SAFA facilitates chromatin opening of immune genes through interacting with anti-viral host RNAs.

Regulation of chromatin structure and accessibility determines the transcription activities of genes, which endows the host with function-specific patterns of gene expression. Upon viral infection, the innate immune responses provide the first line of defense, allowing rapid production of variegated antiviral cytokines. Knowledge on how chromatin accessibility is regulated during host defense against viral infection remains limited. Our previous work found that the nuclear matrix protein SAFA surveilled viral RNA and regulated antiviral immune genes expression. However, how SAFA regulates the specific induction of antiviral immune genes remains unknown. Here, through integration of RNA-seq, ATAC-seq and ChIP-seq assays, we found that the depletion of SAFA specifically decreased the chromatin accessibility, activation and expression of virus induced genes. And mutation assays suggested that the RNA-binding ability of SAFA was essential for its function in regulating antiviral chromatin accessibility. RIP-seq results showed that SAFA exclusively bound with antiviral related RNAs following viral infection. Further, we combined the CRISPR-Cas13d mediated RNA knockdown system with ATAC-qPCR, and demonstrated that the binding between SAFA and according antiviral RNAs specifically mediated the openness of the corresponding chromatin and following robust transcription of antiviral genes. Moreover, knockdown of these associated RNAs dampened the accessibility of related genes in an extranuclear signaling pathway dependent manner. Interestingly, VSV infection cleaved SAFA protein at the C-terminus which deprived its RNA binding ability for immune evasion. Thus, our results demonstrated that SAFA and the interacting RNA products collaborated and remodeled chromatin accessibility to facilitate antiviral innate immune responses.

Ultrasound contrast-enhanced radiomics model for preoperative prediction of the tumor grade of clear cell renal cell carcinoma: an exploratory study.

BACKGROUND: This study aims to explore machine learning(ML) methods for non-invasive assessment of WHO/ISUP nuclear grading in clear cell renal cell carcinoma(ccRCC) using contrast-enhanced ultrasound(CEUS) radiomics. METHODS: This retrospective study included 122 patients diagnosed as ccRCC after surgical resection. They were divided into a training set (n = 86) and a testing set(n = 36). CEUS radiographic features were extracted from CEUS images, and XGBoost ML models (US, CP, and MP model) with independent features at different phases were established. Multivariate regression analysis was performed on the characteristics of different radiomics phases to determine the indicators used for developing the prediction model of the combined CEUS model and establishing the XGBoost model. The training set was used to train the above four kinds of radiomics models, which were then tested in the testing set. Radiologists evaluated tumor characteristics, established a CEUS reading model, and compared the diagnostic efficacy of CEUS reading model with independent characteristics and combined CEUS model prediction models. RESULTS: The combined CEUS radiomics model demonstrated the best performance in the training set, with an area under the curve (AUC) of 0.84, accuracy of 0.779, sensitivity of 0.717, specificity of 0.879, positive predictive value (PPV) of 0.905, and negative predictive value (NPV) of0.659. In the testing set, the AUC was 0.811, with an accuracy of 0.784, sensitivity of 0.783, specificity of 0.786, PPV of 0.857, and NPV of 0.688. CONCLUSIONS: The radiomics model based on CEUS exhibits high accuracy in non-invasive prediction of ccRCC. This model can be utilized for non-invasive detection of WHO/ISUP nuclear grading of ccRCC and can serve as an effective tool to assist clinical decision-making processes.

Deep drug-target binding affinity prediction with multiple attention blocks.

Drug-target interaction (DTI) prediction has drawn increasing interest due to its substantial position in the drug discovery process. Many studies have introduced computational models to treat DTI prediction as a regression task, which directly predict the binding affinity of drug-target pairs. However, existing studies (i) ignore the essential correlations between atoms when encoding drug compounds and (ii) model the interaction of drug-target pairs simply by concatenation. Based on those observations, in this study, we propose an end-to-end model with multiple attention blocks to predict the binding affinity scores of drug-target pairs. Our proposed model offers the abilities to (i) encode the correlations between atoms by a relation-aware self-attention block and (ii) model the interaction of drug representations and target representations by the multi-head attention block. Experimental results of DTI prediction on two benchmark datasets show our approach outperforms existing methods, which are benefit from the correlation information encoded by the relation-aware self-attention block and the interaction information extracted by the multi-head attention block. Moreover, we conduct the experiments on the effects of max relative position length and find out the best max relative position length value $k \in \{3, 5\}$. Furthermore, we apply our model to predict the binding affinity of Corona Virus Disease 2019 (COVID-19)-related genome sequences and $3137$ FDA-approved drugs.

Screening and identification of differential-expressed RNAs in thrombin-induced in vitro model of intracerebral hemorrhage.

Survival of olfactory mucosal mesenchymal stem cells (OM-MSCs) remains the low level in the cerebral microenvironment during intracerebral hemorrhage (ICH). This article aims to reveal the differential expression profile of ICH-stimulated OM-MSCs based on whole transcriptome sequence analysis. OM-MSCs were isolated from 6-week C57BL/6 mice. Morphology and surface markers of OM-MSCs were investigated by light microscope and flow cytometry, respectively. OM-MSCs were incubated with 20 U/mL thrombin for 24 h to mimic ICH-induced injury in vitro. Total RNA was extracted for whole transcriptome sequencing and qPCR. OM-MSCs were characterized by negative for CD45 and CD34, and positive for CD44, CD90 and CD29. Thrombin led to decrease in cell viability and increase in senescence and apoptosis in OM-MSCs. In total, 736 lncRNAs (upregulated: 393; downregulated: 343), 21 miRNAs (upregulated: 7; downregulated: 14) and 807 mRNAs (upregulated: 422; downregulated: 385) were identified. GO and KEGG pathways were enriched in protein heterodimerization activity, trans-synaptic signaling, membrane pathway, alcohol metabolic process, organic hydroxy compound biosynthesis process, secondary alcohol metabolic process, alcoholism, neutrophil extracellular trap formation, systemic lupus erythematosus, metabolic process, steroid biosynthesis and drug metabolism-cytochrome P450. 200 lncRNA-miRNA-mRNA were predicted in thrombin-induced OM-MSCs. Based on qPCR, we validated COMMD1B, MOAP1, lncRNA CAPN15, lncRNA ALDH1L2, miR-3473b and miR-1964-3p were upregulated in thrombin-stimulated OM-MSCs, and GM20431, lncRNA GAPDH and miR-122b-3p were downregulated. Our findings provide novel understanding for thrombin-induced injury in OM-MSCs. Differently-expressed RNAs can be the targets of improving therapeutic application of OM-MSCs.

Ferroptosis: An emerging therapeutic target in stroke.

Stroke is a disastrous neurological disease with high morbidity and mortality. The mechanism of the pathological process is extremely complicated and unclear. Although many basic studies have confirmed molecular mechanism of brain injury after stroke, these studies have not yet translated into treatment and clinical application. Ferroptosis is a form of cell death that is distinct from necrosis, apoptosis, and autophagy morphologically and biochemically and is characterized by iron-dependent accumulation of lipid peroxides. Despite ferroptosis being first identified in cancer cells, it was recently revealed to also be a significant factor in the pathological process of stroke. A better understanding of ferroptosis in stroke may provide us with better therapeutic targets to treat this devastating disease. Here, we systematically summarized the current mechanism of ferroptosis and reviewed the current studies regarding the relationship between ferroptosis and stroke.

miR-489-3p promotes malignant progression of non-small cell lung cancer through the inactivation of Wnt/ß-catenin signaling pathway via regulating USP48.

BACKGROUND: Non-small cell lung cancer (NSCLC) is the most prevalent form of lung cancer globally, with average age of cancer patients becoming younger gradually. It is of significance to gain a comprehensive understanding of molecular mechanism underlying NSCLC. METHODS: Quantitative polymerase chain reaction (qPCR) and western blot were applied to measure RNA and protein levels separately. Functional assays and western blot were performed to determine the effects of miR-489-3p and USP48 on cell growth, migration and epithelial-mesenchymal transition (EMT) in NSCLC. TOP/FOP flash luciferase reporter assay was carried out to detect the activity of Wnt pathway. Besides, qPCR, RNA pulldown and luciferase reporter assays were conducted to probe into the target gene of miR-489-3p. Immunoprecipitation-western blot (IP-western blot) analysis was implemented to assess the effect of USP48 on the ubiquitination of ß-catenin. RESULTS: miR-489-3p hampers NSCLC cell proliferation, migration and EMT in vitro and NSCLC tumorigenesis and metastasis in vivo. Additionally, miR-489-3p inactivates Wnt/ß-catenin signaling pathway and regulates USP48 to inhibit the ubiquitination of ß-catenin. Moreover, USP48 propels the development of NSCLC cells. CONCLUSIONS: The current study demonstrated that miR-489-3p promotes the malignant progression of NSCLC cells via targeting USP48, which might offer a new perspective into NSCLC treatment.

The role of autophagy and apoptosis in early brain injury after subarachnoid hemorrhage: an updated review.

Subarachnoid hemorrhage (SAH) is a worldwide devastating type of stroke with high mortality and morbidity. Accumulating evidence show early brain injury (EBI) as the leading cause of mortality after SAH. The pathological processes involved in EBI include decreased cerebral blood flow, increased intracranial pressure, vasospasm, and disruption of the blood-brain barrier. In addition, neuroinflammation, oxidative stress, apoptosis, and autophagy have also been proposed to contribute to EBI. Among the various processes involved in EBI, neuronal apoptosis has been proven to be a key factor contributing to the poor prognosis of SAH patients. Meanwhile, as another important catabolic process maintaining the cellular and tissue homeostasis, autophagy has been shown to be neuroprotective after SAH. Studies have shown that enhancing autophagy reduced apoptosis, whereas inhibiting autophagy aggravate neuronal apoptosis after SAH. The physiological substrates and mechanisms of neuronal autophagy and apoptosis by which defects in neuronal function are largely unknown. In this review, we summarize and discuss the role of autophagy and apoptosis after SAH and contribute to further study for investigation of the means to control the balance between them.

Correlated Insulating States and Transport Signature of Superconductivity in Twisted Trilayer Graphene Superlattices.

Layers of two-dimensional materials stacked with a small twist angle give rise to beating periodic patterns on a scale much larger than the original lattice, referred to as a "moiré superlattice." Here, we demonstrate a higher-order "moiré of moiré" superlattice in twisted trilayer graphene with two consecutive small twist angles. We report correlated insulating states near the half filling of the moiré of moiré superlattice at an extremely low carrier density (∼10^{10} cm^{-2}), near which we also report a zero-resistance transport behavior typically expected in a 2D superconductor. The full-occupancy (ν=-4 and ν=4) states are semimetallic and gapless, distinct from the twisted bilayer systems.

CBRPP: a new RNA-centric method to study RNA-protein interactions.

RNA and protein are interconnected biomolecules that can influence each other's life cycles and functions through physical interactions. Abnormal RNA-protein interactions lead to cell dysfunctions and human diseases. Therefore, mapping networks of RNA-protein interactions is crucial for understanding cellular processes and pathogenesis of related diseases. Different practical protein-centric methods for studying RNA-protein interactions have been reported, but few robust RNA-centric methods exist. Here, we developed CRISPR-based RNA proximity proteomics (CBRPP), a new RNA-centric method to identify proteins associated with an endogenous RNA of interest in native cellular context without pre-editing of the target RNA, cross-linking or RNA-protein complexes manipulation in vitro. CBRPP is based on a fusion of dCas13 and proximity-based labelling (PBL) enzyme. dCas13 can deliver PBL enzyme to the target RNA with high specificity, while PBL enzyme labels the surrounding proteins of the target RNA, which are then identified by mass spectrometry.

Visible-to-UVC driven upconversion photocatalyst sterilization efficiency and mechanisms of ß-NaYF4: Pr3+, Li+@BiOCl with a core-shell structure.

UVC (wavelength < 280 nm) has a wide range of applications in the field of water disinfection due to its excellent bactericidal performance. In this work, we synthesized an upconversion luminescent material, ß-NaYF4: Pr3+, Li+ (NYF), which can generate UVC, and compounded it with a BiOCl photocatalyst to synthesize ß-NaYF4: Pr3+, Li+@BiOCl (NYF-Bi) with a core-shell structure. The NYF-Bi composite material can be driven under visible light and has high photocatalytic activity. The bactericidal performance of NYF and NYF-Bi were evaluated using Escherichia coli, Staphylococcus aureus, Shigella and Salmonella. The NYF-Bi composite material killed 99.99% of E. coli under visible light (λ ≥ 420 nm) within 180 min and maintained high germicidal efficacy after 4 cycles. Finally, we deduced the sterilization mechanism of the NYF-Bi composite material through carrier dynamics studies and catching agent experiments. The death of bacteria was mainly caused by UVC light and active species, including h+, OH, and O- 2. This research provides a new material for water disinfection.

Inhibition of EZH2 (Enhancer of Zeste Homolog 2) Attenuates Neuroinflammation via H3k27me3/SOCS3/TRAF6/NF-κB (Trimethylation of Histone 3 Lysine 27/Suppressor of Cytokine Signaling 3/Tumor Necrosis Factor Receptor Family 6/Nuclear Factor-κB) in a Rat Model of Subarachnoid Hemorrhage.

BACKGROUND AND PURPOSE: Neuroinflammation has been proven to play an important role in the pathogenesis of early brain injury after subarachnoid hemorrhage (SAH). EZH2 (enhancer of zeste homolog 2)-mediated H3K27Me3 (trimethylation of histone 3 lysine 27) has been recognized to play a critical role in multiple inflammatory diseases. However, there is still a lack of evidence to address the effect of EZH2 on the immune response of SAH. Therefore, the aim of this study was to determine the role of EZH2 in SAH-induced neuroinflammation and explore the effect of EZH2 inhibition with its specific inhibitor EPZ6438. METHODS: The endovascular perforation method was performed on rats to induce subarachnoid hemorrhage. EPZ6438, a specific EZH2 inhibitor, was administered intraperitoneally at 1 hour after SAH. SOCS3 (Suppressor of cytokine signaling 3) siRNA and H3K27me3 CRISPR were administered intracerebroventricularly at 48 hours before SAH to explore potential mechanisms. The SAH grade, short-term and long-term neurobehavioral tests, immunofluorescence staining, and western blots were performed after SAH. RESULTS: The expression of EZH2 and H3K27me3 peaked at 24 hours after SAH. In addition, inhibition of EZH2 with EPZ6438 significantly improved neurological deficits both in short-term and long-term outcome studies. Moreover, EPZ6438 treatment significantly decreased the levels of EZH2, H3K27Me3, pathway-related proteins TRAF6 (TNF [tumor necrosis factor] receptor family 6), NF-κB (nuclear factor-κB) p65, proinflammatory cytokines TNF-α, IL (interleukin)-6, IL-1ß, but increased the expression levels of SOCS3 and anti-inflammatory cytokine IL-10. Furthermore, administration of SOCS3 siRNA and H3k27me3-activating CRISPR partly abolished the neuroprotective effect of EPZ6438, which indicated that the neuroprotective effect of EPZ6438 acted, at least partly, through activation of SOCS3. CONCLUSIONS: In summary, the inhibition of EZH2 by EPZ6438 attenuated neuroinflammation via H3K27me3/SOCS3/TRAF6/NF-κB signaling pathway after SAH in rats. By targeting EZH2, this study may provide an innovative method to ameliorate early brain injury after SAH.

Research Advances of Germinal Matrix Hemorrhage: An Update Review.

Germinal matrix hemorrhage (GMH) refers to bleeding that derives from the subependymal (or periventricular) germinal region of the premature brain. GMH can induce severe and irreversible damage attributing to the vulnerable structure of germinal matrix and deleterious circumstances. Molecular mechanisms remain obscure so far. In this review, we summarized the newest preclinical discoveries recent years about GMH to distill a deeper understanding of the neuropathology, and then discuss the potential diagnostic or therapeutic targets among these pathways. GMH studies mostly in recent 5 years were sorted out and the authors generalized the newest discoveries and ideas into four parts of this essay. Intrinsic fragile structure of preterm germinal matrix is the fundamental cause leading to GMH. Many molecules have been found effective in the pathophysiological courses. Some of these molecules like minocycline are suggested active to reduce the damage in animal GMH model. However, researchers are still trying to find efficient diagnostic methods and remedies that are available in preterm infants to rehabilitate or cure the sequent injury. Merits have been obtained in the last several years on molecular pathways of GMH, but more work is required to further unravel the whole pathophysiology.

Tamibarotene Improves Hippocampus Injury Induced by Focal Cerebral Ischemia-Reperfusion via Modulating PI3K/Akt Pathway in Rats.

GOAL: The present study aimed to examine whether Am80 (tamibarotene) protects the hippocampus against cerebral ischemia-reperfusion (I/R) injury and whether phosphoinositide-3-kinase/Akt (PI3K/Akt) pathway mediates this effect. MATERIALS AND METHODS: Rats were subjected to 90 minutes of middle cerebral artery occlusion followed by 24 hours of reperfusion. The animals were randomly divided into 7 groups: sham-operated group; I/R group; groups pretreated with 2 mg/kg, 6 mg/kg, and 10 mg/kg of Am80; Am80 (6 mg/kg) combined with the selective PI3K inhibitor wortmannin (0.6 mg/kg), and wortmannin (0.6 mg/kg) only group. After 24 hours of reperfusion, neurological deficits and infarct volume were measured. Pathological changes in hippocampal neurons were analyzed by transmission electron microscopy. Neuronal survival was examined by TUNEL staining. The expression of Bcl-2, Bax, and Akt, and Akt phosphorylation (p-Akt) were measured by Western blotting and quantitative real-time polymerase chain reaction. FINDINGS: The pretreatment with Am80 improved the neurologic deficit score, reduced infarct volume, and decreased the number of TUNEL-positive cells in the hippocampus. Moreover, Am80 pretreatment downregulated the expression of Bax, upregulated the expression of Bcl-2, and increased the level of p-Akt. Wortmannin abolished in part the increase in p-Act and the neuroprotective effect exerted on the ischemic by Am80 pretreatment. CONCLUSIONS: Our results documented that Am80 pretreatment protects ischemic hippocampus after cerebral I/R by regulating the expression of apoptosis-related proteins through the activation of the PI3K/Akt signaling pathway.

Target enhanced 3D reconstruction based on polarization-coded structured light.

Structured light is a prevailing and reliable active approach of 3D object reconstruction. But complex ambience is undesirable in the measurement because it could cause severe noise and increase computing overhead. In this paper, we propose a structured light coded by spatially-distributed polarization state of the illuminating patterns. The proposed structured light has the advantage of enhancing target in 3D reconstruction by polarization cues. Specifically, this method can estimate the degree of linear polarization (DOLP) in the scene, distinguish target by DOLP and selectively reconstruct it. The coding strategy and the corresponding polarimetric principle are presented and verified by experimental results. As our approach takes advantage of the intrinsic properties of liquid crystal display (LCD) projector and requires no rotation of polarizer, it is effective and efficient for practical applications.

Compact polarization-based dual-view panoramic lens.

Panoramic annular lens (PAL) is a type of special optical system that can transform the cylindrical side view onto a planar annular image. We propose a compact polarization-based dual-view panoramic lens to solve the two major limitations of the conventional PAL structure: large front annular lens and lack of forward view. Dual-view imaging capability, which is highly needed for some applications, is achieved by using a polarization technique. The diameter ratio of the proposed front PAL lens and the sensor is reduced to less than 1.5, while it is larger than 2.5 for traditional PAL systems, expanding its applications in space-confined environments.

Polarimetric target depth sensing in ambient illumination based on polarization-coded structured light.

Depth sensing is a basic issue in three-dimensional computer vision, and structured light is one of the most prevailing methods for it. However, complex surroundings and strong ambient illumination are fairly unfavorable to depth sensing based on structured light. Complex surroundings increase computation overhead and require extra effort to be separated from the target object. Strong ambient illumination is unfavorable to the signal-noise ratio of structured light and, thus, increases the difficulty of decoding. In this paper, we propose that the polarization-coded structured light is capable of target enhanced depth sensing in ambient illumination. We present the polarimetric principle, an improved algorithm of polarization-coded structured light, and signal-noise-ratio analysis in ambient illumination. Experimental results show that polarization-coded structured light is efficient and robust for target depth sensing of a complicated environment. The polarization-coded structured light is promising to the target depth sensing in an outdoor scenario and industrial inspection.

Non-blind area PAL system design based on dichroic filter.

An inevitable problem of Panoramic Annular Lens (PAL) System is the blind area in the central part of image plane, which vastly reduces the pixel efficiency of detector. Here we present a design of PAL system based on dichroic filter, which can combine two channels of rays in different bands and image them on the same detector. The dichroic filter in this paper is designed to make ultraviolet rays reflect and visible rays transmit, and the ultraviolet rays are imaged on the PAL imaging area while the visible rays are imaged on the blind area of conventional PAL image plane. In order to image both bands of rays on the same plane, we add a correcting lens group in front of PAL system. As a result, the FOV of ultraviolet channel is ranging from 30°~90° and the one of visible channel is ranging from 0°~10°.

Identification and characterization of microRNAs from Chinese pollination constant non-astringent persimmon using high-throughput sequencing.

BACKGROUND: microRNAs (miRNAs) have been shown to play key roles in regulating gene expression at post-transcriptional level, but miRNAs associated with natural deastringency of Chinese pollination-constant nonastringent persimmon (CPCNA) have never been identified. RESULTS: In this study, two small RNA libraries established using 'Eshi No. 1' persimmon (Diospyros kaki Thunb.; CPCNA) fruits collected at 15 and 20 weeks after flowering (WAF) were sequenced through Solexa platform in order to identify miRNAs involved in deastringency of persimmon. A total of 6,258,487 and 7,634,169 reads were generated for the libraries at 15 and 20 WAF, respectively. Based on sequence similarity and hairpin structure prediction, 236 known miRNAs belonging to 65 miRNA families and 33 novel miRNAs were identified using persimmon transcriptome data. Sixty one of the characterized miRNAs exhibited pronounced difference in the expression levels between 15 and 20 WAF, 17 up-regulated and 44 down-regulated. Expression profiles of 12 conserved and 10 novel miRNAs were validated by stem loop qRT-PCR. A total of 198 target genes were predicted for the differentially expressed miRNAs, including several genes that have been reported to be implicated in proanthocyanidins (PAs, or called tannin) accumulation. In addition, two transcription factors, a GRF and a bHLH, were experimentally confirmed as the targets of dka-miR396 and dka-miR395, respectively. CONCLUSIONS: Taken together, the present data unraveled several important miRNAs in persimmon. Among them, miR395p-3p and miR858b may regulate bHLH and MYB, respectively, which are influenced by SPL under the control of miR156j-5p and in turn regulate the structural genes involved in PA biosynthesis. In addition, dka-miR396g and miR2911a may regulate their target genes associated with glucosylation and insolubilization of tannin precursors. All of these miRNAs might play key roles in the regulation of (de)astringency in persimmon fruits under normal development conditions.

Identification and sex expression profiles of candidate chemosensory genes from Atherigona orientalis via the antennae and leg transcriptome analysis.

Atherigona orientalis Schiner (1868) is an acknowledged agricultural pest owing to its feeding habits and breeding locations. This insect is a tropical and subtropical pest in fruits and vegetables, in which >50 varieties of fruits and vegetables in 26 families, such as Capsicum annuum, Lycopersicon esculentum, and Cucumis melo have been attacked. Moreover, A. orientalis may also develop in rotten crops and feces or insect carcasses, which are also considered one kind of sanitary pest and medical insect. At present, the invasion ranges of A. orientalis are still increasing and more preventive and management measures are to be processed. To gain a better understanding of the molecular mechanisms involved in olfactory reception in A. orientalis, the transcriptome of male and female antennae and legs was systematically analyzed. In total, 131 chemosensory-related genes, including 63 odorant receptors (ORs), 20 gustatory receptors (GRs), 18 ionotropic receptors (IRs), 27 odorant binding proteins (OBPs), 1 chemosensory protein (CSP), and 2 sensory neuron membrane proteins (SNMPs), were identified. The analysis focused on obtaining expression information of candidate olfactory genes at the transcriptomic level by examining the differentially expressed genes (DEGs) in all samples. Totally, 41 DEGs were identified between male antennae (MA) and female antennae (FA), including 32 ORs, 5 OBPs, 1 IR, 2 GRs and 1 SNMP. In MA versus male legs (ML), 78 DEGs were identified (45 ORs, 18 OBPs, 6 GRs, 6 IRs, 1 CSP and 2 SNMPs). In FA and female legs (FL), 96 DEGs were identified (51 ORs, 21 OBPs, 9 GRs, 12 IRs, 1 CSP and 2 SNMPs). For ML and FL, 3 DEGs were identified, including 2 ORs and 1 SNMP. Our results supplement valuable insights for future research on the chemoreception mechanisms in A. orientalis.

A Highly Stable Multifunctional Bi-Based MOF for Rapid Visual Detection of S2- and H2S Gas with High Proton Conductivity.

Metal organic frameworks (MOFs) constructed with bismuth metal have not been widely reported, especially multifunctional Bi-MOFs. Therefore, developing multifunctional MOFs is of great significance due to the increasing requirements of materials. In this work, a 3D Bi-MOF (Bi-TCPE) with multifunctionality was successfully constructed, demonstrating high thermal stability, water stability, a porous structure, and strong blue fluorescence emission. We evaluated the properties of Bi-TCPE in detecting anions (S2-, Cr2O72-, and CrO42-) in aqueous solution, along with the rapid visual detection of H2S gas and proton conduction. In terms of anion detection, Bi-TCPE achieved the rapid detection of trace S2- in aqueous solutions, while the Ksv value was 1.224 × 104 M-1 with a limit of detection (LOD) value of 1.93 µM through titration experiments. Furthermore, Bi-TCPE could sensitively detect Cr2O72- and CrO42-, with Ksv values of 1.144 × 104 and 1.066 × 104 M-1, respectively, while LOD reached 2.07 and 2.18 µM. Subsequently, we conducted H2S gas detection experiments, and the results indicated that Bi-TCPE could selectively detect H2S gas at extremely low concentrations (2.08 ppm) and with a fast response time (<10 s). We also observed significant color changes under both UV light and sunlight. Therefore, we developed a H2S detection test paper for the rapid visual detection of H2S gas. Finally, we evaluated the proton conductivity of Bi-TCPE, and the experimental results showed that the proton conductivity of Bi-TCPE reached 4.77 × 10-2 S·cm-1 at 98% RH and 90 °C, achieving an excellent value for unmodified and encapsulated MOFs. In addition, Bi-TCPE showed high stability in proton conduction experiments (it remained stable after 21 consecutive days of testing and 12 cycles of testing), demonstrating relatively high application value. These results indicate that Bi-TCPE is a multifunctional MOF material with great application potential.