Promoting the healing of infected diabetic wound by nanozyme-containing hydrogel with anti-bacterial inflammation suppressing, ROS-scavenging and oxygen-generating properties.

Bacterial infections already pose a significant threat to skin wounds, especially in diabetic patients who have difficulty healing wounds. However, wound or bacterial infections are known to produce excess reactive oxygen species (ROS), and hypoxia may further hinder wound healing and the development of chronic wounds. In this study, a multifunctional hydrogel for ROS scavenging and bacterial inhibition was developed by cross-linking polyvinyl alcohol (PVA) and sodium alginate (SA) with graphene oxide (GO) loaded with silver-platinum hybrid nanoparticles (GO@Ag-Pt). The PVA/SA hydrogel loaded with GO@Ag-Pt exhibited the ability to scavenge different types of ROS, generate O2, and kill a broad spectrum of bacteria in vitro. The silver-platinum hybrid nanoparticles significantly increased the antibacterial ability against Escherichia coli and Staphylococcus aureus compared with silver nanoparticles (AgNps). GO@Ag-Pt loaded hydrogel was effective in treating infections caused by S.aureus, thereby significantly promoting wound healing during the inflammatory phase. Hydrogel therapy significantly reduced the level of ROS and alleviated inflammation levels. Notably, our ROS-scavenging, antibacterial hydrogels can be used to effectively treat various types of wounds, including difficult-to-heal diabetic wounds with bacterial infections. Thus, this study proposes an effective strategy for various chronic wound healing based on ROS clearance and bacteriostatic hydrogels.

Fabrication of micron-sized boronate-decorated polyethyleneimine-grafted magnetic agarose beads for specific enrichment of ribonucleic acid.

Exploiting high-performance magnetic beads for specific enrichment of ribonucleic acid (RNA) has important significance in the biomedical research field. Herein, a simple strategy was proposed for fabricating boronate-decorated polyethyleneimine-grafted magnetic agarose beads (BPMAB), which can selectively isolate cis-diol-containing substances through boronate affinity. The size of the basic magnetic agarose beads was controlled through the emulsification of the water-in-oil emulsion with a high-speed shear machine, which enhanced the specific surface area of BPMAB. Subsequently, to modify more boronic acid ligands, branched PEI with excellent hydrophilicity and numerous reaction sites was grafted. 2,4-Difluoro-3-formylphenyl boronic acid (2,4-DFPBA) was covalently immobilized for selectively capturing cis-diol-containing substances under physiological condition (pH 7.4). The BPMAB with a diameter range from 1.86 µm to 11.60 µm possessed clearly spherical structure, and excellent magnetic responsiveness and suspension ability in aqueous solution. ß-Nicotinamide adenine dinucleotide (ß-NAD), a short-chain cis-diol carrying agent, was selected as a target molecule for evaluating the adsorption property of BPMAB and the maximum adsorption capacity of BPMAB for ß-NAD could reach 205.11 mg g-1. In addition, the BPMAB as adsorbent was used to selectively enrich RNA from mammalian cells. The maximum adsorption capacity of BPMAB for RNA was 140.50 mg g-1. Under optimized conditions, the BPMAB-based MSPE successfully enriched the high-quality total RNA with 28S to 18S ribosomal RNA ratios ranging from 2.06 to 2.16. According to the PCR analysis of GADPH gene, the extracted total RNA was successfully reverse transcribed into cDNA. Therefore, we believe that the BPMAB-based MSPE could be applicable for the specific enrichment of RNA from complex biological systems.

Synthesis and Characterization of Boronate Affinity Three-Dimensionally Ordered Macroporous Materials.

Sample pretreatment is a key step for qualitative and quantitative analysis of trace substances in complex samples. Cis-dihydroxyl (cis-diol) group-containing substances exist widely in biological samples and can be selectively bound by boronate affinity adsorbents. Based on this, in this article, we proposed a simple method for the preparation of novel spherical three-dimensionally ordered macropore (3DOM) materials based on a combination of the boronate affinity technique and colloidal crystal template method. The prepared 3DOM materials were characterized using Fourier transform-infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and thermo-gravimetric analysis, and results showed that they possessed the characteristics of a high specific surface area, high porosity, and more boronic acid recognition sites. The adsorption performance evaluation results showed that the maximum adsorption capacity of the boron affinity 3DOMs on ovalbumin (OVA) could reach to 438.79 mg/g. Kinetic and isothermal adsorption experiments indicated that the boronate affinity 3DOM material exhibited a high affinity and selectivity towards OVA and adenosine. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the proteins in egg whites was conducted and proved that the glycoprotein in the egg whites could be separated and enriched with a good performance. Therefore, a novel boronate affinity 3DOM material a with highly ordered and interconnected pore structure was prepared and could be applied in the separation and enrichment of molecules with cis-diol groups from complex samples with a good selectivity, efficiency, and high throughput.

Accurately recognizing chromium species with multi-functionalized nano Au-based sensor array.

High-resolution identification of chromium (Cr) species, especially various organic-Cr complexes, in a convenient and economically-feasible manner is the prerequisite for achieving the advanced treatment of chromium wastewater. To this end, a colorimetric nano-Au sensor array was developed by taking advantage of the UV-spectra shift of gold nanoparticles (Au NPs) upon interaction with Cr species; specifically, four molecular modifiers [i.e., iminodiacetic acid (IDA), tripolyphosphate (TPP), cetyltrimethylammonium bromide (CTAB), and 1,5-diphenylcarbazide (DPC)] were intentionally employed for assembling nano-Au array receptors, which showed respective responses toward different Cr species through the formation of coordination, hydrophobic interaction, electrostatic attraction, and redox reaction, respectively; the "fingerprint" differences of the unique optical properties were then integrated for semi-quantitatively recognizing Cr species by pattern recognition techniques. Eleven ubiquitous Cr species [i.e., Cr(III), Cr(VI), and various Cr(III)-organic complexes] served as the model samples, which could be sensitively identified, no matter in individual or mixture mode, by the developed nano-Au sensor array on the basis of the colorimetric responses resulted from diverse nano-Au-aggregation behaviors, with excellent anti-interference ability in the simulated or actual water scenario. Attractively, the nano-Au sensor array can achieve very sensitive detection limit of the quantitative analyses of Cr species in a prompt in-situ manner, which usually requires a two-step process of separation and detection for the conventional analytical methods. Such a convenient strategy of Cr species discrimination conduces to rationally designing specific protocols for the advanced treatment of chromium wastewater.

System-level time computation and representation in the suprachiasmatic nucleus revealed by large-scale calcium imaging and machine learning.

The suprachiasmatic nucleus (SCN) is the mammalian central circadian pacemaker with heterogeneous neurons acting in concert while each neuron harbors a self-sustained molecular clockwork. Nevertheless, how system-level SCN signals encode time of the day remains enigmatic. Here we show that population-level Ca2+ signals predict hourly time, via a group decision-making mechanism coupled with a spatially modular time feature representation in the SCN. Specifically, we developed a high-speed dual-view two-photon microscope for volumetric Ca2+ imaging of up to 9000 GABAergic neurons in adult SCN slices, and leveraged machine learning methods to capture emergent properties from multiscale Ca2+ signals as a whole. We achieved hourly time prediction by polling random cohorts of SCN neurons, reaching 99.0% accuracy at a cohort size of 900. Further, we revealed that functional neuron subtypes identified by contrastive learning tend to aggregate separately in the SCN space, giving rise to bilaterally symmetrical ripple-like modular patterns. Individual modules represent distinctive time features, such that a module-specifically learned time predictor can also accurately decode hourly time from random polling of the same module. These findings open a new paradigm in deciphering the design principle of the biological clock at the system level.

A smartphone-based diagnostic analyzer for point-of-care milk somatic cell counting.

BACKGROUND: Mastitis, a pervasive and detrimental disease in dairy farming, poses a significant challenge to the global dairy industry. Monitoring the milk somatic cell count (SCC) is vital for assessing the incidence of mastitis and the quality of raw cow's milk. However, existing SCC detection methods typically require large-scale instruments and specialized operators, limiting their application in resource-constrained settings such as dairy farms and small-scale labs. To address these limitations, this study introduces a novel, smartphone-based, on-site SCC testing method that leverages smartphone capabilities for milk somatic cell identification and enumeration, offering a portable and user-friendly testing platform. RESULTS: The central findings of our study demonstrate the effectiveness of the proposed method for counting milk somatic cells. Its on-site applicability, facilitated by the microfluidic chip, optical system, and smartphone integration, heralds a paradigm shift in point-of-care testing (POCT) for dairy farms and smaller laboratories. This approach bypasses complex processing and presents a user-friendly solution for real-time SCC monitoring in resource-limited settings. This device boasts several unique features: small size, low cost (<$1,000 total manufacturing cost and <$1 per test), and high accuracy. Remarkably, it delivers test results within just 2 min. Actual-sample testing confirmed its consistency with results from the commercial Bentley FTS/FCM cytometer, affirming the reliability of the proposed method. Overall, these results underscore the potential for transformative change in dairy farm management and laboratory testing practices. SIGNIFICANCE: In summary, this study concludes that the proposed smartphone-based method significantly contributes to the accessibility and ease of SCC testing in resource-limited environments. By fostering the use of POCT technology in food safety control, particularly in the dairy industry, this innovative approach has the potential to revolutionize the monitoring and management of mastitis, ultimately benefiting the global dairy sector.

High-efficient separation of deoxyribonucleic acid from pathogenic bacteria by hedgehog-inspired magnetic nanoparticles microextraction.

Efficient separation of deoxyribonucleic acid (DNA) through magnetic nanoparticles (MN) is a widely used biotechnology. Hedgehog-inspired MNs (HMN) possess a high-surface-area due to the distinct burr-like structure of hedgehog, but there is no report about the usage of HMN for DNA extraction. Herein, to improve the selection of MN and illustrate the performance of HMN for DNA separation, HMN and silica-coated Fe3O4 nanoparticles (Fe3O4@SiO2) were fabricated and compared for the high-efficient separation of pathogenic bacteria of DNA. Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are typical Gram-negative and Gram-positive bacteria and are selected as model pathogenic bacteria. To enhance the extraction efficiency of two kinds of MNs, various parameters, including pretreatment, lysis, binding and elution conditions, have been optimized in detail. In most separation experiments, the DNA yield of HMN was higher than that of Fe3O4@SiO2. Therefore, a HMN-based magnetic solid-phase microextraction (MSPE) and quantitative real-time PCR (qPCR) were integrated and used to detect pathogenic bacteria in real samples. Interestingly, the HMN-based MSPE combined qPCR strategy exhibited high sensitivity with a limit of detection of 2.0 × 101 CFU mL-1 for E. coli and 4.0 × 101 CFU mL-1 for S. aureus in orange juice, and 2.8 × 102 CFU mL-1 for E. coli and 1.1 × 102 CFU mL-1 for S. aureus in milk, respectively. The performance of the proposed strategy was significantly better than that of commercial kit. This work could prove that the novel HMN could be applicable for the efficient separation of DNA from complex biological samples.

Effect of mitotane in patients with ectopic adrenocorticotropic hormone syndrome caused by advanced pancreatic neuroendocrine tumors: a case series and review of the literature.

Ectopic adrenocorticotropic hormone syndrome (EAS) is a rare condition caused by pancreatic neuroendocrine tumors (p-NETs). The severe hypercortisolemia that characterizes EAS is associated with a poor prognosis and survival. Mitotane is the only adrenolytic drug approved by the Food and Drug Administration and is often used to treat adrenocortical carcinoma. Combination therapy with mitotane and other adrenal steroidogenesis inhibitors is common for patients with Cushing's syndrome (CS). Here, we describe three patients who developed EAS secondary to the liver metastasis of p-NETs. All three rapidly developed hypercortisolemia but no typical features of CS. They underwent anti-tumor and mitotane therapy, which rapidly reduced their blood cortisol concentrations and ameliorated their symptoms. Their hypercortisolemia was controlled long term using a low dose of mitotane. The principal adverse effects were a slight loss of appetite and occasional dizziness, and there were no severe adverse effects. Importantly, even when the tumor progressed, the patients' circulating cortisol concentrations remained within the normal range. In summary, the present case series suggests that mitotane could be used to treat hypercortisolemia in patients with EAS caused by advanced p-NETs, in the absence of significant adverse effects.

Imaging microglia surveillance during sleep-wake cycles in freely behaving mice.

Microglia surveillance manifests itself as dynamic changes in cell morphology and functional remodeling. Whether and how microglia surveillance is coupled to brain state switches during natural sleep-wake cycles remains unclear. To address this question, we used miniature two-photon microscopy (mTPM) to acquire time-lapse high-resolution microglia images of the somatosensory cortex, along with EEG/EMG recordings and behavioral video, in freely-behaving mice. We uncovered fast and robust brain state-dependent changes in microglia surveillance, occurring in parallel with sleep dynamics and early-onset phagocytic microglial contraction during sleep deprivation stress. We also detected local norepinephrine fluctuation occurring in a sleep state-dependent manner. We showed that the locus coeruleus-norepinephrine system, which is crucial to sleep homeostasis, is required for both sleep state-dependent and stress-induced microglial responses and ß2-adrenergic receptor signaling plays a significant role in this process. These results provide direct evidence that microglial surveillance is exquisitely tuned to signals and stressors that regulate sleep dynamics and homeostasis so as to adjust its varied roles to complement those of neurons in the brain. In vivo imaging with mTPM in freely behaving animals, as demonstrated here, opens a new avenue for future investigation of microglia dynamics and sleep biology in freely behaving animals.

Evaluating the zoonotic potential of RNA viromes of rodents provides new insight into rodent-borne zoonotic pathogens in Guangdong, China.

Emerging and re-emerging infectious diseases have been on the rise, with a significant proportion being zoonotic. Rodents, as the natural reservoirs of numerous diverse zoonotic viruses, pose a substantial threat to human health. To investigate the diversity of known and unknown viruses harbored by rodents in Guangdong (southern province of China), we conducted a comprehensive analysis of viral genomes through metagenomic sequencing of organs from 194 rodents. Our analysis yielded 2163 viral contigs that were assigned to 25 families known to infect a wide range of hosts, including vertebrates, invertebrates, amoebas, and plants. The viral compositions vary considerably among different organs, but not in rodent species. We also assessed and prioritized zoonotic potential of those detected viruses. Ninety-two viral species that are either known to infect vertebrates and invertebrates or only vertebrates were identified, among which 21 are considered high-risk to humans. The high-risk viruses included members of the Hantavirus, Picobirnaviruses, Astroviruses and Pestivirus. The phylogenetic trees of four zoonotic viruses revealed features of novel viral genomes that seem to fit evolutionarily into a zone of viruses that potentially pose a risk of transmission to humans. Recognizing that zoonotic diseases are a One Health issue, we approached the problem of identifying the zoonotic risk from rodent-transmitted disease in the Guangdong province by performing next-generation sequencing to look for potentially zoonotic viruses in these animals.

Complexation-based selectivity of organic phosphonates adsorption from high-salinity water by neodymium-doped nanocomposite.

Organic phosphonates have been widely used in various industries and are ubiquitous in wastewaters, and efficient removal of phosphonates is still a challenge for the conventional processes because of the severe interferences from the complex water constitutions. Herein, an Nd-based nanocomposite (HNdO@PsAX) was fabricated by immobilizing hydrated neodymium oxide (HNdO) nanoparticles inside a polystyrene anion exchanger (PsAX) to remove phosphonates from high-salinity aqueous media. Batch experiments demonstrated that HNdO@PsAX had an excellent adsorption capacity (∼90.5 mg P/g-Nd) towards a typical phosphonate (1-hydrox-yethylidene-1,1-diphosphonic acid, HEDP) from the background of 8 g/L NaCl, whereas negligible HEDP adsorption was achieved by PsAX. Attractively, various coexisting substances (humic acid, phosphate, citrate, EDTA, metal ligands, and anions) exerted negligible effects on the HEDP adsorption by HNdO@PsAX under high salinity. FT-IR and XPS analyses revealed that the inner-sphere complexation between HEDP and the immobilized HNdO nanoparticles is responsible for HEDP adsorption. Fixed-bed experiments further verified that HNdO@PsAX was capable of successively treating more than 4500 bed volumes (BV) of a synthetic high-salinity wastewater (1.0 mg P/L of HEDP), whereas only ∼2 BV of effective treatment capacity was received by PsAX. The exhausted HNdO@PsAX was amenable to a complete regeneration by a binary NaOHNaCl solution without significant loss in capacity. The capability in removing other organic phosphonates and treating a real electroplating wastewater by HNdO@PsAX was further validated. Generally, HNdO@PsAX exhibited a great potential in efficiently removing phosphonates from high-salinity wastewater.

Succinate dehydrogenase is essential for epigenetic and metabolic homeostasis in hearts.

A hallmark of heart failure is a metabolic switch away from fatty acids ß-oxidation (FAO) to glycolysis. Here, we show that succinate dehydrogenase (SDH) is required for maintenance of myocardial homeostasis of FAO/glycolysis. Mice with cardiomyocyte-restricted deletion of subunit b or c of SDH developed a dilated cardiomyopathy and heart failure. Hypertrophied hearts displayed a decrease in FAO, while glucose uptake and glycolysis were augmented, which was reversed by enforcing FAO fuels via a high-fat diet, which also improved heart failure of mutant mice. SDH-deficient hearts exhibited an increase in genome-wide DNA methylation associated with accumulation of succinate, a metabolite known to inhibit DNA demethylases, resulting in changes of myocardial transcriptomic landscape. Succinate induced DNA hypermethylation and depressed the expression of FAO genes in myocardium, leading to imbalanced FAO/glycolysis. Inhibition of succinate by α-ketoglutarate restored transcriptional profiles and metabolic disorders in SDH-deficient cardiomyocytes. Thus, our findings reveal the essential role for SDH in metabolic remodeling of failing hearts, and highlight the potential of therapeutic strategies to prevent cardiac dysfunction in the setting of SDH deficiency.

Synthesis of micron-sized magnetic agarose beads chelated with nickel ions towards the affinity-based separation of histidine-tagged/rich proteins.

Developing high-performance magnetic particles for the effective separation and purification of target proteins has become an important topic in the area of biomedical research. In this work, a simple and novel strategy was proposed for fabricating magnetic Fe3O4@agarose-iminodiacetic acid-Ni microspheres (MAIN), which can efficiently and selectively isolate histidine-tagged/rich proteins (His-proteins). Based on the thermoreversible sol-gel transition of agarose, basic magnetic agarose microspheres were prepared through the inverse emulsion method, in which the emulsion contained agarose and amine-modified Fe3O4 nanoparticles. The size of the emulsion was controlled by the emulsification of a high-speed shear machine, which improved the specific surface area of MAIN. Subsequently, the amine-modified Fe3O4 nanoparticles were covalently crosslinked with agarose through epichlorohydrin, which could avoid leakage of the magnetic source during use and increase the stability of MAIN. The microsized MAIN exhibited a clearly visible spherical core-shell structure with a diameter range from 3.4 µm to 9.8 µm, and excellent suspension ability in aqueous solution. The maximum adsorption capacity of MAIN for histidine-rich bovine hemoglobin was 1069.2 mg g-1 at 35 °C, which was higher than those of commercialized and most reported magnetic agarose microspheres/nanoparticles. The MAIN showed excellent adsorption ability and selectivity toward His-proteins in a mixture of histidine-rich bovine serum albumin (BSA) and histidine-poor lysozyme (LYZ). When the amount of LYZ was 5-fold higher than that of BSA, the recovery of BSA reached 75.0%. To prove its practicability, MAIN was successfully employed for the enrichment of histidine-tagged RSV-F0 from the cell culture medium supernatant. According to the optimized conditions, MAIN could enrich approximately 0.1 mg of RSV-F0 from 1 mL of complex biological sample. Therefore, we believe that the novel MAIN could be applicable for efficient separation and purification of His-proteins from complex biological systems.

C17orf80 binds the mitochondrial genome to promote its replication.

Serving as the power plant and signaling hub of a cell, mitochondria contain their own genome which encodes proteins essential for energy metabolism and forms DNA-protein assemblies called nucleoids. Mitochondrial DNA (mtDNA) exists in multiple copies within each cell ranging from hundreds to tens of thousands. Maintaining mtDNA homeostasis is vital for healthy cells, and its dysregulation causes multiple human diseases. However, the players involved in regulating mtDNA maintenance are largely unknown though the core components of its replication machinery have been characterized. Here, we identify C17orf80, a functionally uncharacterized protein, as a critical player in maintaining mtDNA homeostasis. C17orf80 primarily localizes to mitochondrial nucleoid foci and exhibits robust double-stranded DNA binding activity throughout the mitochondrial genome, thus constituting a bona fide new mitochondrial nucleoid protein. It controls mtDNA levels by promoting mtDNA replication and plays important roles in mitochondrial metabolism and cell proliferation. Our findings provide a potential target for therapeutics of human diseases associated with defective mtDNA control.

Preparation of carbon nanotubes by catalytic pyrolysis of dechlorinated PVC.

Plastic waste is attracting growing interest for its utilization potential as a valuable resource. However, conventional thermochemical methods can hardly achieve high-value utilization of certain plastics, such as polyvinyl chloride (PVC) characterized with high chlorine content. Here, a low-temperature aerobic pretreatment method was introduced to realize high-efficiency dechlorination of PVC, and then the dechlorinated PVC was used to prepare carbon nanotubes (CNTs) by a catalytic pyrolysis. The results demonstrate that oxygen can significantly promote the HCl release in a pretty low-temperature range (260-340 °C). Chlorine was almost completely eliminated at 280 °C under 20 % oxygen concentration. Compared to untreated PVC, using the dechlorinated PVC as raw material, higher carbon deposition was obtained and over 60 % CNTs could be collected from the carbon deposition. This study provides a high-value utilization way for the production of CNTs from waste PVC.

Anastomotic leak risk factors following colon cancer resection: a systematic review and meta-analysis.

BACKGROUND: Despite improved surgical techniques, anastomotic leakage is still a serious complication that can occur after colon cancer resection, resulting in increased morbidity and mortality. The aim of this study was to evaluate the risk factors for anastomotic leakage after colon cancer surgery, provide a theoretical basis for reducing its occurrence, and guide the practice of clinicians. METHODS: A systematic review of PubMed, Ovid, Web of Science and Cochrane Central Register of Controlled Trials databases was conducted by using a combination of subject terms and free words for online searches. The databases were searched from their inception to 31 March 2022, and all cross-sectional, cohort or case‒control studies examining the risk factors for the development of anastomotic fistula after surgery for colon cancer were identified. RESULT: A total of 2133 articles were searched for this study, and 16 publications were ultimately included, all of which were cohort studies. A total of 115,462 subjects were included, and a total of 3959 cases of anastomotic leakage occurred postoperatively, with an incidence of 3.4%. The odds ratio (OR) and 95% confidence interval (CI) were used for evaluation. Male sex (OR = 1.37, 95% CI: 1.29-1.46, P < 0.00001), BMI (OR = 1.04, 95% CI: 1.00-1.08, P = 0.03), diabetes (OR = 2.80, 95% CI: 1.81-4.33, P < 0.00001), combined lung disease (OR = 1.28, 95% CI: 1.15-1.42, P < 0.00001), anaesthesia ASA score (OR = 1.35, 95% CI: 1.24-1.46, P < 0.00001), ASA class ≥ III (OR = 1.34, 95% CI: 1.22-1.47, P < 0.00001), emergency surgery (OR = 1.31, 95% CI: 1.11-1.55, P = 0.001), open surgery (OR = 1.94, 95% CI: 1.69-2.24, P < 0.00001) and type of surgical resection (OR = 1.34, 95% CI: 1.12-1.61, P = 0.002) are risk factors for anastomotic leakage after colon cancer surgery. There is still a lack of strong evidence on whether age (OR = 1.00, 95% CI: 0.99-1.01, P = 0.36) and cardiovascular disease (OR = 1.18, 95% CI: 0.94-1.47, P = 0.16) are factors influencing the occurrence of anastomotic leakage after colon cancer surgery. CONCLUSIONS: Male sex, BMI, obesity, coexisting pulmonary disease, anaesthesia ASA score, emergency surgery, open surgery and type of resection were risk factors for anastomotic leakage after colon cancer surgery. The effect of age and cardiovascular disease on postoperative anastomotic leakage in patients with colon cancer needs further study.

Bioconjugation of nanozyme and natural enzyme to enable a one-step cascade reaction for the detection of metabolites.

Nanozyme, with enzyme-mimicking activity and excellent stability, has attracted extensive attention. However, some inherent disadvantages, including poor dispersion, low selectivity, and insufficient peroxidase-like activity, still limit its further development. Therefore, an innovative bioconjugation of a nanozyme and natural enzyme was conducted. In the presence of graphene oxide (GO), histidine magnetic nanoparticles (H-Fe3O4) were first synthesized by a solvothermal method. The GO-supported H-Fe3O4 (GO@H-Fe3O4) exhibited superior dispersity and biocompatibility because GO was the carrier and possessed outstanding peroxidase-like activity because of the introduction of histidine. Furthermore, the mechanism of the peroxidase-like activity of GO@H-Fe3O4 was the generation of •OH. Uric acid oxidase (UAO) was selected as the model natural enzyme and covalently linked to GO@H-Fe3O4 with hydrophilic poly(ethylene glycol) as a linker. UAO could specifically catalyze the oxidation of uric acid (UA) to generate H2O2, and subsequently, the newly produced H2O2 oxidized the colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue ox-TMB under the catalysis of GO@H-Fe3O4. Based on the above cascade reaction, the GO@H-Fe3O4-linked UAO (GHFU) and GO@H-Fe3O4-linked ChOx (GHFC) were used for the detection of UA in serum samples and cholesterol (CS) in milk, respectively. The method based on GHFU exhibited a wide detection range (5-800 µM) and a low detection limit (1.5 µM) for UA, and the method based on GHFC exhibited a wide detection range (4-400 µM) and a low detection limit (1.13 µM) for CS. These results demonstrated that the proposed strategy had great potential in the field of clinical detection and food safety.

Functionalized pyrite nanozyme probe and imprinted polymer modified with hydrophilic layer for rapid colorimetric analysis of glycoprotein in serum.

The biological molecules used in the sandwich detection method have problems such as complex extraction processes, high costs, and uneven quality. Therefore we integrated glycoprotein molecularly controllable-oriented surface imprinted magnetic nanoparticles (GMC-OSIMN) and boric acid functionalized pyrite nanozyme probe (BPNP) to replace the traditional antibody and horseradish peroxidase for sensitive detection of glycoproteins through sandwich detection. In this work, a novel nanozyme functionalized with boric acid was used to label glycoproteins that were captured by GMC-OSIMN. The substrate in the working solution catalyzed by the nanozyme labeled on the protein underwent visible color changes to the naked eye, and the generated signal can be quantitatively detected by a spectrophotometer, and the best color development conditions of the novel nanozyme under the influence of many factors were determined through multi-dimensional investigation. The optimum conditions of sandwich are optimized with ovalbumin (OVA), and it was extended to the detection of transferrin (TRF) and alkaline phosphatase (ALP) in the application. The detection range for TRF was 2.0 × 10-1-1.0 × 104 ng mL-1 with a detection limit of 1.32 × 10-1 ng mL-1, The detection range for ALP was 2.0 × 10-3-1.0 × 102 U L-1 with the detection limit of 1.76 × 10-3 U L-1. This method was subsequently used to detect TRF and ALP levels in 16 liver cancer patients, and the standard deviation of the test results of each patient was less than 5.7%.

Hydrogen-rich syngas production from biomass gasification using biochar-based nanocatalysts.

Nanocatalysts are beneficial for tar elimination and syngas production during biomass gasification. In this study, novel biochar-based nanocatalysts loaded with Ni/Ca/Fe nanoparticles was prepared by one-step impregnation method for catalytic steam gasification of biomass. Results showed that the metal particles were evenly distributed with the particle size of less than 20 nm. With the introduction of nanoparticles, H2 yield and tar conversion were obviously increased. Ni and Fe particles help to maintain the stability of the carrier microporous structure. Fe loaded biochar showed the best catalytic gasification performance, with 87% tar conversion and 42.46 mmol/g H2 production. The catalytic effect of Fe was also higher than that of Ni and Ca if deducting the influence of carrier consumption. It demonstrated that Fe-loaded biochar was a promising catalyst candidate for hydrogen-rich syngas production from biomass gasification.