Search Results (2,859)

Developing an ultrasensitive electrochemiluminescence (ECL) detection platform remains challenging due to the limited enrichment efficiency of ECL emitters and co-reactants at the electrode interface, as well as the insufficient catalytic enhancement of co-reactant conversion. Moreover, simultaneous in situ analyte enrichment and efficient anti-interference capability are often difficult to achieve in a single sensing interface. Herein, a new ECL platform was developed based on nanocatalyst-supported nanochannel-confined surfactant micelle (SM) system, which integrates an enhanced luminol-dissolved oxygen (DO) ECL response for the ultrasensitive detection of antibiotic rifampicin (RIF). A nanocomposite comprising nitrogen-doped graphene quantum dots and a molybdenum disulfide nanosheet (NGQDs@MoS₂) was modified on an indium tin oxide (ITO) electrode. This nanocomposite layer catalyzed the oxygen reduction reaction (ORR), boosting the co-reactant efficiency of DO. Vertically ordered mesoporous silica film filled with surfactant micelles (SM@VMSF) was subsequently grown in situ on the NGQDs@MoS₂ surface. The hydrophobic micelles enable the simultaneous enrichment of luminol, DO, and RIF. Integrating the triple-enrichment effect of surfactant micelles with the high electrocatalytic effect of NGQDs@MoS₂ nanocomposite results in significant ECL enhancement of the luminol–DO. SM@VMSF also provides an excellent molecular sieving effect, endowing the sensor with high anti-interference capability and stability. RIF quenches the ECL signal by consuming superoxide anion radicals, enabling sensitive detection. Detection of RIF was established with a high sensitivity (2927 a.u. per nM) wide linear range (10 pM to 10 μM) and a low limit of detection (LOD, 2.5 pM). The fabricated sensor exhibits good selectivity and high fabrication reproducibility (relative standard deviation, RSD, of 1.9%). Additionally, the determination of RIF in eye drops and seawater samples was realized. This work offers new insights for the design of high-performance ECL sensing interfaces and sensitive detection of RIF. Full article

Two-dimensional (2D) materials exhibit electronic and collective excitation properties that are highly sensitive to surface chemistry and thickness, requiring surface-sensitive characterization at low electron energies. Here, we investigate graphene, hexagonal boron nitride (h-BN), molybdenum disulfide (MoS₂), and titanium carbide (Ti₃C₂) MXene using an advanced home-built scanning low-energy electron microscopy system combined with time-of-flight electron spectroscopy (SLEEM/ToF). The system uniquely records electron energy-loss spectra (EELS) from transmitted electrons rather than from the reflected electrons used in conventional SLEEM. Compared with high-energy EELS, our low-energy ToF-EELS approach offers enhanced surface sensitivity and reduced beam-induced damage, enabling direct probing of π and π + σ plasmon excitations. Additionally, complementary techniques, including scanning transmission electron microscopy (STEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS), were employed to characterize structural and chemical properties. EELS were acquired for all investigated 2D materials at electron landing energies of 500–1500 eV, and in the 5–50 eV range for selected materials, including graphene and MoS₂. Analysis of these spectra enabled determination of the average plasmon positions across the measured energy range for all studied materials. Furthermore, a quantitative determination of the inelastic mean free path (IMFP) was achieved for graphene in the 10–50 eV range, yielding a value of 1.9 ± 0.2 nm. These results demonstrate the potential of SLEEM–ToF for surface-sensitive analysis of 2D materials. Full article

The anchovy (Engraulis japonicus) is a highly abundant but underutilized fish resource in China, primarily due to its extreme post-harvest perishability. This study expanded the utilization of anchovy by developing a blended surimi from anchovy and golden threadfin bream, an I-optimal mixing design experiment was performed to optimize the formulation, and the effects of soy protein isolate (SPI), egg white powder (EWP), and yeast protein (YP) on the gel properties were investigated. The results of sensory evaluation and model prediction indicated that SPI had the most pronounced positive effect on the sensory characteristics of the gels, especially improving the elasticity, followed by EWP. Furthermore, the SPI-rich sample exhibited superior gel strength and chewiness, which was attributed to the increased β-sheet structure and the highest content of disulfide bonds in the protein network. And the water hold capacity of SPI-rich sample increased by 6.0%. The YP-rich group showed the strongest hydrophobic interactions and exhibited a significant enhancement in water hold capacity of 7.7%, which also provided a notable improvement in gel strength. The results showed that EWP contributed to the smoothness of the surimi, but it had no significant impact on water distribution, water-holding capacity, or the content of disulfide bonds within the gel network. Moreover, the EWP-rich group exhibited reduced the gel strength, hardness, and chewiness of the gel, resulting in the lowest overall sensory score of the surimi. Therefore, the optimal composite ratio was determined to be SPI:EWP:YP = 5.45%:2.55%:2.00%. These findings provided a precise blending strategy for developing high-quality surimi products from anchovy, offering a viable technical pathway for the value-added utilization of this resource. Full article

Bacterial β-barrel pore-forming toxins, including Staphylococcus aureus α-toxin (Hla) and Bacillus cereus toxins hemolysin II (HlyII) and cytolytic toxin K2 (CytK-2), are secreted by bacterial cells as water-soluble monomers. These monomers assemble within lipid bilayers to form cylindrical pores, leading to lysis of target eukaryotic cells. We created mutant forms of these toxins that, based on the results of X-ray structural analysis of Hla and the prediction of the 3D structure of HlyII and CytK2, can form intramolecular disulfide bonds in monomers. The substitutions were made in the region responsible for toxin insertion into the target membrane. The mutant forms reversibly altered their hemolytic activity depending on the presence of reducing reagents and were non-toxic when injected into experimental animals. The immune response to injection of the mutant forms of Hla and CytK-2 toxins resulted in higher antibody titers against the wild-type toxins and a higher level of immunological memory than with injection of the HlyII mutant. The mutant form of CytK-2 demonstrates the properties of a prototype vaccine, as immunization with this protein protects animals against the effects of the wild-type toxin. Full article

Antiretroviral therapy (ART) effectively controls Human Immunodeficiency Virus Type-1 (HIV-1) infection in people with HIV-1 (PWH), preventing the progression of their infections to AIDS. However, as PWH age, they experience lifestyle- and age-related diseases, notably various types of cancer beyond those traditionally associated with AIDS, with greater incidence and mortality than their non-HIV-1-positive counterparts, despite effective arrest of HIV-1 infection by ART. Dysregulation of redox enzymes presents an underexplored linkage between HIV-1 infection and cancer comorbidity, impacting reactive oxygen/nitrogen species (RONS) management, inflammation, immune function, and mitochondrial function. Chronic HIV-1 infection increases both RONS production and RONS neutralization responses, accelerating development of a sustained RONS-rich environment that still possesses sufficient dampening to prevent outright cytotoxic effects. Such an environment promotes both tumor proliferation and resistance adaptations to chemo- and radiotherapies. This review considers the effects of chronic HIV-1 infection on redox enzyme function and links these effects to tumorigenic mechanisms as potentially shared pathways. We then examine current methods of modulating redox function, consider how these could potentially impact both HIV-1 infection and cancer progression, and lastly propose future methods of co-treatment that could be explored. Full article

Blood glutathione (GSH), its oxidized form glutathione disulfide (GSSG), and especially the ratio of reduced to oxidized glutathione (GSH/GSSG) are recognized as robust biomarkers of oxidative stress. However, the broader application of these biomarkers has been limited by two major challenges: (1) the high risk of artifact formation during sample handling, which can artificially increase GSSG levels and bias redox balance measurements, and (2) the reliance on complex, instrument-intensive analytical procedures and the requirement for venous blood. We present an adaptation of the highly sensitive and easy-to-perform Tietze recycling method for microvolumes of blood. The challenge is to achieve accurate and precise measurements while avoiding artifacts, taking advantage of the high sensitivity of this enzymatic recycling analytical procedure. The method uses a simplified sample preparation protocol compatible with small blood volumes (up to 10 μL) and requires only basic laboratory equipment, such as a standard spectrophotometer or microplate reader. As this is an enzyme-based assay, we also carefully evaluate the main factors that can affect the measurements. This novel procedure provides a practical tool for monitoring GSH/GSSG as a biomarker of oxidative stress in various experimental settings by eliminating the need for trained personnel for blood sampling (it is suitable for capillary blood), minimizing discomfort for subjects, and avoiding complex procedures or instruments for analyte detection. Full article

Traditional chemical hair dyes are associated with potential health risks, while botanical alternatives are often hampered by poor stability and limited color longevity. In this study, discarded squid ink was used to prepare bionic hair colorants of high performance. By synergizing ultrasound disruption with enzymatic hydrolysis, the crude ink aggregates were transformed into highly uniform squid ink melanin nanoparticles (SIMNPs) with size and zeta potential of ~174 nm and −37.5 mV, respectively. This effectively improved the solubility but reduced the steric limitation of natural melanin. To overcome the weak affinity between melanin and human hair, a biomimetic interface where Fe(III) ions act as supramolecular bridges was further engineered to stably bind the SIMNPs to hair keratin. Under optimized conditions (pH 8.0, 45 °C, and 80 min), the dyed hair achieved a natural deep black with a total color difference (ΔE*) of 68.79 ± 0.29, which was maintained at 63.19 ± 0.27 even after 13 consecutive water washing cycles. Unlike destructive oxidative dyes, this SIMNP dyeing system assisted by coordination-driven assembly preserved the native α-helical architecture and disulfide bond networks of hair keratin. Furthermore, the deposited SIMNP layer effectively protected hair fibers from ultraviolet (UV) damage due to its powerful UV-shielding capacity. Crucially, in vitro and in vivo evaluations confirmed the exceptional biosafety of this formulation, demonstrating robust cellular tolerance and absence of murine skin irritation. The work demonstrates a green, low-damage paradigm for the development of bio-based hair colorants of high performance and presents a promising pathway for the high-value utilization of marine by-products. Full article

Aluminium alloys are extensively considered in aviation and automobiles owing to their lightweight properties and favourable specific strength-to-weight ratio. Generally, the poor surface properties of these alloys limit their application, particularly in sliding conditions. To enhance the surface qualities, particularly the material’s wear resilient features, a unique surface modification process using electro-discharge coating (EDC) has been employed. This work investigates the optimisation of coating variables produced by the EDC technique utilising green compact electrodes composed of 50 wt.% tungsten disulfide (WS₂) and 50 wt.% copper (Cu) powder. The substrate material utilised was AA7075 alloy. The Taguchi–TOPSIS approach was employed to determine optimal EDC process variables, with pulse-on time (T_on), current (I_p), and pulse-off time (T_off). Wear rate (WR), surface roughness (SR), and friction coefficient (CoF) were used to assess the coating features. A wear study was performed with a pin-on-disc device with an undeviating sliding speed (0.25 m/s) and a 25 N load. The results revealed that the supreme features derived from the linear plots were I_p (4 A), T_on (80 µs), and T_off (5 µs). The ANOVA found that I_p had the utmost significant impact, accounting for 44.09%; T_off, 28.01%; T_on, 20.33%; and minimum error, 8.58%. A validation trial with perfect parameters returned values of 0.000179 mm³/Nm (WR), 0.204 (CoF), and 2.818 µm (SR). These findings are significantly better than those of the other coatings. The discrepancy among the estimated and experimental relative closeness in optimal settings is 6.34%, demonstrating that the Taguchi–TOPSIS method is more appropriate for multi-criteria optimisation. Full article

Human serum albumin (HSA) is the most abundant protein in plasma, and the redox state of circulating HSA has been used as a biomarker of systemic oxidative stress (OS) for decades. While informative, many traditional biomarkers of OS measure short-lived or downstream products of oxidative damage that offer limited perspectives on the dynamic and integrated processes that govern systemic redox biology within human populations. By moving beyond single-analyte damage markers and towards coordinated patterns of protein modifications, HSA-Cys³⁴ adductomics offers a systems-level approach that simultaneously captures change in multiple layers of OS. Because of its high abundance in plasma and HSA’s unique and highly reactive single free thiol (Cys³⁴), HSA-Cys³⁴ serves as an ideal sentinel target for monitoring reactions with reactive oxygen species (ROS), reactive nitrogen species (RNS), and electrophilic species produced by endogenous metabolism and responses to exogenous chemical exposures. The reaction of HSA with ROS, RNS, and reactive electrophiles yields a diverse array of protein modifications, including direct oxidation products (sulfenic, sulfinic, and sulfonic acid), low molecular weight thiol-disulfide exchange, and lipid peroxidation (LPO)-derived reactive aldehydes. With a mean residence time of about a month, these accumulated adducts serve as an integrated picture of oxidative and electrophilic stress that together function as a molecular record of systemic redox physiology. Previous studies using high-resolution mass spectrometry-based adductomics have enabled global untargeted analysis of HSA-Cys³⁴ modifications, yielding an expansive inventory of novel redox signatures of environmental stressors and disease states. In this paper we review the chemistry and biology underlying OS-related modifications of HSA-Cys³⁴ and highlight the important role of HSA-Cys³⁴ adducts as integrative biomarkers of OS at the interface of molecular biology, exposure assessment, and public health research. Full article

Cancer remains a major global health challenge, and the limitations of conventional therapies have intensified interest in treatment strategies that combine improved selectivity with reduced systemic toxicity. Photothermal therapy and photodynamic therapy have emerged as minimally invasive approaches capable of achieving spatiotemporally controlled tumour ablation. In this context, molybdenum disulfide (MoS₂), a transition metal dichalcogenide with strong near-infrared absorption, high photothermal conversion efficiency, and versatile surface chemistry, has gained increasing attention as a multifunctional platform for drug delivery and light-triggered cancer therapy. This review examines recent advances in engineered MoS₂ nanoplatforms for drug-enhanced cancer phototherapy, with emphasis on how surface design and therapeutic cargoes mechanistically amplify light-triggered tumour killing. Approaches such as polymer coatings, biomimetic membranes, targeting ligands, chemotherapeutic agents, nucleic acids, and photosensitisers have been explored to improve colloidal stability, tumour targeting, immune evasion, and stimulus-responsive drug release, while also adding complementary cytotoxic pathways such as chemotherapy, ROS generation, or gene silencing. Available in vitro and in vivo studies indicate that these systems generally exhibit favourable short-term biocompatibility under the tested conditions and can produce significant antitumour effects following irradiation. The review also discusses key biological barriers and translational challenges, including biodistribution, long-term safety, reproducibility, and regulatory considerations, highlighting opportunities for the development of clinically viable MoS₂-based phototherapeutic platforms. Full article

Pregnancy in dairy cattle is characterized by marked metabolic adaptations that may influence oxidative balance. In this study, oxidative stress markers and thiol–disulfide homeostasis were evaluated in transported and non-transported Holstein heifers during the last trimester of gestation. Clinically healthy 2-year-old heifers were divided into transported pregnant (n = 21) and non-transported pregnant (n = 9) groups. Blood samples were collected from the jugular vein approximately 90 days (3 months) after the mid-gestation transport event. These samples were analyzed for total antioxidant capacity (TAC), total oxidant status (TOS), oxidative stress index (OSI), malondialdehyde (MDA), native thiol (NTL), total thiol (TTL), and disulfide levels. Total oxidant status and oxidative stress index values were significantly higher in the non-transported group (p < 0.05). However, no significant differences were observed between groups in total antioxidant capacity, malondialdehyde, or thiol–disulfide parameters (p > 0.05). These findings suggest that metabolic adaptations specific to late gestation may influence systemic oxidant levels independently of transport exposure. Under the conditions of this study, transport did not induce a marked redox imbalance in pregnant Holstein heifers. Full article

Background: Thrombotic thrombocytopenic purpura (TTP) is a life-threatening condition resulting from a disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13 (ADAMTS13) deficiency, leading to the accumulation of ultra-large von Willebrand factor (vWF) multimers and widespread microvascular thrombosis. While therapeutic plasma exchange and immunosuppression have significantly improved response, refractory and relapsed disease are significant challenges. N-acetylcysteine (NAC) has emerged as a biologically plausible adjunctive therapy due to its potential to reduce disulfide bonds in vWF multimers. However, its clinical role is unclear. This systematic review aimed to evaluate the clinical evidence regarding the efficacy and safety of N-acetylcysteine in patients with immune-mediated TTP. Methods: We performed a systematic review in accordance with the PRISMA guidelines. PubMed/MEDLINE, Google Scholar, and ClinicalTrials.gov were searched until January 2026. Studies involving patients with immune-mediated TTP treated with NAC were included. Case reports, case series, and observational studies involving patients with immune-mediated TTP treated with NAC were included. Risk of bias was evaluated using adapted quality assessment tools. Results: Sixteen studies encompassing 69 patients met the inclusion criteria. Most reports were case reports or small case series; two were larger observational cohorts. NAC was predominantly used as adjunctive therapy in relapsed or refractory TTP. Dose regimens varied. Platelet recovery following NAC was reported within 1–15 days in responding cases. Predominantly positive haematological responses were observed in small series. Significant heterogeneity in patient populations, timing of initiation, concomitant therapies, and outcome reporting limited causal inference. Conclusions: The current evidence suggests that NAC has a biologically rational and potentially adjunctive value in TTP, particularly in refractory disease or resource-constrained settings. However, current data are largely heterogeneous and derived from low-level evidence. Well-designed prospective studies and randomized controlled trials are needed to determine whether NAC provides significant clinical benefit beyond standard therapy. Full article

Neurotoxicity caused by snake venom phospholipase A₂ (PLA₂) activity derived from coral snakes (e.g., Micrurus tener, Micrurus fulvius, group IA PLA₂) and some rattlesnakes (e.g., Crotalus scutulatus, group IIA PLA₂) is medically significant. Of interest, the catalytic site of PLA₂ also binds to activated clotting factor X, causing anticoagulation. Given that ruthenium (Ru)-containing compounds have been demonstrated to inactivate hemotoxic venoms in a solvent-dependent manner (e.g., 0.9% NaCl, phosphate-buffered saline), we wished to determine if RuCl₃ would cause solvent-dependent inhibition of snake venom group IA and group IIA PLA₂ in human plasma with thrombelastography. It was determined that RuCl₃ significantly decreased the anticoagulant effects of group IA PLA₂ derived from M. tener and M. fulvius venoms in the presence of 0.9% NaCl, but not phosphate-buffered saline. In contrast, group IIA PLA₂ anticoagulant activity derived from C. scutulatus venom was inhibited by RuCl₃ in both solvents. It is concluded that the different ions formed by RuCl₃ in different solvents may interact with novel disulfide bridges unique to group IA and IIA PLA₂ or through some other mechanism. In vivo validation of Ru-based enzyme inhibitor effects on neurotoxicity associated with either group IA or IIA remains a critical translational issue. Full article

We investigate covalent bond healing and mechanical property recovery in a cross-linked epoxy vitrimer containing disulfide bonds by combining quantum chemical calculations and molecular dynamics simulations. Quantum chemical calculations based on the GRRM method are first performed to explore energetically accessible post-scission recombination pathways of sulfur-centered radicals generated by disulfide bond cleavage. The resulting energetic ordering of bonding configurations is incorporated into molecular dynamics simulations through recombination rules derived from the quantum chemical calculations, allowing assessment of network repair and mechanical response. The results indicate that sulfur-centered radicals can undergo post-scission recombination via transient interactions with the aromatic ring prior to reformation of the disulfide bond. Tensile simulations further show that disulfide bonds preferentially break compared with other covalent bonds in the cross-linked network. Incorporation of the recombination pathways identified by the quantum chemical calculations leads to enhanced bond reformation and partial recovery of mechanical properties compared with a model assuming direct sulfur–sulfur recombination only. Full article

Cobalt disulfide (CoS₂) features highly active catalytic sites and is regarded as a promising candidate for electrocatalytic hydrogen evolution. In this study, molybdenum-doped cobalt disulfide (CoS₂:Mo) was synthesized via a facile hydrothermal approach. XRD analysis confirms that the obtained samples crystallize in a cubic pyrite structure, with diffraction peaks consistently shifting towards lower angles. SEM characterization reveals that the samples exhibit microrod-like morphologies with an average size of approximately 1 μm. Integrated analyses from XRD, XPS, and EDS mapping demonstrate that Mo is uniformly distributed across the surface and successfully doped into the CoS₂ lattice. Electrochemical measurements indicate that the CoS₂:Mo sample delivers a low overpotential of 122 mV and a Tafel slope of 128 mV dec⁻¹ at a current density of 10 mA cm⁻² in alkaline media, significantly surpassing the performance of pure CoS₂ and MoS₂. Moreover, the CoS₂:Mo exhibits an enhanced double-layer capacitance, with a C_dl value of 2.72 mF cm⁻², superior to that of pure CoS₂ (1.63 mF cm⁻²) and MoS₂ (0.31 mF cm⁻²). Mo doping enhances conductivity and active sites, thereby boosting electrocatalysis. This work presents an effective strategy for the development of cost-efficient and high-performance non-precious metal electrocatalysts. Full article