Unbiased MD simulations identify lipid binding sites in lipid transfer proteins

The characterization of lipid binding to lipid transfer proteins (LTPs) is fundamental to understand their molecular mechanism. However, several structures of LTPs, and notably those proposed to act as bridges between membranes, do not provide the precise location of their endogenous lipid ligands. To address this limitation, computational approaches are a powerful alternative methodology, but they are often limited by the high flexibility of lipid substrates. Here, we develop a protocol based on unbiased coarse-grain molecular dynamics simulations in which lipids placed away from the protein can spontaneously bind to LTPs. This approach accurately determines binding pockets in LTPs and provides a working hypothesis for the lipid entry pathway. We apply this approach to characterize lipid binding to bridge LTPs of the Vps13-Atg2 family, for which the lipid localization inside the protein is currently unknown. Overall, our work paves the way to determine binding pockets and entry pathways for several LTPs in an inexpensive, fast, and accurate manner.

Identification of potential inhibitors for drug resistance in acute lymphoblastic leukemia through differentially expressed gene analysis and in silico screening

Acute lymphoblastic leukemia (ALL) is a disease of lymphocyte origin predominantly diagnosed in children. While its 5-year survival rate is high, resistance to chemotherapy drugs is still an obstacle. Our aim is to determine differentially expressed genes (DEGs) related to Asparaginase, Daunorubicin, Prednisolone, and Vincristine resistance and identify potential inhibitors via docking. Three datasets were accessed from the Gene Expression Omnibus database; GSE635, GSE19143, and GSE22529. The microarray data was analyzed using R4.2.0 and Bioconductor packages, and pathway and protein-protein interaction analysis were performed. We identified 1294 upregulated DEGs, with 12 genes consistently upregulated in all four resistant groups. KEGG analysis revealed an association with the PI3K-Akt pathway. Among DEGs, 33 hub genes including MDM2 and USP7 were pinpointed. Within common genes, CLDN9 and HS3ST3A1 were subjected to molecular docking against 3556 molecules. Following ADMET analysis, three drugs emerged as potential inhibitors: Flunarizine, Talniflumate, and Eltrombopag. Molecular dynamics analysis for HS3ST3A1 indicated all candidates had the potential to overcome drug resistance, Eltrombopag displaying particularly promising results. This study promotes a further understanding of drug resistance in ALL, introducing novel genes for consideration in diagnostic screening. It also presents potential inhibitor candidates to tackle drug resistance through repurposing.

High sensitivity profiling of N-glycans from mouse serum using fluorescent imidazolium tags by HILIC electrospray ionisation spectrometry

N-linked glycosylation is a ubiquitous protein post-translational modification in which aberrant glycan biosynthesis has been linked to severe conditions like cancer. Accurate qualitative and quantitative analysis of N-glycans are crucial for investigating their physiological functions. Owing to the intrinsic absence of chromophores and high polarity of the glycans, current detection methods are restricted to liquid chromatography and mass spectrometry. Herein, we describe three new imidazolium-based glycan tags: 2'GITag, 3'GITag, and 4'GITag, that significantly improve both the limit of detection and limit of quantification of derivatized oligosaccharides, in terms of fluorescence intensity and ionisation efficiency. Our top-performing derivatisation agent, 4'GITag, shifted the detection sensitivity range from high femtomole to sub-femtomole levels in ESI-MS compared to traditional glycan label, 2AB, enabling the identification of 24 N-glycans in mouse serum, including those bearing sialic acids. Additionally, 4'GITag stabilized Na-salt forms of sialic acids, simplifying the simultaneous analysis of neutral and negative charged N-glycans significantly, avoiding the need for complex derivatisation procedures typically required for the detection of sialylated species. Overall, the favorable performance of imidazolium tags in the derivatisation and sensitive profiling of glycans has the potential for labeling tissue or live cells to explore disease biomarkers and for developing new targeted therapeutic strategies.

Integrating the 2D/2D heterostructure of the MXene monolayer and BiOBr nano-sheets for superior photo-catalysis

The highly efficient photo-oxidation of alcohols has sparked significant potential to cope with environmental pollution and the ever-increasing energy crisis. This study reports a unique Ti3C2/BiOBr (TB) heterojunction with a rich inter-face based on in situ exfoliation of MXene and subsequently anchored onto BiOBr sheets. The TB nano-composites exhibited substantially improved photo-catalytic activity towards the photo-oxidation of benzyl alcohol (BA) to benzaldehyde and achieved a formation rate of 1.73 mmol g-1 h-1, greater than pristine BiOBr. The ultra-thin inter-facial contact boosted the oxygen vacancies (Ov) and Ti3+ and possessed the most negative adsorption energy, which boosted the transfer and separation of inter-facial charge carriers and the adsorption and dissociation of BA. Overall, the successful synthesis of TB composite, along with its exceptional photo-catalytic performance, offers valuable insights for applications in green chemistry and environmental remediation.

One-step electrodeposition synthesis of NiFePS on carbon cloth as self-supported electrodes for electrochemical overall water splitting

Electrocatalytic water splitting (EWS) for hydrogen production is considered an ideal strategy for utilizing renewable energy, reducing fossil fuel consumption, and addressing environmental pollution issues. Traditional noble metal electrocatalysts have excellent performance, but their cost is high. Developing efficient, stable, and relatively inexpensive dual functional electrocatalysts is crucial for promoting large-scale EWS hydrogen production processes. Herein, a simple one-step electrodeposition method was used to grow nickel-iron phosphorus-sulfides (NiFePS) on the surface of hydrophilic treated carbon cloth (CC). The resultant NiFePS/CC with a phosphorus to sulfur ratio of 1:4 exhibited the best electrocatalytic performance, requiring only -91 mV and 216 mV overpotentials to generate the current densities of 10 mA·cm-2 in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. When it was used as a bifunctional electrocatalyst to overall water splitting (OWS), a voltage of 1.536 V can generate a current density of 10 mA·cm-2. The excellent electrocatalytic performance can be ascribed to two factors: 1) the CC with excellent conductivity serves as a growth substrate, reducing the impedance of charge transfer from the electrode to the electrolyte and accelerating the electron transfer rate; 2) The large number of ultra-thin nanosheets formed on the surface of the catalyst increase the electrochemical specific surface area, expose more reaction sites, and thus improve the electrocatalytic reaction performance. This work provides a new approach for designing efficient non-noble metal electrocatalysts for water splitting.

Calibrating cryogenic temperature of TEM specimens using EELS

Cryogenic Scanning/Transmission Electron Microscopy has been established as a leading method to image sensitive biological samples and is now becoming a powerful tool to understand materials' behavior at low temperatures. However, achieving precise local temperature calibration at low temperatures remains a challenge, which is especially crucial for studying phase transitions and emergent physical properties in quantum materials. In this study, we employ electron energy loss spectroscopy (EELS) to measure local cryogenic specimen temperatures. We use the temperature-dependent characteristics of aluminum's bulk plasmon peak in EEL spectra, which shifts due to changes in electron density caused by thermal expansion and contraction. We successfully demonstrate the versatility of this method by calibrating different liquid nitrogen cooling holders in various microscopes, regardless of whether a monochromated or non-monochromated electron beam is used. Temperature discrepancies between the actual temperature and the setpoint temperatures are identified across a range from room temperature to 100 K. This work demonstrates the importance of temperature calibrations at intermediate temperatures and presents a straightforward, robust method for calibrating local temperatures of cryogenically-cooled specimens in electron microscopes.

Sialylation in the gut: From mucosal protection to disease pathogenesis

Sialylation, a crucial post-translational modification of glycoconjugates, entails the attachment of sialic acid (SA) to the terminal glycans of glycoproteins and glycolipids through a tightly regulated enzymatic process involving various enzymes. This review offers a comprehensive exploration of sialylation within the gut, encompassing its involvement in mucosal protection and its impact on disease progression. The sialylation of mucins and epithelial glycoproteins contributes to the integrity of the intestinal mucosal barrier. Furthermore, sialylation regulates immune responses in the gut, shaping interactions among immune cells, as well as their activation and tolerance. Additionally, the gut microbiota and gut-brain axis communication are involved in the role of sialylation in intestinal health. Altered sialylation patterns have been implicated in various intestinal diseases, including inflammatory bowel disease (IBD), colorectal cancer (CRC), and other intestinal disorders. Emerging research underscores sialylation as a promising avenue for diagnostic, prognostic, and therapeutic interventions in intestinal diseases. Potential strategies such as sialic acid supplementation, inhibition of sialidases, immunotherapy targeting sialylated antigens, and modulation of sialyltransferases have been utilized in the treatment of intestinal diseases. Future research directions will focus on elucidating the molecular mechanisms underlying sialylation alterations, identifying sialylation-based biomarkers, and developing targeted interventions for precision medicine approaches.

A supported Ni2 dual-atoms site hollow urchin-like carbon catalyst for synergistic CO2 electroreduction

Dual-atoms catalysts (DACs), while inheriting the advantages of maximum atom utilization ratio and excellent selectivity of single-atom catalysts (SACs), can better enhance the catalytic activity through the synergy of adjacent atoms. Therefore, DACs are considered to be very potential catalysts for CO2 to CO conversion. Its catalytic activity is greatly influenced by the coordination environment and morphology. Here, hollow urchin-like NiNC catalysts (Ni-NC(HU)-x, x = 100, 50, 25, 0) were synthesized using urchin-like nickel particles as template. By adjusting the amount of additional nitrogen source, the percentage content of pyridinic-N was adjusted as well as further affecting the coordination environment. Among them, Ni-NC(HU)-50, which had the highest content of pyridinic-N, formed a dual-atoms coordination structure and had the best catalytic performance that the CO Faradaic efficiency (FECO) reached 97.2 % at -0.9 V vs. reversible hydrogen electrode (RHE) and sustained above 95 % within 50 h. In-situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) and density functional theory (DFT) calculations showed that Ni-NC(HU)-50 exhibited the best performance of CO2 reduction reaction (CO2RR) by lowering the *COOH formation free energy barrier and its favorable dual desorption mechanism of *COL and *COB.

Nanoparticles in drinking water: Assessing health risks and regulatory challenges

Nanoparticles (NPs) pose a significant concern in drinking water due to their potential health risks and environmental impact. This review provides a comprehensive analysis of the current understanding of NP sources and contamination in drinking water, focusing on health concerns, mitigation strategies, regulatory frameworks, and future perspectives. This review highlights the importance of nano-specific pathways, fate processes, health risks & toxicity, and the need for realistic toxicity assessments. Different NPs like titanium dioxide, silver, nanoplastics, nanoscale liquid crystal monomers, copper oxide, and others pose potential health risks through ingestion, inhalation, or dermal exposure, impacting organs and potentially leading to oxidative stress, inflammatory responses, DNA damage, cytotoxicity, disrupt intracellular energetic mechanisms, reactive oxygen species generation, respiratory and immune toxicity, and genotoxicity in humans. Utilizing case studies and literature reviews, we investigate the health risks associated with NPs in freshwater environments, emphasizing their relevance to drinking water quality. Various mitigation and treatment strategies, including filtration systems (e.g., reverse osmosis, and ultra/nano-filtration), adsorption processes, coagulation/flocculation, electrocoagulation, advanced oxidation processes, membrane distillation, and ultraviolet treatment, all of which demonstrate high removal efficiencies for NPs from drinking water. Regulatory frameworks and challenges for the production, applications, and disposal of NPs at both national and international levels are discussed, emphasizing the need for tailored regulations to address NP contamination and standardize safety testing and risk assessment practices. Looking ahead, this review underscores the necessity of advancing detection methods and nanomaterial-based treatment technologies while stressing the pivotal role of public awareness and tailored regulatory guidelines in upholding drinking water quality standards. This review emphasizes the urgency of addressing NP contamination in drinking water and provides insights into potential solutions and future research directions. Lastly, this review worth concluded with future recommendations on advanced analytical techniques and sensitive sensors for NP detection for safeguarding public health and policy implementations.

One-step time-resolved cascade logic gate microfluidic chip for home testing of SARS-CoV-2 and flu B

Home testing technology strategy is critical for early screening of disease. However, current home testing technologies often require complex processes, which limits their application. In this study, a time-resolved cascade logic gate microfluidic chip (TCLMC) was revealed to enable capillary force-based one-step operation without manual intervention or professional equipment. By analogy with logic gates in the circuit, TCLMC could automatically control the fluid flow and regulate the incubation time to optimize the immunoassay. The limit of detection of TCLMC for SARS-CoV-2 and influenza B virus (Flu B) was 134.94 and 79.17 pg mL-1 within 10 min. Additionally, this study tested saliva samples from 12 Flu B patients and 24 healthy controls to verify its clinical application. The results showed that TCLMC had high sensitivity (100%), specificity (100%), and accuracy (100%). This study provides a new one-step strategy for home testing and demonstrates its great potential in the diagnosis field.

Light-activated nanoclusters with tunable ROS for wound infection treatment

Infected wounds pose a significant clinical challenge due to bacterial resistance, recurrent infections, and impaired healing. Reactive oxygen species (ROS)-based strategies have shown promise in eradicating bacterial infections. However, the excess ROS in the infection site after treatments may cause irreversible damage to healthy tissues. To address this issue, we developed bovine serum albumin-iridium oxide nanoclusters (BSA-IrOx NCs) which enable photo-regulated ROS generation and scavenging using near infrared (NIR) laser. Upon NIR laser irradiation, BSA-IrOx NCs exhibit enhanced photodynamic therapy, destroying biofilms and killing bacteria. When the NIR laser is off, the nanoclusters' antioxidant enzyme-like activities prevent inflammation and repair damaged tissue through ROS clearance. Transcriptomic and metabolomic analyses revealed that BSA-IrOx NCs inhibit bacterial nitric oxide synthase, blocking bacterial growth and biofilm formation. Furthermore, the nanoclusters repair impaired skin by strengthening cell junctions and reducing mitochondrial damage in a fibroblast model. In vivo studies using rat infected wound models confirmed the efficacy of BSA-IrOx NCs. This study presents a promising strategy for treating biofilm-induced infected wounds by regulating the ROS microenvironment, addressing the challenges associated with current ROS-based antibacterial approaches.

A singlet oxygen-storing covalent organic framework for "Afterglow" photodynamic therapy

Photodynamic therapy (PDT) is an emerging treatment but often restricted by the availability of oxygen. Enhancing the lifespan of singlet oxygen (1O2) by fractionated generation is an effective approach to improve the efficacy of PDT. Herein, an imine-based nanoscale COF (TpDa-COF) has been synthesized and functionalized with a pyridone-derived structure (Py) to create a 1O2-storing nanoplatform TpDa-COF@Py, which can reversibly capture and release 1O2. Under 660 nm laser exposure, Py interacts with 1O2 produced by the porphyrin motif in COF backbones to generate 1O2-enriched COF (TpDa-COF@Py + hv), followed by the release of 1O2 through retro-Diels-Alder reactions at physiological temperatures. The continuous producing and releasing of 1O2 upon laser exposure leads to an "afterglow" effect and a prolonged 1O2 lifespan. In vitro cytotoxicity assays demonstrates that TpDa-COF@Py + hv exhibits an extremely low half-maximal inhibitory concentration (IC50) of 0.54 µg/mL on 4T1 cells. Remarkably, the Py-mediated TpDa-COF@Py nanoplatform demonstrates enhanced cell-killing capability under laser exposure, attributed to the sustained 1O2 cycling, compared to TpDa-COF alone. Further in vivo assessment highlights the potential of TpDa-COF@Py + hv as a promising strategy to enhance phototheronostics and achieve effective tumor regression. Accordingly, the study supplies a generalized 1O2 "afterglow" nanoplatform to improve the effectiveness of PDT.

Insights into the catalytic effect of atmospheric organic trace species on the hydration of Criegee intermediates

The bimolecular reactions between Criegee intermediates (CIs) and atmospheric trace species have been extensively investigated, with a particular focus on the reaction with water, while the catalytic role of atmospheric organic compounds in hydration reactions was often neglected. In this study, we employed quantum chemical calculations and Born-Oppenheimer molecular dynamics (BOMD) simulations to investigate the catalytic effects of atmospheric organic amines, organic acids, and alcohols on the hydration reactions of CIs in the gas phase and at the gas-liquid interface. The catalytic reactions were found to follow a cyclic catalytic structure and a stepwise reaction mechanism. Gas-phase studies revealed that organic acids exhibited stronger catalytic effects compared to amines and alcohols, and the catalytic efficiency of amines and alcohols was similar to those of single water molecule. In addition, the catalytic reaction barriers of organic acids and alcohols were positively correlated with their gas-phase acidity (R2 = 0.94 to 0.97). A negative correlation was observed between the catalytic reaction barrier of amines and their gas-phase basicity (R2 = 0.84 to 0.90) and proton affinity (R2 = 0.84 to 0.92). At the gas-liquid interface, organic acids promoted the formation of hydroxyethyl hydroperoxide (HEHP, CH3CH(OH)(OOH)), organic acid ions, and H3O+, whereas the catalytic hydration of CIs by organic amines resulted in the formation of CH3CH(OH)OO and amine ions. Both HEHP and CH3CH(OH)OO can be further decomposed to form OH and HO2, or participate in new particles formation as precursors. This study complements the research gap on the reaction of CIs with water, providing valuable insights into the atmospheric sources of HEHP and HOx as well as the formation of secondary organic aerosols (SOAs).

Recent advances in MOF-based nanozymes: Synthesis, activities, and bioapplications

Nanozymes have garnered considerable research interest for their unique capacity to bridge nanotechnology and biology. Current studies predominantly concentrate on exploring nanozymes with diverse catalytic activities and their potential applications across various disciplines. Among them, nanoscale metal-organic frameworks (MOFs) are promising nanomaterials for constructing nanozymes. In this review, we firstly introduce the general construction strategies for MOF-based nanozymes. In addition, we also classify the MOF-based nanozymes in detail based on their catalytic performance. Thirdly, the recent research progress of MOF-based nanozymes in the field of biosensing, cancer therapy, antibacterial infection, and antioxidation are also comprehensively reviewed. Finally, we discuss the current challenges and future perspectives of MOF-based nanozymes, with the aim of assisting in their construction and maximizing their potential in bioapplications. It is hoped that we could provide scientists in materials science and biomedical research with valuable and comprehensive information, fostering advancements in interdisciplinary fields.

A mitochondria-targeted fluorescent sensor for imaging endogenous peroxynitrite changes in acute lung injury

Acute lung injury (ALI) is a serious pulmonary inflammatory disease resulting from excessive reactive oxygen species (ROS) which could cause the damage of the alveolar epithelial cells and capillary endothelial cells. Peroxynitrite, as one of short-lived reactive oxygen species, is closely related to the process of ALI. Thus, it is important to monitor the fluctuation of peroxynitrite in living system for understanding the process of ALI. Herein, the novel mitochondria-targeted fluorescent probe BHMT was designed to respond to peroxynitrite and pH with distinct fluorescence properties respectively. The absorption spectrum of the probe BHMT exhibited a notable red shift as the pH value declined from 8.8 to 2.6. Upon reaction with peroxynitrite, BHMT had a significant increase of fluorescence intensity (63-fold) with maintaining a detection limit of only 43.7 nM. Furthermore, BHMT could detect the levels of endogenous peroxynitrite and image the intracellular pH in ratiometric channels utilizing cell imaging. In addition, BHMT was successfully applied to revealing the relationship between the peroxynitrite and the extent of ALI. Thus, these results indicated the probe BHMT could be a potential tool for diagnosing the early stage of ALI and revealed the peroxynitrite was likely to be a crucial therapeutic target in ALI treatment.

Cathodic electrochemiluminescence of boron and nitrogen-codoped carbon dots for the detection of dissolved oxygen in seawater

Electrochemiluminescence (ECL) is widely used in various fields due to its high sensitivity and controllable characteristics. Carbon dots (CDs) have emerged as promising ECL emitters due to their simple synthesis, low toxicity, and excellent biocompatibility. However, the practical application of many CDs emitters is hindered by their limited luminous efficiency, often necessitating additional coreactants to enhance the ECL signal intensity. In this study, we synthesized boron and nitrogen-codoped carbon dots (BN-CDs) as ECL emitters, utilizing dissolved oxygen (DO) as the coreactant. The BN-CDs/DO system exhibited a strong cathodic ECL signal. We proposed a reaction mechanism for the BN-CDs/DO ECL system. Additionally, we developed an ECL sensor for DO detection based on this system, showing a linear correlation between ECL peak intensity and DO concentration from 0.5 to 19.8 mg/L, with a detection limit of 0.12 mg/L. It was proven reliable for DO analysis in seawater and freshwater environments. This study provides insights into the synthesis and utilization of BN-CDs, highlighting the potential of DO as an intrinsic coreactant in CDs ECL systems. Furthermore, it provides new perspectives on the detection of DO in seawater and the design of innovative DO sensors.

Unveiling the influence of hydrophobicity on inhibiting hydrogen dissociation for enhanced photocatalytic hydrogen evolution of covalent organic frameworks

Covalent organic frameworks (COFs) have gained considerable interest as candidate photocatalysts for hydrogen evolution. In this work, we synthesized β-keto-enamine-based COFs (TpPa-X, TpDB, and TpDTP) to explore the relations between structures and photocatalytic hydrogen evolution. COFs were divided into two groups: (1) TpPa-X with different substituents attached to the TpPa backbone and (2) COFs featuring diamine linkers of varied lengths (TpDB and TpDTP). Experiments and density functional theory (DFT) calculations show that moderate hydrophobicity is favorable for the photocatalytic hydrogen evolution process, and acceptable contact angles are anticipated to range from 65° to 80°. Naturally, there are comprehensive factors that affect photocatalytic reactions, and the regulation of different backbones and substituents can considerably affect the performance of COFs for photocatalytic hydrogen evolution in terms of electronic structure, specific surface area, surface wettability, carrier separation efficiency, and hydrogen dissociation energy. Results show that TpPa-Cl2 (TpPa-X, X  = Cl2) demonstrates the highest photocatalytic activity, approximately 14.51 mmol g-1h-1, with an apparent quantum efficiency of 4.62 % at 420 nm. This work provides guidance for designing efficient COF-based photocatalysts.

An NIR-propelled janus nanomotor with enhanced ROS-scavenging, immunomodulating and biofilm-eradicating capacity for periodontitis treatment

Periodontitis is an inflammatory disease caused by bacterial biofilms, which leads to the destruction of periodontal tissue. Current treatments, such as mechanical cleaning and antibiotics, struggle to effectively address the persistent biofilms, inflammation, and tissue damage. A new approach involves developing a Janus nanomotor (J-CeM@Au) by coating cerium dioxide-doped mesoporous silica (CeM) with gold nanoparticles (AuNPs). This nanomotor exhibits thermophoretic motion when exposed to near-infrared (NIR) laser light due to the temperature gradient produced by the photothermal effects of asymmetrically distributed AuNPs. The NIR laser provides the energy for propulsion and activates the nanomotor's antibacterial properties, allowing it to penetrate biofilms and kill bacteria. Additionally, the nanomotor's ability to scavenge reactive oxygen species (ROS) can modulate the immune response and create a regenerative environment, promoting the healing of periodontal tissue. Overall, this multifunctional nanomotor offers a promising new approach for treating periodontitis by simultaneously addressing biofilm management and immune modulation with autonomous movement.

A novel magnetic ligand-based assay for the electrochemical determination of BRD4

The first magnetic ligand-based electrochemical assay aimed at the determination of BRD4 was developed and validated. BRD4 is an epigenetic regulator of great interest in oncology in relation to its overexpression observed in the pathogenesis of several cancer diseases. BRD4 also represents a major target for the development of innovative treatments aimed at protein inhibition or degradation. Despite the relevance of BRD4 both for diagnostics and therapeutic purposes, current methodologies for its determination are limited to commercial ELISA kits. We present a novel magnetic ligand-based assay for the electrochemical determination of BRD4. The developed assay is based on the use of a small synthetic fragment of the natural protein ligand for BRD4 as receptor, thus exploiting the intrinsic biological protein-protein recognition mechanism. In addition, the assay features the use of magnetic beads as immobilization platforms and peroxidase-conjugated monoclonal anti-BRD4 antibody for the generation of the electrochemical signal. The ligand-based assay shows outstanding performance in terms of rapidity, with results achievable in less than 20 min, no matrix effect when applied to human plasma or cell lysate samples, and excellent specificity. The proposed method exhibits a limit of detection of 2.66 nM and a response range tunable as a function of the amount of immobilized receptor. The developed ligand-based assay was successfully applied to the accurate determination of BRD4 in untreated cell lysates, as proven by the ELISA reference method. The good performance of the proposed bioassay for determination of BRD4 showed potential application of this strategy in convenient point-of-care testing.

Sulfur-based fluorescent probes for biological analysis: A review

The widespread adoption of small-molecule fluorescence detection methodologies in scientific research and industrial contexts can be ascribed to their inherent merits, including elevated sensitivity, exceptional selectivity, real-time detection capabilities, and non-destructive characteristics. In recent years, there has been a growing focus on small-molecule fluorescent probes engineered with sulfur elements, aiming to detect a diverse array of biologically active species. This review presents a comprehensive survey of sulfur-based fluorescent probes published from 2017 to 2023. The diverse repertoire of recognition sites, including but not limited to N, N-dimethylthiocarbamyl, disulfides, thioether, sulfonyls and sulfoxides, thiourea, thioester, thioacetal and thioketal, sulfhydryl, phenothiazine, thioamide, and others, inherent in these sulfur-based probes markedly amplifies their capacity for detecting a broad spectrum of analytes, such as metal ions, reactive oxygen species, reactive sulfur species, reactive nitrogen species, proteins, and beyond. Owing to the individual disparities in the molecular structures of the probes, analogous recognition units may be employed to discern diverse substrates. Subsequent to this classification, the review provides a concise summary and introduction to the design and biological applications of these probe molecules. Lastly, drawing upon a synthesis of published works, the review engages in a discussion regarding the merits and drawbacks of these fluorescent probes, offering guidance for future endeavors.

Tumor associated antigens combined with carbon dots for inducing durable antitumor immunity

Although therapeutic nanovaccines have made a mark in cancer immunotherapy, the shortcomings such as poor homing ability of lymph nodes (LNs), low antigen presentation efficiency and low antitumor efficacy have hindered their clinical transformation. Accordingly, we prepared advanced nanovaccines (CMB and CMC) by integrating carbon dots (CDs) with tumor-associated antigens (B16F10 and CT26). These nanovaccines could forwardly target tumors harbouring LNs, induce strong immunogenicity for activating cytotoxic T cells (CTLs), thereby readily eliminating tumor cells and suppressing primary/distal tumor growth. This work provides a promising therapeutic vaccination strategy to enhance cancer immunotherapy.

Multi-component ion equilibria and transport in ion-exchange membranes

At the interface between an ion-exchange membrane and a multi-electrolyte solution, charged species redistribute themselves to minimize the free energy of the system. In this paper, we explore the Donnan equilibrium of membranes with quaternary electrolyte (Na+/Mg2+/K+/Ca2+/Cl-) solutions, experimentally. The data was used to calculate the ion activity coefficients for six commercial cation-exchange membranes (CEMs). After setting one of the activity coefficients to an arbitrary value, we used the remaining (N-1) activity coefficients as fitting parameters to describe the equilibrium concentrations of (N) ionic species with a mean relative error of 3 %. At increasing solution ionic strengths, the equivalent ion fractions of monovalent counter-ions inside the membrane increased at the expense of the multivalent ones in alignment with the Donnan equilibrium theory. The fitted activity coefficients were employed in a transport model that simulated a Donnan dialysis experiment involving all four cations simultaneously. The arbitrary value assigned to one activity coefficient affects the calculated Donnan potential at the membrane interface. Nevertheless, this arbitrary value does not affect the prediction of the ion concentrations inside the membrane and consequently does not affect the modeled ion fluxes.

Superfast, large-scale harvesting of cellulose molecules via ethanol pre-swelling engineering of natural fibers

Cellulose molecules, as the basic unit of biomass cellulose, have demonstrated advancements in versatile engineering and modification of cellulose toward sustainable and promising materials in our low-carbon society. However, harvesting high-quality cellulose molecules from natural cellulosic fibers (CF) remains challenging due to strong hydrogen bonds and unique crystalline structure, which limit solvents (such as ionic liquid, IL) transport and diffusion within CF, making the process energy/time-intensively. Herein, we superfast and sustainably engineer biomass fibers into high-performance cellulose molecules via ethanol pre-swelling of CF followed by IL treatment in the microwave (MW) system. Ethanol-pre-swelled cellulosic fibers (SCF) feature modified morphological and structural distinctions, with improved fiber width, pore size, and specific surface area. The ethanol in the SCF structure is appropriately removed through MW heating and cooling, leaving transport and diffusion pathways of IL within the SCF. Such strategy enables the superfast (140 s) and large-scale (kilogram level) harvesting of cellulose molecules with high molecular weight, resulting in high-performance, versatile cellulose ionogel with a 300 % increase in strength and 1027 % in toughness, monitoring human movement, external pressure, and temperature. Our strategy paves the way for time/energy-effectively, sustainably harvesting high-quality polymer molecules from natural sources beyond cellulose toward versatile and advanced materials.

Base on photothermal interfacial molecular transfer for efficient biodiesel catalysis via enzyme@cyclodextrin metal-organic frameworks loaded MXene

Efficient, green and stable catalysis has always been the core concept of enzyme catalysis in industrial processes for manufacturing. Therefore, we construct a new strategy with photothermal interfacial molecular transfer for green and efficient biodiesel catalysis. We encapsulate Candida albicans lipase B (CalB) in a γ-cyclodextrin metal-organic framework (γ-CD-MOF) loading with Ti3C2TX by in situ growth and electrostatic assembly. The γ-CD-MOF not only protects the fragile enzyme, but also enhances the catalytic performance through the synergistic effects of porous adsorption (MOF pore structure) and interfacial enrichment (cyclodextrins host-guest assembly structure) for accelerating substrate transfer (642.6 %). The CalB@γ-CD-MOF/MXene-i activity can be regulated up to 274.6 % by exposure to near-infrared (NIR). Importantly, CalB@γ-CD-MOF/MXene-i achieves 93.3 % biodiesel conversion under NIR and maintained 86.9 % activity after 6 cycles. Meanwhile, the MXene after the CalB@γ-CD-MOF/MXene catalytic cycle can be almost completely recovered. We verify the mechanism of high catalytic activity of γ-CD-MOF and rationalize the mechanism of CD molecular channel by DFT. Therefore, this highly selective enzyme catalytic platform offers new possibilities for green and efficient preparation of bioenergy.

Variable-transmittance bio-based phase change composites based on the photothermal property of pectin

In this study, the possibility of using a natural polysaccharide, pectin, in a novel function as a photothermal material was investigated by fabricating a Pectin/Polyethylene glycol (PEG)/Poly(methyl methacrylate) (PMMA) composite via the infiltration of PEG/PMMA polymer mixture into freeze-casted pectin cryogel template. The Pectin/PEG/PMMA composite has high latent heat of 48 J/g, excellent UV blocking ability, and tailorable transmittance as well as capacity to energy storage via photothermal heating to the melting point of PEG under sunlight. The photothermal effect can be enhanced with the increase of pectin concentration and irradiation intensity. Furthermore, by using the Pectin/PEG/PMMA composite as a window of a model house could effectively reduce the temperature rise inside the house under irradiation and reduce the temperature drop after turning off the irradiation, as compared to a model house with conventional glass as the window material. Therefore, this work provides a new application of pectin as photothermal material and opens the opportunity to develop novel sustainable bio-based photothermal materials.

Introducing high-performance star-shaped bimetallic nanotags into SERS aptasensor: An ultrasensitive and interference-free method for chlorpyrifos detection

Implementation of cost-effective, reliable, and efficient technologies for the sensitive, rapid, and accurate detection of pesticide residues in agriproducts presents a promising solution to the escalating food safety concerns. Herein, a high-performance surface-enhanced Raman scattering (SERS) aptasensor based on nanotag (AuNS@4-MBN@Ag-aptamer) was introduced for ultrasensitive, reliable, and interference-free detection of chlorpyrifos (CPF). This aptasensor featured star-shaped bimetallic nanotag as the principal Raman signal enhancement material and 4-mercaptobenzonitrile (4-MBN) as "biological-silent"-window reporter (at 2228 cm-1). Moreover, cDNA-linked Fe3O4@AuNPs (FA-cDNA) served as magnetic substrates to simplify the separation process of FA-cDNA-combined nanotags. In the aptasensor, the formation of FA-cDNA-aptamer-AuNS@4-MBN@Ag hybrids was hindered by CPF, and its Raman intensity decreased with increasing CPF concentration. Under optimal SERS conditions, the aptasensor exhibited a broad linear detection range from 2.5 × 102 to 5.0 × 104 pg⋅mL-1, with an impressively low limit of detection of 220.35 pg⋅mL-1 (signal-to-noise ratio = 3). The selectivity and reproducibility assessments highlighted its exceptional sensitivity and interference-free capabilities. Furthermore, practical applications on wheat and apples demonstrated satisfactory spiked recovery rates, ranging from 89.61% to 107.33% (relative standard deviation ≤ 14.55%). Consequently, the high-performance "biological-silent"-window nanotag-based aptasensor is a promising tool for monitoring trace CPF in complex matrices.

Simultaneous targeting and monitoring of free antigen and in-situ membrane antigen in prostate cancer cells via an aggregation-induced emission-based bifunctional probe

The precise clinical diagnosis of prostate cancer still presents inherent challenges, and usually a monitoring of multiple biomarkers is required. In this study, a new aggregation-induced emission (AIE)-based bifunctional strategy was developed for the simultaneous detection of prostate cancer-specific in situ membrane antigens (PSMA) and free antigens (PSA). First, a bifunctional fluorescent probe with double sensing sites (a PSA-specific sensing site and a PSMA-targeted ligand) was constructed. In the presence of PSA, it specifically binds to the PSA-specific sensing site of the probe, resulting in the restoration of the fluorescence signal, enabling linear sensing of PSA. For the detection of PSMA, the PSMA-targeted ligand modified on the probe can specifically recognize PSMA, inducing the aggregation of the AIE material and resulting in an enhanced fluorescence signal. Moreover, a liposome-based artificial cell was developed to simulate the real prostate cancer cell, and it was used to investigate the feasibility of monitoring the two types of antigens. Utilizing this bifunctional fluorescent strategy, a dual-analysis of free serum antigen biomarker of PSA and in-situ membrane antigen of PSMA was achieved. The assay exhibited a wide linearity range for PSA detection from 0.0001 to 0.1 μg/mL, with a low limit of detection (LOD) of 6.18 pg/mL. For PSMA, the obtained LOD is 8.79 pg/mL, with a linearity range from 0.0001 to 0.1 μg/mL. This strategy allows us to simultaneously assess the levels of two types of biomarkers in living human prostatic cancer cells, providing a highly accurate and selective tool for early screening and monitoring of prostatic cancer.

Interaction analysis of RNA G-quadruplex with ligands and in situ imaging application

RNA G4, as an integral branch of G4 structure, possesses distinct interactions with ligands compared to the common DNA G4, thus the investigation of RNA G4/ligand interactions might be considered as a fresh breakthrough to improve the biosensing performance of G4/ligand system. In this study, we comparatively explored the structural and functional mechanisms of RNA G4 and DNA G4 in the interaction with ligands, hemin and thioflavin T (ThT), utilizing the classical PS2.M sequence as a model. We found that although the catalytic performance of RNA G4/hemin system was lower than DNA G4/hemin, RNA G4/ThT fluorescence system exhibited a significant improvement (2∼3-fold) compared to DNA G4/ThT, and adenine modification could further enhance the signaling. Further, by exploring the interaction between RNA G4 and ThT, we deemed that RNA G4 and ThT were stacked in a bimolecular mode compared to single-molecule binding of DNA G4/ThT, thus more strongly limiting the structural spin in ThT excited state. Further, RNA G4/ThT displayed higher environmental tolerance and lower ion dependence than DNA G4/ThT. Finally, we employed RNA G4/ThT as a highly sensitive label-free fluorescent signal output system for in situ imaging of isoforms BCR-ABL e13a2 and e14a2. Overall, this study successfully screened a high-performance RNA G4 biosensing system through systematic RNA G4/ligands interaction studies, which was expected to provide a promising reference for subsequent G4/ligand research.

Hydrogen peroxide and glucose detection using surface plasmon resonance imaging biosensor with corrodible silver thin film

A surface plasmon resonance imaging (SPRI)-based biosensor is demonstrated for the detection of both hydrogen peroxide (H2O2) and glucose. The H2O2 to be detected acts as an oxidant and etch the silver film. This process gradually effects on resonance condition and consequently the reflected light intensity at a fixed angle. The etching rate of the silver film shows a clear relation with the H2O2 concentration. Therefore, monitoring the reflected light intensity progressively changing over a few minutes, enables accurate detection of H2O2 concentrations ranging from 0 to 200 μM (within physiological range of 0.25-50 μM), with a remarkable limit of detection (LOD) as low as 40 nM. In this regard, the behavior of the surface plasmon resonance (SPR) dip in response to the reduction of the silver film thickness is predicted by Winspall simulation software. These simulation results are in good agreement with the experimental results. Moreover, the proposed method can be applied to determine glucose concentrations ranging from 0 to 10 mM, encompassing the physiological range of 3-8 mM. This is achieved by observing the generated H2O2 through the enzymatic oxidation reaction between glucose and glucose oxidase (Gox). The sensor demonstrates remarkable sensitivity and selectivity, with a detection limit as low as 175 μM for glucose concentration. Furthermore, accurate measurement of glucose concentration in an actual human serum sample is achievable with the proposed sensor, using the standard addition method. The suggested glucose sensor shows promising prospects for use in routine glucose testing, employing a label-free, real-time, and multiplex detection approach.© 2017 Elsevier Inc. All rights reserved.

A gradient-distributed binder with high energy dissipation for stable silicon anode

Silicon is considered as a promising alternative to traditional graphite anode for lithium-ion batteries. Due to the dramatic volume expansion of silicon anode generated from the insertion of Li+ ions, the binder which can suppress the severe volume change and repeated massive stress impact during cycling is required greatly. Herein, we design a gradient-distributed two-component binder (GE-PAA) to achieve excellent cyclic stability, and reveal the mechanism of high energy dissipative binder stabilized silicon electrodes. The inner layer of the electrode is the polyacrylic acid polymer (PAA) with high Young's modulus, which is used as the skeleton binder to stabilize the silicon particle interface and the electrode structure. The outer layer is the gel electrolyte polymer (GE) with lower Young's modulus, which releases the stress generated during the lithiation and de-lithiation process effectively, achieving the high structural stability at the molecular level and silicon particles. Due to the synergistic effect of the gradient binder design, the silicon electrode retains a reversible capacity of 1557.4 mAh g-1 after 200 cycles at the current density of 0.5 C and 1539.2 mAh g-1 at a high rate of 1.8 C. This work provides a novel binder design strategy for Si anode with long cycle stability.

Utilizing excited-state proton transfer fluorescence quenching mechanism, layered rare earth hydroxides enable ultra-sensitive detection of nitroaromatic

Convenient, rapid, and accurate detection of nitroaromatic organic toxins and harmful substances is of great significance in research. In the present study, two-dimensional layered rare-earth hydroxides (LYH) were used as ion-exchange matrix materials, and the anionic fluorescent dye molecules (HPTS) were successfully introduced into the LYH structures in situ via a simple and effective "plug-and-play" strategy, which gave the compounds ultra-sensitive fluorescence sensing detection of nitrobenzene, p-nitrotoluene and p-nitrophenol (Fluorescence response time < 1 sec, and the LOD for nitrobenzene, p-nitrophenol and p-nitrotoluene reached an impressive 349 ppb, 22 ppb and 98 ppb, respectively). Combined with theoretical calculations, we elucidated in detail the fluorescence quenching response mechanism of the LYH-HPTS towards nitroaromatic. Additionally, we also constructed fluorescent paper sensor, which effectively transformed the LYH-HPTS from theoretical detection to device application. The LYH-HPTS material is not only simple to synthesize, cost-effective and stable, but also has the features of fast response, excellent sensitivity and selectivity, and good reproducibility, which provides a new approach for the rapid and accurate detection of nitroaromatic.

Integrated in silico analysis of transcriptomic alterations in nanoparticle toxicity across human and mouse models

Nanoparticles, due to their exceptional physicochemical properties are used in our day-to-day environment. They are currently not regulated which might lead to increased levels in the biological systems causing adverse effects. However, the overall mechanism behind nanotoxicity remains elusive. Previously, we analysed the transcriptome datasets of copper oxide nanoparticles using in silico tools and identified IL-17, chemokine signaling pathway, and cytokine-cytokine receptor interaction as the key pathways altered. Based on the findings, we hypothesized a common pathway could be involved in transition metal oxide nanoparticles toxicity irrespective of the variables. Further, there could be unique transcriptome changes between metal oxide nanoparticles and other nanoparticles. To accomplish this, the overall transcriptome datasets of nanoparticles consisting of microarray and RNA-Seq were obtained. >90 studies for 17 different nanoparticles, performed in humans, rats, and mice were assessed. After initial screening, 24 mouse studies (with 196 datasets) and 34 human studies (with 200 datasets) were used for further analyses. The common genes that are dysregulated upon NPs exposure were identified for human and mouse datasets separately. Further, an overrepresentation functional enrichment analysis was performed. The common genes, their gene ontology, gene-gene, and protein-protein interactions were assessed. The overall results suggest that IL-17 and its related pathways might be commonly altered in nanoparticle exposure with lung as one of the major organs affected.

Novel magnetic iron oxide-dextran sulphate nanocomposites as potential anticoagulants: Investigating interactions with blood components and assessing cytotoxicity

Examining the critical role of anticoagulants in medical practice, particularly their central function in preventing abnormal blood clotting, is of the utmost importance. However, the study of interactions between blood proteins and alternative anticoagulant nano-surfaces is still understood poorly. In this study, novel approach involving direct functionalisation of magnetic iron oxide nanoparticles (MNPs) as carriers with sulphated dextran (s-dext) is presented, with the aim of evaluating the potential of magnetically-responsive MNPs@s-dext as anticoagulants. The physicochemical characterisation of the synthesised MNPs@s-dext includes crystal structure analysis, morphology study, surface and electrokinetic properties, thermogravimetric analysis and magnetic properties` evaluation, which confirms the successful preparation of the nanocomposite with sulfonate groups. The anticoagulant potential of MNPs@s-dext was investigated using a standardised activated partial thromboplastin time (APTT) test and a modified APTT test with a quartz crystal microbalance with dissipation (QCM-D) which confirmed the anticoagulant effect. Time-resolved solid-liquid interactions between the MNPs@s-dext and model blood proteins bovine serum albumin and fibrinogen were also investigated, to gain insight into their hemocompatibility, and revealed protein-repellence of MNPs@s-dext against blood proteins. The study also addressed comprehensive cytotoxicity studies of prepared nanocomposites, and provided valuable insights into potential applicability of MNPs@s-dext as a promising magnetic anticoagulant in biomedical contexts.

Dual-modal analysis of cis-diols in traditional Chinese medicine via boronic acid incorporated metal organic frameworks

In this study, a boronic acid incorporated metal organic frameworks (inBA-MIL-100) were prepared via metal-ligand-fragment co-assembly strategy. The prepared frameworks can be served either as enrichment sorbent or SALDI-MS matrix for cis-diol containing molecules. Thus, a dual-modal analysis of cis-diols in traditional Chinese medicine has been established. Several significant advantages of the proposed strategy have been experimentally demonstrated, including high selectivity, high binding capacity (70 mg/g), good generality (5-250 μg/mL for HPLC based sample preparation, 10-500 ng/mL for SALDI-MS), high sensitivity (LOD: 180 ng/mL for HPLC based sample preparation, 5 ng/mL for SALDI-MS) and reliable quantification (RSD<3 % for HPLC based sample preparation, RSD<12 % for SALDI-MS) performance. Finally, the successful analysis of various cis-diols (active component and mycotoxin) in various Chinese traditional medicine was also achieved.

Side-chain-engineered fluorescent dyes for 3D and long-term dynamic tracking of the plasma membrane in living cells

The plasma membrane involves in many important biological events such as cell fusion and programmed cell death, but most of current plasma membrane probes cannot meet the requirement of long-term specific anchoring to the plasma membrane. Herein, we propose a molecular side-chain engineering strategy to modulate the long-term imaging performance of fluorescent dyes to the plasma membrane by regulating the cell permeability and anchoring ability. A series of FMR dyes with different lengths of side chains were designed and synthesized, and their transmembrane behaviours and staining performance were evaluated in living HeLa cells. We found that short-chain and medium-chain FMR dyes have excellent cell permeability without the labeling ability to the plasma membrane while the long-chain FMR dyes specifically stain the plasma membrane and can be firmly anchored to the plasma membrane for a long period of time. These long-chain FMR dyes have high stain specificality to the plasma membrane, and C10-FMR can be anchored to the plasma membrane of living cells for 2 h, which enables it to continuously monitor dynamic changes of the plasma membrane. The three-dimensional precision imaging of various cells was achieved using C10-FMR, which provides an opportunity to obtain complete information on the three-dimensional spatial morphology of the plasma membrane. The PEG-induced cell fusion of chicken red blood cells and H2O2-induced apoptosis of HeLa cells were monitored by real-time tracking of dynamic changes of the plasma membrane during these processes, which provide solid examples to prove the usefulness of these fluorescent dyes as long-term imaging tools. This work validates the hypothesis that cell permeability of membrane dyes can be readily regulated by tuning the side chains, and provides the effective design strategy of fluorescent dyes for 3D and long-term dynamic tracking of the plasma membrane of diverse animal cells.

Integrating machine learning and biosensors in microfluidic devices: A review

Microfluidic devices are increasingly widespread in the literature, being applied to numerous exciting applications, from chemical research to Point-of-Care devices, passing through drug development and clinical scenarios. Setting up these microenvironments, however, introduces the necessity of locally controlling the variables involved in the phenomena under investigation. For this reason, the literature has deeply explored the possibility of introducing sensing elements to investigate the physical quantities and the biochemical concentration inside microfluidic devices. Biosensors, particularly, are well known for their high accuracy, selectivity, and responsiveness. However, their signals could be challenging to interpret and must be carefully analysed to carry out the correct information. In addition, proper data analysis has been demonstrated even to increase biosensors' mentioned qualities. To this regard, machine learning algorithms are undoubtedly among the most suitable approaches to undertake this job, automatically learning from data and highlighting biosensor signals' characteristics at best. Interestingly, it was also demonstrated to benefit microfluidic devices themselves, in a new paradigm that the literature is starting to name "intelligent microfluidics", ideally closing this benefic interaction among these disciplines. This review aims to demonstrate the advantages of the triad paradigm microfluidics-biosensors-machine learning, which is still little used but has a great perspective. After briefly describing the single entities, the different sections will demonstrate the benefits of the dual interactions, highlighting the applications where the reviewed triad paradigm was employed.

Self-assembled hyaluronic acid nanomicelle for enhanced cascade cancer chemotherapy via self-sensitized ferroptosis

The clinical utility of chemotherapy is often compromised by its limited efficacy and significant side effects. Addressing these concerns, we have developed a self-assembled nanomicelle, namely SANTA FE OXA, which consists of hyaluronic acid (HA) conjugated with ferrocene methanol (FC), oxaliplatin prodrug (OXA(IV)) and ethylene glycol-coupled linoleic acid (EG-LA). Targeted delivery is achieved by HA binding to the CD44 receptors that are overexpressed on tumor cells, facilitating drug uptake. Once internalized, hyaluronidase (HAase) catalyzes the digestion of the SANTA FE OXA, releasing FC and reducing OXA(IV) into an active form. The active oxaliplatin (OXA) induces DNA damage and increases intracellular hydrogen peroxide (H2O2) levels via cascade reactions. Simultaneously, FC disrupts the redox balance within tumor cells, inducing ferroptosis. Both in vivo and in vitro experiments confirmed that SANTA FE OXA inhibited tumor growth by combining cascade chemotherapy and self-sensitized ferroptosis, achieving a tumor inhibition rate of up to 76.61 %. Moreover, this SANTA FE OXA significantly mitigates the systemic toxicity commonly associated with platinum-based chemotherapeutics. Our findings represent a compelling advancement in nanomedicine for enhanced cascade cancer therapy.

Single-atom nanozymes for antibacterial applications

Bacteria have always been a thorny problem that threatens human health and food safety. Conventional antibiotic treatment often leads to the emergence of drug resistance. Therefore, the development of more effective antibacterial agents is urgently needed. Single-atom nanozymes (SAzymes) can efficiently eliminate bacteria due to their high atomic utilization, abundant active centers, and good natural enzyme mimicry, providing a potential alternative choice for antibiotics in antibacterial applications. Here, the antibacterial applications of SAzymes are reviewed and their catalytic properties are discussed from the aspects of active sites, coordination environment regulation and carrier selection. Then, the antibacterial effect of SAzymes is elaborated in combination with photothermal therapy (PTT) and sonodynamic therapy (SDT). Finally, the problems faced by SAzymes in antibacterial applications and their future development potential are proposed.

Establishment of an amplification strategy - specific binding - convenient processing integrated aflatoxin B1 detection method based on Fe3O4-NH4/AuNPs/apt-S1

Aflatoxin B1 (AFB1) is a potent toxin in food, necessitating rapid, instant, and sensitive detection. We have engineered an electrochemical sensor to monitor AFB1 using a system composed of Fe3O4-NH4/AuNPs/apt-S1. The aptamer specifically recognizes AFB1, while 'S1' is functionalized with methylene blue to enhance the current. The RecJf exonuclease promotes the formation of the electrochemical strategy. The Fe3O4 component, with its magnet properties, enables a rapid separation of solids and liquids without the need for instrumentation. The sensor exhibits a linear range for AFB1 ranging from 1 ng to 10 μg. The regression equation is I(nA) = 446.8 × logc+2085 (where I and c represent the peak current and AFB1 concentration, respectively). The correlation coefficient is 0.9508, and the detection limit is 3.447 nM. The relative standard deviation of AFB1 in peanut oil ranges from 4.80% to 6.80%. These results demonstrate that the sensor has high sensitivity, stability, repeatability, and specificity for AFB1 detection.

Ion confinement and separation using asymmetric electrodynamic fields in structures for lossless ion manipulations

RATIONALE

TW-SLIM ion mobility separations have demonstrated exceptional resolution by leveraging long paths with minimal loss. All previously reported experiments have used electrode surfaces which are mirrored to generate symmetrically opposing electric fields for ion confinement. However, work with other planar ion optics indicates this may be unnecessary. This study explores conditions under which separations may be obtained using a SLIM with asymmetric electric fields.

METHODS

The asymmetric field configuration was defined by applying a uniform DC potential to all electrodes of the top PCB of a standard TW-SLIM board pair, with no electrode placement modifications. This configuration was simulated in SIMION to assess transmission through the SLIM. A benchtop TW-SLIM instrument outfitted with a Faraday plate detector was modified likewise, so the top PCB had a uniform DC potential applied to all electrodes, while the bottom board was operated normally.

RESULTS

Simulations show full ion transmission for four different m/z ion populations over a range of DC biases applied to the "pusher" board. Likewise, the modified benchtop instrument is capable of transmitting, separating, and cycling ions with minimal losses. The effect of pusher strength on separation quality is explored, and comparisons between the standard and modified SLIM are made with respect to resolving the +2 and +3 charge states of neurotensin ions.

CONCLUSIONS

A functional IMS instrument using asymmetric confining fields demonstrates additional field modifications may be a means to achieve additional functionality with limited interruption of the analysis. A TW-SLIM PCB specifically designed as a pusher board would benefit from minimized manufacturing cost, simplifying assembly, reducing drive electronics, and improved field consistency.

A high oxidase-like activity, bimetallic single-atom nanozyme FeCe/NC prepared by FeCe-ZIF-8 approach for sensing tannic acid in tea

To improve the activity of single-atom nanozymes (SAzymes) for applications in food analysis, a new bimetal SAzyme FeCe/NC was developed. Its oxidase-like activity is 40% higher than that of single metal SAzyme Fe/NC. Based on a series of characterization investigations, the catalytic mechanism is that it directly catalyzed O2 to generate •OH, O2 •-and 1O2. It could directly catalyze oxidation 3,3',5,5'-tetramethylbenzidine (TMB) to blue oxTMB, thereunder, a FeCe/NC SAzyme-TMB colorimetric method for the detection of tannic acid (TA) was constructed after the optimization of catalytic conditions. The method has a high R2 of 0.995, a low limit of detection (LOD) of 0.26 μmol/L, and high stability. The detection performance was validated by the real samples (tea). Therefore, the prepared bimetallic SAzyme FeCe/NC can be applied for TA detection without the addition of H2O2, and will have broad applications in the areas of food, feed, and life science.

Fluorinated benzothiadiazole fluorescent probe based on ICT mechanism for highly selectivity and sensitive detection of fluoride ion

Excessive fluoride ion (F-) in the environment can affect health and even endanger life when ingested by the human body. However, most fluoride probes have the disadvantages of low sensitivity and long detection time. Herein, fluorescent probe 3a is successfully synthesized by linking two acetylenyltrimethylsilyl groups at both ends of the fluorinated benzothiadiazole core. After the addition of F- to 3a, the emission at 436 nm is significantly quenched and slightly blue-shifted. It is confirmed by electrospray ionization high-resolution mass spectrometry (ESI-HRMS) and density functional theory calculations (DFT) that these changes are due to the F- triggered Si-C bond cleavage and the subsequent inactivation of intramolecular charge transfer (ICT). The detection limit and response time of probe 3a for F- are 10-8 mol/L and 25 s, respectively. Importantly, fluorescent material 3a can be processed into portable test tools for the visual detection of fluoride ion.

Fluorescence sensing of water in various organic solvents based on a novel cyclic polymer

A sensor capable of sensing of water in various organic solvents ranging from water-soluble to water-miscible solvents is still a challenging task. In this research, a cyclic polymer fluorescence chemosensor (CPFC) has been developed for sensing of water by turn-on model in 9 organic solvents and turn-off model in DMA, where the broadest concentration range and the lowest detection limit was obtained for water in DMA (10 %-90 %) and dioxane (0.011 %), respectively. The sensing mechanism is explored by theory calculation and experimental investigation. The amphiphilic nature endows the polymer probe with great potential for measuring various contaminants from aqueous and nonaqueous mediums. Furthermore, the present search highlights the potential applications of cyclic polymer as fluorescence probes in the field of sensing.

Programmable multimode optical encryption of advanced printable security inks by integrating structural color with Down/Up- conversion photoluminescence

Optical information encryption with high encoding capacities can significantly boost the security level of anti-counterfeiting in the scenario of guaranteeing the authenticity of a wide scope of common and luxury goods. In this work, a novel counterfeiting material with high-degree complexity is fabricated by microencapsulating cholesteric liquid crystals and triplet-triplet annihilation upconversion fluorophores to integrate structural coloration with fluorescence and upconversion photoluminescence. Moreover, the multimode security ink presents tailorable optical behaviors and programmable abilities on flexible substrates by various printing techniques, which offers distinct information encryption under different optical modes. The advanced strategy provides a practical versatile platform for high-secure-level multimode optical inks with largely enhanced encoding capacities, programmability, printability, and cost-effectiveness, which manifests enormous potentials for information encryption and anti-counterfeiting technology.

Hydroxypropyl methylcellulose reinforced bilayer hydrogel dressings containing L-arginine-modified polyoxometalate nanoclusters to promote healing of chronic diabetic wounds

Diabetes-related slow healing of wounds is primarily driven by bacterial infections and angiogenesis disorder and presents a substantial hurdle in clinical treatment. To solve the above problems, an advanced multifunctional hydrogel system based on natural polymer was created here to facilitate wound healing in patients with chronic diabetes. The prepared dressing was composed of an outer hydrogel containing polyvinyl alcohol and hydroxypropyl methyl cellulose in dimethyl sulfoxide and water as binary solvents, and an inner hydrogel containing chitosan quaternary ammonium salt, flaxseed gum, and polyvinyl alcohol. Thus, a polysaccharide based bilayer hydrogel (BH) with superior mechanical strength and biocompatibility was created. This bilayer hydrogel could easily bind to dynamic tissue surfaces, thereby generating a protective barrier. Meanwhile, L-arginine-modified polyoxometalate (POM@L-Arg) nanoclusters were loaded in the inner hydrogel. They released NO when stimulated by the peroxide microenvironment of diabetic wounds. NO as a signal molecule regulated vascular tension and promoted cell proliferation and migration. Additionally, because of the synergistic effect of NO and the chitosan quaternary ammonium salt, the hydrogel system exhibited excellent antibacterial performance. The NO released reduced the levels of proinflammatory factors IL-6 and TNF-α in the diabetic wounds, which thus accelerated wound healing. In short, BH + POM@L-Arg is expected to serve as an ideal wound dressing as it exerts a good promotion effect on diabetes-related wound healing.

Vertasile ferritin nanocages: Applications in detection and bioimaging

Food safety and human health remain significant concerns in the food industry. Detecting food contaminants and diagnosing diseases are critical aspects. Ferritin, an iron storage protein widely found in nature, offers unique advantages. Its hollow protein nanocage structure, distinct interfaces, hydrophobic or hydrophilic channels, and B-C loop regions recognized by transferrin receptor 1 make ferritin versatile for detecting heavy metals, free radicals, and bioimaging both in vitro and in vivo. This review summarizes ferritin's general characteristics, its specific properties as biosensors, and its applications in food safety and in vivo imaging. It emphasizes not only ferritin's role in detecting heavy metals like mercury and chemical hazards but also its potential in early diagnosing chronic diseases such as tumors, macrophages, and kidney diseases. Further research into ferritin promises advancements in enhancing food safety and improving human health diagnostics.

A novel red fluorescent and dynamic nanocomposite hydrogel based on chitosan and alginate doped with inclusion complex of carbon dots

Red fluorescent hydrogels possessing injectable and self-healing properties have widespread potential in biomedical field. It is still a challenge to achieve a biomacromolecules based dynamic hydrogels simultaneously combining with excellent red fluorescence, good mechanical properties, and biocompatibility. Here we first explore hydrophilic inclusion complex of (R-CDs@α-CD) derived from hydrophobic red fluorescent carbon dots (R-CDs) and α-cyclodextrin (α-CD), and then achieved a red fluorescent and dynamic polysaccharide R-CDs@α-CD/CEC-l-OSA hydrogel. The nanocomposite hydrogel can be fabricated through controlled doping of red fluorescent R-CDs@α-CD into dynamic polymer networks, taking reversibly crosslinked N-carboxyethyl chitosan (CEC) and oxidized sodium alginate (OSA) as an example. The versatile red fluorescent hydrogel simultaneously combines the features of injection, biocompatibility, and augmented mechanical properties and self-healing behavior, especially in rapid self-recovery even after integration. The R-CDs@α-CD uniformly dispersed into dynamic hydrogel played the role of killing two birds with one stone, that is, endowing red emission of a hydrophilic fluorescent substance, and improving mechanical and self-healing properties as a dynamic nano-crosslinker, via forming hydrogen bonds as reversible crosslinkings. The novel red fluorescent and dynamic hydrogel based on polysaccharides is promising for using as biomaterials in biomedical field.

Nervous system exposure of different classes of nanoparticles: A review on potential toxicity and mechanistic studies

Nanoparticles (NPs) are generally defined as very small particles in the size range of 1-100 nm. Due to the rapid development of modern society, many new materials have been developed. The widespread use of NPs in medical applications, the food industry and the textile industry has led to an increase in NPs in the environment and the possibility of human contact, which poses a serious threat to human health. The nervous system plays a leading role in maintaining the integrity and unity of the body and maintaining a harmonious balance with the external environment. Therefore, based on two categories of organic and inorganic NPs, this paper systematically summarizes the toxic effects and mechanisms of NPs released into the nervous system. The results showed that exposure to NPs may damage the nervous system, decrease learning and cognitive ability, and affect embryonic development. Finally, a remediation scheme for NPs entering the body via the environment is also introduced. This scheme aims to reduce the neurotoxicity caused by NPs by supplementing NPs with a combination of antioxidant and anti-inflammatory compounds. The results provide a valuable reference for future research in this field.

Photocurrent switchable dual-target bioassay: Signal distinction and interface reconfiguration via pH-responsive triplex DNA programming

Most multiplexed photoelectrochemical (PEC) sensors require additional instrumentation and cumbersome electrode modification and surface partitioning, which limits their portability and instrument miniaturization. Herein, a pH-responsive programmable triple DNA nanomachine was developed for constructing a reconfigurable multiplex PEC sensing platform. By programming the base sequence, T-A·T-riched triple DNA was designed to construct integrated nano-controlled release machine (INCRM) for simultaneous recognition of multiple targets. The INCRM enables to recognize two targets in one step, and sequentially separate the signal labels by pH adjustment. The detached signal label catalyzes glucose to produce gluconic acid, causing the C-riched DNA fold into a triple structure on the electrode surface. As a result, one target can be detected relying on the enhanced photocurrent due to accelerated electron transfer between the CdS QD labeled at the end of C-riched DNA and the electrode. The triplex DNA dissociation in pH 7.4 buffer reconfigures the electrode interface, which can be continued to detect another target. The feasibility of the multiplexed sensor is verified by the detection of extensively coexisting antibiotics enrofloxacin (ENR) and ciprofloxacin (CIP). Under the optimal conditions, wide linear range (10 fg/mL ∼ 1 μg/mL) and low detection limit (3.27 fg/mL and 9.60 fg/mL) were obtained. The pH-regulated programmable triplex DNA nanomachine-based sensing platform overcomes the technical difficulties of conventional multiplexed PEC assay, which may open the way for miniaturization of multiplexed PEC sensors.

A biomimetic lubricating nanosystem for synergistic therapy of osteoarthritis

Failure of articular cartilage lubrication and inflammation are the main causes of osteoarthritis (OA), and integrated treatment realizing joint lubrication and anti-inflammation is becoming the most effective treat model. Inspired by low friction of human synovial fluid and adhesive chemical effect of mussels, our work reports a biomimetic lubricating system that realizes long-time lubrication, photothermal responsiveness and anti-inflammation property. To build the system, a dopamine-mediated strategy is developed to controllably graft hyaluronic acid on the surface of metal organic framework. The design constructs a biomimetic core-shell structure that has good dispersity and stability in water with a high drug loading ratio of 99%. Temperature of the solution rapidly increases to 55 °C under near-infrared light, and the hard-soft lubricating system well adheres to wear surfaces, and greatly reduces frictional coefficient by 75% for more than 7200 times without failure. Cell experiments show that the nanosystem enters cells by endocytosis, and releases medication in a sustained manner. The anti-inflammatory outcomes validate that the nanosystem prevents the progression of OA by down-regulating catabolic proteases and pain-related genes and up-regulating genes that are anabolic in cartilage. The study provides a bioinspired strategy to employ metal organic framework with controlled surface and structure for friction reduction and anti-inflammation, and develops a new concept of OA synergistic therapy model for practical applications.