Stress granules: Guardians of cellular health and triggers of disease

Stress granules are membraneless organelles that serve as a protective cellular response to external stressors by sequestering non-translating messenger RNAs (mRNAs) and regulating protein synthesis. Stress granules formation mechanism is conserved across species, from yeast to mammals, and they play a critical role in minimizing cellular damage during stress. Composed of heterogeneous ribonucleoprotein complexes, stress granules are enriched not only in mRNAs but also in noncoding RNAs and various proteins, including translation initiation factors and RNA-binding proteins. Genetic mutations affecting stress granule assembly and disassembly can lead to abnormal stress granule accumulation, contributing to the progression of several diseases. Recent research indicates that stress granule dynamics are pivotal in determining their physiological and pathological functions, with acute stress granule formation offering protection and chronic stress granule accumulation being detrimental. This review focuses on the multifaceted roles of stress granules under diverse physiological conditions, such as regulation of mRNA transport, mRNA translation, apoptosis, germ cell development, phase separation processes that govern stress granule formation, and their emerging implications in pathophysiological scenarios, such as viral infections, cancer, neurodevelopmental disorders, neurodegeneration, and neuronal trauma.

Recent advances in immunotherapy targeting amyloid-beta and tauopathies in Alzheimer's disease

Alzheimer's disease, a devastating neurodegenerative disorder, is characterized by progressive cognitive decline, primarily due to amyloid-beta protein deposition and tau protein phosphorylation. Effectively reducing the cytotoxicity of amyloid-beta42 aggregates and tau oligomers may help slow the progression of Alzheimer's disease. Conventional drugs, such as donepezil, can only alleviate symptoms and are not able to prevent the underlying pathological processes or cognitive decline. Currently, active and passive immunotherapies targeting amyloid-beta and tau have shown some efficacy in mice with asymptomatic Alzheimer's disease and other transgenic animal models, attracting considerable attention. However, the clinical application of these immunotherapies demonstrated only limited efficacy before the discovery of lecanemab and donanemab. This review first discusses the advancements in the pathogenesis of Alzheimer's disease and active and passive immunotherapies targeting amyloid-beta and tau proteins. Furthermore, it reviews the advantages and disadvantages of various immunotherapies and considers their future prospects. Although some antibodies have shown promise in patients with mild Alzheimer's disease, substantial clinical data are still lacking to validate their effectiveness in individuals with moderate Alzheimer's disease.

Biomaterial-based strategies: a new era in spinal cord injury treatment

Enhancing neurological recovery and improving the prognosis of spinal cord injury have gained research attention recently. Spinal cord injury is associated with a complex molecular and cellular microenvironment. This complexity has prompted researchers to elucidate the underlying pathophysiological mechanisms and changes and to identify effective treatment strategies. Traditional approaches for spinal cord injury repair include surgery, oral or intravenous medications, and administration of neurotrophic factors; however, the efficacy of these approaches remains inconclusive, and serious adverse reactions continue to be a concern. With advancements in tissue engineering and regenerative medicine, emerging strategies for spinal cord injury repair now involve nanoparticle-based nanodelivery systems, scaffolds, and functional recovery techniques that incorporate biomaterials, bioengineering, stem cell, and growth factors as well as three-dimensional bioprinting. Ideal biomaterial scaffolds should not only provide structural support for neuron migration, adhesion, proliferation, and differentiation but also mimic the mechanical properties of natural spinal cord tissue. Additionally, these scaffolds should facilitate axon growth and neurogenesis by offering adjustable topography and a range of physical and biochemical cues. The three-dimensionally interconnected porous structure and appropriate physicochemical properties enabled by three-dimensional biomimetic printing technology can maximize the potential of biomaterials used for treating spinal cord injury. Therefore, correct selection and application of scaffolds, coupled with successful clinical translation, represent promising clinical objectives to enhance the treatment efficacy for and prognosis of spinal cord injury. This review elucidates the key mechanisms underlying the occurrence of spinal cord injury and regeneration post-injury, including neuroinflammation, oxidative stress, axon regeneration, and angiogenesis. This review also briefly discusses the critical role of nanodelivery systems used for repair and regeneration of injured spinal cord, highlighting the influence of nanoparticles and the factors that affect delivery efficiency. Finally, this review highlights tissue engineering strategies and the application of biomaterial scaffolds for the treatment of spinal cord injury. It discusses various types of scaffolds, their integrations with stem cells or growth factors, and approaches for optimization of scaffold design.

External stimuli-responsive drug delivery to the posterior segment of the eye

Posterior segment eye diseases represent the leading causes of vision impairment and blindness globally. Current therapies still have notable drawbacks, including the need for frequent invasive injections and the associated risks of severe ocular complications. Recently, the utility of external stimuli, such as light, ultrasound, magnetic field, and electric field, has been noted as a promising strategy to enhance drug delivery to the posterior segment of the eye. In this review, we briefly summarize the main physiological barriers against ocular drug delivery, focusing primarily on the recent advancements that utilize external stimuli to improve treatment outcomes for posterior segment eye diseases. The advantages of these external stimuli-responsive drug delivery strategies are discussed, with illustrative examples highlighting improved tissue penetration, enhanced control over drug release, and targeted drug delivery to ocular lesions through minimally invasive routes. Finally, we discuss the challenges and future perspectives in the translational research of external stimuli-responsive drug delivery platforms, aiming to bridge existing gaps toward clinical use.

A stacking classifier for distinguishing stages of Alzheimer's disease from a subnetwork perspective

Accurately distinguishing stages of Alzheimer's disease (AD) is crucial for diagnosis and treatment. In this paper, we introduce a stacking classifier method that combines six single classifiers into a stacking classifier. Using brain network models and network metrics, we employ t-tests to identify abnormal brain regions, from which we construct a subnetwork and extract its features to form the training dataset. Our method is then applied to the ADNI (Alzheimer's Disease Neuroimaging Initiative) datasets, categorizing the stages into four categories: Alzheimer's disease, mild cognitive impairment (MCI), mixed Alzheimer's mild cognitive impairment (ADMCI), and healthy controls (HCs). We investigate four classification groups: AD-HCs, AD-MCI, HCs-ADMCI, and HCs-MCI. Finally, we compare the classification accuracy between a single classifier and our stacking classifier, demonstrating superior accuracy with our stacking classifier from a subnetwork-based viewpoint.

Harnessing nanofibers for targeted delivery of phytoconstituents in age-related macular degeneration

Age-related macular degeneration is a degenerative eye condition that affects the macula and results in central vision loss. Phytoconstituents show great promise in the treatment of AMD. AMD therapy can benefit from the advantages of phytoconstituents loaded nanofibers. There are opportunities to improve the effectiveness of phytoconstituents in the treatment of age-related macular degeneration (AMD) through the use of nanofiber-based delivery methods. These novel platforms encapsulate and distribute plant-derived bioactives by making use of the special qualities of nanofibers. These qualities include their high surface area-to-volume ratio, variable porosity, and biocompatibility. Exploring the use of nanofiber-based delivery methods to provide phytoconstituents in AMD treatment is a great choice for enhancing patient adherence, safety, and efficacy in managing this condition. This article explores the potential of nanofiber-based delivery methods to revolutionize AMD treatment, providing an innovative and effective approach to treat this condition.

Antimicrobial capping agents on silver nanoparticles made via green method using natural products from banana plant waste

Herein, we investigated the phytochemical composition and antibacterial activities of the organic layers from biosynthesized silver nanoparticles (AgNPs). AgNPs were synthesized using Musa paradisiaca and Musa sapientum extracts. UV-vis absorption in the 400-450 nm range indicated surface plasmonic resonance peak of AgNPs. Samples analyses using dynamic light scattering and transmission electron microscopy revealed the presence of particles within nanometric ranges, with sizes of 30-140 nm and 8-40 nm, respectively. Fourier transform infrared (FTIR) unveiled the presence of several organic functional groups on the surface of AgNPs, indicating the presence of phytochemicals from plant extracts. Thin layer chromatography (TLC) of the phytochemicals (capping agents) from AgNPs identified multiple groups of secondary metabolites. These phytochemical capping agents exhibited antibacterial activities against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, with minimum inhibitory concentrations ranging from 62.5 to 1000 µg/mL. Regardless of the bacterial species or plant parts (leaves or pseudo-stems), capping agents from M. sapientum nanoparticles displayed significantly enhanced antibacterial effectiveness compared to all other samples, including the raw plant extracts and biosynthesized capped and uncapped AgNPs. These results suggest the presence of antimicrobial phytochemicals on biosynthesized AgNPs, highlighting the promise of green nanoparticle synthesis as a valuable approach in bioprospecting antimicrobial agents.

R, Khoza. S, Dube A. Vitamin D3 loaded polycaprolactone nanoparticles enhance the expression of the antimicrobial peptide cathelicidin in macrophages

Tuberculosis (TB), primarily caused by Mycobacterium tuberculosis, remains a global health burden. Current antibiotic treatments are limited by adverse effects, poor adherence, and drug resistance, necessitating new therapeutic approaches. Recent studies highlight the role of vitamin D3 (VD3) in enhancing host immune responses against the mycobacterium via cathelicidin (an antimicrobial peptide) and autophagy activation. In this study, VD3-loaded poly-ƹ-caprolactone (PCL) nanoparticles (NPs) were synthesized to enhance cathelicidin expression in macrophages. NPs containing cholecalciferol, calcifediol, and calcitriol were synthesized using an emulsification solvent-evaporation technique. Average sizes of synthesized NPs ranged from 304.7 to 458.7 nm, with polydispersity index (PDI) and zeta potential (ZP) ranging from 0.103 to 0.257 and -17.3 to -7.47 mV, respectively. Encapsulation efficiencies were 9.68%, 10.99%, and 19.28% for cholecalciferol, calcifediol, and calcitriol, respectively. VD3-encapsulated NPs stimulated a dose-dependent increase in cathelicidin expression in THP-1 macrophages. Encapsulated calcifediol and calcitriol (100 ng/ml) induced the expression of 243.46 ng/ml ± 4.55 ng/ml and 396.67 ng/ml ± 25.24 ng/ml of cathelicidin, respectively, which was significantly higher than that induced by the free drugs. These findings suggest that NP encapsulation may offer a more efficient approach to using vitamin D3 for inducing cathelicidin expression as a host-directed treatment for TB.

Staphylococcus warneri dampens SUMOylation and promotes intestinal inflammation

Gut bacteria play key roles in intestinal physiology, via the secretion of diversified bacterial effectors. Many of these effectors remodel the host proteome, either by altering transcription or by regulating protein post-translational modifications. SUMOylation, a ubiquitin-like post-translational modification playing key roles in intestinal physiology, is a target of gut bacteria. Mutualistic gut bacteria can promote SUMOylation, via the production of short- or branched-chain fatty acids (SCFA/BCFA). In contrast, several pathogenic bacteria were shown to dampen SUMOylation in order to promote infection. Here, we demonstrate that Staphylococcus warneri, a natural member of the human gut microbiota, decreases SUMOylation in intestinal cells. We identify that Warnericin RK, a hemolytic toxin secreted by S. warneri, targets key components of the host SUMOylation machinery, leading to the loss of SUMO-conjugated proteins. We further demonstrate that Warnericin RK promotes inflammation in intestinal and immune cells using both SUMO-dependent and SUMO-independent mechanisms. We finally show that Warnericin RK regulates the expression of genes involved in intestinal tight junctions. Together, these results highlight the diversity of mechanisms used by bacteria from the gut microbiota to manipulate host SUMOylation. They further highlight that changes in gut microbiota composition may impact intestinal inflammation, by altering the equilibrium between bacterial effectors promoting or dampening SUMOylation.

Interkingdom signaling between gastrointestinal hormones and the gut microbiome

The interplay between the gut microbiota and gastrointestinal hormones plays a pivotal role in the health of the host and the development of diseases. As a vital component of the intestinal microecosystem, the gut microbiota influences the synthesis and release of many gastrointestinal hormones through mechanisms such as modulating the intestinal environment, producing metabolites, impacting mucosal barriers, generating immune and inflammatory responses, and releasing neurotransmitters. Conversely, gastrointestinal hormones exert feedback regulation on the gut microbiota by modulating the intestinal environment, nutrient absorption and utilization, and the bacterial biological behavior and composition. The distributions of the gut microbiota and gastrointestinal hormones are anatomically intertwined, and close interactions between the gut microbiota and gastrointestinal hormones are crucial for maintaining gastrointestinal homeostasis. Interventions leveraging the interplay between the gut microbiota and gastrointestinal hormones have been employed in the clinical management of metabolic diseases and inflammatory bowel diseases, such as bariatric surgery and fecal microbiota transplantation, offering promising targets for the treatment of dysbiosis-related diseases.

Proteins of the SubB family provide multiple mechanisms of serum resistance in Yersinia pestis

The serum complement system is a cornerstone element of the innate immune response. Bacterial resistance to this system is a multifaceted process involving various proteins and molecular mechanisms. Here, we report several genes required for the growth of Yersinia pestis in serum. Among them, we found that ypo0337 encodes an outer-membrane-associated lectin that recruits factor H, C4BP and hemopexin, conferring resistance to the serum complement system. YPO0337 displays high sequence similarity with the SubB subunit of the AB5 toxin from Escherichia coli, as well as other SubB-like proteins, and subB from E. coli restores the ability of Y. pestis Δypo0337 mutant to resist to serum complement. Altogether, the data suggest that at least two members of the SubB protein family function as virulence factors, conferring resistance to serum complement through a unique mode of action.

Deciphering the role of APOE in cerebral amyloid angiopathy: from genetic insights to therapeutic horizons

Cerebral amyloid angiopathy (CAA), characterized by the deposition of amyloid-β (Aβ) peptides in the walls of medium and small vessels of the brain and leptomeninges, is a major cause of lobar hemorrhage in elderly individuals. Among the genetic risk factors for CAA that continue to be recognized, the apolipoprotein E (APOE) gene is the most significant and prevalent, as its variants have been implicated in more than half of all patients with CAA. While the presence of the APOE ε4 allele markedly increases the risk of CAA, the ε2 allele confers a protective effect relative to the common ε3 allele. These allelic variants encode three APOE isoforms that differ at two amino acid positions. The primary physiological role of APOE is to mediate lipid transport in the brain and periphery; however, it has also been shown to be involved in a wide array of biological functions, particularly those involving Aβ, in which it plays a known role in processing, production, aggregation, and clearance. The challenges posed by the reliance on postmortem histological analyses and the current absence of an effective intervention underscore the urgency for innovative APOE-targeted strategies for diagnosing CAA. This review not only deepens our understanding of the impact of APOE on the pathogenesis of CAA but can also help guide the exploration of targeted therapies, inspiring further research into the therapeutic potential of APOE.

Small molecules targeting the eubacterial β-sliding clamp discovered by combined in silico and in vitro screening approaches

Antibiotic resistance stands as the foremost post-pandemic threat to public health. The urgent need for new, effective antibacterial treatments is evident. Protein-protein interactions (PPIs), owing to their pivotal role in microbial physiology, emerge as novel and attractive targets. Particularly promising is the α-subunit/β-sliding clamp interaction, crucial for the replicative competence of bacterial DNA polymerase III holoenzyme. Through pharmacophore-based virtual screening, we identified 4,000 candidate small molecule inhibitors targeting the β-clamp binding pocket. Subsequently, these candidates underwent evaluation using the BRET assay in yeast cells. Following this, three hits and 28 analogues were validated via Protein Thermal Shift and competitive ELISA assays. Among them, thiazolo[4,5-d]-pyrimidinedione and benzanilide derivatives exhibited micromolar potency in displacing the β-clamp protein partner and inhibiting DNA replication. This screening campaign unveiled new chemical classes of α/β-clamp PPI disruptors capable of inhibiting DNA polymerase III activity, which lend themselves for further optimisation to improve their antibacterial efficacy.

Klebsiella pneumoniae derived outer membrane vesicles mediated bacterial virulence, antibiotic resistance, host immune responses and clinical applications

Klebsiella pneumoniae is a gram-negative pathogen that can cause multiple diseases including sepsis, urinary tract infections, and pneumonia. The escalating detections of hypervirulent and antibiotic-resistant isolates are giving rise to growing public concerns. Outer membrane vesicles (OMVs) are spherical vesicles containing bioactive substances including lipopolysaccharides, peptidoglycans, periplasmic and cytoplasmic proteins, and nucleic acids. Emerging studies have reported various roles of OMVs in bacterial virulence, antibiotic resistance, stress adaptation, and host interactions, whereas knowledge on their roles in K. pneumoniae is currently unclear. In this review, we summarized recent progress on the biogenesis, components, and biological function of K. pneumoniae OMVs, the impact and action mechanism in virulence, antibiotic resistance, and host immune response. We also deliberated on the potential of K. pneumoniae OMVs in vaccine development, as diagnostic biomarkers, and as drug nanocarriers. In conclusion, K. pneumoniae OMVs hold great promise in the prevention and control of infectious diseases, which merits further investigation.

Cross-feeding-based rational design of a probiotic combination of Bacterides xylanisolvens and Clostridium butyricum therapy for metabolic diseases

The human gut microbiota has gained interest as an environmental factor that contributes to health or disease. The development of next-generation live biotherapeutic products (LBPs) is a promising strategy to modulate the gut microbiota and improve human health. In this study, we identified a novel cross-feeding interaction between Bacteroides xylanisolvens and Clostridium butyricum and developed their combination into a novel LBP for treating metabolic syndrome. Using in-silico analysis and in vitro experiments, we demonstrated that B. xylanisolvens supported the growth and butyrate production of C. butyricum by supplying folate, while C. butyricum reciprocated by providing pABA for folate biosynthesis. Animal gavage experiments showed that the two-strain combination LBP exhibited superior therapeutic efficacy against metabolic disorders in high-fat diet-induced obese (DIO) mice compared to either single-strain treatment. Further omics-based analyses revealed that the single-strain treatments exhibited distinct taxonomic preferences in modulating the gut microbiota, whereas the combination LBP achieved more balanced modulation to preserve taxonomic diversity to a greater extent, thereby enhancing the stability and resilience of the gut microbiome. Moreover, the two-strain combinations more effectively restored gut microbial functions by reducing disease-associated pathways and opportunistic pathogen abundance. This work demonstrates the development of new LBP therapy for metabolic diseases from cross-feeding microbial pairs which exerted better self-stability and robust efficacy in complex intestinal environments compared to conventional single-strain LBPs.

The role of cisplatin in modulating the tumor immune microenvironment and its combination therapy strategies: a new approach to enhance anti-tumor efficacy

Cisplatin is a platinum-based drug that is frequently used to treat multiple tumors. The anti-tumor effect of cisplatin is closely related to the tumor immune microenvironment (TIME), which includes several immune cell types, such as the tumor-associated macrophages (TAMs), cytotoxic T-lymphocytes (CTLs), dendritic cells (DCs), myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs), and natural killer (NK) cells. The interaction between these immune cells can promote tumor survival and chemoresistance, and decrease the efficacy of cisplatin monotherapy. Therefore, various combination treatment strategies have been devised to enhance patient responsiveness to cisplatin therapy. Cisplatin can augment anti-tumor immune responses in combination with immune checkpoint blockers (such as PD-1/PD-L1 or CTLA4 inhibitors), lipid metabolism disruptors (like FASN inhibitors and SCD inhibitors) and nanoparticles (NPs), resulting in better outcomes. Exploring the interaction between cisplatin and the TIME will help identify potential therapeutic targets for improving the treatment outcomes in cancer patients.

In vivo toxicity of chitosan-based nanoparticles: a systematic review

Chitosan nanoparticles have been extensively utilised as polymeric drug carriers in nanoparticles formulations due to their potential to enhance drug delivery, efficacy, and safety. Numerous toxicity studies have been previously conducted to assess the safety profile of chitosan-based nanoparticles. These toxicity studies employed various methodologies, including test animals, interventions, and different routes of administration. This review aims to summarise research on the safety profile of chitosan-based nanoparticles in drug delivery, with a focus on general toxicity tests to determine LD50 and NOAEL values. It can serve as a repository and reference for chitosan-based nanoparticles, facilitating future research and further development of drugs delivery system using chitosan nanoparticles. Publications from 2014 to 2024 were obtained from PubMed, Scopus, Google Scholar, and ScienceDirect, in accordance with the inclusion and exclusion criteria.The ARRIVE 2.0 guidelines were employed to evaluate the quality and risk-of-bias in the in vivo toxicity studies. The results demonstrated favourable toxicity profiles, often exhibiting reduced toxicity compared to free drugs or substances. Acute toxicity studies consistently reported high LD50 values, frequently exceeding 5000 mg/kg body weight, while subacute studies typically revealed no significant adverse effects. Various routes of administration varied, including oral, intravenous, intraperitoneal, inhalation, and topical, each demonstrating promising safety profiles.

RNase P cleavage of pseudoknot substrates reveals differences in active site architecture that depend on residue N-1 in the 5' leader

We show that a small biotin-binding RNA aptamer that folds into a pseudoknot structure acts as a substrate for bacterial RNase P RNA (RPR) with and without the RNase P C5 protein. Cleavage in the single-stranded region in loop 1 was shown to depend on the presence of a RCCA-motif at the 3' end of the substrate. The nucleobase and the 2'hydroxyl at the position immediately 5' of the cleavage site contribute to both cleavage efficiency and site selection, where C at this position induces significant cleavage at an alternative site, one base upstream of the main cleavage site. The frequencies of cleavage at these two sites and Mg2+ binding change upon altering the structural topology in the vicinity of the cleavage site as well as by replacing Mg2+ with other divalent metal ions. Modelling studies of RPR in complex with the pseudoknot substrates suggest alternative structural topologies for cleavage at the main and the alternative site and a shift in positioning of Mg2+ that activates the H2O nucleophile. Together, our data are consistent with a model where the organization of the active site structure and positioning of Mg2+ is influenced by the identities of residues at and in the vicinity of the site of cleavage.

Exploring the efficacy and constraints of platinum nanoparticles as adjuvant therapy in silicosis management

Silicosis represents a formidable occupational lung pathology precipitated by the pulmonary assimilation of respirable crystalline silica particulates. This condition engenders a cascade of cellular oxidative stress via the activation of bioavailable silica, culminating in the generation of reactive oxygen species (ROS). Such oxidative mechanisms lead to irrevocable pulmonary impairment. Contemporary scholarly examinations have underscored the substantial antioxidative efficacy of platinum nanoparticles (PtNPs), postulating their utility as an adjunct therapeutic modality in silicosis management. The physicochemical interaction between PtNPs and silica demonstrates a propensity for adsorption, thereby facilitating the amelioration and subsequent pulmonary clearance of silica aggregates. In addition to their detoxifying attributes, PtNPs exhibit pronounced anti-inflammatory and antioxidative activities, which can neutralize ROS and inhibit macrophage-mediated inflammatory processes. Such attributes are instrumental in attenuating inflammatory responses and forestalling subsequent lung tissue damage. This discourse delineates the interplay between ROS and PtNPs, the pathogenesis of silicosis and its progression to pulmonary fibrosis, and critically evaluates the potential adjunct role of PtNPs in the therapeutic landscape of silicosis, alongside a contemplation of the inherent limitations associated with PtNPs application in this context.

A surrogate BSL2-compliant infection model recapitulating key aspects of human Marburg virus disease

Marburg virus disease (MVD) is a severe infectious disease caused by the Marburg virus (MARV), posing a significant threat to humans. MARV needs to be operated under strict biosafety Level 4 (BSL-4) laboratory conditions. Therefore, accessible and practical animal models are urgently needed to advance prophylactic and therapeutic strategies for MARV. In this study, we constructed a recombinant vesicular stomatitis virus (VSV) expressing the Marburg virus glycoprotein (VSV-MARV/GP). Syrian hamsters infected with VSV-MARV/GP presented symptoms such as thrombocytopenia, lymphopenia, haemophilia, and multiorgan failure, developing a severe systemic disease akin to that observed in human MARV patients. Notably, the pathogenicity was found to be species-specific, age-related, sex-associated, and challenge route-dependent. Subsequently, the therapeutic efficacy of the MR191 monoclonal antibody was validated in this model. In summary, this alternative model is an effective tool for rapidly screening medical countermeasures against MARV GP in vivo under BSL-2 conditions.

Influences of physical stimulations on the migration and differentiation of Schwann cells involved in peripheral nerve repair

Peripheral nerve injury repair has always been a research concern of scientists. At the tissue level, axonal regeneration has become a research spotlight in peripheral nerve repair. Through transplantation of autologous nerve grafts or other emerging biomaterials functional recovery after facial nerve injury is not ideal in clinical scenarios. Great strides have been made to improve facial nerve repair at the micro-cellular level. Physical stimulation techniques can trigger Schwann cells (SCs) to migrate and differentiate into cells required for peripheral nerve repair. Classified by the sources of physical stimulations, SCs repair peripheral nerves through galvanotaxis, magnetotaxis and durotaxis. This article summarized the activation, directional migration and differentiation of SCs induced by physical stimulations, thus providing new ideas for the research of peripheral nerve repair.

Precursor of H-type II histo-blood group antigen and subterminal sialic acids on gangliosides are significantly implicated in cell entry and infection by a porcine P[11] rotavirus

Rotaviruses, non-enveloped viruses with a double-stranded RNA genome, are the leading etiological pathogen of acute gastroenteritis in young children and animals. The P[11] genotype of rotaviruses exhibits a tropism for neonates. In the present study, a binding assay using synthetic oligosaccharides demonstrated that the VP8* protein of P[11] porcine rotavirus (PRV) strain 4555 binds to lacto-N-neotetraose (LNnT) with the sequence Galβ1,4-GlcNAcβ1,3-Galβ1,4-Glc, one of the core parts of histo-blood group antigen (HBGA) and milk glycans. However, infections were significantly inhibited by blocking of endogenous monosialoganglioside (GM) GM1a with cholera toxin B subunit and preincubation of the virus with exogenous GM1a, suggesting that GM1a is involved in the infection of P[11] PRV 4555. In addition to GM1a, preincubation of the virus with exogenous disialogangliosides (GD) GD1a, GD1b, and trisialoganglioside (GT) GT1b also prevented infection. In contrast, exogenous ganglioside GM3 only inhibited infections at an early time point, and exogenous asyalosphingolipids GA1 and LacCer did not show any inhibitory effect on infections. This indicates that P[11] PRV 4555 preferentially utilizes gangliosides containing subterminal sialic acids. Further experiments revealed that P[11] PRV 4555 infections were prevented by preincubation of the virus with Neu5Ac and Neu5Gc. These results confirmed that sialic acids are essential for P[11] PRV 4555 cell entry, despite the classification as NA-resistant strain. Overall, our results proved that P[11] rotavirus not only binds to the Gal-GlcNAc motif but also utilizes gangliosides containing subterminal sialic acids.

Identifying sex-based disparities in porcine mitochondrial function

In pigs, the effect of sex on production and reproductive traits has been largely reported, however, whether sex exerts its influence through regulating mitochondrial function is still unclear. In this study, we constructed 15 male cells and 15 female fibroblasts derived from 35-day and 50-day fetuses, newborn piglets and 1-year-old pigs to identify the sex effect on mitochondrial functions. Results indicated significant differences on cellular and molecular characteristics between male and female cells, including energy metabolic trait, mitochondrial DNA (mtDNA) replication and transcription, and mRNA expressions of mitochondrial biogenesis genes and mitoprotease genes. Referring to sex, males exhibited significantly higher oxygen consumption rate productions, levels of reactive oxygen species (ROS) and mtDNA copy numbers than those with females in muscle and ear fibroblasts. And the expressions of mtDNA, mitochondrial biogenesis genes (POLG, PPARGC1A, TFAM and TWNK) and XPNPEP3 were higher in males than females in ear fibroblasts derived from 1-year-old adult pigs (EFA cells). While, the cell proliferation and expressions of genes related to ROS metabolism were not influenced by sex. The results highlight the effect of sex on mitochondrial function and gene expression, and provide important data for a comprehensive understanding of the mechanisms underlying sex regulation of energy metabolism-related traits in pigs.

Caspase 3-specific cleavage of ubiquitin-specific peptidase 48 enhances drug-induced apoptosis in AML

Dysfunction or dysregulation of deubiquitination is closely related to the initiation and development of multiple cancers. Targeted regulation of deubiquitination has been recognized as an important strategy in tumor therapy. However, the mechanism by which drugs regulate deubiquitinase is not clear. Here, we identified ubiquitin-specific peptidase 48 (USP48), a member of the ubiquitin-specific protease family highly expressed in various tumors, as a specific substrate for the activated caspase-3. During drug induced apoptosis of AML cells, activated caspase-3 cleaves USP48 through recognizing the conservative motif DEQD located at 611-614 sites of human USP48. Subsequent analysis showed that the cleavage USP48 N-terminal fragment which contains catalytic active domain is easily degraded by ubiquitination. Meanwhile knockdown experiment showed that inhibiting the expression of USP48 could also promotes apoptosis and enhance the efficacy of chemotherapy drugs. Altogether, these results suggest that targeting USP48 may represent a novel therapeutic strategy in AML.

Orally-deliverable liposome-microgel complexes dynamically remodel intestinal environment to enhance probiotic ulcerative colitis therapy via TLR4 inhibition and tryptophan metabolic crosstalk

Probiotics emerges as a promising option for ulcerative colitis (UC) treatment, but its application remains challenging due to insufficient colon-targeted delivery efficiency and survival against the inflammation-associated intestinal oxidative stress. To address these issues, here we report a supramolecular liposome-microgel complex (SLMC) incorporated with Bacillus subtilis spores (BSSs) and dexamethasone (DEX) for orally-deliverable probiotic UC therapy. Specifically, BSSs and cholesterols were conjugated with gelatin via diselenide ligation to prepare microgels, followed by supramolecular complexation with UC-targeted DEX-loaded liposome via microfluidic engineering. The orally-administered SLMC efficiently accumulated in UC-affected colonic sites to release BSSs and DEX. DEX elicited rapid anti-inflammatory effect to reduce ROS generation, which cooperated with the ROS consumption by spore germination and diselenide cleavage to orchestrate an anaerobic intestinal microenvironment, thus promoting Bacillus subtilis colonization to restore gut homeostasis and initiate anti-inflammatory microbiota-macrophage metabolic crosstalk. Indeed, in vivo analysis showed that the SLMC treatment markedly inhibited pro-inflammatory TLR4-NF-κB signaling activities in mucosal macrophages through localized DEX delivery and boosting tryptophan metabolite production, leading to robust and durable UC abolishment. This study offers a practical approach for improving UC treatment in the clinic.

Optimal structural characteristics of osteoinductivity in bioceramics derived from a novel high-throughput screening plus machine learning approach

Osteoinduction is an important feature of the next generation of bone repair materials. But the key structural factors and parameters of osteoinductive scaffolds are not yet clarified. This study leverages the efficiency of high-throughput screening in identifying key structural factors, performs screening of 24 different porous structures using 3D printed calcium phosphate (CaP) ceramic scaffolds. Based on in vitro and in vivo evaluations, along with machine learning and nonlinear fitting, it explores the complex relationship between osteoinductive properties and scaffold configurations. Results indicate that bone regenerative ability is largely affected by porosity and specific surface area (SSA), while pore geometry has a negligible effect. The optimal structural parameters were identified as a porous structure with SSA of 10.49-10.69 mm2 mm-3 and permeability of 3.74 × 10-9 m2, which enhances osteoinductivity and scaffold properties, corresponding to approximately 65 %-70 % porosity. Moreover, nonlinear fitting reveals specific correlations among SSA, permeability and osteogenic gene expressions. We established a data-driven high-throughput screening methodology and proposed a parametric benchmark for osteoinductive structures, providing critical insights for the design of future osteoinductive scaffolds.

STING-activating layered double hydroxide nano-adjuvants for enhanced cancer immunotherapy

Cancer vaccines represent a promising therapeutic strategy in oncology, yet their effectiveness is often hampered by suboptimal antigen targeting, insufficient induction of cellular immunity, and the immunosuppressive tumor microenvironment. Advanced delivery systems and potent adjuvants are needed to address these challenges, though a restricted range of adjuvants for human vaccines that are approved, and even fewer are capable of stimulating robust cellular immune response. In this work, we engineered a unique self-adjuvanted platform (MLDHs) by integrating STING agonists manganese into a layered double hydroxide nano-scaffold, encapsulating the model antigen ovalbumin (OVA). The MLDHs platform encompasses Mn-doped MgAl-LDH (MLMA) and Mn-doped MgFe-LDH (MLMF). Upon subcutaneous injection, OVA/MLDHs specifically accumulated within lymph nodes (LNs), where they were internalized by resident antigen-presenting cells. The endosomal degradation of MLDHs facilitated the cytoplasmic release of antigen and Mn2+, promoting cross-presentation and triggering the STING pathway, which in turn induced a potent cellular immune response against tumors. Notably, OVA/MLMF induced stronger M1 macrophage polarization and a more potent T-cell response within tumor-infiltrating lymphocytes compared to OVA/MLMA, leading to significant tumor regression in B16F10-OVA bearing mice with minimal adverse effects. Additionally, combining MLMF with the vascular disrupting agent Vadimezan disrupted the tumor's central region, typically resistant to immune cell infiltration, further extending survival in tumor-bearing mice. This innovative strategy may show great potential for improving cancer immunotherapy and offers hope for more effective treatments in the future.

A functional cardiac patch with "gas and ion" dual-effect intervention for reconstructing blood microcirculation in myocardial infarction repair

Postinfarction revascularization is critical for repairing the infarcted myocardium and for stopping disease progression. Considering the limitations of surgical intervention, engineered cardiac patches (ECPs) are more effective in establishing rich blood supply networks. For efficacy, ECPs should promote the formation of more mature blood vessels to improve microcirculatory dysfunction and mitigate hypoxia-induced apoptosis. Developing collateral circulation between infarcted myocardium and ECPs for restoring blood perfusion remains a challenge. Here, an ion-conductive composite ECPs (GMA@OSM) with powerful angiogenesis-promoting ability was constructed. Based on dual-effect intervention of oxygen and strontium, the developed ECPs can promote the formation of high-density circulating microvascular network at the infarcted myocardium. In addition, the GMA@OSM possesses effective reactive oxygen species-scavenging capacity and can facilitate electrophysiological repair of myocardium with ionic conductivity. In vitro and in vivo studies indicate that the multifunctional GMA@OSM ECPs form well-developed collateral circulation with infarcted myocardium to protect cardiomyocytes and improve cardiac function. Overall, this study highlights the potential of a multifunctional platform for developing collateral circulation, which can lead to an effective therapeutic strategy for repairing myocardial infarction.

Improved immunocompatibility of active targeting liposomes by attenuating nucleophilic attack of cyclic RGD peptides on complement 3

One of the challenges for the clinical translation of active targeting nanomedicines is the adverse interactions between targeting ligands and blood components. Herein, a novel regularity, which reveals the interactions between cyclic RGD (Arg-Gly-Asp) peptide-modified liposomes and complement components in blood, is reported. As the nucleophilicity of arginine guanidine group within the cyclic RGD-like peptide increases, targeting liposomes potentiate complement cascade via the amplification loop of complement 3 (C3), ultimately leading to accelerated blood clearance, increased deposition in the reticuloendothelial system (RES) organs, enhanced immune responses, and potential side effects. By appropriately reducing the nucleophilicity of guanidine group, cyclic R2 peptide is designed for modification of liposomes to target integrin αvβ3. Compared to the widely used targeting molecule c(RGDyK), R2 eliminates the negative effects of C3 opsonization and specific antibody production, significantly improves the in vivo immunocompatibility of targeting liposomes, and demonstrates superior anti-tumor efficacy in mouse models of orthotopic breast cancer and glioma. Thus, the proposed regularity of interactions between guanidine nucleophilicity and C3, along with the successful application of the low complement activation capacity targeting ligand R2, provides new insights for addressing challenges related to complement activation in the clinical translation of active targeting nanomedicines.

Multifunctional albumin-based hydrogel/microglia composites enhancing the therapeutic potential of neonatal microglia in complex spinal cord injuries and sealing dural rupture

Treatment for spinal cord injuries (SCIs) remains largely ineffective, with scar formation and neural degeneration being major barriers to functional recovery. Neonatal microglia have shown potential in reducing scar formation and promoting axonal regrowth. However, cell viability and retention at the injury site are often suboptimal. The hostile post-SCI inflammatory microenvironment leads to poor cell survival and the dural damage that is frequently associated with SCIs results in cell loss. To address these challenges, we have developed an albumin-based hydrogel. This hydrogel creates a favorable microenvironment for the encapsulated cells, mimicking the extracellular matrix and enhancing the viability of the transplanted cells. In vivo studies demonstrate its efficacy in preventing scar formation, promoting axonal regeneration, and sealing the dura. Importantly, this hydrogel leverages albumin, a natural polymer in the body, and is synthesized through a simple process, making it highly feasible for clinical translation. In summary, this albumin hydrogel is a valuable delivery vehicle that enhances the therapeutic potential of neonatal microglia in treating SCIs, particularly those involving dural rupture.

Pyroptosis, ferroptosis, and autophagy in spinal cord injury: regulatory mechanisms and therapeutic targets

Regulated cell death is a form of cell death that is actively controlled by biomolecules. Several studies have shown that regulated cell death plays a key role after spinal cord injury. Pyroptosis and ferroptosis are newly discovered types of regulated cell deaths that have been shown to exacerbate inflammation and lead to cell death in damaged spinal cords. Autophagy, a complex form of cell death that is interconnected with various regulated cell death mechanisms, has garnered significant attention in the study of spinal cord injury. This injury triggers not only cell death but also cellular survival responses. Multiple signaling pathways play pivotal roles in influencing the processes of both deterioration and repair in spinal cord injury by regulating pyroptosis, ferroptosis, and autophagy. Therefore, this review aims to comprehensively examine the mechanisms underlying regulated cell deaths, the signaling pathways that modulate these mechanisms, and the potential therapeutic targets for spinal cord injury. Our analysis suggests that targeting the common regulatory signaling pathways of different regulated cell deaths could be a promising strategy to promote cell survival and enhance the repair of spinal cord injury. Moreover, a holistic approach that incorporates multiple regulated cell deaths and their regulatory pathways presents a promising multi-target therapeutic strategy for the management of spinal cord injury.

Strategies to enhance the penetration of nanomedicine in solid tumors

Nanomedicine was previously regarded as a promising solution in the battle against cancer. Over the past few decades, extensive research has been conducted to exploit nanomedicine for overcoming tumors. Unfortunately, despite these efforts, nanomedicine has not yet demonstrated its ability to cure tumors, and the research on nanomedicine has reached a bottleneck. For a significant period of time, drug delivery strategies have primarily focused on targeting nanomedicine delivery to tumors while neglecting its redistribution within solid tumors. The uneven distribution of nanomedicine within solid tumors results in limited therapeutic effects on most tumor cells and significantly hampers the efficiency of drug delivery and treatment outcomes. Therefore, this review discusses the challenges faced by nanomedicine in penetrating solid tumors and provides an overview of current nanotechnology strategies (alleviating penetration resistance, size regulation, tumor cell transport, and nanomotors) that facilitate enhanced penetration of nanomedicine into solid tumors. Additionally, we discussed the potential role of nanobionics in promoting effective penetration of nanomedicine.

Engineering adeno-associated viral vectors for CRISPR/Cas based in vivo therapeutic genome editing

The recent approval of the first gene editing therapy for sickle cell disease and transfusion-dependent beta-thalassemia by the U.S. Food and Drug Administration (FDA) demonstrates the immense potential of CRISPR (clustered regularly interspaced short palindromic repeats) technologies to treat patients with genetic disorders that were previously considered incurable. While significant advancements have been made with ex vivo gene editing approaches, the development of in vivo CRISPR/Cas gene editing therapies has not progressed as rapidly due to significant challenges in achieving highly efficient and specific in vivo delivery. Adeno-associated viral (AAV) vectors have shown great promise in clinical trials as vehicles for delivering therapeutic transgenes and other cargos but currently face multiple limitations for effective delivery of gene editing machineries. This review elucidates these challenges and highlights the latest engineering strategies aimed at improving the efficiency, specificity, and safety profiles of AAV-packaged CRISPR/Cas systems (AAV-CRISPR) to enhance their clinical utility.

Bioengineered metastatic cancer nanovaccine with a TLR7/8 agonist for needle-free intranasal immunization

Recent outbreaks and the global spread of infectious diseases increased the need for the development of mucosal vaccines because of their ability to induce both an antigen-specific humoral and cellular immune response. Vaccines are commonly administered via a systemic route which is ineffective at inducing mucosal immunity. Therefore, developing mucosal vaccines is necessary to prevent and treat diseases that could not only elicit mucosal immune responses but also facilitate mass vaccination via a needle-free approach. Despite the benefits of mucosal vaccines, inducing mucosal immunity remains difficult due to the low antigen stability at mucosal sites. Herein, we developed a co-delivery platform using a polymeric nanoparticle carrier to upregulate the immune responses by improving the antigen's stability. Through hydrophobic and ionic interactions, the cationic polymeric nanoparticle composed of secondary bile acid conjugated polyethyleneimine (DA3) can load both TLR7/8 agonist resiquimod (R848) and anionic ovalbumin (OVA) antigen. The DA3/R848/OVA nanovaccine based co-delivery system can boost immune responses through binding affinity with dendritic cells (DCs). The results showed that DA3/R848/OVA could activate DCs better than OVA or OVA + R848. Furthermore, the nanovaccine demonstrated a strong therapeutic effect by significantly suppressing tumor growth in a B16-OVA melanoma model. Additionally, prophylactic immunization with the nanovaccine effectively induced immunological memory, leading to sustained tumor suppression upon challenge. Intranasal delivery of DA3/R848/OVA upregulates the antitumor effect in the metastatic lung tumor foci and the survival rates. These results suggest that intranasal immunization using the DA3/R848/OVA nanovaccine can promote needle-free vaccination.

Ultrasound-activated sonothermal-catalytic synergistic therapy via asymmetric electron distribution for bacterial wound infections

Antibiotic-resistant bacterial infections present a growing global health challenge, requiring innovative therapeutic solutions to overcome current limitations. We introduce boron-integrated bismuth oxide (B-BiO2) nanosheets with an asymmetrically distributed electronic structure for ultrasound-activated synergistic sonothermal and catalytic therapy. Boron incorporation enhances local electron density distribution, optimizing charge separation and significantly improving sonothermal and catalytic efficiency, as validated by density functional theory calculations. These nanosheets exhibit dual functionality, effectively generating localized heat and reactive oxygen species (ROS) under ultrasound, leading to 99.999 % antibacterial efficacy against multidrug-resistant pathogens by disrupting bacterial membranes, as demonstrated through all-atom simulations and in vitro experiments. The simulations further reveal that sonothermal conversion effects enhance bacterial membrane fluidity and induce structural defects, amplifying ROS-induced oxidative damage and membrane destabilization. In vivo, B-BiO2 nanosheets accelerate wound healing in methicillin-resistant Staphylococcus aureus (MRSA)-infected murine models, achieving 99.8 % closure by day 14 by reducing inflammation and promoting angiogenesis and tissue regeneration. Transcriptomic analysis highlights the activation of extracellular matrix remodeling, angiogenesis, and autophagy pathways, underscoring the nanosheets' therapeutic potential. This study establishes ultrasound-activated B-BiO2 nanosheets as a novel nanotherapeutic platform, leveraging asymmetric electron distribution to synergistically combat drug-resistant infections and promote effective wound healing.

Time-resolved T1 and T2 contrast for enhanced accuracy in MRI tumor detection

Stimuli-responsive contrast agents (CAs) have shown great promise in enhancing magnetic resonance imaging (MRI) for more accurate tumor diagnosis. However, current CAs still face challenges in achieving high accuracy due to their low specificity and contrast signals being confounded by potential endogenous MRI artifacts. Herein, an extremely small iron oxide nanoparticle (ESIONP)-based smart responsive MRI contrast agent (LESPH) is proposed, which is meticulously designed with sequential dual biochemical stimuli-initiated, time-resolved T1 and T2 contrast presentation, ensuring high tumor specificity while minimizing interference from endogenous artifacts. LESPH is constructed using emulsion solvent evaporation by assembling poly(2-(hexamethyleneimino) ethyl methacrylate) terminally conjugated with a disulfide bond-linked catechol group (DSPH)-modified ESIONPs, with lauryl betaine serving as a surfactant. When LESPH undergoes sequential responses to the weak acidity and high-concentration glutathione (GSH) in the tumor microenvironment, it experiences an extremely rapid transition from sparse ESIONP assemblies to dispersed ESIONPs, followed by a slower transition to closely aggregated ones, concomitantly providing distinguishable brightening and darkening contrast enhancement at the tumor location on different time scales. By virtue of its sequential dual responsiveness and time-resolved distinguishable contrast enhancements, LESPH successfully detects tumors with extremely high accuracy, providing a novel paradigm for the precise medical diagnosis of cancer.

Immunomodulatory bioadhesive technologies

Bioadhesives have found significant use in medicine and engineering, particularly for wound care, tissue engineering, and surgical applications. Compared to traditional wound closure methods such as sutures and staples, bioadhesives offer advantages, including reduced tissue damage, enhanced healing, and ease of implementation. Recent progress highlights the synergy of bioadhesives and immunoengineering strategies, leading to immunomodulatory bioadhesives capable of modulating immune responses at local sites where bioadhesives are applied. They foster favorable therapeutic outcomes such as reduced inflammation in wounds and implants or enhanced local immune responses to improve cancer therapy efficacy. The dual functionalities of bioadhesion and immunomodulation benefit wound management, tissue regeneration, implantable medical devices, and post-surgical cancer management. This review delves into the interplay between bioadhesion and immunomodulation, highlighting the mechanobiological coupling involved. Key areas of focus include the modulation of immune responses through chemical and physical strategies, as well as the application of these bioadhesives in wound healing and cancer treatment. Discussed are remaining challenges such as achieving long-term stability and effectiveness, necessitating further research to fully harness the clinical potential of immunomodulatory bioadhesives.

A computational study of the aqueous pertechnetate anion: Elucidation of the hydration structure and spectroscopic properties

A computational study of the TcO4- anion in water has been carried out, the study includes an analysis of the structure of the solvation shells, the hydration energy and the electronic transitions that affect the shape of the UV-Vis absorption spectrum. The solvated system was characterized by combined QM/MM molecular dynamics simulations. The second-order perturbation theory restricted active space method and the novel self-consistent field density matrix renormalization group approach were employed to describe the static correlation. Two distinct solvation shells were found with 24 and 65 water molecules, respectively. The water molecules surrounding the anion have a general orientation in which one hydrogen is oriented away from the oxyanion while the remaining atoms are at a similar distance. However, there are specific water molecules that form hydrogen bonds with the oxygens of the oxyanion, while others are oriented with their oxygen atom towards the anion. The observed excitations in the UV-Vis spectrum are of a T2 character, with the main source of the observed behavior being the charge transfer from oxygen atoms to the central technetium atom. The calculations show that the most intense band of the spectrum is broader and has a blue tail with respect to the gas phase spectrum. This difference is due to the lower symmetry caused by the aqueous environment, which allows different states to mix and leads to broadening of the band.

A novel fluorescent sensor for imaging of viscosity and ClO- in plant cells and zebrafish

Viscosity and hypochlorite (ClO-) are two crucial microenvironmental species that play significant roles in biological activities. Their abnormal levels are closely associated with numerous common diseases. Therefore, accurate and real-time detection of hypochlorite and viscosity related to inflammatory microenvironment conduces to elucidate the pathogenesis and further diagnose the disease. In this work, based on the strategy of the phenothiazine (PTZ)-dicyanoisophorone (DCO) dyad system, a new dual-response fluorescent sensor (PBI) was successfully constructed for the simultaneous detection and visualization of viscosity and hypochlorite (ClO-) both in vitro and in vivo. The free sensor emits weak fluorescence in aqueous solution thanks to twisted intramolecular charge transfer (TICT) and photoinduced electron transfer (PET). However, in a high-viscosity system, the fluorescence emission of the sensor at 459 nm was significantly enhanced. Upon introduction of ClO- in aqueous buffer solution, the PBI exhibited apparent fluorescence enhancement at 577 nm, and showed large Stokes shift (177 nm). The fluorescence responsive mechanism was confirmed using HRMS, 1H NMR and DFT calculation analysis. Onion and lotus root cells imaging of PBI towards ClO- was implemented. Furthermore, PBI has been successfully applied to the fluorescence imaging of viscosity and exogenous/endogenous hypochlorite in zebrafish.

Surface-enhanced Raman spectroscopy facilitates the detection of multiple metabolic modulators

Metabolic regulators can improve the athletic ability of athletes by regulating body metabolism, but it is not conducive to fair competition, so it is listed as a prohibited substance. At the same time, the State General Administration of Sport ordered major event organizers to test food for food-borne stimulants. Surface-enhanced Raman scattering (SERS) spectroscopy has been widely used because of its excellent sensitivity and strong spectral characteristics. Based on the available information, SERS spectrum data of metabolic regulators in food-related fields were lacking. In this study, we used gold dodecahedron nanoparticles as SERS active substrate and successfully captured the characteristic peaks of 6 metabolic regulatory factors. A low cost and stable SERS detection technique for detecting trimetazidine in milk samples with good recovery rate was proposed. Therefore, this method can not only protect the food safety of large-scale sports events, but also have broad application prospects in the food field.

Water-stable Ag (Ⅰ) coordination polymer sensors to selectively and sensitively detect the chlortetracycline via fluorescence red-shift and turn-on effect

The antibiotic residue resulting from the abuse and overuse of antibiotics has threatened food safety and the environment. Establishing new detection strategies for antibiotic residues in food and the environment is necessary. A "turn-on" fluorescence sensor-[Ag(BIX)]n⋅ n(HBA) (Ag-CP)(BIX = 1,4-bis(imidazole-1-ylmethyl) benzene, BA = benzoic acid) was constructed herein using a convenient one-pot strategy. The ample benzene ring, imidazole ring, and free BA of Ag-CP provide the specific interaction sites for the interaction between the fluorescence sensor and the target. Due to its excellent chemical and fluorescent properties, it has been used to detect Chlortetracycline (CTC) sensitively. To our knowledge, Ag coordination polymer has not been previously reported for the detection of CTC. It is worth mentioning that the fluorescent intensity of Ag-CP remarkably enhances and the wavelength of the emission peak is red-shifted under the synergistic effect between the CTC and Ag-CP. Selectivity and sensitivity for detecting the CTC have been achieved over the concentration from 0.05 μM to 100 μM, along with the good linear fitting (R2 ≥ 0.9690) and the low limit of detection (34 nm). The recovery percentage in spiked food samples was assessed to be 84.12-96.82 %, and the RSD is less than 4.75 %. These results manifested that the Ag-CP-based fluorescence sensor, validated by the HPLC, represented good sensitivity and high precision. Therefore, our work reveals the advantages of coordination polymer-based fluorescence sensors and puts forward a novel strategy for the detection of antibiotic residues in food safety.

Rod-like D-π-A-π-D Schiff base liquid crystal for continuous ion sensing, live cell imaging, fingerprint imaging and WLED

A series of rod-like D-π-A-π-D Schiff base liquid crystals were synthesized, featuring a BTD central acceptor unit connected to N-trialkoxybenzyl carbazole terminal donor groups through imine linkages at both ends. The series includes hydroxyl-containing derivatives BOH/n (n = 12, 14, 16), hydroxyl-free BH/12, and the corresponding boron complex BOB/12 derived from BOH/12. Among them, BOH/n can self-assemble into the Colrec/c2mm LC phase, while BH/12 can self-assemble into the Colrec/p2mm LC phase, and boron complex BOB/12 can self-assemble into the Colhex/p6mm LC phase. Further compound BOH/n can self-assemble into a luminescent organic gel in organic solvents with wrinkled sheet morphologies. Photophysical studies revealed that all compounds showed J-aggregation form. All compounds except BOB/12 exhibited the AIEE effect. The fluorescence quantum yield in solution and the absolute solid quantum yield of BOB/12, reached as high as 85 % and 41 % respectively which is 14 and 3 times higher than those of the corresponding BOH/12. Based on the ion recognition result of BOH/12, a non-conventional sequential detection method for the identification sequence of Fe3+-Cu2+-Al3+ was constructed and applied successfully as test paper detection. Additionally, BOH/12 was successfully utilized as live cell imaging, potential fingerprint imaging, and white light emitting devices (WLED).

Mitochondria-targeted and near-infrared phosphorescent Ir(III) complexes for specific detection of Hg2+ and photodynamic therapy

S: Mercury ions (Hg2+) are highly toxic and prone to bioaccumulation, showing a strong attraction to proteins and enzymes that contain sulfur. Even minute quantities of Hg2+ can lead to severe health issues. Given that mitochondria are a primary target organelle of Hg2+, it is essential to create a probe that can accurately detect Hg2+ within intracellular mitochondria. In this study, we developed two innovative Ir(III) complex probes that emit near-infrared light. The crystal structure of Ir2 was determined using X-ray techniques, which reveals that Ir2 contains a pyridine group capable of recognizing Hg2+ and targeting mitochondria, allowing for the precise identification of Hg2+ both in vitro and within the mitochondria of living cells. Additionally, these two novel near-infrared phosphorescent Ir(III) complexes demonstrate significant capabilities in producing ROS including singlet oxygen, ·O2- and ·OH, which renders them effective photosensitizers under visible light exposure for photodynamic therapy (PDT). This research offers a promising approach for detecting Hg2+ in vitro and in the mitochondrial microenvironment of living cells, which have some implications for the future development of pertinent transition metal complexes for mitochondria-targeted photodynamic therapy in cancer cells.

Synthesis and spectroscopic analysis of TiO2:Dy3+ phosphor for optical and pharmaceutical applications

The emerging nanomaterial based on titanium dioxide with a series of Dy3+-doped TiO2 nanoparticles were synthesized first time using solvothermal method. X-ray diffraction (XRD) analysis confirmed an anatase-type tetragonal structure (space group I41/amd) with successful incorporation of dysprosium into the TiO2 lattice. Scanning Electron Microscopy (SEM) characterized the morphology and particle size, while Raman spectroscopy further validated the formation of TiO2 nanoparticles and highlighted the influence of Dy3+ doping on phase stability. The luminescence properties of Dy3+-TiO2 were analyzed using photoluminescence (PL) spectroscopy, revealing an intense emission peak at 575 nm under 450 nm excitation (⁶H15/2 → 4I15/2).Normally dysprosium doping results in characteristic emissions in the blue (480 nm), yellow (575 nm), and red (670 nm) regions but this work highlights unexpected single broad emission peak at 575 nm, attributed to the Dy3+ incorporation in a low-symmetry local site. Furthermore, Dy3+-doped TiO2 dispersed in ethanol exhibited enhanced photo oxidation under UV-Vis light irradiation, leading to a significant increase in PL intensity. This study provides valuable insights into the luminescence properties of Dy3+-doped TiO2, offering potential applications in imaging, sensing, and pharmaceutics.

Rational design of dual-state emission fluorophores for sensing nitro explosives by using sulfone unit as an electron acceptor in D-A system

Dual-state emission (DSE) fluorescent molecules have become the preferred type in designing sensing fluorescent molecules due to the virtue of their bright emission in both solid and liquid states. In this study, five D-A molecules were successfully designed and synthesized according to the design concept that structural modification of D-A molecules can lead to DSE molecules. Among them, the balance between the electron donor with a strong electron donation capacity and the twisted conformation in the whole molecule makes the compounds 3c-3e DSE molecules with excellent optical performances, showing significant solvatochromic effects and large Stoke shifts. In addition, the feasibility of the sulfone unit as an electron acceptor in the D-A structure is also verified, extending the application of sulfone group in the field of fluorescence. Interestingly, the fluorescence of 3c can exhibit sensitive and selective quenching of nitro aromatic compounds (NACs) under the synergistic mechanism of fluorescence resonance energy transfer (FRET) and photoinduced electron transfer (PET), with LOD as low as 10-8 M and KSV as high as 104 M-1. Furthermore, the selective, efficient, and sensitive detection of NACs by DSE fluorescent molecule 3c in real aqueous samples and loaded on test strips has demonstrated the potential of its practical applications.

A novel coumarin-incorporated lanthanide coordination nanoprobe for ratiometric sensing of tetracycline

Tetracycline (Tc), a broad-spectrum antibiotic for treating bacterial infections, poses significant risks to human health and the environment. This study presents a novel lanthanide coordination probe, AMP/Eu/CMP, for the ratiometric detection of Tc. The pyridine-appended coumarin derivative, CMP, acting as a stable internal reference, combines with AMP and Eu3+ to form the robust ratiometric probe AMP/Eu/CMP. Upon binding to Tc, Eu3+ fluorescence (emission at 616 nm) is sensitized while CMP fluorescence (emission at 505 nm) remains unchanged, resulting in a clear fluorescence shift from blue-green to red, enabling effective ratiometric detection of Tc. By integrating a smartphone color recognition app, rapid and visual detection of tetracycline concentrations is achieved. Additionally, paper-based test strips were developed for on-site Tc detection, exhibiting a linear response across a wide concentration range, making this method suitable for applications in food safety, pharmaceutical analysis, and environmental monitoring. The use of a fluorescent molecule with unique photophysical properties as an internal reference enables the construction of a high-performance, ratiometric lanthanide coordination polymer probe that is rapid, simple, and cost-effective, providing valuable insights for the development of future fluorescence sensors.

Bimetallic SERS platform with femtomolar sensitivity for in situ monitoring of catalytic reactions

We developed a gold-silver bimetallic surface-enhanced Raman scattering (SERS) chip (AuNPs@AuAg NSs island array chip) that combines excellent SERS enhancement with in situ catalytic properties. This platform exhibits superior plasmonic catalytic capabilities, enabling rapid in situ monitoring of redox reactions without the need for chemical reductants. Additionally, under simulated sunlight, the chip achieved effective degradation of methylene blue (MB) molecules, with a removal rate of 95.65 %, demonstrating its potential for environmental safety applications. The chip's uniform and dense SERS hotspots allow for the detection of pollutants at extremely low concentrations (as low as 10-15 M), offering a powerful tool for trace-level detection of hazardous substances. This work highlights the potential of such nanostructures for in situ monitoring of catalytic reactions and pollutant degradation, as well as for rapid, non-destructive, and high-throughput detection of ultra-low concentrations of analytes.

A smart photosensitive fluorescent probe for sensing Co2+ in extremely alkaline aqueous solution

A novel pH-, viscosity-, and photo-sensitive polymorphic fluorescence probe NHP for sensing Co2+ has been developed. The hydrazone-based NHP can be synthesized by only one step of reflux reaction and purified by washing with poor solvents. Three single crystals of NHP-1, NHP-2, and NHP-3 with different conformations were resolved. As a photo acid generator (PAG), the hydrogen atom on the imino group of the probe NHP can be shed with 365 nm ultraviolet (UV) light illumination or in alkaline conditions. Due to the above two conditions, the negatively charged ligand obtained after dehydrogenation of NHP can accelerate its chelation with Co2+. When irradiated with 365 nm UV light, the product (NHP2-Co2+ (I)) of NHP chelating with Co2+ appears yellowish in aqueous solution. In a strong alkali aqueous solution, the chelate product (NHP2-Co2+ (II)) of NHP and Co2+ showed bright blue-green fluorescence. The formed divalent Co(II) complex NHP2-Co2+ can be oxidized to trivalent Co(III) complex NHP3-Co3+, as confirmed by the resolution of single crystals of NHP3-Co3+.

The enhanced excited-state intramolecular proton transfer energy barrier of flavonols induced by deprotonation

The barrierless excited-state intramolecular proton transfer (ESIPT) is believed to account for the non-radiative decays of flavonols composed of 5-hydroxyl group. However, the ESIPT mechanisms of flavonol anions have never been elucidated. In this work, by using the time-dependent density functional theory (TDDFT) calculations, we have determined the barrierless ESIPT in kaempferol and galangin, in agreement with their non-emissive properties. In contrast, deprotonation at the position 7 of them is demonstrated to decrease the basicity of proton acceptor and acidity of proton donor in the excited state, largely increasing the ESIPT barrier and leading to the fluorescence emission from the normal state. A further deprotonation of mono-deprotonated kaempferol is inferred to induce blue shifted emission. These results elucidate the nature of emissive flavonol anions and give a deep insight into the optical properties of flavonols in different matrices.

Theoretical and experimental spectroscopic analysis of new phenanthrene based compounds for organic solar cell device

This paper presents a combined theoretical and experimental spectroscopic investigation of new phenanthrene derivative compounds, having some new remarkable structural features. Their chemical synthesis was achieved by efficient Mizoroki-Heck coupling. The corresponding properties, including UV-Vis absorption, photoluminescence, thermal stability and electrochemistry data, were deeply elucidated and presented. Besides, theoretical geometry optimization and different simulated spectra were performed via Density Functional Theory (DFT) method, in which both the gas and liquid phases characteristic are elucidated. A representative set of electrons donating groups (methoxy) and withdrawing groups (cyano) are introduced in the main chemical backbone, to elucidate the role of lateral and side backbone substituents. Overall, the theoretical calculation was carried to examine some fundamental parameters: electric dipole moment (μ), EHOMO, ELUMO, electronegativity (χ), global chemical hardness (η), global softness (σ), matched the experimental measurements, showing a good correlation. Among them, some useful information about the interaction of these organic systems with surfaces of SWCNT has been calculated through conceptual DFT. The C2:SWCNT(5,5) molecular blend with two different orientations to the nanotube axis, as active layer for conventional solar cell device, has been investigated. The characteristic parameters of the active layer and the device were consolidated by TD-DFT computational data and SILVACO-ATLAS software simulation results. Compatible energy models have been proposed simulating the electric response and band diagram of such optoelectronic devices.