developed strategies utilized the complicated hybridization of DNA or poorly readable current signal of capacitors for amplification, which limits the practical application in public health emergencies. Here, we present a facile chemical amplification strategy for BFC-SPB. The 5-min amplification was triggered by simply adding H2O2 solution dropwise to the sensing cathode after the formation of the immune sandwich. The Ag NP of immunoprobe were oxidized to Ag(I), which can be served as the electron acceptor of the cathode. The amount of immunoprobe was positively correlated with that of the antigen, resulting in corresponding and high concentration of Ag(I) after the amplification, which enhanced the ability of the cathode as the electron acceptor. Meanwhile the glucose oxidation reaction (GOR) was performed on the bioanode modified with glucose oxidase (GOx). After assembling the bioanode and sensing cathode, the open circuit voltage of the BFC-SPB, measured by digital multimeter, distinctly rised with the elevated concentration of the antigen. To demonstrate the proof of concept, immunoglobulin G (IgG), selecting as a model analyte, was sensitively detected using this method. Result indicated that the limit of detection was 4.4 fg mL−1 (0.03 amol mL−1) in the linear range of 1 pg mL−1-10 μg mL−1. This work initiates a brand-new way of chemical amplification strategy for BFC-SPB, and offers a promising platform for practical applications.