Targeted drug delivery of engineered mesenchymal stem/stromal-cell-derived exosomes in cardiovascular disease: recent trends and future perspectives.

In recent years, stem cells and their secretomes, notably exosomes, have received considerable attention in biomedical applications. Exosomes are cellular secretomes used for intercellular communication. They perform the function of intercellular messengers by facilitating the transport of proteins, lipids, nucleic acids, and therapeutic substances. Their biocompatibility, minimal immunogenicity, targetability, stability, and engineerable characteristics have additionally led to their application as drug delivery vehicles. The therapeutic efficacy of exosomes can be improved through surface modification employing functional molecules, including aptamers, antibodies, and peptides. Given their potential as targeted delivery vehicles to enhance the efficiency of treatment while minimizing adverse effects, exosomes exhibit considerable promise. Stem cells are considered advantageous sources of exosomes due to their distinctive characteristics, including regenerative and self-renewal capabilities, which make them well-suited for transplantation into injured tissues, hence promoting tissue regeneration. However, there are notable obstacles that need to be addressed, including immune rejection and ethical problems. Exosomes produced from stem cells have been thoroughly studied as a cell-free strategy that avoids many of the difficulties involved with cell-based therapy for tissue regeneration and cancer treatment. This review provides an in-depth summary and analysis of the existing knowledge regarding exosomes, including their engineering and cardiovascular disease (CVD) treatment applications.

A novel pencil graphite electrode modified with an iron-based conductive metal-organic framework exhibited good ability in simultaneous sensing bisphenol A and bisphenol S.

Bisphenol A (BPA) and its substitute bisphenol S (BPS) are desirable materials widely used in manufacturing plastic products but can pose carcinogenic risks to humans. A new conductive iron-based metal-organic framework (Fe-HHTP)-modified pencil graphite electrode (PGE) for electrochemically sensing BPA and BPS was prepared and fully characterized by SEM, TEM, FT-IR, XRD, and XPS. Results showed that the optimal conditions for preparing Fe-HHTP/PGE were a pH of 6.5, a Fe-HHTP concentration of 2 mg·mL-1, a deposition potential of 0 V, and a deposition time of 100 s. The Fe-HHTP/PGE prepared under such conditions harbored a significant electrocatalytic activity with a detection limit of 0.8 nM for BPA and 1.7 nM for BPS (S/N = 3). Correspondingly, the electrochemical response current was linearly correlated to BPA and BPS, ranging from 0.01 to 100 µM. Fe-HHTP/PGE also obtained satisfactory recoveries by 93.8-102.1% and 96.0-101.3% for detecting BPA and BPS in plastic food packaging samples. Our work has provided a novel electrochemical tool to simultaneously detect BPA and BPS in food packaging samples and environmental matrixes.

LRRC75A-AS1 drives the epithelial-mesenchymal transition in cervical cancer by binding IGF2BP1 and inhibiting SYVN1-mediated NLRP3 ubiquitination.

Cervical cancer severely affects women's health with increased incidence and poor survival for patients with metastasis. Our study aims to investigate the mechanism by which lncRNA LRRC75A-AS1 regulates the epithelial-mesenchymal transition (EMT) of cervical cancer through modulating m6A and ubiquitination modification. In this study, tumor tissues were collected from patients to analyze the expression of LRRC75A-AS1 and SYVN1. Migratory and invasive capacities of HeLa and CaSki cells were evaluated with wound healing and transwell assays. CCK-8 and EdU incorporation assays were employed to examine cell proliferation. The interaction between LRRC75A-AS1, IGF2BP1, SYVN1, and NLRP3 was evaluated through RNA immunoprecipitation, RNA pull-down, FISH, and Co-IP assays, respectively. MeRIP-qPCR was applied to analyze the m6A modification of SYVN1 mRNA. A subcutaneous tumor model of cervical cancer was established. We showed LRRC75A-AS1 was upregulated in tumor tissues, and LRRC75A-AS1 enhanced EMT through activating NLRP3/IL-1ß/Smad2/3 signaling in cervical cancer. Furthermore, LRRC75A-AS1 inhibited SYVN1-mediated NLRP3 ubiquitination by destabilizing SYVN1 mRNA. LRRC75A-AS1 competitively bound to IGF2BP1 protein and subsequently impaired the m6A modification of SYVN1 mRNA and its stability. Knockdown of LRRC75A-AS1 repressed EMT and tumor growth via inhibiting NLRP3/IL-1ß/Smad2/3 signaling in mice. In conclusion, LRRC75A-AS1 competitively binds to IGF2BP1 protein to destabilize SYVN1 mRNA, subsequently suppresses SYVN1-mediated NLRP3 ubiquitination degradation and activates IL-1ß/Smad2/3 signaling, thus promoting EMT in cervical cancer. Implications: LRRC75A-AS1 promotes cervical cancer progression, and this study suggests LRRC75A-AS1 as a new therapeutic target for cervical cancer.

Delta radiomics analysis for prediction of intermediary- and high-risk factors for patients with locally advanced cervical cancer receiving neoadjuvant therapy.

This study aimed to assess the feasibility of using magnetic resonance imaging (MRI)-based Delta radiomics characteristics extrapolated from the Ax LAVA + C series to identify intermediary- and high-risk factors in patients with cervical cancer undergoing surgery following neoadjuvant chemoradiotherapy. A total of 157 patients were divided into two groups: those without any intermediary- or high-risk factors and those with one intermediary-risk factor (negative group; n = 75). Those with any high-risk factor or more than one intermediary-risk factor (positive group; n = 82). Radiomics characteristics were extracted using Ax-LAVA + C MRI sequences. The data was divided into training (n = 126) and test (n = 31) sets in an 8:2 ratio. The training set data features were selected using the Mann-Whitney U test and the Least Absolute Shrinkage and Selection Operator (LASSO) test. The best radiomics features were then analyzed to build a preoperative predictive radiomics model for predicting intermediary- and high-risk factors in cervical cancer. Three models-the clinical model, the radiomics model, and the combined clinic and radiomics model-were developed in this study utilizing the random forest Algorithm. The receiver operating characteristic (ROC) curve, decision curve analysis (DCA), accuracy, sensitivity, and specificity were used to assess the predictive efficacy and clinical benefits of each model. Three models were developed in this study to predict intermediary- and high-risk variables associated with postoperative pathology for patients who underwent surgery after receiving neoadjuvant radiation. In the training and test sets, the AUC values assessed using the clinical model, radiomics model, and combined clinical and radiomics models were 0.76 and 0.70, 0.88 and 0.86, and 0.91 and 0.89, respectively. The use of machine learning algorithms to analyze Delta Ax LAVA + C MRI radiomics features can aid in the prediction of intermediary- and high-risk factors in patients with cervical cancer receiving neoadjuvant therapy.

Genetic Diversity of Domestic Cat Hepadnavirus in Southern Taiwan.

Domestic cat hepadnavirus (DCH) is an infectious disease associated with chronic hepatitis in cats, which suggests a similarity with hepatitis B virus infections in humans. Since its first identification in Australia in 2018, DCH has been reported in several countries with varying prevalence rates, but its presence in Taiwan has yet to be investigated. In this study, we aimed to identify the presence and genetic diversity of DCH infections in Taiwan. Among the 71 samples tested, eight (11.27%) were positive for DCH. Of these positive cases, three cats had elevated levels of alanine transaminase (ALT) and aspartate transaminase (AST), suggesting an association between DCH infection and chronic hepatitis. Four DCH-positive samples were also tested for feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) coinfection. One sample (25%) was positive for FIV, whereas there was no positive sample for FeLV (0%). In addition, we performed whole genome sequencing on six samples to determine the viral genome sequences. Phylogenetic analyses identified a distinct lineage compared with previously reported sequences. This study highlights the importance of continuous surveillance of DCH and further research to elucidate the pathophysiology and transmission route of DCH.

Human hair follicle-derived mesenchymal stem cells promote tendon repair in a rabbit Achilles tendinopathy model.

BACKGROUND: Hair follicles are easily accessible and contain stem cells with different developmental origins, including mesenchymal stem cells (MSCs), that consequently reveal the potential of human hair follicle (hHF)-derived MSCs in repair and regeneration. However, the role of hHF-MSCs in Achilles tendinopathy (AT) remains unclear. The present study investigated the effects of hHF-MSCs on Achilles tendon repair in rabbits. METHODS: First, we extracted and characterized hHF-MSCs. Then, a rabbit tendinopathy model was constructed to analyze the ability of hHF-MSCs to promote repair in vivo . Anatomical observation and pathological and biomechanical analyses were performed to determine the effect of hHF-MSCs on AT, and quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and immunohistochemical staining were performed to explore the molecular mechanisms through which hHF-MSCs affects AT. Furthermore, statistical analyses were performed using independent sample t test, one-way analysis of variance (ANOVA), and one-way repeated measures multivariate ANOVA as appropriate. RESULTS: Flow cytometry, a trilineage-induced differentiation test, confirmed that hHF-derived stem cells were derived from MSCs. The effect of hHF-MSCs on AT revealed that the Achilles tendon was anatomically healthy, as well as the maximum load carried by the Achilles tendon and hydroxyproline proteomic levels were increased. Moreover, collagen I and III were upregulated in rabbit AT treated with hHF-MSCs (compared with AT group; P  < 0.05). Analysis of the molecular mechanisms revealed that hHF-MSCs promoted collagen fiber regeneration, possibly through Tenascin-C (TNC) upregulation and matrix metalloproteinase (MMP)-9 downregulation. CONCLUSIONS: hHF-MSCs can be a treatment modality to promote AT repair in rabbits by upregulating collagen I and III. Further analysis revealed that treatment of AT using hHF-MSCs promoted the regeneration of collagen fiber, possibly because of upregulation of TNC and downregulation of MMP-9, thus suggesting that hHF-MSCs are more promising for AT.

Closed Cyclic DNA Machine for Sensitive Logic Operation and APE1 Detection.

DNA self-assembly has been developed as a kind of robust signal amplification strategy, but most of reported assembly pathways are programmed to amplify signal in one direction. Herein, based on mutual-activated cascade cycle of hybridization chain reaction (HCR) and catalytic hairpin assembly (CHA), a closed cycle circuit (CCC) based DNA machine is developed for sensitive logic operation and molecular recognition. Benefiting from the synergistically accelerated signal amplification, the closed cyclic DNA machine enabled the logic computing with strong and significant output signals even at weak input signals. The typical logic operations such as OR, YES, AND, INHIBIT, NOR, and NAND gate, are conveniently and clearly executed with this DNA machine through rational design of the input and computing elements. Moreover, by integrating the target recognition module with the CCC module, the proposed DNA machine is further employed in the homogeneous detection of apurinic/apyrimidinic endonuclease 1 (APE1). The precise recognition and exponential signal amplification facilitated the highly selective and sensitive detection of APE1 with limit of detection (LOD) of 7.8 × 10-5 U mL-1 . Besides, the normal cells and tumor cells are distinguished unambiguously by this method according to the detected concentration difference of cellular APE1, which indicates the robustness and practicability of this method.

Label-free and low-background FEN1 sensing based on cleavage-induced ligation of bifunctional dumbbell DNA and in-situ signal readout.

Flap endonuclease 1 (FEN1) is overexpressed in various types of human tumor cells and has been recognized as a promising biomarker for cancer diagnosis in recent years. In this work, a label-free fluorescent nanosensor for FEN1 detection was developed based on cleavage-induced ligation of bifunctional dumbbell DNA and in-situ signal readout by copper nanoparticles (CuNPs). The dumbbell DNA was rationally designed with a FEN1 cleavable 5' flap for target recognition and AT-riched stem-loop template for CuNPs formation. In the presence of FEN1, 5' overhanging DNA flap of dumbbell DNA was effectively removed to form a linkable nick site. After the ligation by T4 DNA ligase, the dumbbell DNA changed to exonuclease-resisted closed structure which enabled in-situ generation of fluorescent CuNPs that served as signal source for target quantification. The low background attributed to synergic digestion by exonucleases facilitated the highly sensitive detection of FEN1 with limit of detection of 0.007 U/mL. Additionally, the sensor was extended to the assay of FEN1 inhibitor (aurintricarboxylic acid) with reasonable results. Last but not least, the normal cells and tumor cells were distinguished unambiguously by this sensor according to the detected concentration difference of cellular FEN1, which indicates the robustness and practicability of this nanosensor.

Simultaneously colorimetric detection and effective removal of mercury ion based on facile preparation of novel and green enzyme mimic.

In this work, an environmentally-friendly and cost-effective enzyme mimic was obtained by facile one-pot preparation of chitosan/Cu/Fe (CS/Cu/Fe) composite. This composite exhibited significantly enhanced oxidase-mimicking activity during catalyzing the oxidation of 3, 3', 5, 5'-tetramethylbenzidine (TMB). The CS/Cu/Fe composite was comprehensively characterized and the possible catalytic mechanism was reasonably explored and discussed. Benefiting from the thermal stability and the compatibility with carbohydrate, the CS/Cu/Fe composite was further integrated with agarose hydrogel to fabricate a portable analytical tube containing oxidase mimic. Based on the inhibition of the catalytic oxidation of TMB in the presence of cysteine, as well as the recovery of oxidase-like activity of CS/Cu/Fe due to the specific complexation of cysteine and mercury ion (Hg2+), the rapid colorimetric detection of Hg2+ was successfully carried out in the analytical tube. This colorimetric method showed good linear response to Hg2+ over the range from 40 nM to 8.0 µM with a detection limit of 8.9 nM. The method also revealed high selectivity and satisfactory results in recovery experiments of Hg2+ detection in tap water and lake water. Furthermore, it was found that the effective removal of Hg2+ could be realized in the analytical tube based on efficient Hg2+ adsorption by CS/Cu/Fe composite and agarose hydrogel. This study not only prepared a robust and low-cost enzyme mimic, but also proposed a smart strategy to simultaneously monitor and remove toxic Hg2+ from contaminated water.

Super-enhancer mediated regulation of adult ß-globin gene expression: the role of eRNA and Integrator.

Super-enhancers (SEs) mediate high transcription levels of target genes. Previous studies have shown that SEs recruit transcription complexes and generate enhancer RNAs (eRNAs). We characterized transcription at the human and murine ß-globin locus control region (LCR) SE. We found that the human LCR is capable of recruiting transcription complexes independently from linked globin genes in transgenic mice. Furthermore, LCR hypersensitive site 2 (HS2) initiates the formation of bidirectional transcripts in transgenic mice and in the endogenous ß-globin gene locus in murine erythroleukemia (MEL) cells. HS2 3'eRNA is relatively unstable and remains in close proximity to the globin gene locus. Reducing the abundance of HS2 3'eRNA leads to a reduction in ß-globin gene transcription and compromises RNA polymerase II (Pol II) recruitment at the promoter. The Integrator complex has been shown to terminate eRNA transcription. We demonstrate that Integrator interacts downstream of LCR HS2. Inducible ablation of Integrator function in MEL or differentiating primary human CD34+ cells causes a decrease in expression of the adult ß-globin gene and accumulation of Pol II and eRNA at the LCR. The data suggest that transcription complexes are assembled at the LCR and transferred to the globin genes by mechanisms that involve Integrator mediated release of Pol II and eRNA from the LCR.

Recent Advances in Biomaterials for the Treatment of Bone Defects.

Bone defects or fractures generally heal in the absence of major interventions due to the high regenerative capacity of bone tissue. However, in situations of severe/large bone defects, these orchestrated regeneration mechanisms are impaired. With advances in modern medicine, natural and synthetic bio-scaffolds from bioceramics and polymers that support bone growth have emerged and gained intense research interest. In particular, scaffolds that recapitulate the molecular cues of extracellular signals, particularly growth factors, offer potential as therapeutic bone biomaterials. The current challenges for these therapies include the ability to engineer materials that mimic the biological and mechanical properties of the real bone tissue matrix, whilst simultaneously supporting bone vascularization. In this review, we discuss the very recent innovative strategies in bone biomaterial technology, including those of endogenous biomaterials and cell/drug delivery systems that promote bone regeneration. We present our understanding of their current value and efficacy, and the future perspectives for bone regenerative medicine.

Exosomes from adipose­derived stem cells promote chondrogenesis and suppress inflammation by upregulating miR­145 and miR­221.

Osteoarthritis (OA) is one of the most prevalent joint disorders globally. Patients suffering from OA are often obese and adiposity is linked to chronic inflammation. In the present study, the potential of using exosomes isolated from adipose­derived stem cells (ADSCs) as a therapeutic tool for reducing chronic inflammation and promoting chondrogenesis was investigated using patient­derived primary cells. First, it was tested whether patient­derived ADSCs could differentiate into chondrogenic and osteogenic lineages. The ADSCs were then used as a source of exosomes. It was found that exosomes isolated from ADSCs, when co­cultured with activated synovial fibroblasts, downregulated the expression of pro­inflammatory markers interleukin (IL)­6, NF­κB and tumor necrosis factor­α, while they upregulated the expression of the anti­inflammatory cytokine IL­10; without exosomes, the opposite observations were made. In addition, inflammation­inflicted oxidative stress was induced in vitro by stimulating chondrocytes with H2O2. Treatment with exosomes protected articular chondrocytes from H2O2­induced apoptosis. Furthermore, exosome treatment promoted chondrogenesis in periosteal cells and increased chondrogenic markers, including Collagen type II and ß­catenin; inhibition of Wnt/ß­catenin, using the antagonist ICG­001, prevented exosome­induced chondrogenesis. Periosteal cells treated with exosomes exhibited higher levels of microRNA (miR)­145 and miR­221. The upregulation of miR­145 and miR­221 was associated with the enhanced proliferation of periosteal cells and chondrogenic potential, respectively. The present study provided evidence in support for the use of patient­derived exosomes, produced from ADSCs, for potential chondrogenic regeneration and subsequent amelioration of osteoarthritis.

Recent advances in natural therapeutic approaches for the treatment of cancer.

Plants and natural compounds have been widely recognized to have potential for the prevention of cancer progression and as complementary or standalone treatments for cancer patients. The major benefits of natural compounds are their reduced toxicity compared to more aggressive and widely utilized cancer treatment approaches. Preclinical studies have led to the discovery of a number of natural anticancer compounds, including preparations of Vitex negundo L., green tea, mandarin peel oil, ursolic acid, curcumin and resveratrol. Although the in vitro data highlights the potential of these natural alternatives, their benefits in clinical cancer treatment remain less conclusive. In this review, we will discuss some of the recent advances in natural anticancer treatment discovery for the four most prominent global cancers, namely, breast, lung, prostate and skin metastases. As the exploration of natural therapeutics continues to expand, these substances have the potential to be utilized as preventative strategies and complimentary therapeutics. In some cases, they may have sufficient anti-tumor and anti-carcinogenic properties to function as standalone cancer treatments.

Ratiometric SERS biosensor for sensitive and reproducible detection of microRNA based on mismatched catalytic hairpin assembly.

MicroRNAs (miRNAs) serve as significant regulators in a variety of diseases and have been emerging as a class of promising biomarkers for early cancer diagnosis. Herein, an enzyme-free surface-enhanced Raman scattering (SERS) platform was proposed for sensitive and reliable detection of target miRNA-21 using a corrective internal standard (IS)-based ratiometric SERS probe coupled with mismatched catalytic hairpin assembly (CHA) amplification. The 4-aminothiophenol (4-ATP) was used as IS molecule and modified on the surface of silver nanoparticles decorated silicon wafer. In principle, the presence of miRNA-21 could cyclically trigger the allosteric effects of mismatched CHA amplification and the 3'-R6G labeled hairpin probe 1 (H1) was opened. Then, the hairpin probe 2 (H2) hybridized with H1 to form H1-H2 complex and the released miRNA-21 was free to participate in the next cycle of CHA reaction. Meanwhile, the H1-H2 complex could hybridize with the capture DNA on the SERS chip, making the Raman tag of R6G close to the surface of SERS substrate, and the intensity of SERS signal from R6G labels increase while that from 4-ATP remain relatively unchanged. Benefiting from outstanding performances of the ratiometric SERS strategy and enzyme-free CHA amplification system, this platform exhibits sensitivity toward miRNA-21 with a limit of detection of 3.5 fM and a broad dynamic range from 10 fM to 100 nM. More importantly, this proposed method presents an excellent reliable SERS analysis with the correction of IS. The developed strategy holds a potential alternative tool for miRNA detection in biomedical research and early clinical diagnosis.

Recent advances in oncolytic virus-based cancer therapy.

Administration of oncolytic viruses (OVs) is an emerging anticancer strategy that exploits the lytic nature of viral replication to enhance the killing of malignant cells. OVs can be used as tools to directly induce cancer cell death and to trigger local and/or systemic immune responses to metastatic cancer in vivo. The effectiveness of OV therapy was initially highlighted by the clinical use of the genetically modified herpes virus, talimogene laherparepvec, for melanoma therapy. A number of OVs are now being evaluated as potential treatments for cancer in clinical trials. In spite of being engineered to specifically target tumor cells, the safety and off-target effects of OV therapy are a concern. The potential safety concerns of OVs are highlighted by current clinical trial criteria, which exclude individuals harbouring other viral infections and people who are immunocompromised. Despite the potential for adverse effects, clinical trials to date revealed relatively minimal adverse immune-related effects, such as fever. With advances in our understanding of virus replication cycles, several novel OVs have emerged. Reverse genetic systems have facilitated the insertion of anticancer genes into a range of OVs to further enhance their tumor-killing capacity. In this review, we highlight the recent advances in OV therapy for a range of human cancers in in vitro and in in vivo animal studies. We further discuss the future of OVs as a therapeutic strategy for a range of life-threatening cancers.

Migration of titanium dioxide from PET/TiO2 composite film for polymer-laminated steel.

PET/TiO2 composite film is the most widely used film for polymer-laminated steel, and the migration of TiO2 is very important for the safety evaluation of its packaged food. Microwave digestion, wet digestion and dry ashing were used for pretreatment of composite film to determine the content of TiO2 in composite film. Migration tests were carried out at 40°C, 60°C and 80°C 4% using acetic acid and 50% ethanol as the acid and ester food simulants. The migration amount of TiO2 was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). With increasing temperature and time, the migration of TiO2 increased. In 4% acetic acid, the migration amount of TiO2 at 40°C for 10 days was 1.88 mg kg-1 and the migration amount at 80°C for 8 h was 3.32 mg kg-1, indicating that the effect of temperature on migration was more obvious. Under the same conditions, the migration amount of TiO2 in 4% acetic acid was greater than in 50% ethanol. X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimeter (DSC) were used to analyse the crystal structure, morphology, chemical groups and thermal properties of the film before and after the migration tests. The results showed that filmTiO2 had a stable rutile type crystal structure and it was almost uniformly distributed. PET and TiO2 were combined with strong chemical bonds. After TiO2 migration, the crystallinity and the glass transition temperature (Tg) of the film decreased, but the change of melting temperature (Tm) was not obvious.

Impact of radical hysterectomy on the transobturator sling pathway: a retrospective three-dimensional magnetic resonance imaging study.

INTRODUCTION AND HYPOTHESIS: Morphological and functional anomalies of the urethra may cause stress urinary incontinence after radical hysterectomy (RH). We introduce a novel three-dimensional (3D) magnetic resonance imaging (MRI) technique to assess the impact of RH on the transobturator sling pathway. METHODS: 3D-MRI reconstruction models were retrospectively developed for the measurement of various parameters before and after RH, including puncture angle, orientation and distance from the midurethral puncture site to the obturator membrane (DUO), in 31 patients with cervical cancer. Additionally, the correlations between DUO and body height and interspinal diameter were evaluated. RESULTS: No significant differences were noted between the preoperative and postoperative inclination angle (-7.1 ± 33.5° vs. -0.68 ± 23.9°, ranges -62.4 to 46.8° vs. -54.1 to 42.2°, respectively) or between the preoperative and postoperative left and right mean rotation angles (left 69.0 ± 8.0° vs. 67.8 ± 9.2°; right 65.1 ± 8.38° vs. 64.3 ± 10.5°). Similarly, there were no statistically or clinically significant differences between the preoperative and postoperative DUO, although slight differences were noted between the two sides before and after RH (P = 0.018 and P = 0.023, respectively). None of the parameters differed significantly between the groups with and without postoperative urodynamic stress incontinence. Further, there was no clinically significant correlation between DUO and height or interspinal diameter. CONCLUSIONS: The sling procedure via the transobturator approach is technically safe from a 3D anatomical standpoint. However, wide variability in the anatomical parameters must be taken into account when planning the procedure.

Target-protecting dumbbell molecular probe against exonucleases digestion for sensitive detection of ATP and streptavidin.

In this work, a versatile dumbbell molecular (DM) probe was designed and employed in the sensitively homogeneous bioassay. In the presence of target molecule, the DM probe was protected from the digestion of exonucleases. Subsequently, the protected DM probe specifically bound to the intercalation dye and resulted in obvious fluorescence signal which was used to determine the target molecule in return. This design allows specific and versatile detection of diverse targets with easy operation and no sophisticated fluorescence labeling. Integrating the idea of target-protecting DM probe with adenosine triphosphate (ATP) involved ligation reaction, the DM probe with 5'-end phosphorylation was successfully constructed for ATP detection, and the limitation of detection was found to be 4.8 pM. Thanks to its excellent selectivity and sensitivity, this sensing strategy was used to detect ATP spiked in human serum as well as cellular ATP. Moreover, the proposed strategy was also applied in the visual detection of ATP in droplet-based microfluidic platform with satisfactory results. Similarly, combining the principle of target-protecting DM probe with streptavidin (SA)-biotin interaction, the DM probe with 3'-end biotinylation was developed for selective and sensitive SA determination, which demonstrated the robustness and versatility of this design.

Nickel-Catalyzed Regioselective Cleavage of C(sp(2))-S Bonds: Method for the Synthesis of Tri- and Tetrasubstituted Alkenes.

We describe here an efficient route for the synthesis of (Z)-vinylic sulfides 3 via the highly regio- and stereoselective coupling of (Z)-1,2-bis(aryl(alkyl)thio)alkenes and Grignard reagents over a Ni catalyst under mild conditions. (Z)-Vinylic sulfides 3 are important intermediates in the synthesis of tri- and tetrasubstituted alkenes that are important construction blocks for drugs and natural products. The directing organosulfur groups (SR) can be converted to diaryl(alkyl) disulfides (RSSR) using H2O2 as oxidant, hence avoiding the waste of sulfur resources. The protocol provides a general method that is highly regio- and stereoselective for the synthesis of a diversity of tri- and tetrasubstituted alkenes.

Multifunctional Dumbbell-Shaped DNA-Templated Selective Formation of Fluorescent Silver Nanoclusters or Copper Nanoparticles for Sensitive Detection of Biomolecules.

In this work, a multifunctional template for selective formation of fluorescent silver nanoclusters (AgNCs) or copper nanoparticles (CuNPs) is put forward. This dumbbell-shaped (DS) DNA template is made up of two cytosine hairpin loops and an adenine-thymine-rich double-helical stem which is closed by the loops. The cytosine loops act as specific regions for the growth of AgNCs, and the double-helical stem serves as template for the CuNPs formation. By carefully investigating the sequence and length of DS DNA, we present the optimal design of the template. Benefiting from the smart design and facile synthesis, a simple, label-free, and ultrasensitive fluorescence strategy for adenosine triphosphate (ATP) detection is proposed. Through the systematic comparison, it is found that the strategy based on CuNPs formation is more sensitive for ATP assay than that based on AgNCs synthesis, and the detection limitation was found to be 81 pM. What's more, the CuNPs formation-based method is successfully applied in the detection of ATP in human serum as well as the determination of cellular ATP. In addition to small target molecule, the sensing strategy was also extended to the detection of biomacromolecule (DNA), which illustrates the generality of this biosensor.