Mitochondria-targeted fluorescent probe for simultaneously imaging viscosity and sulfite in inflammation models.

Many diseases in the human body are related to the overexpression of viscosity and sulfur dioxide. Therefore, it is essential to develop rapid and sensitive fluorescent probes to detect viscosity and sulfur dioxide. In the present work, we developed a dual-response fluorescent probe (ES) for efficient detection of viscosity and sulfur dioxide while targeting mitochondria well. The probe generates intramolecular charge transfer by pushing and pulling the electron-electron system, and the ICT effect is destroyed and the fluorescence quenched upon reaction with sulfite. The rotation of the molecule is inhibited in the high-viscosity system, producing a bright red light. In addition, the probe has good biocompatibility and can be used to detect sulfite in cells, zebrafish and mice, as well as upregulation of viscosity in LPS-induced inflammation models. We expect that the dual response fluorescent probe ES will be able to detect viscosity and sulfite efficiently, providing an effective means of detecting viscosity and sulfite-related diseases.

A novel sensitive fluorescent probe with double channels for highly effective recognition of biothiols.

Biothiols play a crucial role in maintaining redox balance in organisms, and anomalous levels of biothiols in human organs can lead to various sicknesses and biological disorders. This work developed a novel sensitive fluorescent probe TZ-NBD with double channels for highly efficient recognition of biothiols. TZ-NBD adopts 4-Chloro-7-nitrobenzofurazan (NBD-Cl) as the recognition moiety with simultaneous fluorescence output. By incorporating NBD-Cl with the other fluorophore, benzothiazole dihydrocyclopentachromene derivative (TZ-OH), the dual-channel sensitive fluorescence probe TZ-NBD was built. The existence of Cys/ Hcy could significantly trigger both the green and red fluorescent emissions, which were derived from fluorophores amine-substituted NBD and TZ-OH, respectively. While exposing to GSH, only the red-channel fluorescence signal could be detected, indicating the release of TZ-OH. The phenomena was mainly attributed to the fact that sulfur-substituted NBD has nearly no fluorescence, while amine-substituted NBD shows obvious green fluorescence. In our study, TZ-NBD exhibited dual-channel sensitivity, fast response, and excellent selectivity to biothiols in vitro. Moreover, TZ-NBD was favorably utilized for recognition of biothiols in vivo. We believe that the sensitive fluorescence probe with double channels can afford an alternate approach for monitoring biothiols in organisms and would be useful for studying diseases associated with biothiols.

Borane-catalyzed arylation of aryldiazoacetates with N,N-dialkylanilines.

A selective arylation of donor-acceptor diazo compounds with aniline derivatives catalyzed by Lewis acidic boranes is developed. This simple reaction protocol provides an efficient method for the synthesis of diarylacetates under metal-free conditions.

Language models for the prediction of SARS-CoV-2 inhibitors.

The COVID-19 pandemic highlights the need for computational tools to automate and accelerate drug design for novel protein targets. We leverage deep learning language models to generate and score drug candidates based on predicted protein binding affinity. We pre-trained a deep learning language model (BERT) on ∼9.6 billion molecules and achieved peak performance of 603 petaflops in mixed precision. Our work reduces pre-training time from days to hours, compared to previous efforts with this architecture, while also increasing the dataset size by nearly an order of magnitude. For scoring, we fine-tuned the language model using an assembled set of thousands of protein targets with binding affinity data and searched for inhibitors of specific protein targets, SARS-CoV-2 Mpro and PLpro. We utilized a genetic algorithm approach for finding optimal candidates using the generation and scoring capabilities of the language model. Our generalizable models accelerate the identification of inhibitors for emerging therapeutic targets.

A near-infrared fluorescent probe for monitoring leucine aminopeptidase in living cells.

Leucine aminopeptidase (LAP), one of the important cancer-related biomarkers, is significantly over-expressed in many malignant tumor cells. Developing an effective fluorescent probe for high-specificity and in situ trapping of endogenous LAP in living samples is still challenging. In this project, we report a water-soluble near-infrared (NIR) fluorescent probe (CHMC-M-Leu) for specific monitoring of LAP in vitro and in vivo. The novel fluorescent probe (CHMC-M-Leu) contains a NIR-emitting fluorophore (CHMC-M) as the reporter and l-leucine as the enzyme-active trigger moiety which are linked together by a p-aminobenzyl alcohol (PABA) section. Upon exposure to LAP, the fluorescence at 625 nm gets impressively enhanced, which belongs to the near-infrared region and is beneficial for imaging in vivo. Furthermore, the novel fluorescent probe exhibits fast response and highly chemoselective detection of LAP in various bio-related species. In addition, CHMC-M-Leu shows favourable cellular uptake and was successfully used to monitor endogenous LAP in living cells.

Highly Sensitive Ratiometric Self-Assembled Micellar Nanoprobe for Nitroxyl and Its Application In Vivo.

Nitroxyl (HNO) is a derivative of nitric oxide (NO) that plays an essential role in various biological and pharmacological events. Until now, the in situ trapping and specific detection of HNO in living samples is still challenging. In this project, we fabricated a novel BODIPY-based micellar nanoprobe for monitoring nitroxyl in vitro and in vivo in ratiometric mode in aqueous solution. The probe (P-BODIPY-N) contains an asymmetrical BODIPY dye for fluorescent signaling and a diphenylphosphinobenzoyl as the trigger moiety; then we encapsulated P-BODIPY-N into the hydrophobic interior of an amphiphilic copolymer (mPEG-DSPE) and prepared a novel BODIPY-based micellar nanoprobe: NP-BODIPY-N. As far as we know, this probe is the first reported ratiometric fluorescent nanoprobe for HNO, which exhibits ultrasensitivity, high selectivity, and good biocompatibility. Above all, this nanoprobe shows favorable cellular uptaken and was successfully used to detect intracellular HNO released by Angeli's salt in living cells and zebrafish larvae. These results indicate that our newly designed nanoprobe will provide a promising tool for the studies of HNO in living system.

A Ratiometric Fluorescent Probe for Monitoring Leucine Aminopeptidase in Living Cells and Zebrafish Model.

Leucine aminopeptidase (LAP) is an important cancer-related biomarker, which shows significant overexpression in malignant tumor cells like liver cancer. Developing an effective method to monitor LAP in tumor cells holds great potential for cancer diagnosis, treatment, and management. In this work, we report a novel BODIPY-based fluorescent probe (BODIPY-C-Leu) capable of monitoring LAP in vitro and in vivo in both ratiometric and turn-on model. BODIPY-C-Leu contains an asymmetrical BODIPY dye for fluorescent signaling and a dipeptide (Cys-Leu) as the triggered moiety. Activation occurs by cleavage of the amide bond in dipeptides and subsequently an intramolecular S → N conversion to convert sulfur-substituted BODIPY to amino-substituted BODIPY, resulting in a dramatic fluorescence variation to realize the detection of LAP. Furthermore, we have successfully employed BODIPY-C-Leu to monitor LAP activity in different cancer cells, indicating that HeLa cells have a higher level of LAP activity than A549 cells. Importantly, we demonstrated the capability of the probe for real-time monitoring the drug-induced LAP level changes in zebrafish.

A fluorescent turn-on probe for visualizing lysosomes in hypoxic tumor cells.

A fluorescent probe for fulfilling a lysosome targeting function in hypoxic tumor cells is reported, wherein azoreductase triggers a dramatic fluorescence enhancement and specific imaging of lysosomes in hypoxic cancer cells.

Förster Resonance Energy Transfer Switchable Self-Assembled Micellar Nanoprobe: Ratiometric Fluorescent Trapping of Endogenous H2S Generation via Fluvastatin-Stimulated Upregulation.

H2S produced in small amounts by mammalian cells has been identified in mediating biological signaling functions. However, the in situ trapping of endogenous H2S generation is still handicapped by a lack of straightforward methods with high selectivity and fast response. Here, we encapsulate a semi-cyanine-BODIPY hybrid dye (BODInD-Cl) and its complementary energy donor (BODIPY1) into the hydrophobic interior of an amphiphilic copolymer (mPEG-DSPE), especially for building up a ratiometric fluorescent H2S nanoprobe with extraordinarily fast response. A remarkable red-shift in the absorption band with a gap of 200 nm in the H2S response can efficiently switch off the Förster resonance energy transfer (FRET) from BODIPY1 to BODInD-Cl, subsequently recovering the donor fluorescence. Impressively, both the interior hydrophobicity of supramolecular micelles and electron-withdrawing nature of indolium unit in BODInD-Cl can sharply increase aromatic nucleophilic substitution with H2S. The ratiometric strategy based on the unique self-assembled micellar aggregate NanoBODIPY achieves an extremely fast response, enabling in situ imaging of endogenous H2S production and mapping its physiological and pathological consequences. Moreover, the amphiphilic copolymer renders the micellar assembly biocompatible and soluble in aqueous solution. The established FRET-switchable macromolecular envelope around BODInD-Cl and BODIPY1 enables cellular uptake, and makes a breakthrough in the trapping of endogenous H2S generation within raw264.7 macrophages upon stimulation with fluvastatin. This study manifests that cystathione γ-lyase (CSE) upregulation contributes to endogenous H2S generation in fluvastatin-stimulated macrophages, along with a correlation between CSE/H2S and activating Akt signaling pathway.

Fluorescent In Situ Targeting Probes for Rapid Imaging of Ovarian-Cancer-Specific γ-Glutamyltranspeptidase.

γ-Glutamyltranspeptidase (GGT) is a tumor biomarker that selectively catalyzes the cleavage of glutamate overexpressed on the plasma membrane of tumor cells. Here, we developed two novel fluorescent in situ targeting (FIST) probes that specifically target GGT in tumor cells, which comprise 1) a GGT-specific substrate unit (GSH), and 2) a boron-dipyrromethene (BODIPY) moiety for fluorescent signalling. In the presence of GGT, sulfur-substituted BODIPY was converted to amino-substituted BODIPY, resulting in dramatic fluorescence variations. By exploiting this enzyme-triggered photophysical property, we employed these FIST probes to monitor the GGT activity in living cells, which showed remarkable differentiation between ovarian cancer cells and normal cells. These probes represent two first-generation chemodosimeters featuring enzyme-mediated rapid, irreversible aromatic hydrocarbon transfer between the sulfur and nitrogen atoms accompanied by switching of photophysical properties.

Development of a small molecule probe capable of discriminating cysteine, homocysteine, and glutathione with three distinct turn-on fluorescent outputs.

The simultaneous discrimination of Cys, Hcy, and GSH by a single probe is still an unmet challenge. The design and synthesis of a small molecule probe MeO-BODIPY-Cl (BODIPY=boron dipyrromethene) is presented, which can allow Cys, Hcy, and GSH to be simultaneously discriminated on the basis of three distinct fluorescence turn-on responses. The probe reacts with these thiols to form sulfenyl-substituted BODIPY, which is followed by intramolecular displacement to yield amino-substituted BODIPY. The kinetic rate of the intramolecular displacement reaction determines the observed different sensing behavior. Therefore, the probe responds to Cys, Hcy, and GSH with fluorescence turn-on colors of yellow, yellow and red, and red, respectively. With this promising feature in hand, the probe was successfully used in imaging of Cys, Hcy and GSH in living cells.

Memory modeling of counterfactual generation.

We use a computational model of memory search to study how people generate counterfactual outcomes in response to an established target outcome. Hierarchical Bayesian model fitting to data from six experiments reveals that counterfactual outcomes that are perceived as more desirable and more likely to occur are also more likely to come to mind and are generated earlier than other outcomes. Additionally, core memory mechanisms such as semantic clustering and word frequency biases have a strong influence on retrieval dynamics in counterfactual thinking. Finally, we find that the set of counterfactuals that come to mind can be manipulated by modifying the total number of counterfactuals that participants are prompted to generate, and our model can predict these effects. Overall, our findings demonstrate how computational memory search models can be integrated with current theories of counterfactual thinking to provide novel insights into the process of generating counterfactual thoughts. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Borane-Catalyzed Coupling of Diazooxindoles and Difluoroenoxysilanes to Tetrasubstituted Monofluoroalkenes.

A highly stereoselective coupling reaction of diazooxindoles with difluoroenoxysilanes catalyzed by Lewis acidic boranes has been developed. The reaction proceeded at ambient temperature under transition metal-free conditions with wide functional group tolerance. By using this simple procedure, a series of tetrasubstituted monofluoroalkenes can be accessed in good yield with high selectivity.

Rational design of a ratiometric fluorescent nanoprobe for real-time imaging of hydroxyl radical and its therapeutic evaluation of diabetes.

Hydroxyl radical (•OH), one of the most reactive and deleterious substances in organisms, belongs to a class of reactive oxygen species (ROS), and it has been verified to play an essential role in numerous pathophysiological scenarios. However, due to its extremely high reactivity and short lifetime, the development of a reliable and robust method for tracking endogenous •OH remains an ongoing challenge. In this work, we presented the first ratiometric fluorescent nanoprobe NanoDCQ-3 for •OH sensing based on oxidative C-H abstraction of dihydroquinoline to quinoline. The study mainly focused on how to modulate the electronic effects to achieve an ideal ratiometric detection of •OH, as well as solving the inherent problem of hydrophilicity of the probe, so that it was more conducive to monitoring •OH in living organisms. The screened-out probe NanoDCQ-3 exhibited an exceptional ratiometric sensing capability, better biocompatibility, good cellular uptake, and appropriate in vivo retention, which has been reliably used for detecting exogenous •OH concentration fluctuation in living cells and zebrafish models. More importantly, NanoDCQ-3 facilitated visualization of •OH and evaluation of drug treatment efficacy in diabetic mice. These findings afforded a promising strategy for designing ratiometric fluorescent probes for •OH. NanoDCQ-3 emerged as a valuable tool for the detection of •OH in vivo and held potential for drug screening for inflammation-related diseases.

AgNPs loaded adenine-modified chitosan composite POSS-PEG hybrid hydrogel with enhanced antibacterial and cell proliferation properties for promotion of infected wound healing.

Wound healing is a dynamic and complex process, it's urgent to develop new wound dressings with excellent performance to promote wound healing at the different stages. Here, a novel composite hydrogel dressing composed by silver nanoparticles (AgNPs) impregnated adenine-modified chitosan (CS-A) and octafunctionalized polyhedral oligomeric silsesquioxane (POSS) of benzaldehyde-terminated polyethylene glycol (POSS-PEG-CHO) solution was presented to solve the problem of wound infection. Modification of chitosan with adenine, not only can improve the water solubility of chitosan, but also introduce bioactive substances to promote cell proliferation. CS-A and POSS-PEG-CHO were cross-linked by Schiff-base reaction to form the injectable self-healing hydrogel. On this basis, AgNPs were added into the hydrogel, which endows the hydrogel with better antibacterial activity. Moreover, this kind of hydrogel exhibits excellent cell proliferation properties. Studies demonstrated that the hydrogel can significantly accelerate the closure of infected wounds. The histological analysis and immunofluorescence staining demonstrated that the wounds treated with the composite hydrogel exhibited fewer inflammatory cells, more collagen deposition and angiogenesis, faster regeneration of epithelial tissue. Above all, adenine-modified chitosan composite hydrogel with AgNPs loaded was considered as a dressing material with great application potential for promoting the healing of infected wounds.

Applying a genetic risk score model to enhance prediction of future multiple sclerosis diagnosis at first presentation with optic neuritis.

Optic neuritis (ON) is associated with numerous immune-mediated inflammatory diseases, but 50% patients are ultimately diagnosed with multiple sclerosis (MS). Differentiating MS-ON from non-MS-ON acutely is challenging but important; non-MS ON often requires urgent immunosuppression to preserve vision. Using data from the United Kingdom Biobank we showed that combining an MS-genetic risk score (GRS) with demographic risk factors (age, sex) significantly improved MS prediction in undifferentiated ON; one standard deviation of MS-GRS increased the Hazard of MS 1.3-fold (95% confidence interval 1.07-1.55, P < 0.01). Participants stratified into quartiles of predicted risk developed incident MS at rates varying from 4% (95%CI 0.5-7%, lowest risk quartile) to 41% (95%CI 33-49%, highest risk quartile). The model replicated across two cohorts (Geisinger, USA, and FinnGen, Finland). This study indicates that a combined model might enhance individual MS risk stratification, paving the way for precision-based ON treatment and earlier MS disease-modifying therapy.

Water-Soluble Dual-Channel Fluorescent Probe for Sensitive Detection of Biothiols In Vitro and In Vivo.

Benefiting from high spatiotemporal resolution, deep tissue penetration, and excellent sensitivity, fluorescence imaging technology has been widely applied in cancer diagnosis and treatment. In recent years, a large number of fluorescent probes for monitoring the levels of endogenous biothiols have been reported, which have significant implications for cancer diagnosis and treatment. However, most probes still suffer from poor biological compatibility and easy attachment by the environment. This work presents the development of a water-soluble dual-channel fluorescent probe, named MAL-NBD, for sensitively detecting biothiols. Nonfluorescent MAL-NBD is transformed into fluorescent groups MAL and NBD-SR/NR through nucleophilic substitution by biologically active thiols, producing dual-channel fluorescence signals for precise detection of biologically active thiols. Taking advantage of the excellent biocompatibility and low biotoxicity, MAL-NBD is successfully used for imaging HeLa cancer cells and zebrafish larvae, promoting its potential application for the precise detection of biological thiols involved in physiological and pathological processes.

Injectable self-healing chitosan-based POSS-PEG hybrid hydrogel as wound dressing to promote diabetic wound healing.

Promoting the healing of diabetic wounds remains a major challenge in scientific research today. A star-like eight-arm cross-linker octafunctionalized POSS of benzaldehyde-terminated polyethylene glycol (POSS-PEG-CHO) was synthesized, and crosslinked with hydroxypropyltrimethyl ammonium chloride chitosan (HACC) via Schiff base reaction to obtain Chitosan-based POSS-PEG hybrid hydrogels. The designed composite hydrogels exhibited strong mechanical strength, injectability, excellent self-healing efficiency, good cytocompatibility and antibacterial properties. Furthermore, the composite hydrogels could accelerate cells migration and proliferation, as expected by remarkably promoting wound healing in diabetic mice. The wounds treated with the composite hydrogels displayed faster regeneration of epithelial tissue, fewer inflammatory cells, more collagen deposition and higher expression level of VEGF. Therefore, Chitosan-based POSS-PEG hybrid hydrogel has great application potential as a dressing for promoting the healing of diabetic wounds.

Recognition of soybean pods and yield prediction based on improved deep learning model.

As a leaf homologous organ, soybean pods are an essential factor in determining yield and quality of the grain. In this study, a recognition method of soybean pods and estimation of pods weight per plant were proposed based on improved YOLOv5 model. First, the YOLOv5 model was improved by using the coordinate attention (CA) module and the regression loss function of boundary box to detect and accurately count the pod targets on the living plants. Then, the prediction model was established to reliably estimate the yield of the whole soybean plant based on back propagation (BP) neural network with the topological structure of 5-120-1. Finally, compared with the traditional YOLOv5 model, the calculation and parameters of the proposed model were reduced by 17% and 7.6%, respectively. The results showed that the average precision (AP) value of the improved YOLOv5 model reached 91.7% with detection rate of 24.39 frames per millisecond. The mean square error (MSE) of the estimation for single pod weight was 0.00865, and the average coefficients of determination R2 between predicted and actual weight of a single pod was 0.945. The mean relative error (MRE) of the total weight estimation for all potted soybean plant was 0.122. The proposed method can provide technical support for not only the research and development of the pod's real-time detection system, but also the intelligent breeding and yield estimation.

Borane-catalyzed cascade Friedel-Crafts alkylation/[1,5]-hydride transfer/Mannich cyclization to afford tetrahydroquinolines.

An unprecedented redox-neutral annulation reaction of tertiary anilines with electron-deficient alkynes was developed that proceeds through a cascade Friedel-Crafts alkylation/[1,5]-hydride transfer/Mannich cyclization sequence. Under B(C6F5)3 catalysis, a range of functionalized 1,2,3,4-tetrahydroquinolines were facilely constructed in moderate to good yields with exclusive 3,4-anti-stereochemistry. The commercial availability of the catalyst and the high atom and step economy of the procedure, together with metal-free and external oxidant-free conditions, make this an attractive method in organic synthesis.