Synthesis of N-heterocyclic carbene‑selenium complexes modulating apoptosis and autophagy in cancer cells: Probing the interactions with biomolecules and enzymes

Growing cancer resistance is a global threat that calls for development of newer chemotherapeutic analogues especially targeted based therapy to enhance efficacy and selectivity. In this contribution, herein, we report synthesis of selenium incorporated N-heterocyclic carbene (NHC) compounds to explore their potential cytotoxicity against HeLa cells. Test compounds were assured for suitability as drug candidates through physiochemical properties that showed lipophilicity logP 0.85-1.45 for C1-C3 and found stable in biological media (DMEM), whereas, least reactive with N-acetyl cysteine (NAC) and L-glutathione. All the studied compounds showed good cytotoxicity against various cancer strains while compound C1 [3,3-(hexane-1,6-diyl)bis(1-phenethyl-1H-imidazole-2(3H)-selenone)] and C2 [3,3-(hexane-1,6-diyl)bis(1-decyl-1H-imidazole-2(3H)-selenone)] showed promising results with IC50 values of 14.65 ± 0.66 and 8.05 ± 0.35 μg/mL respectively as compared to positive control 21.5 ± 0.05 μg/mL against HeLa cell lines. These compounds showed six-fold higher apoptosis than control with higher accumulation of Ca+ ions intracellularly that alters the expression level of autophagy proteins and increased capase-9 activity. Cell cycle analysis indicated an arrest of cycle in G1 phase of HeLa cells when treated with C1 & C2. Test compounds showed prominent affinity for binding with DNA and inhibiting thioredoxin reductase enzymes in time dependent manners. These findings indicate that Selenium NHC compounds are promising drug candidates to induce cytotoxicity via apoptosis, autophagy and mitochondrial membrane disruptions to manage tumor growth.

Advancing biosensing through super-resolution fluorescence microscopy

Advancement of super-resolution fluorescence microscopy (SRM) has recently allowed applications to the biosensing by offering significant advantages over conventional methods. Its nanoscale spatial resolution and single-molecule sensitivity allow visualization and quantification of biomolecular targets without the need of signal amplification steps typically required in traditional biosensing methods. Moreover, recent innovations in probe design and imaging protocols have expanded SRM capabilities to enable dynamic biosensing in living cells, revealing molecular processes in their native cellular contexts. In this review, we discuss these applications of various SRM techniques to biosensing by highlighting their unique capabilities in providing spatial distribution information and high molecular sensitivity. We address several challenges that must be overcome for the broader application of SRM-based biosensing. Finally, we discuss perspectives on future directions for advancing this field towards practical applications.

Molecularly imprinted Fe3O4 nanoparticles-based magnetic 3D photonic crystal microspheres for specific adsorption of aflatoxin B1 in grains

Aflatoxin B1 (AFB1) is the major toxic mycotoxin that contaminates grains at trace levels, necessitating the development of an efficient and simple extraction method to enrich it in samples. Here, magnetic molecularly imprinted Fe3O4 nanoparticles (MMIPs) were first synthesized by employing 5,7-dimethoxy coumarin as the template and methacrylic acid combined with styrene as the functional monomers. These MMIPs exhibited excellent selective recognition capabilities for AFB1, based on which, a novel molecularly imprinted magnetic inverse opal photonic crystal microsphere (MIP@MIPCM) was fabricated via a droplet-based microfluidic self-assembly technique. The MIP@MIPCMs enabled specific recognition of AFB1 and were used as an extraction material, achieving a binding capacity of 842.7 ng/mg within 20 min. Coupled with high-performance liquid chromatography (HPLC), a sensitive and accurate analytical method was established for AFB1 detection with a detection limit of 0.35 μg/kg and recovery rates of 90-109 % in real samples.

Aptamers and MIPs as alternative molecular recognition elements for vasopressin and oxytocin sensing: A review

Arginine vasopressin (AVP) and oxytocin (OT) are two important hormones that regulate various physiological and behavioral functions, such as blood pressure, water balance, social bonding, and stress response. The detection and quantification of these hormones are of great interest in clinical diagnosis and research. However, the conventional methods based on antibodies or enzymes have some limitations, such as high cost, low stability, and ethical issues. Therefore, alternative molecular recognition elements, such as aptamers and molecularly imprinted polymers (MIPs), have been developed to overcome these drawbacks. Aptamers are short nucleic acid sequences that can bind to specific targets with high affinity and specificity, while MIPs are synthetic polymers with imprinted binding sites mimicking natural receptors. Both aptamers and MIPs have advantages such as low cost, high stability, easy synthesis, and modification. In this review, we summarize the recent advances in the development and application of aptamers and MIPs for the sensing of vasopressin and oxytocin, and compare their performances. We also discuss the challenges and future perspectives of aptamers and MIPs as alternative molecular recognition elements for vasopressin and oxytocin sensing.

Acetyl-lysine human serum albumin nanoparticles activate CD44 receptors, with preferential uptake by cancer stem cells, leading to tumor eradication

CD44 receptors in cancer stem cells (CSCs) are a key biomarker associated with cancer recurrence, progression, and metastasis. Acetylation is a post-translational modification used to regulate protein function at the end of protein synthesis. In this study, we found that acetylated human serum albumin (Ac-HSA) acts an uptake ligand on CD44 receptors. This promising finding motivated us to develop an Ac-HSA-based nanocarrier for cancer chemotherapy. By conjugating maleimide-polylactic acid (MAL-PLA) with Ac-HSA, the resulting amphiphile formed nanoparticles (Ac-HSA-PLA NPs) which were shown to rapidly enter CD44+ cancer cells and cancer stem cells via CD44-mediated endocytosis. This contrasts with the comparatively slow uptake of CD44 antibodies. Abraxane®, an approved human serum albumin (HSA) nanoparticle formulation of paclitaxel (PTX) demonstrates that PTX may be delivered by HSA nanoparticles. However, Abraxane® is not clinically superior to solvent-based PTX formulations. In a CD44+ tumor model, PTX-loaded Ac-HSA-PLA NPs outperformed Abraxane®, achieving complete tumor elimination without recurrence, two months post-treatment, while Abraxane treated tumors continued to grow (tumor volume increased five fold). The Ac-HSA-PLA (PTX) NPs also demonstrated minimal systemic toxicity, suggesting that Ac-HSA could be a promising alternative for targeted cancer therapy in CD44-expressing cancers.

Development of radioligands with an albumin-binding moiety of 4-(P-Iodophenyl) butyric acid for theranostic applications

The rapid clearance of imaging probes from blood circulation is beneficial for receptor imaging, as it minimizes non-target tissue exposure and improves tumor-to-background contrast. However, this rapid clearance can hinder radioligand therapy by limiting tumor uptake of radiolabeled compounds. An optimal blood half-life is crucial, as it enhances the uptake of radiolabeled compounds in targets, improving tumor uptake and retention of small molecule drugs, and thus therapeutic outcomes. To address this, strategies to extend blood half-life have been developed, with the addition of an albumin-binding moiety (ABM) being particularly effective. Among these, 4-(p-iodophenyl)butyric acid (IPBA) has emerged as a versatile ABM for radiopharmaceutical design. IPBA conjugation has successfully enhanced tissue distribution profiles across various cancer types. This review highlights recent progress in the design, radiosynthesis, and application of IPBA-based small molecular radioligands, providing insights for future clinical development of IPBA-based radiopharmaceuticals.

Current strategies for senescence treatment: Focused on theranostic performance of nanomaterials

Age-related diseases imposed heavy burdens to the healthcare systems globally, while cell senescence served as one fundamental molecular/cellular basis for these diseases. How to tackle the senescence-relevant problems is a hotspot for biomedical research. In this review article, the hallmarks and molecular pathways of cell senescence were firstly discussed, followed by the introduction of the current anti-senescence strategies, including senolytics and senomorphics. With suitable physical or chemical properties, multiple types of nanomaterials were used successfully in senescence therapeutics, as well as senescence detection. Based on the accumulating knowledges for senescence, the rules of how to use these nanoplatforms more efficiently against senescence were also summarized, including but not limited to surface modification, material-cargo interactions, factor responsiveness etc. The comparison of these "senescence-selective" nanoplatforms to other treatment options (prodrugs, ADCs, PROTACs, CART etc.) was also given. Learning from the past, nanotechnology can add more choice for treating age-related diseases, and provide more (diagnostic) information to further our understanding of senescence process.

Advancements in delivery Systems for Proteolysis-Targeting Chimeras (PROTACs): Overcoming challenges and expanding biomedical applications

PROTAC (Proteolysis-Targeting Chimera), an emerging drug development strategy based on small molecule technology, has garnered widespread attention due to its high efficiency, broad applicability, low resistance, and dosage advantages. However, PROTAC molecules still exhibit certain limitations that require urgent resolution. Although significant progress has been made in designing PROTACs that target various disease-related proteins, research on drug delivery systems (DDS) for PROTACs remains relatively limited. This review aims to explore the critical role of delivery system design in addressing the inherent challenges associated with PROTAC molecules from a novel perspective. Beginning with five major challenges-insufficient targeting, poor pharmacokinetic properties, low cell permeability, limited accessibility, and the Hook effect-this article introduces formulation strategies to mitigate these deficiencies. It discusses potential solutions through targeted modifications, nano-delivery systems, intelligent response systems, and membrane biomimetic technologies, among others. Furthermore, it elucidates the mechanisms and principles underlying these approaches and analyzes the advantages of various delivery strategies. The insights provided in this review offer insights for designing delivery systems tailored to PROTACs with diverse characteristics for different disease applications.

Safety of nanoparticle therapies during pregnancy: A systematic review and meta-analysis

The exclusion of pregnant women from clinical trials has led to insufficient safety data for many treatments, making it necessary to evaluate their potential benefits and risks during preclinical stages. Nanomedicines show potential for reduced toxicity but there is limited evidence about their safety for pregnant women and their fetuses. We conducted the first systematic review and meta-analysis of the effect of nanoparticles (NPs) on a key outcome of fetal toxicity (low birth weight) in murine models. In the meta-analysis of mouse models, negatively charged NPs tended to decrease birth weight (-69.8 mg, 95 % CI: -196 to 56.5), as did small (-191 mg, 95 % CI: -369 to -13.3) and plain inorganic nanosystems (-249 mg, 95 % CI: -535 to 37.4). In contrast, positively charged NPs resulted in increased birth weight (+29.3 mg, 95 % CI: 23.4 to 35.2). All findings were validated in studies with low heterogeneity and low risk of publication bias. Neither large NPs (+4.37 mg; 95 % CI: -45.3 to 54.0) nor polymer-coated NPs (+16.5 mg; 95 % CI: -44.7 to 77.6) had any clear association with birth weight. Similar results were observed in other models and experimental designs from articles not included in the meta-analysis, although no conclusions were drawn for other parameters due to high variability. Our findings pave the way for future research and the rational development of safer nanomedicines for use during pregnancy.

Synergistic chemo-photothermal treatment via MXene-encapsulated nanoparticles for targeted melanoma therapy

Owing to its high photothermal conversion efficiency, MXene has garnered strong interest in biomedical applications. MXene has demonstrated significant promise particularly in chemo-photothermal cancer therapy. However, MXene's inherent instability in aqueous environments poses challenges for advanced biological applications. Here, we address this limitation by encapsulating MXene nanoparticles (NPs) within an amphiphilic polymer matrix of hyaluronic acid and poly(lactide-co-glycolide) (HA-PLGA/MX NPs), enhancing photothermal stability and functionality in physiological conditions. Moreover, to achieve targeted chemo-photothermal therapy, we co-loaded the anticancer agent paclitaxel (PTX) with HA-PLGA/MX (HA-PLGA/MXP NPs), facilitating simultaneous delivery of heat and drug to tumor sites. The HA-PLGA/MXP NPs were synthesized using a straightforward water-oil-water emulsion method and extensively characterized for drug release assays to confirm their suitability as dual-functional nanocarriers. Both in vitro and in vivo studies demonstrated that HA-PLGA/MXP NPs, under laser irradiation, achieved obviously enhanced therapeutic efficacy, with an ∼81.9 % cell death rate and a ∼95.7 % tumor inhibition rate, outperforming the effects of chemotherapy or photothermal therapy alone. Integrating MXene in HA-PLGA encapsulation introduces a potent platform for melanoma treatment, offering synergistic therapeutic potential by combining photothermal activity with sustained drug release, highlighting a promising approach to targeted cancer therapy, and advancing the field of NP-based chemo-photothermal therapeutics.

Breaking the barriers in effective and safe Toll-like receptor stimulation via nano-immunomodulators for potent cancer immunotherapy

Immunotherapy is an emerging strategy that awakens the intrinsic immune system for cancer treatment. Generally, successful immunotherapy of malignant tumours relies on the effective production of tumour-associated antigens and their lymph node delivery, antigen processing and presentation for T-cell activation, and the dismantling of the immunosuppressive tumour microenvironment. Toll-like receptor (TLR) agonists are potent stimulants in cancer immunotherapy, which can directly activate antigen-presenting cells (APCs) and further induce T cell activation for antitumour immune response and convert immunosuppressive tumour microenvironment to an immunogenic one for cooperative tumour ablation. However, TLR agonists for effective cancer immunotherapy have encountered essential challenges, such as insufficient immune activation and systemic side effects. In recent years, nano-immunomodulators with TLR agonists have been employed for tumour- and/or lymph node-targeted immune activation to improve the antitumour immune response and alleviate their systemic toxicities, providing a promising strategy for enhanced cancer immunotherapy. Herein, we introduce the recent progress in developing various TLR nano-immunomodulators for cancer immunotherapy via APC activation and tumour microenvironment remodelling. Upon elucidating the rational design principles of nano-immunomodulators, we elucidate the advancement of TLR nanoagonists to break the barriers in effective and safe Toll-like receptor stimulation for potent cancer immunotherapy.

Regulated cell death mechanisms in mitochondria-targeted phototherapy

Phototherapy, comprising photodynamic therapy (PDT) and photothermal therapy (PTT), was first introduced over a century ago and has since evolved into a versatile cancer treatment modality. While numerous studies have explored regulated cell death (RCD) mechanisms induced by phototherapy, a comprehensive synthesis centered on mitochondria-targeted phototherapeutic strategies and agents as mediators of RCD is still lacking. This review provides a systematic and in-depth analysis of recent advances in mitochondria-centered mechanisms driving phototherapy-induced death pathways, including apoptosis, autophagy, pyroptosis, immunogenic cell death, ferroptosis, and cuproptosis. We highlight the critical role of mitochondria as central regulators of these death pathways in response to phototherapeutic interventions. Moreover, we discuss fundamental design strategies for developing precision-targeted phototherapeutic materials to enhance efficacy and minimize off-target effects. Finally, we identify prevailing challenges and propose future research directions to address these hurdles, paving the way for next-generation mitochondria-targeted phototherapy as a highly effective strategy for cancer management.

Engineering- nanochannels with pH-responsive gates for direct detection of glucose in human blood serum

BACKGROUND

An abnormal blood glucose (Glu) level is a key signal of diabetes. The gluconic acid produced by Glu catalytic oxidation can cause changes in pH value.

RESULTS

Inspired by nature, in which organisms use pH as a chemical gate to regulate ion transport through cell membranes, we report a pH-gated electrochemical luminescence (ECL) sensing system for Glu detection based on the relationship between Glu metabolism and pH. The pH gate was designed on a TiO2 nanochannel membrane (NM) by modifying the channel entrance with polystyrene-b-poly(4-vinylpyridine) (P4VP) chains that convert from a hydrophobic into a hydrophilic state via a pH-responsive conformational switching at pKa 5.2. Due to the nanoconfinement effect of zeolite imidazolate (ZIF-8) frameworks and TiO2 nanochannels, the glucose oxidase (GOD) embedded in ZIF-8 exhibits enhanced catalytic efficiency for Glu oxidation, enabling the acidic product to regulate the hydrophilicity of the P4VP-based pH-responsive gate. The ECL luminophore Ru(dcbpy)32+ subsequently passes through the hydrophilic gate to reach the detection cell. This pH-gated Glu-responsive NM can effectively separate biological matrices from the detection cell, allowing direct sensing of Glu in complex biomatrices.

SIGNIFICANCE

The ECL technology, combined with the pH-triggered gate design enables straightforward Glu determination in undiluted serum, demonstrating an alternative ECL device for pretreatment-free clinical analysis.

Identification of microplastics and nanoplastics in environmental water by AFM-IR

BACKGROUND

Microplastics and nanoplastics have gained worldwide attention as environmental hazards, and reliable analysis of these tiny particles is critical to accurate assessment of their impact to the environment and human health. Among the typical methods developed for analysis of microplastics, mass spectrometry-based methods are destructive and not applicable to individual nanoplastic particles, whereas vibrational spectroscopic techniques in combination with optical microscopy do not have sufficient spatial resolution needed for characterization of the much smaller nanoplastics. Therefore, a new tool is needed for the identification of nanoplastics in the environment.

RESULTS

Here we report for the first time identification of individual nanoplastics in an environmental water sample directly by atomic force microscopy-infrared (AFM-IR), a spectroscopic technique with a spatial resolution of ∼100 nm. On the basis of their spectral characteristics, four different nanoplastics, including poly(3-hydroxybutyrate) (P3HB) and a bisphenol-A based epoxy, as well as microplastics of the latter and two different polyesters were identified unambiguously, and the P3HB nanoplastic particle was found to be highly crystalline. Particles of fatty acid salt, lactic acid salt and sulfate were also identified. Amide bands were observed in the spectra of some of these particles, indicative of protein contamination. In addition, a diatom and a bacterium were identified based on their IR spectra in conjunction with the morphology and elemental composition.

SIGNIFICANCE

This work demonstrates that AFM-IR is a powerful tool for studying individual nanoplastic particles in environmental samples, capable of providing not only their identities but also detailed structure information.

Glycosaminoglycans: Mechanisms and therapeutic potential in neurological diseases: A mini-review

Glycosaminoglycans (GAGs) are vital polysaccharides that constitute key elements of the extracellular matrix (ECM), particularly within chondroitin sulfate proteoglycans (CSPGs). GAGs exhibit a dual role in neural tissue: they facilitate synaptic plasticity and cellular adhesion, essential for neural function, while posing as barriers to axonal regeneration following injury. Through interactions with diverse proteins, including enzymes, cytokines, and growth factors, GAGs critically influence neural development, repair, and homeostasis. Recent advancements have underscored the therapeutic potential of modulating GAG synthesis, degradation, and receptor interactions to address neuroinflammation, promote neural repair, and counteract inhibitory signals in the injured CNS. Furthermore, combining GAG-targeted therapies with complementary approaches, such as gene therapy or nanoparticle-based delivery systems, holds promise for achieving synergistic effects and enhancing treatment outcomes. This mini-review explores the multifaceted roles of GAGs in neural physiology and pathology, highlighting their emerging potential as therapeutic targets for neurological disorders.

Plasmon-enhanced fluorescence sensor based on Au nanocages for sensitive detection of norepinephrine

BACKGROUND

Norepinephrine (NE) as a crucial monoamine neurotransmitter in the central and sympathetic nervous system, plays an important role in different physiological and pathophysiological processes. Brain NE can modulate cerebrospinal fluid flux and neurovascular coupling, regulate cortical and hippocampal neuronal circuitry, and participate the immune system. In addition, the reduced concentration of NE in brain was currently deemed to be the internal reason of major depression. However, development of detection method of NE with high spatiotemporal resolution in living systems remains a great challenge.

RESULTS

Herein, a plasmon-enhanced fluorescence (PEF) sensor based on Au nanocages (Aucages) were designed and prepared for ultra-sensitive detection of NE. Aucages with porous walls, hollow interior and systematically tunable localized surface plasmon resonance (LSPR) wavelengths (536 nm, 654 nm, 754 nm) were prepared to obtain a highly fluorescent enhancement of Au nanoclusters (Au NCs). Moreover, polyethylene glycol (PEG) with different molecular weight (1000, 5000, 10000 Da) were applied to control the distance between the Aucages and Au NCs. 3D-FDTD simulation results indicated that the fluorescence enhancement was primarily due to the internal and external enhanced electric field effects of Aucages. This sensor was applied for the turn-on detection of NE in commonly used clinical injectable norepinephrine bitartrate with the recovery rate of 98.06-105.34 %. Meanwhile, real-time fluorescence imaging of NE in living pheochromocytoma (PC-12) cells was explored with a red-emitted fluorescence.

SIGNIFICANCE

This study first employed Aucages with more "hot spot" for red-emitted Au NCs to realize fluorescence enhancement. It provides a new method for the development of more sensitive, accurate and convenient analysis of NE in clinical drug analysis, cell monitor and metabolism study.

Rapid identification of multiplexed pathogens via a two-step dual-channel fluorescence turn-on array

Bacterial infections have been an increasingly serious threat to human health. However, the rapid identification of multiplexed bacteria remains challenging due to their intricate composition. Herein, we developed a two-step, dual-channel fluorescence "turn-on" sensor array that sequentially amplifies signals via Indicator Displacement Analysis (IDA) and Aggregation-Induced Emission (AIE). Three weakly fluorescent, positively charged conjugated fluorophores (A1-A3) with AIE properties were designed to form electrostatic complexes (C1-C3) with negatively charged graphene oxide (GO). Upon addition of bacteria, fluorophores were released from the electrostatic complexes via IDA, resulting in fluorescence turn-on. These fluorophores then aggregated on the bacterial surface, further enhancing fluorescence. This array accurately differentiated among 10 distinct bacterial strains, achieving 98.3 % classification accuracy within 30 s. Finally, the approach facilitated semi-quantitative bacterial analysis, multiplex identification, and robust differentiation in artificial urine samples, presenting a promising method for early infectious disease diagnosis.

Assembling metal nanoclusters with high luminescence performance and anti-interference ability for sensing p-nitrophenol

BACKGROUND

The fluorescence quantum yield (QY) of water-soluble gold nanoclusters (AuNCs) can be prominently improved by adding l-arginine (Arg) owing to rigidifying ligands. However, these fluorescence systems exhibit poor anti-interference ability in sensing application due to exposure guanidine, amino, and carboxyl groups of Arg.

RESULTS

We have developed the encapsulation of AuNCs into zeolitic imidazolate framework-8 (ZIF-8) to improve the anti-interference property due to the protection of Arg functional groups. The ligand of 6-aza-2-thiothymine (ATT)-decorated AuNCs (ATT-AuNCs) is rigidified after introducing Arg (referred as Arg/ATT-AuNCs), yielding higher QY of 59.31 % compared to ATT-AuNCs with QY of 1.18 %. Subsequently, the shell of Arg/ATT-AuNCs encapsulated into ZIF-8 (Arg/ATT-AuNCs@ZIF-8) does not only tremendously increase green fluorescence emission, but also enhance the anti-interference capability (high salt concentration, pH change, metal ions coordination, and solution dilution) due to the structural confinement effect and protection of ligand functional groups. Interestingly, Arg/ATT-AuNCs@ZIF-8 fluorescence can be quenched by p-nitrophenol (PNP) through an internal filtration effect (IFE). Thus, a fluorescence method is established for PNP analysis. The linear detection range for PNP is 0.1-80 μM with limit of detection (LOD) at 0.033 μM, which is much lower than the maximum allowable value (0.43 μM) in drinking water by EPA. This approach has been successfully applied to the detection of PNP spiked into the real samples with excellent recovery rates. This platform opens a broad avenue for metal nanocluster-based materials in the sensing application.

Construction of carboxyl-functionalized hyper-cross-linked porous polymers using waste polystyrene for effective adsorption of phenolic contaminants

The extensive presence of phenolic organic contaminants (POCs) poses a serious threat to humans. Meanwhile, the upcycling/reusing of waste polystyrene to reduce the exponential growth of plastic pollution is a very important environmental issue. Addressing these demands, a series of carboxyl-functional hypercrosslinked polymers (labeled PP-HCPs) were constructed by knitting waste polystyrene with pyromellitic dianhydride at different ratios through a one-step Friedel-Crafts reaction for effective adsorption of POCs. Among the prepared PP-HCPs, PP-HCP2 displayed a large specific surface area with high adsorption capacity (37.3 mg g-1) for POCs. Using PP-HCP2 as solid phase extraction sorbent, six POCs were effectively extracted from water and peach drink samples, then subjected to high-performance liquid chromatography-ultraviolet detection. The method demonstrated good linearity in the range of 0.03-100.0 ng mL-1 for water samples and 0.06-100.0 ng mL-1 for peach drinks under optimum experimental conditions. At a signal-to-noise ratio of 3, low detection limits were found to be 0.01-0.10 ng mL-1 for water samples and 0.02-0.15 ng mL-1 for peach drinks. Good accuracy and repeatability were achieved with recoveries of 85.3-111.8 % and the relative standard deviations below 8.6 %. The PP-HCP2-based approach can be employed as a dependable and sensitive tool to detect POCs in water and peach drink samples. This work delivers a simple and economically viable approach to fabricate carboxyl-functional HCPs by converting waste foam into high-value-added sorbent, with great significance for sustainable development.

De novo design and discovery of broad-spectrum affinity peptide ligands for influenza A vaccines

Seasonal Influenza viruses, owing to their continued evolution and high level of contagion, present a significant threat to public health around world each year. Vaccination remains the most effective strategy for preventing complications of influenza virus infection, particularly for vulnerable populations such as elderly individuals, children, and individuals with underlying health conditions. In this study, we described the de novo design for the discovery of affinity ligands targeting the conserved receptor binding site (RBS) of the influenza virus hemagglutinin (HA). Based on three-round of molecular docking, three candidate peptides, pep1, pep3 and pep4, with top-rankings were identified. Molecular dynamic simulation and per-residue decomposition further revealed the different binding mechanisms of the three peptides with HA and the key residue's contribution to the binding. The result of microscale thermophoresis indicated that the three peptides had broad-spectrum affinity for various influenza A strains and, among them, pep1 had the highest binding affinity for HA (Kd = 0.58-0.73 μmol/L). By coupling pep1 onto Sepharose gels, the affinity gel was applied to the evaluation of the chromatographic performance in the purification of HA and influenza A vaccine from mimic egg- and mammalian-based feedstocks. A recovery of 68.3 %-72.2 % at the purity of 95.9 %-97.2 % was obtained in vaccine purification, demonstrating the excellent feature of the peptide ligand. This work provided new insight into the rational design of broad-spectrum affinity peptide targeting HA and the result has potential application in the production of influenza vaccines.

Acidobasic equilibria of inubosin derivatives studied by UV-Vis spectroscopy

Inubosin derivatives were suggested as compounds supporting the regeneration of neurons. For practical pharmaceutical applications their physicochemical properties need to be optimized in terms of bioavailability, possible side effects, and efficiency. We focused on four inubosin B derivatives, where acidobasic constants as key players in the biological activity were determined using the UV-Vis spectroscopy. The constants were correlated with the structure on the basis of the Hammett theory. In addition, water-organic solvent equilibria were studied for selected compounds. A software for semi-automated processing of the UV-Vis titration data was developed and tested. Time dependent density functional theory (TDDFT) was used to model and interpret the experimental spectra, which made it possible, for example, to assign the most characteristic cationic band to the S0 → S2 transition. For the acridine acid, both the TDDFT computations and the experimental data indicate that it forms zwitterion in the aqueous solution, whereas it is not dissociated in the organic phase.

Harnessing machine learning for the rational design of high-performance fluorescent dyes

The design of fluorescent dyes with optimized performance is crucial for advancements in various fields, including bioimaging, diagnostics, and optoelectronics. Traditional approaches to dye design often rely on trial-and-error experimentation, which can be time-consuming and resource-intensive. 42 ML models are tried for each property. One best model is selected for each property. Gradient boosting regressor is best model for the prediction of excitation values while extra trees regressor is best model for the prediction of emission values. A database of 5000 new dyes is generated and analyzed. 30 dyes with higher excitation and emission values are selected. Synthetic accessibility analysis is done for 30 dyes and majority of dyes are easy to synthesized. Our results demonstrate that ML-assisted design can significantly accelerate the discovery process, reduce the need for costly experimental iterations, and lead to the development of dyes with tailored properties for specific applications.

Discovery of novel rigid STING PROTAC degraders as potential therapeutics for acute kidney injury

Acute kidney injury (AKI) is a critical condition resulting from intrinsic immune overactivation for which no ideal therapeutic agent is available. The development of therapeutic drugs with new targets and mechanism has become one of the important challenges in the pharmaceutical field. The interferon gene stimulating protein (STING) directly regulates the intrinsic immune processes and is a potential target for AKI therapy. Herein, we designed synthesized and evaluated a series of novel STING-PROTAC degraders via a rigid strategy. Among them, compound ST9 performed the highest degradation capacity with a DC50 of 0.62 μM in THP-1 cells. In a cisplatin-induced HK-2 cell model, ST9 could down-regulate the STING/NF-κB signaling axis and thus inhibit the expression of inflammatory factors. Additionally, ST9 showed a significantly improved metabolic stability profile. Furthermore, ST9 displayed favorable in vivo anti-AKI efficacy and has no toxic side effects on other organs. These results suggest that the novel rigid STING-PROTAC ST9 has clinical potential as a renoprotective agent for the treatment/prevention of acute kidney injury.

Unveiling the effects of conjugated gradient bridges: Inducing intramolecular charge transfer significantly enhances nonlinear response

As an important π-conjugated bridge, (E)-2-styrylthiophene possesses excellent electronic transport and optical properties, showing great potential in nonlinear optical (NLO) applications. In order to investigate the influence of different donor units on (E)-2-styrylthiophene in NLO, we synthesized three thiophene-based D-π-A conjugates with dicyanoacetylene as the acceptor and different donors (MS, PS, FS) by inducing intramolecular charge transfer (ICT). Their third-order nonlinear absorption was studied using Z-scan experiments and transient absorption spectroscopy. Due to the significant ICT, MS exhibited the highest nonlinear absorption coefficient (β = 1.5 × 10-9 m W-1) and effective third order refractive index (n2 = -12 × 10-17 m2 W-1). Taking the strongest performing MS molecule as an example, we analyzed four types of conjugated bridges through theoretical calculations, which indicated that (E)-2-styrylthiophene has the strongest dipole moment difference (Δμ = 34.73 D). Finally, transient absorption (TA) spectroscopy revealed that the nonlinear absorption of these molecules is primarily caused by reverse saturable absorption (RSA).

"Turn-on" mode fluorescence detection of amines based on a cationic covalent organic framework linked with C-C single bond

Developing methods to detect amine pollutants at trace levels is urgently needed due to their high toxicity to both human health and environment. Covalent organic frameworks (COFs) have emerged as promising candidates for amine sensing due to their exceptional stability when exposed to corrosive amines. While several COF-based sensors have recently been developed for amine detection, to the best of our knowledge, fluorescent "turn-on" sensors have been limited to imine-linked COFs. However, the relatively low stability of imine linkages may compromise structural integrity in the presence of corrosive amines. Here, for the first time, we constructed a cationic C-C single bond linked COF (CSBL-COF-4) through the reaction between cationic porphyrin TMPyP and terephthaldicarboxaldehyde. The abundant cationic sites distributing throughout the networks not only improved the dispersity of CSBL-COF-4 in aqueous solution but also provided numerous acidic sites to enhance the affinity with alkaline amines via Lewis acid-base interaction. CSBL-COF-4 exhibited an efficient response to amine solutions or vapors and was further utilized to evaluate the freshness of meat samples, highlighting its potential for practical applications. Our result would thus open up a new avenue towards constructing a broader class of COF-based sensors for the fluorescence "turn-on" detection of amines.

Tetracationic tetraaryltetranaphtho[2,3]porphyrins for photodynamic inactivation against Staphylococcus aureus biofilm

Antimicrobial photodynamic therapy (aPDT) has emerged as a promising strategy for addressing bacterial infections, particularly those involving biofilm formation. The electrostatic attraction between the negatively charged bacterial cell walls and the cationic charges of photosensitizers facilitates the accumulation of PSs on bacterial surfaces, thereby enhancing aPDT efficacy. In this study, three series of tetracationic tetraaryltetranaphtho[2,3]porphyrins (TNPs), each incorporating different cationic groups with alkyl chains of varying lengths, were designed and synthesized. Their photodynamic inactivation efficacy against S. aureus, E. coli and C. albicans was evaluated, respectively. These TNPs exhibited strong absorption at ∼730 nm with high molar extinction coefficients (>51,500 L·mol-1·cm-1), fluorescence emission at ∼758 nm and efficient singlet oxygen generation capabilities. Among them, TNPs with shorter alkyl chains (I1, II1 and Ⅲ1) exhibited enhanced phototoxicity against planktonic microbes, with I1 (containing pyridinium substituents) showing the highest activity. These three compounds effectively disrupted mature S. aureus biofilms, with Ⅲ1 (bearing diethylmethylammonium groups) demonstrating superior biofilm eradication capabilities. These findings highlight the dual antibacterial and biofilm-disrupting potential of these Ar4TNP derivatives. Furthermore, their selective toxicity toward bacterial cells over mammalian cells at therapeutic doses provides a foundation for developing safer antimicrobial agents, offering promising alternatives to antibiotics for tackling drug-resistant pathogens and persistent biofilm-associated infections.

Recent advances in medicinal chemistry strategies for the development of METTL3 inhibitors

N6-methyladenosine (m6A), the most abundant RNA modification in eukaryotic cells, exerts a critical influence on RNA function and gene expression. It has attracted considerable attention within the rapidly evolving field of epitranscriptomics. METTL3 is a key enzyme for m6A modification and is essential for maintaining normal m6A levels. High expression of METTL3 is closely associated with various cancers, including gastric cancer, liver cancer, and leukemia. Inhibiting METTL3 has shown potential in slowing cancer progression, thereby driving the development of METTL3 inhibitors. In this work, we summarize recent advancements in the development of METTL3 inhibitor, with a focus on medicinal chemistry strategies employed during discovery and optimization phases. We explore the application of structure-activity relationship (SAR) studies and protein-targeted degradation techniques, while addressing key challenges associated with their characterization and clinical translation. This review underscores the therapeutic potential of METTL3 inhibitors in modulating epitranscriptomic pathways and aims to offer perspectives for future research in this rapidly evolving field.

Growth inhibitory peptides: a potential novel therapeutic approach to cancer treatment

Cancer remains a major global public health concern, with considerable interest in exploring biological molecules for cancer treatment and prevention. Growth inhibitory peptide (GIP), a promising new class of biological therapeutics, has drawn attention for its distinct anti-tumor properties. Derived from human alpha-fetoprotein (HAFP), this synthetic 34-amino-acid peptide has demonstrated substantial anti-tumor effects across various cancer cell lines, effectively inhibiting tumor cell proliferation, migration, and metastasis. Studies reveal that GIP mediates its effects through a range of mechanisms, including interactions with G protein-coupled receptors (GPCRs), anti-cell adhesion activities, inhibition of cell spreading and metastatic processes, morphological alterations, platelet aggregation inhibition, immune enhancement, cell membrane disruption, ion channel blockade, and cell cycle arrest. While GIP has exhibited promising anti-tumor activity in both in vitro and in vivo models, further investigation is essential to advance its development as a therapeutic drug, particularly regarding pharmacokinetics, safety profiles, storage stability, and clinical efficacy.

A mitochondria targeted hydrogen peroxide fluorescent probe for monitoring oxidative stress during influenza virus infection

Hydrogen peroxide (H2O2), an important marker of oxidative stress, plays a significant role in infectious diseases. Oxidative stress induced by influenza virus infection is intricately linked to the pathological processes of host cells. In this work, a fluorescent probe QLC1 based on the coumarin was developed for fluorescence imaging of mitochondrial H2O2 level in host cells during influenza virus infection. The self-immolative reaction of QLC1 triggered by H2O2 will lead to a 250-fold fluorescence enhance and the limit of detection was determined to be 0.176 μM. Using this probe, we monitored oxidative stress during influenza infection and identified a link between redox status and influenza virus replication.

Cellular internalization pathways of environmentally exposed microplastic particles: Phagocytosis or macropinocytosis?

Microplastic particles (MP) ubiquitously occur in all environmental compartments where they interact with biomolecules, forming an eco-corona on their surfaces. The eco-corona affects the surface properties of MP and consequently how they interact with cells. Proteins, an integral component within the eco-corona, may serve as a ligand driving the interaction of MP with membrane receptors. To date, it is not known, whether eco-coronae originating from different environmental media differ in their proteinaceous compositions and whether these particles interact differently with cells. We show that the protein composition of the eco-coronae formed in freshwater (FW) and salt water (SW) are distinct from each other. We did not observe different adhesion strengths between MP coated with different eco-coronae and cells. However, the internalization efficiency and the underlying internalization mechanisms significantly differed between FW- and SW eco-coronae. By inhibiting actin-driven and receptor-mediated internalization processes using Cytochalasin-D, Amiloride, and Amantadine, we show that FW microplastic particles predominantly become internalized via phagocytosis, while macropinocytosis is more important for SW microplastic particles. Overall, our findings show that the origin of eco-coronae coatings are important factors for the cellular internalization of microplastic particles. This highlights the relevance of eco-coronae for adverse effects of environmentally relevant microplastic particles on cells and organisms.

Photo-enzyme cascade catalysis treatment of bisphenol A in water: Synergistic hydroxylation pathway for mineralization and detoxification

The development of peroxidases-mediated systems for bisphenol A (BPA) degradation suffer from limitations such as incomplete degradation and the accumulation of potentially toxic degradation byproducts. This study reports a strategy to construct a photo-enzyme cascade catalytic system (PECCS) by integrating a tailored 3D carbon nitride photocatalyst with horseradish peroxidases (HRP). Under visible light irradiation, this PECCS achieved the complete removal of BPA with the rate constant at 0.069 min⁻¹ . Furthermore, the mineralization rate is 45 % higher than that of a single enzymatic degradation. Degradation intermediates and products were identified using LC-MS/MS. Results indicate that the complete mineralization is accelerated by hydroxylation and isopropylidene chain cleavage, which depend on the introduced •OH generation. Furthermore, this PECCS follows a degradation pathway that effectively reduces toxicity, as evidenced by the changes in the calculated toxicity of the identified products. Overall, this study may inspire the development of green technologies for the degradation and detoxification of bisphenols and other structurally similar pollutants.

Roles of ESIPT and TICT in the photophysical process of a Zn2+ sensor: Ratiometric or turn-on

The cis-trans isomerization of the C=N bond is generally believed to induce quenching in molecules containing a Schiff base. These molecules typically serve as turn-on sensors for cations, with only a few acting as ratiometric sensors. This study presents a comprehensive investigation into the photophysical processes of an unusual ratiometric sensor for Zn2+ based on Schiff base, utilizing density-functional theory (DFT) and time-dependent DFT (TDDFT). By examining the potential energy surface (PES) of the S1 state, multiple dynamic processes including excited state intramolecular proton transfer (ESIPT), bond twisting, and C=N isomerization were analyzed. Energy barriers and rate constants for these processes were obtained and compared to evaluate their likelihood of occurrence. It was found that C=N isomerization can only take place after an ESIPT process and leads to a non-emissive twisted intramolecular charge transfer (TICT) state, turning the probe into a turn-on sensor. However, the electron-withdrawing nature of the cyano group induces strong intramolecular charge transfer during photoexcitation and leaves the Schiff base unexcited. As a result, the ESIPT process is unfavorable, and the subsequent C=N isomerization is prevented, making the probe a ratiometric sensor. Moreover, two additional sensors with electron-donating and electron-withdrawing groups were designed, and their photophysical processes were studied, providing further support for the proposed theory.

In vitro reversible photoinactivation in a novel variant of Mnemiopsin 2

Incubation of Mnemiopsin with coelenterazine in a dark medium in the presence of oxygen molecules leads to the formation of functional bioluminescent complexes, which initiate light emission upon coordination of calcium ions. However, the functional complex is inhibited when exposed to environmental light. The photoinactivation is reversible in vivo by restoring the live organism to a dark medium, but it is irreversible in Mnemiopsin extracts in vitro. It has been suggested that the photoinactivation of Mnemiopsin results from the dissociation of coelenterazine and oxygen from the photoprotein. Accordingly, the dissociated chromophore differs from free coelenterazine due to the coordination of oxygen in its structure. In this study, while working on several mutants of Mnemiopsin 2, we accidentally observed that a mutant of Mnemiopsin 2, P181D, can recover its light-emitting ability after being treated with light. Compared with the wild-type Mnemiopsin, which completely loses its luminescence activity after 1 min of exposure to light, under similar conditions, the mutant exhibited 71 % of its original activity. Further studies showed that its activity after 60 min of exposure to light was 20.3 % of the original activity under standard conditions. To elucidate this observation, we extended our study and found that replacing Proline, a neutral residue with limited conformational space, with Aspartic acid, a charged residue with greater conformational space, increased the cooperativity of interactions within the photoprotein molecule and enhanced the affinity of the core structure for coelenterazine and oxygen.

Genetic engineering-powered dual-mode lateral flow immunosensor for colorimetric and fluorescent detection of ochratoxin A in pepper

Ochratoxin A (OTA) poses significant risks to both environment and human health, necessitating the development of rapid and sensitive detection methods. Lateral flow immunosensors (LFIs) typically use monoclonal antibodies and artificial antigens for mycotoxin detection; however, the preparation of these components is time-intensive, laborious, costly, and environmentally harmful. Herein, we developed an innovative genetic engineering-powered colorimetric/fluorescent dual-mode LFI (CM/FL-dLFI) using nanobodies and the mimotope peptide (MP) of OTA. Initially, a heptameric bifunctional fusion (sfGFP-C4bpα-Y4) containing the superfolder green fluorescent protein, the C4-binding protein α-chain, and the MP Y4 was constructed. The fusion was subsequently labeled on gold nanoflowers (AuNFs) to create the AuNFs@sfGFP-C4bpα-Y4 probe, which can be captured by the nanobody heptamer (Nb-C4bpα) and provides colorimetric/fluorescent signals. The optimized CM/FL-dLFI achieved a colorimetric limit of detection (LOD) of 0.01 ng/mL and a fluorescent LOD of 0.05 ng/mL. It exhibited high selectivity for OTA, good recovery rates of 82.85-102.81 % with relative standard deviations not exceeding 14 %, and excellent long-term stability. Moreover, it showed strong correlation with high-performance liquid chromatography in the analysis of 11 real pepper samples. Therefore, this study highlights the promising application potential of nanobodies and MPs in developing an economical and eco-friendly LFI for OTA detection in pepper.

Design, synthesis and biological evaluation of Golgi-targeting anion transporters as inducers of Golgiphagy and apoptosis in cancer cells

Disruption in the homeostasis of anions within organelles in cancer cells by synthetic small-molecule anion transporters may lead to significant inhibition in the proliferation of cancer cells. However, the specific impact of anion transporters on organelles, in particular on the Golgi apparatus remains to be explored. In this study, we designed and synthesized a novel series of Golgi-targeting anion transporters composed of squaramido moiety for transporting chloride anions and benzenesulfonamido group for targeting the Golgi apparatus. These compounds were able to efficiently facilitate the transport of anions across liposomal and cellular membranes, and exhibit significant cytotoxicity toward several selected cancer cells. Among them, compound 10 was the most active in efficiently disrupting the homeostasis of chloride anions specifically within the Golgi apparatus. This disruption led to profound perturbations in the structure and function of the Golgi apparatus, and triggered Golgiphagy and further apoptosis. More importantly, compound 10 displayed potent antitumor efficacy toward HepG2 xenograft mouse models, with low toxicity and minimal adverse effects on major organs. The present findings underscore the critical role of regulating the homeostasis of chloride anions within the Golgi apparatus in triggering the Golgiphagy and apoptosis of cancer cells, and thus provide a new strategy for the discovery of innovative chemotherapy for cancers.

Spectroscopic insights into the thermal aging process of lithium-ion battery electrolytes

The thermal aging process of lithium-ion battery electrolyte was studied using Raman spectroscopy and fluorescence spectroscopy. The system studied is specifically a carbonate-based electrolyte containing lithium hexafluorophosphate (LiPF6). Raman spectroscopy results show that LiPF6 will decompose and produce substances with significant fluorescence effects under the thermal aging. The fluorescence spectrum results also show that the concentration of this fluorescent substance has a significant positive correlation with the intensity of thermal aging. The mechanism behind the above experimental phenomena was explained and verified by Ab Initio Molecular Dynamics (AIMD) and Density Functional Theory (DFT). AIMD confirmed that LiPF6 can decompose and polymerize into polyfluorophos-phoric acid (PFPA) with different degrees of polymerization at elevated temperature. Then, the theoretical fluorescence spectra and excited state transition of PFPA based on DFT prove that the source of the fluorescence effect is the PFPA molecule, and specifically comes from the transition of π electrons and lone pair electrons on oxygen atoms.

Stereoselective behavior of naproxen chiral enantiomers in promoting horizontal transfer of antibiotic resistance genes

Antibiotic resistance poses a global threat to public health, with recent studies highlighting the role of non-antibiotic pharmaceuticals in the transmission of antibiotic resistance genes (ARGs). This study provides insights into the comprehensive profile, horizontal gene transfer potential, hosts, and public health risks associated with antibiotic resistomes in river ecosystems exposed to chiral naproxen (NAP). Our findings demonstrate that NAP stress selectively enriches ARGs and mobile genetic elements (MGEs), thereby bolstering bacterial resistance to specific antibiotics. Importantly, the spatial variation of NAP chiral enantiomers influences the enantioselective response of bacterial communities to antibiotics. While (S)-NAP and (R)-NAP exhibit differing degrees of horizontal transfer potential, (S/R)-NAP notably facilitates microbial aggregation and DNA transport via type IV secretion system (T4SS)-related functional genes, promoting the conjugation of sul1. Moreover, (S/R)-NAP promotes the horizontal transfer of ARGs by stimulating ROS production and altering cell membrane permeability. Chiral NAP exposure induces pathogens to acquire ARGs and accelerates the proliferation of Burkholderia. ARG-Rank analysis indicates that the health risk posed by (R)-NAP exposure surpasses that of (S)-NAP, with the highest risk observed when both enantiomers are present. This study elucidates the horizontal transfer and transmission mechanisms of ARGs under chiral NAP stress, underscoring the potential health hazards associated with NAP chiral enantiomers.

The dual selective adsorption mechanism on low-concentration Cu(II): Structural confinement and bridging effect

In this study, sulfur was introduced into the graphene oxide-based aerogel system based on the theory of bridging effect, and an oxygen-sulfur synergistic system was established to realize the dual-mechanism selective adsorption to low-concentration Cu(II) with slit structure and targeted binding sites. Based on the difference of chemical properties between organic acids and surfactants, the surface of graphene oxide (GO) was functionalized to realize the regulation of the order of its lamellar structure and the construction of carbon defects. On this basis, sulfur source modified GO-based aerogel was created to accomplish selective adsorption to low-concentration Cu(II) by combining the self-accumulation of montmorillonite and GO with the cross-linking mechanism of Ca(II) and sodium alginate. Based on the density functional theory, the formation process of radicals on the material's surface both prior to and following the adsorption to Cu(II) was simulated, and the effective improvement on the catalytic ability of the material after loading Cu(II) was verified. This means that using Cu(II) saturated adsorbent as a photocatalyst to degrade organic pollutants, is a promising reuse strategy for hazardous waste. The above research provides a new research idea for the subsequent removal of low-concentration metal ions and the potential application of hazardous wastes.

The Liebeskind-Srogl cross-coupling reaction towards the synthesis of biologically active compounds

In this review, we emphasize the significance of the Liebeskind-Srogl cross-coupling reaction, a palladium-catalyzed process involving the reaction between a thioester and a boronic acid. This reaction has emerged as a fundamental technique in synthetic methodologies aimed at the development of biologically active compounds. The Liebeskind-Srogl cross-coupling method has become an essential approach in chemistry, facilitating the diversification of complex structures that would be significantly more challenging to synthesize through alternative approaches. In this review, we aim to outline the numerous possibilities for preparing a wide range of derivatives, each with notable biological potential.

Small molecules for Kirsten rat sarcoma viral oncogene homolog mutant cancers: Past, present, and future

Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations have been identified in more than 20% of human cancers as one of the most common oncogenes, especially in non-small cell lung, colorectal, and pancreatic cancers. KRAS regulates the activation of multiple proteins involved in cell growth and proliferation, such as extracellular regulated protein kinases and mammalian target of rapamycin, as a hub between the epidermal growth factor receptor (EGFR) and downstream MAPK and AKT pathways. However, due to the lack of a binding pocket, KRAS has long been considered an undruggable target in recent decades until the discovery of Sotorasib (AMG510). With the approval of Glecirasib (JAB-21822), there are three approved small molecule inhibitors of KRAS, all of which are KRAS G12C inhibitors. At the same time, the limited clinical benefits and rapid emergence of drug resistance to the approved inhibitors have also promoted the emergence of more therapeutics, such as tri-complexes and proteolysis-targeting chimeras (PROTAC). In this paper, we summarize the development of KRAS inhibitors (KRASG12C, KRASG12D, and KRASmulti inhibitors, PROTAC, and tri-complex) and discuss the challenges and opportunities in the discovery of KRAS inhibitors in the hope of providing insights into the development of novel medications for KRAS.

Wearable SERS devices in health management: Challenges and prospects

Surface-Enhanced Raman Scattering (SERS) is an advanced analytical technique renowned for its heightened sensitivity in detecting molecular vibrations. Its integration into wearable technologies facilitates the monitoring of biofluids, such as sweat and tears, enabling continuous, non-invasive, real-time analysis of human chemical and biomolecular processes. This capability underscores its significant potential for early disease detection and the advancement of personalized medicine. SERS has attracted considerable research attention in the fields of wearable flexible sensing and point-of-care testing (POCT) within medical diagnostics. Nonetheless, the integration of SERS with wearable technology presents several challenges, including device miniaturization, reliable biofluid sampling, user comfort, biocompatibility, and data interpretation. The ongoing advancements in nanotechnology and artificial intelligence are instrumental in addressing these challenges. This review provides a comprehensive analysis of design strategies for wearable SERS sensors and explores their applications within this domain. Finally, it addresses the current challenges in this area and the future prospects of combining SERS wearable sensors with other portable health monitoring systems for POCT medical diagnostics. Wearable SERS is a promising innovation in future healthcare, potentially enhancing individual health outcomes and reducing healthcare costs by fostering preventive health management approaches.

Fabrication of a flexible nanofiber membrane for SERS detection of pollutants: An efficient and eco-friendly approach

The development of electrospun nanomaterials as highly efficient and portable substrates for surface-enhanced Raman scattering (SERS) is of great significance for rapid detection of pollutant molecules. In this work, we prepared sustainable polylactic acid (PLA) electrospun nanofibers decorated with silver nanoparticles (Ag NPs) as a flexible SERS substrate through a combined process of facile electrospinning and green plasma treatment. Using rhodamine 6G (R6G) as probe molecule, the PLA/Ag NPs composite nanofibers show excellent SERS performance and allow the detection of R6G at a low concentration of 10-10 M. In addition, the SERS substrate could be used for trace detection of pesticide thiram, and exhibits high sensitivity with a detection limit of 10-8 M. By taking advantage of the flexibility of the nanofibers, the nanofibrous membrane was pasted on the surface of an apple to sample and detect residual thiram, and the pesticide could be distinctly identified even at a low concentration of 10-7 M. The presence of dense Ag NPs with numerous hot-spots played a crucial role in the substrate's high sensitivity for SERS detection. This environmentally friendly, self-supporting SERS substrate holds great promise for diverse applications, including environmental monitoring and medical diagnostics.

Trypsin-catalyzed asymmetric aldol reactions of isatins with cyclic ketones and the mechanistic insights on activity differences at theoretical level

The promiscuous activity of bovine trypsin was explored in asymmetric aldol reactions between isatins and cyclic ketones. Detailed screening on the conditions with model substrates allowed to provide better catalytic performance. Especially, addition of calcium ion, as a natural stabilizer of trypsin, could improve stereoselectivity although slight losing yield. Furthermore, acceptability of various substrates was examined, a greatly impact on the yield and stereoselectivity have been observed from the different sizes of cyclic ketones. Docking and dynamics simulations were utilized to reveal the possible molecular basis of these phenomena.

Recent advances in the photothermocatalytic oxidation of formaldehyde in air

A synergistic combination of photocatalysis and thermocatalysis (photothermocatalysis) has been realized to harness the full solar spectrum with a particular focus on the infrared region to support sustainable oxidation reactions of carcinogenic oxygenated volatile organic compounds such as formaldehyde (FA). Here, recent advances in the oxidative removal of FA in air have been reviewed systematically. First, the fundamentals of the photothermocatalytic mechanism are introduced and discussed. Second, various aspects of the development and application of photothermocatalytic systems are described and reviewed. A specific focus is placed on the physicochemical characteristics of photothermocatalysts with respect to reaction conditions and oxidation performance using FA as a model compound. Third, the pathways and mechanisms of FA oxidation are elaborated and discussed in detail to provide insights into associated surface phenomena and surface chemistry at the molecular level. Finally, current shortcomings and future research directions are identified and discussed to help expand this research field further into the practical realm.

Regulating interfacial microenvironment via anion adsorption to boost oxygen evolution reaction

The often-overlooked anions in raw materials have been less explored in terms of their promotion of the oxygen evolution reaction (OER) from the perspective of interfacial microenvironment regulation. In this study, we obtained the catalyst (CoOOH-NO3-) by a one-step electrochemical reconstruction method, in which anion adsorption onto the active catalyst can optimize the interfacial microenvironment to promote OER under alkaline conditions. This is because the issue of excessive OH- adsorption within the inner compact layer of CoOOH can be ameliorated by the adsorption of anions, making it easier for active sites to branch OH-, thereby regulating the interfacial microenvironment. It was validated through a series of experiments that after tuning the interfacial microenvironment, reduction in the contact angle on the electrode surface facilitates the release of O2, promotes Co transformation to a higher oxidation state (Co(IV)) and lowers the onset potential for the reaction. Furthermore, the one-step synthesis method, along with the strategy of microenvironment regulation, applies to various metal salts (chlorides, acetates). Our research introduces a non-chemical synthesis method for the direct use of metal salts, providing a rational approach and insight for understanding how anion adsorption regulates interfacial microenvironment to enhance catalytic activity.

Unveiling the impact of the fluorophore pyrrole, indole, furan, benzofuran, thiophene, benzothiophene, and pyrene attachments on the C7 atom of the isomorphic fluorescent thieno-guanine: A theoretical investigation

Thieno-guanine (thG) is a prominent emissive surrogate of natural guanine (G), which almost perfectly mimics G in nucleic duplexes. In this paper, to widen the utility of thG, the C7 attachment effects by aromatic pyrrole, indole, furan, benzofuran, thiophene, benzothiophene, and pyrene on the structural, electronic, and photophysical properties of thG were theoretically examined by using the density functional theory (DFT) and the time-dependent DFT (TD-DFT). Calculations were performed employing the hybrid B3LYP and the long-range corrected CAM-B3LYP density functionals in combination with the 6-311++G(d, p) basis set. Rigid scan calculations and optimizations were performed to obtain the most stable rotamers, and totally 14 bases (including thG) were studied. The hole-electron theory and the interfragment charge transfer (IFCT) method were applied to reveal the intrinsic characteristics of the low-lying electron excitation processes. In water solution, all the S1 states of the thG-derivatives are highly allowed ππ∗ states dominated by HOMO (L)→LUMO (L) with some charges (0.028-0.193 e) been transferred from the introduced groups to the thG-moiety. The introduced groups can tune the photophysics of thG resulting in improved fluorescent properties, including visible excitation and emission wavelengths, greater absorption and emission intensities (oscillator strengths), and larger Stokes shifts. In water solution, all substituents display fluorescence wavelength longer than 500 nm and the Stokes shifts are larger than 100 nm. Also examined are the effects of base pairing with cytosine (C), and it was revealed that the S1 states of all the studied base pairs (totally 14) are local excitations of the thG-derivatives. Both the S1 state excitation energies and the fluorescence wavelengths are red-shifted to some extent after base pair with C, with a concomitantly decrease of the corresponding oscillator strength.

Targeting amyloidogenic proteins through cyclic peptides - A medicinal chemistry perspective

Alzheimer's Disease (AD) is characterized by the formation of amyloid-β (Aβ) in the extracellular region, neurofibrillary tangles (NFTs) in the intracellular region accompanied with neuroinflammation and decreased neurotransmitters in various regions of brain leading to neuroinflammation and neurodegeneration. Of the various bioactive molecules, Cyclic Peptides (CPs) are small circular chains of amino acids that can alter the structure and function of the proteins they interact with. They can be synthesized using chemical or genetic approach leading to the generation of diverse libraries of CPs that are screened for binding with desired target proteins. In AD, CPs can interfere at various levels, by either imitating the structure or altering the conformation of amyloidogenic proteins. They can also interfere with signal transduction by competing with amyloid proteins for various receptors which are involved in AD pathology. This review highlights the application of CPs as scaffolds for the identification of novel small molecules that can interfere with amyloid aggregation or for the formulation of vaccination against AD. Other proteins involved in the pathophysiological pathways of AD that can potentially be targeted for CP design have also been discussed.

Structure-activity relationship study of navarixin analogues as dual CXCR2 and CCR7 antagonists

Despite the promise of the human chemokine receptor 7 (CCR7) as drug target for the treatment of cancer metastasis and autoimmune diseases, there are no potent and selective CCR7 antagonists known in literature. In this work, a 1,2,5-thiadiazole 1,1-dioxide with low μM activity as a CXCR2 and CCR7 antagonist was selected as starting point for a structure-activity relationship study. The replacement of the central thiadiazole dioxide motif with squaramide led to low nanomolar CCR7 antagonism. Additional systematic structural variations afforded various squaramide analogues that displayed potent CCR7 antagonism in a calcium mobilization assay with IC50 values in the low nM range. Unfortunately, the same compounds also displayed potent CXCR2 antagonistic activity and should therefore be considered as dual CCR7/CXCR2 antagonists.

Polycarboxybetaine in advanced drug delivery systems: From structure-function relationship to therapeutic applications

Zwitterionic polycarboxybetaines (PCBs), combining quaternary ammonium cations and carboxylate anions in their repeating units, have emerged as promising materials for drug delivery applications. Their exceptional hydration, biocompatibility, and antifouling properties make them attractive alternatives to polyethylene glycol (PEG), particularly given growing concerns about immunogenicity of PEG. PCBs can be functionalized through various methods, including modification of side-chain moieties, adjustment of spacer length between charged groups, and incorporation of responsive elements. When applied to delivery drug, PCBs have been successfully developed into multiple formats including micelles, hydrogels, liposomes, and nanoparticles. Notably, in protein drug delivery, PCBs demonstrate significant advantages such as enhancing protein stability, extending circulation time, improving penetration through biological barriers, and reducing immunogenicity. Despite these promising features, several challenges remain, including complex synthesis requirements, limited mechanical properties, and pending FDA approval as pharmaceutical excipients. This review provides a comprehensive analysis of PCBs from the structure-function relationship, synthesis methods, and applications in drug delivery systems, while examining current limitations and future prospects.

Targeted conversion of waste PET into dimethyl terephthalate and ethylene carbonate under metal-free conditions

Ionic liquid-catalyzed methanolysis emerges as an efficient technique for transforming PET into premium-grade dimethyl terephthalate (DMT). However, incomplete depolymerization remains a major obstacle to the further industrial application of IL-catalyzed PET methanolysis. The proposed method utilized dimethyl carbonate (DMC) as the solvent for the complete methanolysis of waste PET under mild conditions, resulting in pure DMT and ethylene carbonate (EC) within 2.5 ​h. The use of 1-ethyl-3-methylimidazolium acetate ([EMIm][OAc]) as the IL catalyst significantly enhanced the reaction efficiency. Spectroscopic analyses using 1H NMR and FT-IR confirmed the pivotal role of [EMIm][OAc] in establishing multiple hydrogen bonds with the reactants (PET, DMC, and MeOH) and the intermediate [ethylene glycol (EG)] during the catalytic process. This catalytic system exhibited remarkable performance, achieving complete conversion of PET, which resulted in the production of DMT and EC with yields of 99% and 91%, respectively. Moreover, this versatile approach is applicable to the upcycling of a wide variety of commercial polyesters and polycarbonates, underscoring its potential as a comprehensive solution for plastic waste management.