JARID2 activation by NFYA promotes stemness of triple-negative breast cancer cells through the PI3K/AKT pathway.

BACKGROUND: This study aimed to investigate the role of Jumonji AT Rich Interacting Domain 2 (JARID2) in regulating triple-negative breast cancer (TNBC) stemness and its mechanism. RESEARCH DESIGN AND METHODS: Bioinformatics analysis examined JARID2 expression, prognosis, and transcription factors. Quantitative polymerase chain reaction, western blot, and immunohistochemistry detected expression. Dual luciferase reporter gene and chromatin immunoprecipitation assays verified binding. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and colony formation assay detected viability and proliferation. Sphere formation assay detected the sphere formation efficiency. Flow cytometry detected CD44+/CD24- -marked stem cells. A xenograft tumor model verified the effect of JARID2 in vivo. RESULTS: JARID2 and nuclear transcription factor Y subunit α (NFYA) were upregulated in TNBC tissues and positively correlated. Knockdown of JARID2 or NFYA inhibited cell stemness by inhibiting the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/AKT) signaling pathway. Enforced JARID2 expression rescued the suppressive effect of NFYA knockdown on the PI3K/AKT signaling pathway and cell stemness. Knockdown of JARID2 inhibited tumor growth and cell stemness in mice but was alleviated by concurrent overexpression of NFYA. CONCLUSIONS: NFYA promotes TNBC cell stemness by upregulating JARID2 expression and regulating the PI3K/AKT signaling pathway, suggesting JARID2 as a potential target for innovating drugs that target TNBC stem cells.

Piezoelectric Bilayer Nickel-Iron Layered Double Hydroxide Nanosheets with Tumor Microenvironment Responsiveness for Intensive Piezocatalytic Therapy.

Piezocatalytic therapy (PCT) based on 2D layered materials has emerged as a promising non-invasive tumor treatment modality, offering superior advantages. However, a systematic investigation of PCT, particularly the mechanisms underlying the reactive oxygen species (ROS) generation by 2D nanomaterials, is still in its infancy. Here, for the first time, biodegradable piezoelectric 2D bilayer nickel-iron layered double hydroxide (NiFe-LDH) nanosheets (thickness of ≈1.86 nm) are reported for enhanced PCT and ferroptosis. Under ultrasound irradiation, the piezoelectric semiconducting NiFe-LDH exhibits a remarkable ability to generate superoxide anion radicals, due to the formation of a built-in electric field that facilitates the separation of electrons and holes. Notably, the significant excitonic effect in the ultrathin NiFe-LDH system enables long-lived excited triplet excitons (lifetime of ≈5.04 µs) to effectively convert triplet O2 molecules into singlet oxygen. Moreover, NiFe-LDH exhibited tumor microenvironment (TME)-responsive peroxidase (POD)-like and glutathione (GSH)-depleting capabilities, further enhancing oxidative stress in tumor cells and inducing ferroptosis. To the best of knowledge, this is the first report on piezoelectric semiconducting sonosensitizers based on LDHs for PCT and ferroptosis, providing a comprehensive understanding of the piezocatalysis mechanism and valuable references for the application of LDHs and other 2D materials in cancer therapy.

ILP1 and NTR1 affect the stability of U6 snRNA during spliceosome complex disassembly in Arabidopsis.

U6 snRNA is one of the uridine-rich non-coding RNAs, abundant and stable in various cells, function as core particles in the intron-lariat spliceosome (ILS) complex. The Increased Level of Polyploidy1-1D (ILP1) and NTC-related protein 1 (NTR1), two conserved disassembly factors of the ILS complex, facilitates the disintegration of the ILS complex after completing intron splicing. The functional impairment of ILP1 and NTR1 lead to increased U6 levels, while other snRNAs comprising the ILS complex remained unaffected. We revealed that ILP1 and NTR1 had no impact on the transcription, 3' end phosphate structure or oligo(U) tail of U6 snRNA. Moreover, we uncovered that the mutation of ILP1 and NTR1 resulted in the accumulation of ILS complexes, impeding the dissociation of U6 from splicing factors, leading to an extended half-life of U6 and ultimately causing an elevation in U6 snRNA levels. Our findings broaden the understanding of the functions of ILS disassembly factors ILP1 and NTR1, and providing insights into the dynamic disassembly between U6 and ILS.

The impact of rivers and lakes on urban transportation expansion: A case study of the century-long evolution of the road network in Wuhan, China.

Throughout history, rivers and lakes have wielded a profound influence on the dynamics of urban transportation expansion. To illustrate this phenomenon, we turn to the century-long evolution of the road network in Wuhan, China, as a case study. The study aims to explore the relationship framework between water bodies and urban transportation, characterized by the sequence of "strong connection" to "weakened connection", then to "mutual restriction", and ultimately to "mutual benefit". Additionally, the analysis of the impact mechanisms of rivers and lakes on urban transportation at different stages of development is also a key research objective. To facilitate our exploration, we select the road networks in Wuhan from four years of 1922, 1969, 1995, and 2023 as the primary research subjects. By establishing water buffers, we scrutinize the evolving characteristics of riverside and lakeside transportation amidst the city's expansion. Based on the modified shortest path model, we introduce the innovative concepts of "Detour Index" and "Weighted Detour Index" to assess the road accessibility of each node in the city based on its inherent environmental conditions. This allows for the effective analysis of the potential impact of water bodies as "obstacles" on the road network at different stages of urban development. The study found that in the areas adjacent to the rivers and lakes in Wuhan, there is insufficient road accessibility based on their inherent environmental conditions. Particularly, some areas along the rivers may become "terminals" in the urban road network. Furthermore, during the process of urban expansion, the correlation between the urban road network and rivers continues to weaken, while the correlation with lakes continues to strengthen. These conclusions can provide valuable insights for the planning of urban roads near water bodies.

Enzyme Core Spherical Nucleic Acid That Enables Enhanced Cuproptosis and Antitumor Immune Response through Alleviating Tumor Hypoxia.

Cuproptosis, a copper-dependent cell death process, has been confirmed to further activate the immune response and mediate the immune resistance. However, hypoxic tumor microenvironment hampers cuproptosis sensitivity and suppresses the body's antitumor immune response. Herein, we have successfully immobilized and functionalized catalase (CAT) with long single-stranded DNA containing polyvalent CpG sequences through rolling circle amplification (RCA) techniques, obtaining an enzyme-cored spherical nucleic acid nanoplatform (CAT-ecSNA-Cu) to deliver copper ions for cuproptosis. The presence of long-stranded DNA-protected CAT enhances mitochondrial respiration by catalyzing the conversion of H2O2 to O2, thereby sensitizing cuproptosis. Meanwhile, increased tumor oxygenation suppresses the expression of the hypoxia-inducible factor-1 (HIF-1) protein, resulting in the alleviation of the immunosuppressive tumor microenvironment. Of note, cuproptosis induces immunogenic cell death (ICD), which facilitates dendritic cell (DC) maturation and enhances antigen presentation through polyCpG-supported Toll-like receptor 9 (TLR9) activation. Furthermore, cuproptosis-induced PD-L1 upregulation in tumor cells complements checkpoint blockers (αPD-L1), enhancing antitumor immunity. The strategy of enhancing cuproptosis-mediated antitumor immune responses by alleviating hypoxia effectively promotes the activation and proliferation of effector T cells, ultimately leading to long-term immunity against cancer.

Iron-Single-Atom Nanozyme with NIR Enhanced Catalytic Activities for Facilitating MRSA-Infected Wound Therapy.

Patients with methicillin-resistant Staphylococcus aureus (MRSA) infections may have higher death rates than those with non-drug-resistant infections. Nanozymes offer a promising approach to eliminating bacteria by producing reactive oxygen species. However, most of the conventional nanozyme technologies encounter significant challenges with respect to size, composition, and a naturally low number of active sites. The present study synthesizes a iron-single-atom structure (Fe-SAC) via nitrogen doped-carbon, a Fe-N5 catalyst (Fe-SAC) with a high metal loading (4.3 wt.%). This catalyst permits the development of nanozymes consisting of single-atom structures with active sites resembling enzymes, embedded within nanomaterials. Fe-SAC displays peroxidase-like activities upon exposure to H2O2. This structure facilitates the production of hydroxyl radicals, well-known for their strong bactericidal effects. Furthermore, the photothermal properties augment the bactericidal efficacy of Fe-SAC. The findings reveal that Fe-SAC disrupts the bacterial cell membranes and the biofilms, contributing to their antibacterial effects. The bactericidal properties of Fe-SAC are harnessed, which eradicates the MRSA infections in wounds and improves wound healing. Taken together, these findings suggest that single Fe atom nanozymes offer a novel perspective on the catalytic mechanism and design, holding immense potential as next-generation nanozymes.

Risk factors for perioperative blood transfusion in patients undergoing total laparoscopic hysterectomy.

PURPOSE: The goal is to identify risk factors associated with receiving a blood transfusion during the perioperative period in patients who undergo total laparoscopic hysterectomy (TLH) using a large-scale national database. METHODS: In this retrospective analysis, data from the Nationwide Inpatient Sample (NIS) was utilized to review the medical records of all patients who underwent TLH from 2010 to 2019. The researchers identified patients who had received a blood transfusion during the perioperative period and compared with those who had not. The subsequent factors associated with blood transfusion were examined: hospital characteristics (type of admission and payer, patient demographics (age and race), bed size, teaching status, location, and region of hospital), length of stay (LOS), total charges during hospitalization, in-hospital mortality, comorbidities, and perioperative complications. The data was analyzed using descriptive statistics. The independent risk factors of perioperative blood transfusion after TLH was identified by performing multivariate logistic regression. RESULTS: A total of 79,933 TLH were captured from the NIS database, among which 3433 (4.40%) patients received a perioperative blood transfusion. TLH patients affected by blood transfusion were 2 days longer hospital stays (P < 0.001), higher overall costs (P < 0.001), the patients who received a transfusion after a long-term hospitalization had a significantly higher rate of mortality (0.5% vs. 0.1%; P < 0.001). Perioperative blood transfusion after TLH was associated with chronic blood loss anemia, deficiency anemia, coagulopathy, congestive heart failure, fluid and electrolyte disorders, renal failure, metastatic cancer, sepsis, weight loss, deep vein thrombosis, gastrointestinal hemorrhage, shock, acute myocardial infarction, and pneumonia, stroke, hemorrhage, pulmonary embolism, and disease of the genitourinary system. CONCLUSION: Studying the risk factors of perioperative blood transfusion after TLH is advantageous in order to ensure proper management and optimize outcomes.

A Cardiac-Targeted Nanozyme Interrupts the Inflammation-Free Radical Cycle in Myocardial Infarction.

Severe systemic inflammation following myocardial infarction (MI) is a major cause of patient mortality. MI-induced inflammation can trigger the production of free radicals, which in turn ultimately leads to increased inflammation in cardiac lesions (i.e., inflammation-free radicals cycle), resulting in heart failure and patient death. However, currently available anti-inflammatory drugs have limited efficacy due to their weak anti-inflammatory effect and poor accumulation at the cardiac site. Herein, a novel Fe-Cur@TA nanozyme is developed for targeted therapy of MI, which is generated by coordinating Fe3+ and anti-inflammatory drug curcumin (Cur) with further modification of tannic acid (TA). Such Fe-Cur@TA nanozyme exhibits excellent free radicals scavenging and anti-inflammatory properties by reducing immune cell infiltration, promoting macrophage polarization toward the M2-like phenotype, suppressing inflammatory cytokine secretion, and blocking the inflammatory free radicals cycle. Furthermore, due to the high affinity of TA for cardiac tissue, Fe-Cur@TA shows an almost tenfold greater in cardiac retention and uptake than Fe-Cur. In mouse and preclinical beagle dog MI models, Fe-Cur@TA nanozyme preserves cardiac function and reduces scar size, suggesting promising potential for clinical translation in cardiovascular disease.

An Intelligent DNA Nanoreactor for Easy-to-Read In Vivo Tumor Imaging and Precise Therapy.

Nanomaterial-based in vivo tumor imaging and therapy have attracted extensive attention; however, they suffer from the unintelligent "always ON" or single-parameter responsive signal output, substantial off-target effects, and high cost. Therefore, achieving in vivo easy-to-read tumor imaging and precise therapy in a multi-parameter responsive and intelligent manner remains challenging. Herein, an intelligent DNA nanoreactor (iDNR) was constructed following the "AND" Boolean logic algorithm to address these issues. iDNR-mediated in situ deposition of photothermal substance polydopamine (PDA) can only be satisfied in tumor tissues with abundant membrane protein biomarkers "AND" hydrogen peroxide (H2 O2 ). Therefore, intelligent temperature-based in vivo easy-to-read tumor imaging is realized without expensive instrumentation, and its diagnostic performance matches with that of flow cytometry, and photoacoustic imaging. Moreover, precise photothermal therapy (PTT) of tumors could be achieved via intelligent heating of tumor tissues. The precise PTT of primary tumors in combination with immune checkpoint blockade (ICB) therapy suppresses the growth of distant tumors and inhibits tumor recurrence. Therefore, highly programmable iDNR is a powerful tool for intelligent biomedical applications.

Smartphone-Based Fluorescent Profiling of Quaternary MicroRNAs in Urine for Rapid Diagnosis of Urological Cancers Using a Multiplexed Isothermal Exponential Amplification Reaction.

Urological cancers such as bladder or prostate cancer represent one of the most malignant tumors that accounts for an extremely high mortality. However, conventionally standard diagnostics for urological cancers are hardly available in low-resource settings. We developed herein a hand-held fluorescent imaging platform by integrating a multiplexed isothermal exponential amplification reaction (EXPAR) with a microgel-enriched methodology for sensitive profiling of quaternary microRNAs (miRNAs) in urine and quick diagnosis of urological cancers at the early stage. The target miRNA mixtures in the urine underwent four parallel EXPARs without cross-reactivity, followed by surface concentration and hybridization by the encoded polyacrylamide microgels. This mix-and-read strategy allowed for one-pot analysis of several key miRNAs simultaneously and provided 5-fold enhancement in fluorescent detection sensitivities compared to the individual EXPAR-based assays. Four urinary miRNAs (let-7a, miRNA-155, -223, and -143) could be quantitatively determined in a wide linear range from 50 fM to 30 nM, with the limits of detection at femtomolar levels. Using a smartphone-based imaging microreader, healthy and cancerous cohorts with prostate, bladder, and renal cell cancers could be discriminated in 30 min with the accuracy >83% using linear discriminant analysis. The developed detection platform has proven to be a portable, noninvasive, and useful complement to the toolbox for miRNA-based liquid biopsies, which holds immense potential and advantage for regular and large-scale applications in early cancer diagnosis.

Advances of hafnium based nanomaterials for cancer theranostics.

Hafnium-based nanomaterials (Hf-NMs) have attracted the interest of numerous biomedical researchers by their unique properties. Recent years have witnessed significant advancements in the field of Hafnium-based nanomaterials, particularly in the context of cancer diagnosis and treatment. However, research in this area, especially concerning the clinical application of Hafnium-based nanomaterials, has not been thoroughly reviewed. This review will cover: 1) Classification and synthesis of Hafnium-based nanomaterials including Hafnium oxide nanomaterials, Hafnium Metal-Organic Frameworks/nanoscale coordination polymers (MOFs/NCPs); 2) Hafnium-based nanomaterials act as contrast enhancement agent for cancer imaging, and hafnium-based nanomaterials used for diagnosis in cancer liquid biopsy; 3) hafnium-based nanomaterials for cancer therapy, including hafnium-based nanomaterials for radiotherapy, hafnium-based nanomaterials for photodynamic therapy, hafnium-based nanomaterials for various combined therapy; and 4) Translation, toxicity, and safety for Hf-NMs in human and preclinical animal models. More attention will be given to the clinical translation of Hf-NMs in cancer.

Covalent LYTAC Enabled by DNA Aptamers for Immune Checkpoint Degradation Therapy.

Immune checkpoint blockade (ICB) therapy, while achieving tremendous clinical successes, still suffers from a low objective response rate in clinical cancer treatment. As a proof-of-concept study, we propose a new immune checkpoint degradation (ICD) therapy relying on lysosome-targeting chimera (LYTAC) to deplete immune checkpoint programmed death ligand-1 (PD-L1) on the tumor cell surface. Our designed chimeric aptamer on one side targets lysosome-trafficking receptor, and on the other side allows biorthogonal covalent-conjugation-reinforced specific binding of PD-L1. This covalent LYTAC is able to hijack PD-L1 for lysosomal degradation with greatly improved efficiency over its noncovalent counterpart in complex in vivo environment. Beyond abolishing the PD-1/PD-L1 axis associated immune resistance, we demonstrate for the first time that LYTAC-triggered PD-L1 degradation could directly cause immunogenic apoptosis of tumor cells to elicit tumor-specific immune responses, offering unparalleled advantages over ICB antibody therapy. Remarkably, ICD therapy with covalent LYTAC achieves comparable or higher antitumor efficacy while causing significantly less inflammatory injury compared to antibody-based ICB therapy. Moreover, covalent LYTAC can serve as a general platform for specifically degrading other membrane-associated proteins, making it a promising tool for future applications. Our work presents a novel molecular tool for effective LYTAC in complex environments, offering valuable insights in pushing DNA-based LYTAC drugs toward in vivo and clinical applications.

Metal-DNA Nanocomplexes Enhance Chemo-dynamic Therapy by Inhibiting Autophagy-Mediated Resistance.

Chemo-dynamic therapy (CDT) based on the Fenton or Fenton-like reaction has emerged as a promising approach for cancer treatment. However, autophagy-mediated self-protection mechanisms of cancer cells pose a significant challenge to the efficacy of CDT. Herein, we developed metal-DNA nanocomplexes (DACs-Mn) to enhance CDT via DNAzyme inhibition of autophagy. Specifically, Mn-based catalyst in DACs-Mn was used to generate highly hydroxyl radicals (⋅OH) that kill cancer cells, while the ATG5 DNAzyme incorporated into DACs-Mn inhibited the expression of autophagy-associated proteins, thereby improving the efficacy of CDT. By disrupting the self-protective pathway of cells under severe oxidative stress, this novel approach of DACs-Mn was found to synergistically enhance CDT in both in vitro and in vivo models, effectively amplifying tumor-specific oxidative damage. Notably, the Metal-DNA nanocomplexes can also induce immunogenic cell death (ICD), thereby inhibiting tumor metastasis. Specifically, in a bilateral tumor model in mice, the combined approach of CDT and autophagy inhibition followed by immune checkpoint blockade therapy shown significant potential as a novel and effective treatment modality for primary and metastatic tumors.

Small breast epithelial mucin as a useful prognostic marker for breast cancer patients.

This study aimed to evaluate the clinical utility of small breast epithelial mucin (SBEM) as a prognostic biomarker in an independent patient cohort. The paraffin-embedded tissues and clinicopathological data of 105 patients with breast cancer were collected, and the expression of SBEM in breast cancer samples was detected by immunohistochemical staining. The correlations between clinicopathological variables and the expression of SBEM were analyzed, and its significance as a prognostic indicator for breast cancer patients was determined. Immunohistochemical staining revealed that SBEM was expressed mostly in the cytomembrane and cytoplasm, with markedly increased SBEM expression (≥4 points on staining intensity) observed in 34 of 105 breast cancer tissues (32.4%). Elevated expression of SBEM was found to be significantly associated with larger tumor size (P = 0.002), more frequent lymph node metastasis (P = 0.029), advanced tumor node metastasis stage (P = 0.005), reduced expression of the progesterone receptor (PR) (P = 0.002), and a higher Ki-67 index (P = 0.006). Survival analysis indicated that patients with elevated SBEM expression had worse overall survival (OS) (5-year OS rate: 50.5 vs 93.9% for high and low SBEM expression, respectively, P < 0.001) and disease-free survival (DFS) (5-year DFS rate: 52.8 vs 81.7% for high and low SBEM expression, respectively, P = 0.001) rates than those with low expression of SBEM. Univariate and multivariate Cox analyses demonstrated that elevated expression of SBEM (hazard ratio [HR] = 1.994, 95% confidence interval [CI]: 1.008-3.945, P = 0.047), tumor size (HR = 2.318, 95% CI: 1.071-5.017, P = 0.033), and PR status (HR = 0.195, 95% CI: 0.055-0.694, P = 0.012) were independent predictors of OS in breast cancer patients. Elevated expression of SBEM was associated with both aggressive tumor characteristics and poor survival, indicating its potential as a useful prognostic biomarker for breast cancer patients.

Rapid Diagnosis of Urinary Tract Cancers on a LEGO-Inspired Detection Platform via Chemiresistive Profiling of Volatile Metabolites.

Rapid and in situ profiling of volatile metabolites from body fluids represents a new trend in cancer diagnosis and classification in the early stages. We report herein an on-chip strategy that combines an array of conductive nanosensors with a chaotic gas micromixer for real-time monitoring of volatiles from urine and for accurate diagnosis and classification of urinary tract cancers. By integrating a class of LEGO-inspired microchambers immobilized with MXene-based sensing nanofilms and zigzag microfluidic gas channels, it enables the intensive intermingling of volatile organic chemicals with sensor elements that tremendously facilitate their ion-dipole interactions for molecular recognition. Aided with an all-in-one, point-of-care platform and an effective machine-learning algorithm, healthy or diseased samples from subpopulations (i.e., tumor subtypes, staging, lymph node metastasis, and distant metastasis) of urinary tract cancers can be reliably fingerprinted in a few minutes with high sensitivity and specificity. The developed detection platform has proven to be a noninvasive supplement to the liquid biopsies available for facile screening of urinary tract cancers, which holds great potential for large-scale personalized healthcare in low-resource areas.

Metallic nanoplatforms for COVID-19 diagnostics: versatile applications in the pandemic and post-pandemic era.

The COVID-19 pandemic, which originated in Hubei, China, in December 2019, has had a profound impact on global public health. With the elucidation of the SARS-CoV-2 virus structure, genome type, and routes of infection, a variety of diagnostic methods have been developed for COVID-19 detection and surveillance. Although the pandemic has been declared over, we are still significantly affected by it in our daily lives in the post-pandemic era. Among the various diagnostic methods, nanomaterials, especially metallic nanomaterials, have shown great potential in the field of bioanalysis due to their unique physical and chemical properties. This review highlights the important role of metallic nanosensors in achieving accurate and efficient detection of COVID-19 during the pandemic outbreak and spread. The sensing mechanisms of each diagnostic device capable of analyzing a range of targets, including viral nucleic acids and various proteins, are described. Since SARS-CoV-2 is constantly mutating, strategies for dealing with new variants are also suggested. In addition, we discuss the analytical tools needed to detect SARS-CoV-2 variants in the current post-pandemic era, with a focus on achieving rapid and accurate detection. Finally, we address the challenges and future directions of metallic nanomaterial-based COVID-19 detection, which may inspire researchers to develop advanced biosensors for COVID-19 monitoring and rapid response to other virus-induced pandemics based on our current achievements.

Metal-polyDNA nanoparticles reconstruct osteoporotic microenvironment for enhanced osteoporosis treatment.

Current clinical approaches to osteoporosis primarily target osteoclast biology, overlooking the synergistic role of bone cells, immune cells, cytokines, and inorganic components in creating an abnormal osteoporotic microenvironment. Here, metal-polyDNA nanoparticles (Ca-polyCpG MDNs) composed of Ca2+ and ultralong single-stranded CpG sequences were developed to reconstruct the osteoporotic microenvironment and suppress osteoporosis. Ca-polyCpG MDNs can neutralize osteoclast-secreted hydrogen ions, provide calcium repletion, promote remineralization, and repair bone defects. Besides, the immune-adjuvant polyCpG in MDNs could induce the secretion of osteoclastogenesis inhibitor interleukin-12 and reduce the expression of osteoclast function effector protein to inhibit osteoclast differentiation, further reducing osteoclast-mediated bone resorption. PPi4- generated during the rolling circle amplification reaction acts as bisphosphonate analog and enhances bone targeting of Ca-polyCpG MDNs. In ovariectomized mouse and rabbit models, Ca-polyCpG MDNs prevented bone resorption and promoted bone repair by restoring the osteoporotic microenvironment, providing valuable insights into osteoporosis therapy.

Oxidase-like Fe-N/C single atom nanozyme enables sensitive detection of ascorbic acid and acid phosphatase.

The development of cost-effective and easy-to-use strategies for the detection of ascorbic acid (AA) and acid phosphatase (ACP) is in high demand but challenging. Thus, we report a novel colorimetric platform based on Fe-N/C single atom nanozyme with efficient oxidase mimicking activity for their highly sensitive detection. The designed Fe-N/C single atom nanozyme can directly oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to produce a blue oxidation product (oxTMB) in the absence of H2O2. In addition, L-ascorbic acid 2-phosphate can be hydrolyzed to ascorbic acid in the presence of ACP, which inhibits the oxidation reaction and results in a significant bleaching of the blue color. Based on these phenomena, a novel colorimetric assay with high catalytic activity was developed for the determination of ascorbic acid and acid phosphatase with detection limits of 0.092 µM and 0.048 U/L, respectively. Notably, this strategy was successfully applied to the determination of ACP in human serum samples and evaluate ACP inhibitors, indicating its potential as a valuable tool for clinical diagnosis and research.

IrO2 clusters loaded on dendritic mesoporous silica nanospheres with superior peroxidase-like activity for sensitive detection of acetylcholinesterase and its inhibitors.

Nanomaterials-based enzyme mimics (nanozymes), by simulating enzyme catalysis, have shown potential in numerous biocatalytic applications, but nanozymes face significant challenges of catalytic activity and reusability that may restrict their practical uses. Herein, we report facile fabrication of surface-clean IrO2 clusters supported on dendritic mesoporous silica nanospheres (DMSNs), which exhibit superior peroxidase-like activity, high thermal/long-term stability, and good recyclability. The IrO2 clusters (1.4 ± 0.2 nm in size) are obtained by the laser ablation without any ligands and possess negative surface charge, which are efficiently loaded on the amino-functionalized DMSNs by electrostatic adsorption. Owing to morphological and structural advantages, the resulted DMSN/IrO2 heterostructure displays outstanding peroxidase-like catalytic performance. Compared with horseradish peroxidase, it shows comparable affinities but higher reaction rate (2.95 × 10-7 M·s-1) towards H2O2, resulting from rapid electron transfer during the catalysis. This value is also larger than those of mesoporous silicas supported metal or metal oxides nanoparticles/clusters in the previous studies. Benefitting from excellent peroxidase-catalysis of the DMSN/IrO2, the colorimetric assays are further successfully established for the detection of acetylcholine esterase and its inhibitor, showing high sensitivity and selectivity. The work provides novel design of supported nanozymes for biosensing.