Insoluble Precipitate Research Articles

Co-Delivery of Renal Clearable Cerium Complex and Synergistic Antioxidant Iron Complex for Treating Sepsis.

The mononuclear phagocytic system clears the circulating inorganic nanomaterials from the bloodstream, which raises concerns about the chronic toxicity of the accumulated metal species. A better understanding of the behavior of each metal after systemic injection is thus required for clinical translations. This study investigates the significance of the metal-ligand interaction on the accumulation of cerium and demonstrates that only the form in which cerium is coordinated to a multidentate chelator with a strong binding affinity does not accumulate in major organs. Specifically, cerium complexed with diethylenetriamine pentaacetic acid (DTPA) forms renally excretable nanoparticles in vivo to circumvent the leaching of cerium ions, whereas weakly coordinated cerium-based nanomaterials produce insoluble precipitates upon encountering physiological phosphate anions. Ceria-based renally clearable nanoparticles (CRNs) derived from cerium-DTPA are utilized as the antioxidant pair with iron-DTPA, in which their combination leverages the Fenton reaction to synergistically scavenge hydrogen peroxide. This reduces the gene expression of pro-inflammatory factors in the macrophages activated with lipopolysaccharide as well as improves the survival rate of septic mice by alleviating the systemic inflammatory response and its downstream tissue injury in the liver, spleen, and kidneys. This study demonstrates that CRNs combined with iron-DTPA can be utilized as nonaccumulative nanomedicines for treating systemic inflammation, thereby overcoming the limitations of conventional ceria nanoparticle-based treatments.

Removal of Lead Cations by Novel Organoclays Derived from Bentonite and Amphoteric and Nonionic Surfactants.

For many decades, natural and modified clay minerals have been used as adsorbents to clean up aquatic and soil ecosystems contaminated with organic and inorganic pollutants. In this study, organoclays based on bentonite and various amphoteric and nonionic surfactants were synthesized and tested as effective sorbents for lead ions. The maximum values of R were obtained when describing the sorption processes using the Langmuir model, which ranged from 0.97 to 0.99. The adsorption of lead ions by these organoclays was investigated using different sorption models including the Langmuir, Freundlich, and BET. It was found that, according to the values of limiting adsorption to the Langmuir equation, the synthesized organoclays formed an increasing series: organoclay with cocamide diethanolamine < bentonite < organoclay with lauramine oxide < organoclay with sodium cocoiminodipropionate < organoclay with disodium cocoamphodiacetate < organoclay with alkyl polyglucoside. The Gibbs energy for all of the analyzed samples was calculated and found to be negative, indicating the spontaneity of the cation adsorption process in the forward direction. The maximum value of the adsorption capacity of lead cations on organoclay-based bentonite with alkyl polyglucoside was 1.49 ± 0.05 mmol/g according to the Langmuir model, and 0.523 ± 0.003 mmol/g as determined by the BET model. In the process of modifying bentonite, there was an increase in negative values of the zeta potential for organoclays compared to the initial mineral, which clearly enhanced their electrostatic interactions with the positively charged lead ions. It was hypothesized, based on the physicochemical principles, that exchange adsorption is the main mechanism for lead absorption. Based on chemical approaches, organoclays based on amphoteric surfactants absorb lead mainly through the mechanisms of electrostatic attraction, ion exchange, and complexation as well as the formation of insoluble precipitates. Organoclays based on nonionic surfactants, on the other hand, absorb lead through mechanisms of complexation (including chelation) and the formation of insoluble chemical precipitates. The comparison of isotherms from different models allows us to find the most accurate match between the model and the experimental data, and to better understand the nature of the processes involved.

A highly sensitive and specific fluorescent probe for thrombin detection and high-throughput screening of thrombin inhibitors in complex matrices

Thrombin plays a critical role in hemostasis and hemolysis, and is a significant biomarker for blood-related diseases. Detection and inhibitors screening of thrombin are essential in medical research. In this study, we developed a fluorescent sensor based on the interaction between quantum dots (QDs) and fibrinogen (Fib) for thrombin detection and its inhibitors screening. Upon the presence of thrombin, the fibrinogen of soluble QDs-Fib were converted into insoluble fibrin precipitate, causing a change of fluorescence intensity in the supernatant. Under optimized conditions, our method exhibited an excellent linearity (R2 ≥0.99) over the range of 2∼100 U/L with a limit of detection (LOD) as low as 0.29 U/L. Moreover, we employed this method to screen for thrombin inhibitors using dabigatran as an exemplary direct thrombin inhibitor (DTI), even at concentrations as low as 1 nM. Finally, the established method was successfully used to screen thrombin inhibitors in 23 different extracts from Eupolyphaga sinensis walker. The method provided not only a sensitive, specific and high throughput assay for the detection of thrombin activity in biological samples, but also a reliable strategy for the screening of thrombin inhibitors in complex matrices.

The renewed tin-weighting treatment as sustainable and durable flame-retardant approach for protein silk fabric

The facile development of a sustainable and durable flame-retardant approach for protein silk is of interest. Inspired by silk tin-weighting technology, this study developed a novel and sustainable in-situ deposition strategy based on biomass phytic acid to impart durable flame-retardant performance to silk fabrics. The chemical structure of insoluble chelating precipitation, and the surface morphology, thermal stability, combustion behavior, flame-retardant capacity, laundering resistance, and flame-retardant mode of action of the tin-weighting silk samples, were explored. The Sn-, P-, Si-containing insoluble chelating precipitation formed within the fiber interior and combined with silk fibers through electrostatic attraction and metal salt chelation. As a result, the tin-weighting silk displayed excellent self-extinguishing capacity, with the damaged length reduced to 9.2 cm and the LOI increased to 31.6 %; it also achieved self-extinguishing after 30 washing cycles, demonstrating high flame-retardant efficacy and laundering resistance. Moreover, the tin-weighting silk also showed the obvious suppression in smoke and heat generation by 55.6 % and 35.7 %, respectively. The synergistic charring action of phosphate groups, tin metal salts, and silicates was beneficial for enhancing the fire safety of silk. The tin-weighting treatment also displayed a minor impact on mechanical performance of silk fabrics.

Exploration on the corrosion inhibition performance of Salvia miltiorrhiza extract as a green corrosion inhibitor for Q235 steel in HCl environment

Salvia Miltiorrhiza, extensively distributed and commonly employed as a traditional Chinese medicinal herb, has garnered significant attention. In this study, the Salvia Miltiorrhiza extract (SME) was prepared by one-step water extraction method, and was firstly used as a novel corrosion inhibitor for Q235 steel in 1 mol/L HCl solution. As identified via liquid chromatography-mass spectrometry, the findings reveal that Salvianic acid A, tanshinone II A, danshenxinkun D, dihydrotanshinone, and methylene tanshinquinone are the primary constituents of SME. The optimum corrosion inhibition efficiency reached 92.8 % at 200 mg/L and maintained at 90.4 % after 72 h. Based on in-situ scanning vibration electrode technology (SVET) monitoring, the adsorption of inhibitor molecules on metal surface greatly retarded the propagation of localized corrosion. AFM examination of the corroded surface reveals that the samples supplemented with SME exhibit a smoother surface compared to the blank group. The force curve graph for the SME-added group demonstrates a more evenly distributed point array and an elevated average adhesion force, indicating that the addition of SME improves the corrosion resistance of the metal surface. XPS characterization illustrated that SME interacted with iron ions to form insoluble precipitate. This work investigated the application of SME as an eco-friendly corrosion inhibitor for carbon steel in acidic medium, providing a new approach for the high value-added utilization of Salvia Milliorrhiza.

Effect of hematoma on early degradation behavior of magnesium after implantation.

The corrosion of magnesium (Mg)-based bioabsorbable implanting devices is influenced by implantation environment which dynamically changes by biological response including wound healing. Understanding the corrosion mechanisms along the healing process is essential for the development of Mg-based devices. In this study, a hematoma model was created in a rat femur to analyze Mg corrosion with hematoma in the early stage of implantation. Pure Mg specimen (99.9%,ϕ1.2 × 6 mm) was implanted in rat femur under either hematoma or non-hematoma conditions. After a designated period of implantation, the specimens were collected and weighed. The insoluble salts formed on the specimen surfaces were analyzed using scanning electron microscopy, energy-dispersive x-ray spectroscopy, and Raman spectroscopy on days 1, 3, and 7. The results indicate that hematomas promote Mg corrosion and change the insoluble salt precipitation. The weight loss of the hematoma group (27.31 ± 5.91 µg mm-2) was significantly larger than that of the non-hematoma group (14.77 ± 3.28 µg mm-2) on day 7. In the non-hematoma group, carbonate and phosphate were detected even on day 1, but the only latter was detected on day 7. In the hematoma group, hydroxide was detected on day 1, followed by the formation of carbonate and phosphate on days 3 and 7. The obtained results suggest the hypoxic and acidic microenvironment in hematomas accelerates the Mg corrosion immediately after implantation, and the subsequent hematoma resorption process leads to the formation of phosphate and carbonate with organic molecules. This study revealed the risk of hematomas as an acceleration factor of the corrosion of Mg-based devices leading to the early implant failure. It is important to consider this risk in the design of Mg-based devices and to optimize surgical procedures controlling hemorrhage at implantation and reducing unexpected bleeding after surgery.

Ultrasensitive “signal-inversion” photoelectrochemical aptasensor based on semiconductive MOF integrated with the manganese ferrite nanozyme-regulation for the selective detection of fumonisin B1

In this work, we developed a novel “signal-inversion” photoelectrochemical (PEC) aptasensor based on the photoelectric active CuCo-based metal–organic framework with 2,3,6,7,10,11-hexaiminotriphenylene (HITP) as ligand [denoted as Cu2.46Co0.54(HITP)2] for sensitively detecting fumonisin B1 (FB1) using the enzyme-assisted biocatalytic precipitation reaction. The bimetallic semiconductive Cu2.46Co0.54(HITP)2 exhibited large specific surface area and pore size, graphene-like nanostructure, narrow band gap, enhanced photoabsorption ability, and high functionality. Thus, large amounts of single-strand DNA (sDNA) were immobilized over the Cu2.46Co0.54(HITP)2-modified electrode because of Van der Waal force, electrostatic force, and π−π stacking interaction. Then, sDNA was hybridized with the MnFe2O4-decorated FB1-target aptamer because of the complementary bases. As such, FB1 was recognized by generating the G-quadruplex between FB1 and aptamer. This G-quadruplex was released from the electrode surface. In the presence of H2O2, 3,3-diaminobenzidine was electrocatalytically oxidized by the remnant MnFe2O4, thereby producing the brown insoluble precipitate. The cover of modified electrode by the precipitate efficiently weakened the output photocurrent. With the increase of the level of FB1, the gradually declined amount of MnFe2O4 on the developed aptasensor resulted in the recovery of the photocurrent, realizing the signal inversion. The “signal-inversion” PEC aptasensor based on Cu2.46Co0.54(HITP)2 had a wide linear range of 0.1 pg mL−1 to 10 ng mL−1 and an ultralow detection limit of 65 fg mL−1, together with comprehensive aptasensing performances. By integrating the enhanced photoelectric conversion efficiency of Cu2.46Co0.54(HITP)2 and the superior electrocatalytic activity of MnFe2O4, the present strategy exhibits a wide application toward the sensitive analysis of mycotoxins.

The potential of using curcumin in dairy and milk-based products-A review.

This review examines the potential of curcumin as a technological and functional food additive in dairy and milk-based products. The advantages of incorporating curcumin in these products include its antimicrobial properties, support for the activity of lactic acid bacteria, improvement in sensory characteristics, and shelf-life extension. Curcumin notably enhances antioxidant activity and acts as a natural preservative in cheese, cheese-like products, and butter. In ice cream and dairy desserts, curcumin contributes to attractive color formation and offers functional benefits such as antioxidant activity, photostability, and increased nutritional value. However, the use of turmeric extract, a common source of curcumin, presents challenges including low bioavailability, color instability, and the formation of insoluble precipitates. The application of specialized curcumin formulations with enhanced water dispersion, purity, and bioavailability can mitigate these issues, improve the product's technological properties, and ensure compliance with local regulations. This review highlights the importance of continued research and development to optimize the use of curcumin in dairy and milk-based products, offering valuable insights for scientists and food industry professionals.

Kinetic study of reaction formation of phosphate products from thermal dissolution of wolframite using fusion technique

This study examined an alternative technique of extracting tungsten from wolframite ore using a fusion method with ammonium phosphate salt. Current techniques use alkali salts to decompose tungsten ores and use various purification methods to produce ammonium paratungstate, which is a key intermediate precursor in the extraction of tungsten. In this study, a two-step extraction process, which involves thermal decomposition of the ore using fusion and a separation stage, is examined. The novelty of this technique is the ability to completely decompose wolframite ore and form an unstable tungsten oxide phosphate (WO2(PO3)2) compound. The instability of WO2(PO3)2 in deionized water enables selective isolation of tungsten as insoluble precipitates of WO3 and WO2. The decomposition reaction of WO2(PO3)2 is influenced by the presence of oxygen and determined to be first order under ambient conditions. Scanning electron micrographs and X-ray diffraction analysis showed above 80% of the tungsten precipitated compared with the amount that remained in the filtrate solution.

Retrieval and reuse of surfactants from microemulsions enabled by a pH-triggered precipitation-dissolution strategy.

How to retrieve and reuse surfactants efficiently from surfactant-based microemulsions (MEs) has long been a problem, which is full of challenges and needs to be solved urgently. To this end, a pH-triggered precipitation-dissolution (PTPD) strategy is developed. The surfactant sodium 3-(laurylamino)propane-1-sulfonate (LMPS) transforms into an insoluble precipitate (the inner salt of LMPS, LMP) after reaction with HCl, by which the monophasic LMPS-based MEs demulsified entirely, giving a separable mixture of oil, water and LMP. LMP can be retrieved efficiently (~95.3%) regardless of the ME type, and can then be conveniently restored to LMPS via reactions with NaOH. Conceptually, the retrieval of LMPS (~96.6%), toxic benzo[a]pyrene (BaP, ~99.5%) and a mixture of co-surfactant n-butanol and the oil phase n-heptane (~97.1%) from the sufficiently emulsified soil eluents is achievable by respectively using the PTPD strategy and distillation, wherein the soil eluents were generated from the remediation of BaP-contaminated soil using an oil-in-water LMPS-based ME as washing agent. It reveals a promising future for the PTPD strategy in the post-processing of soil eluents containing toxic hydrophobic organic contaminants and excessive surfactants.

Triple quenching effect of nanozyme catalyzed precipitation combined with enzyme-free amplification for photoelectrochemical biosensing of circulating tumor DNA

In this work, a new photoelectrochemical (PEC) biosensor based on triple quenching effect of nanozyme catalyzed precipitation to PEC signal of MgIn2S4 was constructed for ultrasensitive detection of circulating tumor DNA (ctDNA). Enzyme-free amplification technology was used to convert target ctDNA into a large number of product chains (PC) to improve the detection sensitivity. Co3O4 nanozyme with excellent peroxidase (POD)-like activity was introduced to the surface of MgIn2S4 by PC. Co3O4 could oxidize chromogenic agent 3-Amino-9-ethylcarbazole (AEC) to produce red insoluble precipitation in the presence of H2O2, resulting in the PEC signal “off” of MgIn2S4 to achieve ultrasensitive detection of ctDNA. In particular, Co3O4 nanozyme showed three synergistic quenching effects on PEC signal of MgIn2S4, which contributed greatly to improving the detection sensitivity. Firstly, the light absorption range of Co3O4 could reach 1000 nm, and compete with MgIn2S4 for light absorption. Secondly, the produced red precipitation belonged to the insulating material and had large electrochemical impedance, which hindered the transmission of photogenerated carriers. Thirdly, the precipitation also prevented the electron donor ascorbic acid (AA) from transferring electrons to MgIn2S4. This biosensor provided a promising sensitive PEC detection technology for ctDNA, and further broadened the application of nanozymes in the field of PEC analysis.

Investigation of rheological and filtration characteristics of sedimentary gel-forming compounds

In producing wells, complete wetting often occurs, during which most of the oil reserves in them remain unproductive. This feature is typical for various fields, as well as for the fields of Kazakhstan. In this case, the most reliable way to increase oil recovery is to limit oil recovery through the use of modern technologies and chemicals. This article discusses the type of technology that allows to increase the efficiency of processing the bottom of the well – the use of sedimentary gel-forming compounds – SRFC the basis of the SRFC technology is to reduce the permeability of the flushed zones in the bottom of the formation and reduce the degree of its heterogeneity. The effect of these formulations is based on the formation of an insoluble precipitate and a gel polymer in the pore space in the lower part of the layer, the specified precipitate and gel block or reduce the permeability of the intervals washed. In the article, as a result of experimental studies, an assessment of the physico-chemical properties of gel-forming compositions was carried out using statistical methods for processing values and analyzing data, in connection with which the rheological properties of sedimentation compositions were simulated, taking into account the composition and average concentrations of various components (polymer, alkali).

A dual-mode biosensor based on CdIn2S4 hollow microsphere combined with Au@CuO/Cu2O nanozyme for sensitive detection of Sa-16S rDNA

A dual-mode biosensor used CdIn2S4 hollow microspheres as electrochemiluminescence (ECL) and photoelectrochemistry (PEC) dual signal probes combined with Au@CuO/Cu2O nano-enzyme catalysis was fabricated for sensitive detection of Sa-16S rDNA. Firstly, CdIn2S4 microspheres displayed excellent ECL and PEC signals, then the target Sa-16S rDNA introduced a large number of Au@CuO/Cu2O nanoparticles to the electrode via Exo-III amplification strategy. Au@CuO/Cu2O is a highly efficient peroxidase mimicase, and can effectively promote H2O2 to produce ·OH, which further oxidized 4-chloro-1-naphthol (4-CN) to produce a large amount of insoluble precipitate on the electrode surface, then significantly reduced the PEC and ECL signals of CdIn2S4 for target detection. This study opens up a new multifunctional photoelectric microspheres and a flexible biosensor by using CdIn2S4 and nanozymes, showing a new channel for the detection of DNA molecules and providing valuable insights for the development of PEC biosensing technologies based on nanozymes.

A pilot-scale study on the in-situ remediation of acid mine drainage with supplemental of external nutrition: Performance, heavy metal removal and microbial community evolution

Acid mine drainage (AMD), a common environmental problem around the world, is characterized by low pH, high concentrations of heavy metals and sulfate. AMD treatment technology based on stimulating in-situ microorganisms has received widespread attention, but lack of organic matter is a limiting factor that restricts the remediation by heterotrophic microorganisms such as sulfate-reducing bacteria (SRB). In this study, a pilot scale reactor was set up next to an acid reservoir to evaluate the effect of livestock wastes on the in-situ bioremediation of AMD, focusing on performance assessment, heavy metal removal efficacy, and the evolution of the microbial community. Results indicated that the pH of AMD rises rapidly from 3.23 to 4.11, and metals (e.g., Fe, Cu, and Zn) rapidly got removed in Stage I. However, AMD experienced significant stratification in Stage Ⅱ (biogas slurry supplemented). The pH of surface layer (0.5 m below the surface) gradually dropped to 3.67, and the bottom layer (2.3 m below the surface) remained around 4.1, and the metal removal efficiencies further improved. Microbial communities were dominated by Fe-OB and Fe-RB in surface layer, while SRB dominated in bottom layer. The addition of biogas slurry significantly increased the relative abundance of functional microbe in bioremediation. The growth of SRB in the bottom of the reactor made an important contribution to heavy metal removal. Heavy metals were mainly removed through the formation of insoluble hydroxide and sulfide precipitation and co-precipitation. This study innovatively integrates low-cost, locally sourced livestock waste as nutrient supplements into AMD bioremediation processes, and demonstrated the potential for integrating AMD treatment with livestock waste management, addressing both the nutrient needs for AMD processing and the challenge of livestock waste disposal. The findings contribute to the development of cost-effective and eco-friendly strategies for AMD management while advancing the understanding of microbial mechanisms of in-situ bioremediation.

MXene@MnIn2S4‐Gated Organic Photoelectrochemical Transistors with Nanozyme‐Mediated Multiple Quenching Effects for Ultrasensitive Detection of Okadaic Acid

AbstractOrganic optoelectronics have attracted widespread interdisciplinary research interest but lags far behind in the application in marine environmental detection. The organic photoelectrochemical transistor (OPECT) shows promise as a powerful tool for comprehensive monitoring and early warning of marine conditions, which can be further enhanced by the valuable signal amplification strategy of nanozyme‐mediated catalytic precipitation. Herein, OPECT technology is integrated with nanozyme‐mediated catalytic precipitation for the first time, establishing an ultrasensitive detection platform for okadaic acid (OA). Specifically, MXene@MnIn2S4 (MXMnIS) hybrid composed of Schottky‐junction is synthesized via a hydrothermal method, which can efficiently modulate the device with high current gain. Linking with a sandwich immunoassay, the Ru‐C3N4 nanozyme with peroxidase‐mimicking activity can catalyze the oxidation of 4‐chloro‐1‐naphthol (4‐CN) to form an insoluble precipitate on the electrode surface, resulting in a decrease in the photocurrent and altering the transistor response. Importantly, the proposed OPECT biosensor presented an excellent sensitivity and a low detection limit (32.5 pM), fully satisfying the fundamental requirements for the quantitative detection of intracellular and extracellular OA in the practical culture media of Prorocentrum lima at different growth stages. This OPECT platform based on the nanozyme‐mediated quenching effect is significant for effectively monitoring the safety of the marine ecological environment and food safety.

Photoelectrochemical immunoassay of cardiac troponin I based on ZnTCPP/CdIn2S4 type-II heterojunction and co-catalyzed precipitation biolabeling.

CdIn2S4 and zinc tetrakis(4-carboxyphenyl)porphyrin (ZnTCPP) were synthesized by hydrothermal method, and an organic dye-sensitized inorganic semiconductor ZnTCPP/CdIn2S4 type II heterojunction was constructed on a fluorine-doped tin oxide (FTO) substrate electrode. Asandwich immunostructure forsignal-attenuation photoelectrochemical (PEC) detection of cardiac troponin I (cTnI) was constructed using the ZnTCPP/CdIn2S4/FTO photoanode and a horseradish peroxidase (HRP)-ZnFe2O4-Ab2-bovine serum albumin (BSA) immunolabeling complex. The bioenzyme HRP and the HRP-like nanozyme ZnFe2O4 can co-catalyze the oxidation of 4-chloro-1-naphthol (4-CN) by H2O2 to produce an insoluble precipitate on the photoanode, thus notably reducing the anodic photocurrent for quantitative determination of cTnI. Under the optimal conditions, the photocurrent at 0V vs. SCE in 0.1M phosphate buffer solution (pH 7.40) containing 0.1M ascorbic acid was linear with the logarithm of cTnI concentration from 500fg mL-1 to 50.0 ng mL-1, and the limit of detection (LOD, S/N = 3) is 0.15 pg mL-1. Spiked recoveries were 95.1% ~ 104% for assay of cTnI in human serum samples.

Inhibition of Skin Cancer using Human Epidermal Keratinocytes (HaCaT) Cells from Siam Weeds (Chromolaena odorata L.)

Cancer can usually develop due to exposure to sunlight. UV radiation from sunlight is known to damage DNA and is bad for the skin. Skin P stem cell carcinogenesis is caused by UV-A rays that penetrate deep into the dermis layer. UV-B damages cell DNA by being absorbed by proteins in the epidermis. Chromolaena odorata was extracted using methanol solvent, then partitioned into 5 solutions in the form of n-Hexane, Ethyl Acetate, Acetonitrate, n-Buthanol, and Ethanol. The five extracts obtained were tested with Human Epidermal Keratinocyte cells using the bioassay method. Results obtained from the microplate reader after incubation. Each extract was divided into three concentrations, it is 100, 50, 20(µg/mL). Then in the positive control (Etoposide), it was divided into four concentrations, 100, 50, 20, 10(µg/mL). After being analyzed with the results of the microplate reader, the IC50 of Chromolaena odorata was 48% in the ethyl acetate extract with a concentration of 100µg/mL. HaCaT cell proliferation was determined at indicated intervals using the MTT colorimetric assay. This assay was based on the ability of live cell succinate dehydrogenase to reduce the yellow salt MTT (3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide)) (Sigma-Aldrich, St. Louis, MO, USA) to insoluble purple-blue formazan precipitate. Experiments were carried out on 96-well plates containing a final volume of 100µl of medium/well.

Fe-single-atom catalysts boosting electrochemiluminescence via bipolar electrode integrated with its peroxidase-like activity for bioanalysis

Multifunctional single-atom catalysts (SACs) have been extensively investigated as outstanding signal amplifiers in bioanalysis field. Herein, a type of Fe single-atom catalysts with Fe-nitrogen coordination sites in nitrogen-doped carbon (Fe–N/C SACs) was synthesized and demonstrated to possess both catalase and peroxidase-like activity. Utilizing Fe–N/C SACs as dual signal amplifier, an efficient bipolar electrode (BPE)-based electrochemiluminescence (ECL) immunoassay was presented for determination of prostate-specific antigen (PSA). The cathode pole of the BPE-ECL platform modified with Fe–N/C SACs is served as the sensing side and luminol at the anode as signal output side. Fe–N/C SACs could catalyze decomposition of H2O2 via their high catalase-like activity and then increase the Faraday current, which can boost the ECL of luminol due to the electroneutrality in a closed BPE system. Meanwhile, in the presence of the target, glucose oxidase (GOx)-Au NPs-Ab2 was introduced through specific immunoreaction, which catalyzes the formation of H2O2. Subsequently, Fe–N/C SACs with peroxidase-like activity catalyze the reaction of H2O2 and 4-chloro-1-naphthol (4-CN) to generate insoluble precipitates, which hinders electron transfer and then inhibits the ECL at the anode. Thus, dual signal amplification of Fe–N/C SACs was achieved by increasing the initial ECL and inhibiting the ECL in the presence of target. The assay exhibits sensitive detection of PSA linearly from 1.0 pg/mL to 100 ng/mL with a detection limit of 0.62 pg/mL. The work demonstrated a new ECL enhancement strategy of SACs via BPE system and expands the application of SACs in bioanalysis field.

Assessing Target Specificity of the Small Molecule Inhibitor MARIMASTAT to Snake Venom Toxins: A Novel Application of Thermal Proteome Profiling

New treatments that circumvent the pitfalls of traditional antivenom therapies are critical to address the problem of snakebite globally. Numerous snake venom toxin inhibitors have shown promising cross-species neutralization of medically significant venom toxins in vivo and in vitro. The development of high-throughput approaches for the screening of such inhibitors could accelerate their identification, testing, and implementation and thus holds exciting potential for improving the treatments and outcomes of snakebite envenomation worldwide. Energetics-based proteomic approaches, including thermal proteome profiling and proteome integral solubility alteration (PISA) assays, represent “deep proteomics” methods for high throughput, proteome-wide identification of drug targets and ligands. In the following study, we apply thermal proteome profiling and PISA methods to characterize the interactions between venom toxin proteoforms in Crotalus atrox (Western Diamondback Rattlesnake) and the snake venom metalloprotease (SVMP) inhibitor marimastat. We investigate its venom proteome-wide effects and characterize its interactions with specific SVMP proteoforms, as well as its potential targeting of non-SVMP venom toxin families. We also compare the performance of PISA thermal window and soluble supernatant with insoluble precipitate using two inhibitor concentrations, providing the first demonstration of the utility of a sensitive high-throughput PISA-based approach to assess the direct targets of small molecule inhibitors for snake venom.

Lead immobilization in tailings–based alkali–activated materials

Our research explores the intricate mechanisms between lead (Pb) and alkali–activated materials (AAMs) derived from lead–zinc tailings. We delve into the lead immobilization process and its impact on material behavior. Our findings indicate that Pb2+ shortened the induction period and accelerated later hydration by offering additional nucleation sites. Notably, Pb2+ manifest a dual impact on the compressive strength of AAMs: a marginal increase at low concentrations (Pb2+ = 0.5%) and a decrease at higher ones (Pb2+ = 1.5%). Micro-analysis indicates that the hydrolysis of Pb2+ forms new materials that bridge larger pores within the AAMs matrix, resulting in reduced pore size. However, an excess of Pb2+ hampers gel polymerisation, impairing the gel’s structural integrity and the stability of immobilization. The interplay of these phenomena determines the overall strength of the material. Our leaching tests demonstrate that AAMs can effective immobilize Pb2+ at concentrations up to 1%, with a remarkable containment efficiency of 99.5% at 0.5% Pb2+. This is facilitated by several mechanisms, including the formation of insoluble precipitate, ion exchange with Na+/Ca2+, covalent bonding with Si, and physical encapsulation. These insights shed light on the promising applications of tailings–based AAMs for the effective immobilization of lead.