A label-free aptasensor for the detection of ATP based on turn-on fluorescence DNA-templated silver nanoclusters.

A label-free aptasensor has been fabricated in order to detect adenosine triphosphate (ATP) using turn-on fluorescence DNA-Ag NCs. The fluorescence of the DNA-Ag NCs could increase remarkably with the addition of ATP mainly because ATP specifically interacts with its aptamer to change the microenvironment of the darkish DNA-Ag NCs located at one terminus or two termini due to the conformational alteration of the aptamer structure. The proposed sensor can detect ATP in a linear range of 6-27 mM with a good detection limit of 5.0 µM. Additionally, the proposed method succeeded in detecting ATP in fetal bovine serum.

Hydrothermal Synthesis of Co-Exposed-Faceted WO3 Nanocrystals with Enhanced Photocatalytic Performance.

In this paper, rod-shaped, cuboid-shaped, and irregular WO3 nanocrystals with different co-exposed crystal facets were prepared for the first time by a simple hydrothermal treatment of tungstic acid colloidal suspension with desired pH values. The crystal structure, morphology, specific surface area, pore size distribution, chemical composition, electronic states of the elements, optical properties, and charge migration behavior of as-obtained WO3 products were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), fully automatic specific surface area and porosity analyzer, UV-vis absorption spectra, photoluminescence (PL) spectra, and electrochemical impedance spectroscopy (EIS). The photocatalytic performances of the synthesized pHx-WO3 nanocrystals (x = 0.0, 1.5, 3.0, 5.0, and 7.0) were evaluated and compared with the commercial WO3 (CM-WO3) nanocrystals. The pH7.0-WO3 nanocrystals with co-exposed {202} and {020} facets exhibited highest photocatalytic activity for the degradation of methylene blue solution, which can be attributed to the synergistic effects of the largest specific surface area, the weakest luminescence peak intensity and the smallest arc radius diameter.

Novel CdS/MOF Cathodic Photoelectrochemical (PEC) Platform for the Detection of Doxorubicin Hydrochloride and Gentamicin Sulfate.

Nanomaterial selection is critical for photoelectrochemical (PEC) sensing. In this report, a novel cathodic photoelectrochemical (PEC) strategy was proposed for the detection of doxorubicin hydrochloride (Dox) and gentamicin sulfate (CN). The photocathode was synthesized by noncovalently coupling cadmium sulfide (CdS) to the porphyrin-derived metal-organic framework (CdS@PCN-224). This type of assembly created a pleasant interface for the combination of doxorubicin hydrochloride and gentamicin sulfate, resulting in a good CdS@PCN-224 donor-acceptor system. When compared to a single optoelectronic material, its photocurrent is enhanced by unprecedented nine times. This research could pave the way for the realization of PCN-224's enormous potential in PEC sensing.

Carbon dots for specific "off-on" sensing of Co2+ and EDTA for in vivo bioimaging.

Fluorescent carbon dots (CDs) were hydrothermally synthesized from a mixture of frozen tofu, ethylenediamine and phosphoric acid in an efficient 64% yield. The resulting CDs exhibit good water solubility, low cytotoxicity, high stability, and excellent biocompatibility. The CDs selectively and sensitively detect Co2+ through fluorescent quenching with a detection limit of 58 nM. Fluorescence can be restored through the introduction of EDTA, and this phenomenon can be used to quantify EDTA in solution with a detection limit of 98 nM. As both analytes are detected by the same CD platform, this is an "off-on" fluorescence sensor for Co2+ and EDTA. The technique's robustness for real-world samples was illustrated by quantifying cobalt in tap water and EDTA in contact lens solution. The CDs were also evaluated for in vivo imaging as they show low cytotoxicity and excellent cellular uptake. In a zebrafish model, the CDs are rapidly adsorbed from the intestine into the liver, and are essentially cleared from the body in 24 h with no appreciable bioaccumulation. Their simple and efficient synthesis, combined with excellent physical and chemical performance, renders these CDs attractive candidates for theranostic applications in targeted "smart" drug delivery and bioimaging.

Tunable NIR AIE-active optical materials for lipid droplet imaging in typical model organisms and photodynamic therapy.

Near infrared (NIR) luminescent materials with aggregation-induced emission (AIE) features have attracted enormous attention in the areas of medical imaging and diagnostic therapeutics because of their low background fluorescence and strong tissue penetration. This study reports a series of easily synthesized AIEgen molecules that feature NIR emission. These molecules have a donor-donor-π-acceptor (D1-D2-π-A) structure with intramolecular charge transfer (ICT) character. The nature of charge transfer transition can be modified by different structures of D2, i.e. phenyl, thiophene, and furan ring. These AIEgens have high selectivity towards lipid droplets (LDs) in vitro and in vivo, such as zebrafish, Caenorhabditis elegans, and oil crop tissue. In addition, the effect of photodynamic therapy (PDT) on SMMC-7721 cells was investigated, and the results indicate that these AIEgens have potential application for PDT on cancer cells with white light illumination. This study reveals that these triphenylamine (TPA)-based AIEgens have great potential for biological imaging and preclinical applications of PDT.

Fluorometric probe for the lipase level: Design, mechanism and biological imaging application.

To realize accurate regulation for fluorescent substrate of lipase, two series compounds (I, II) with similar structure were designed and synthesized. The flexible diphenylmethane was permitted I to go deep into the catalytic site of lipase, while rigid structure of 9H-fluoren makes itself difficult to approach the center. Series I could be effectively hydrolyzed by porcine pancreatic lipase (PPL), and the product emitted fluorescence based on aggregation-induced emission (AIE) mechanism, meanwhile different substituent groups (-Br, -Cl, -Ph, -H) on I induced the tunable hydrolysis rate. The limit of detection (LOD) was 0.05 U/mL, and linear calibration range was 0.1-4.0 U/mL, this would be effectively applied to biological detection. This result was well supported by theories calculation and molecular docking. Moreover, substrate 1 was selected to describe the distribution of lipase in many living biology such as zebrafish, Locusta migratoria and Helianthus annuus seeds coat. It was found that lipase and lipid droplets (LDs) coexist in biological systems, but there is no lipase in LDs. The designed probe gives us an opportunity to describe lipase distribution in many important tissues, including biology and medical science.

Fluorescent PEI@Pd nanoclusters: facile synthesis and application.

Metal nanoclusters (NCs) have recently emerged as a novel class of luminescent nanomaterials and held significant potential in analytical chemistry. In this work, novel polyethyleneimine stabilized palladium nanoclusters (PEI-Pd NCs) were synthesized by chemical reduction at 60 °C for 6 h, and used as a fluorescent nanosensor for the detection of oxytetracycline (OTC). The spectral characteristics, surface structure and morphology of the Pd NCs were studied. The selectivity and stability of the nanosensor were also investigated. The experimental results showed that the Pd NCs had good biocompatibility, stability and photobleaching resistance in aqueous solution. The fluorescence quenching effect showed a good linear relationship with the degree of fluorescence quenching of Pd NCs and OTC in the range of 25-440 nM, with a correlation coefficient of 0.99. The limit of detection (LOD) of the proposed nanosensor for OTC was calculated to be 22 nM. The mechanism of determination was thought to be an inner filter effect (IFE) between OTC and Pd NCs. Based on this, we have established a new nanosensing analysis method for detecting OTC.

PCN-222@g-C3N4 cathodic materials for "signal-off" photoelectrochemical sensing of kanamycin sulfate.

A novel cathodic photoelectrochemical (PEC) sensor was developed for the ultrasensitive detection of kanamycin sulfate (KAM) based on the g-C3N4 coupled zirconium-based porphyrinic metal-organic framework (PCN-222). Photocathodes made by double n-type semiconductors, which was attributed to the transfer of electrons and holes from g-C3N4 broad band to PCN-222 with narrow band gap. The photocurrent decreased when KAM was added, which was conducive to the construction of the PEC sensor. Then, the PCN-222@g-C3N4 was used as a photosensitive platform to construct a label-free strategy and ultrasensitive detection of KAM with wide linear range from 1 to 1000 nM and a low detection limit of 0.127 nM. Moreover, this sensing platform shows good selectivity, favourable reproducibility and brilliant stability. The reported sensors provided great potential for the detection of KAM in actual samples.

Rational construction of AIEgens with wide color tunability and their specific lipid droplet imaging applications.

Organic light-emitting materials with aggregation-induced emission (AIE) character have experienced a rapid development in imaging, visualization and sensing. In this paper, by installing rotors to an aggregation-caused quenching (ACQ) compound, we constructed an AIE luminogen (AIEgens) system (A2-A4, B1-B3) with wide emission tunability, which covers almost all regions of visible light (400-780 nm). The calculated energy gap of the compounds is consistent with the value of the absorption transition. In the biological experiments, B3 showed excellent lipid droplet (LD) targeting ability in PC12 cells, and higher photostability compared with the commercial LDs bioprobe. Moreover, as a hydrophobic compound, B3 can distinguish blood from a hyperlipidemia patient and normal people. Thus, this study provides a strategy to construct red/NIR fluorescent materials with AIE character, and further apply it to identify the blood of people with hyperlipidemia.

Mitochondria-targeted reversible ratiometric fluorescent probe for monitoring SO2/HCHO in living cells.

Sulfur dioxide (SO2) maintains a certain steady state balance in the body, high concentration SO2 will be harmful to human health. Seeking a suitable detection method to monitor sulfur dioxide in real time becomes an urgent requirement owing to the transient nature of sulfur dioxide in organisms. Here, a novel NIR ratiometric fluorescent probe for detection of SO2 was developed based on a conjugation of coumarin and indol salt with excellent water solubility. The probe Mito-CI displayed highly sensitive (69 nM), fast response time (30 s), large Stokes shift (174 nm) and the NIR fluorescence emission wavelength (655 nm). In the reversibility process of the SO3--probe Mito-CI system induced by HCHO in vitro was also detected. Besides, cell imaging showed that Mito-CI possesses mitochondria-targeted ability. Particularly, Mito-CI was proved to reversibly detect SO2/HCHO in living cells.

Paper sensor of curcumin by fluorescence resonance energy transfer on nitrogen-doped carbon quantum dot.

Paper Sensor detection methods are attractive in wide analytical applications. Presented herein is a paper sensor and fluorescence methods that was firstly developed to detect curcumin (Cur) based on fluorescence resonance energy transfer (FRET) between nitrogen-doped carbon quantum dots (NCQDs) and Cur. The facile fluorescent method was demonstrated to detect Cur in the range of 0-2600 µM with a detection limit of 0.13 µM. And facile paper sensor of Cur was fabricated and displayed at concentration of 0 µM, 100 µM, 200 µM, 300 µM, 400 µM, 500 µM and 600 µM, respectively. In additions, it was realized for determination of Cur in real samples including orange juice and curry solution. Compared with the reported methods, the present method is simple, rapid and sensitive for detecting Cur.

Enzyme free glucose sensing by amino-functionalized silicon quantum dot.

Silicon quantum dots have become one of the most popular nanomaterials in biological applications for their excellent biocompatibility and optical properties. Herein, we synthesized amino-functionalized silicon quantum dots (NH2@SiQDs) via a simple microemulsion method, in which silicon tetrachloride and allylamine were used as source of silicon and functional group. NH2@SiQDs exhibits good water-solubility, high fluorescence quantum yield and optical stability. A non-enzymatic biosensor of glucose was developed based on the fluorescence quenching of NH2@SiQDs in response to glucose. The fluorescence response was linearly proportional to glucose in the concentration range of 1.0 × 10-6-9.0 × 10-5 mol/L and the detection limit was determined to be 3.0 × 10-7 mol/L. The developed glucose sensor was successfully applied in blood glucose analysis of human serum. Satisfactory result that agreed very well with traditional method was obtained.

[Long-term efficacy of laparoscope-assisted transanal total mesorectal excision for rectal cancer].

OBJECTIVE: To investigate the long-term outcome of laparoscope-assisted transanal total mesorectal excision (taTME) for rectal cancer. METHODS: Clinicopathological data of 29 patients with mid-low rectal cancer undergoing laparoscope-assisted taTME at Department of Gastrointestinal Surgery, the First Affiliated Hospital of Guangzhou Medical University from May 2010 to December 2015 were collected for the retrospective case-series study. All the operations were performed with transabdominal and transanal procedure simultaneously or sequentially. Perioperative presentations, pathological examinations, and oncologic outcomes were retrospectively analyzed. Long-term recurrence, metastasis and survival were assessed during follow-up. Outpatient clinic and telephone survey were used for follow-up. The follow-up time ended in December 2018. The overall survival (OS) rate and disease-free survival (DFS) rate were calculated by the Kaplan-Meier method. RESULTS: The average intra-operative blood loss was (75.9±9.5) ml (range,20 to 200). The average operating time was (223.6±4.1) minutes (range, 165 to 280). The average number of harvested lymph node was 22.3±2.0. The average length of pathological specimen was (13.1±0.6) cm. The average distal resection margin was (2.9±0.2) cm. 89.7% (26/29) of specimens was complete and 10.3% (3/29) near complete. Two cases (6.9%) had positive cutting circumferential margin. Median follow-up was 56 (range, 22 to 91) months. Local recurrence rate, distant metastasis rate, 3-year OS rate, 3-year DFS rate, 5-year OS rate, 5-year DFS rate were 10.3% (3/29), 20.7%(6/29), 96.6%, 83.2%, 87.6% and 79.6%, respectively. No incisional hernia or adhesive intestinal obstruction was found. CONCLUSION: Long-term outcomes of mid-low rectal cancer patients undergoing laparoscope-assisted taTME are satisfactory.

PIK3CD induces cell growth and invasion by activating AKT/GSK-3ß/ß-catenin signaling in colorectal cancer.

The catalytic subunit p110δ of phosphoinositide 3-kinase (PI3K) encoded by PIK3CD has been implicated in some human solid tumors. However, its roles in colorectal cancer (CRC) remain largely unknown. Here we found that PIK3CD was overexpressed in colon cancer tissues and CRC cell lines and was an independent predictor for overall survival (OS) of patients with colon cancer. The ectopic overexpression of PIK3CD significantly promoted CRC cell growth, migration and invasion in vitro and tumor growth in vivo. In contrast, inhibition of PIK3CD by specific small-interfering RNA or idelalisib dramatically suppressed CRC cell growth, migration and invasion in vitro and tumor growth in vivo. Moreover, PIK3CD overexpression increased AKT activity, nuclear translocation of ß-catenin and T-cell factor/lymphoid enhancer factor (TCF/LEF) transcriptional activity and decreased glycogen synthase kinase 3ß (GSK-3ß) activity, whereas PIK3CD inhibition exhibited the opposite effects. Furthermore, PIK3CD-mediated cell growth, migration and invasion were reversed by blockade of AKT signaling or depletion of ß-catenin. In addition, PIK3CD expression in colon cancer tissues positively correlated with ß-catenin abnormal expression, which was an independent predictor for OS of colon cancer patients. Taken together, our findings demonstrate that PIK3CD is an independent prognostic factor in CRC and that PIK3CD induces CRC cell growth, migration and invasion by activating AKT/GSK-3ß/ß-catenin signaling, suggesting that PIK3CD might be a novel prognostic biomarker and a potential therapeutic target for CRC.

A novel nonenzymatic cascade amplification for ultrasensitive photoelectrochemical DNA sensing based on target driven to initiate cyclic assembly of hairpins.

A novel cascade photoelectrochemical (PEC) signal amplification biosensing tactics was developed for DNA detection based on a target-driven DNA association to induce cyclic hairpin assembly. In the circulatory system there are two ssDNA (A and B) and two hairpins (C and D). The hybridization of these ssDNA led to the formation of an A-target-B structure. The close proximity of their toehold and branch-migration regions was able to induce the cyclic hairpin assembly. Afterwards, the assembly result further causes the separation of a double-stranded probe DNA (Q:F) to switch the PEC signal via toehold-mediated strand replacement. As such, the signal stranded DNA-CdS QDs (F) as the signal tag was released in the presence of the target DNA. The signal DNA-CdS QDs was then coated to F-doped tin oxide (FTO) electrode leading to the "signal-on" PEC signal. The designed biosensing strategy showed a low detection limit of 21.3 pM for target DNA and a broad linear range from 50 pM to 100 nM. This signal amplification PEC sensing method exhibited a potential application to detect protein molecules, RNA or metal ions via changing the sequence of A and B recognition.

Assembly and disassembly activity of two AIEE model compounds and its potential application.

Aggregation-induced emission (AIE) has received great attention. In this paper, Cu2+ induced self-assembly and H2S induced disassembly of two aggregation-induced emission enhancement (AIEE) compounds were reported in this paper. Two salicylaldehyde azine Schiff base were synthesized and characterized. It is found that 1 and 2 are AIEE active molecular both in aqueous solution and crystal state with strong yellow fluorescence. Theirs fluorescence can be selectively quenched in the presence of Cu2+ ions with the formation of self-assembly system [1-Cu2+]n. The interaction mechanism has been researched by multiple means. Depending on this reaction, energy changes (ΔG) from 1 to [1-Cu2+]n was also estimated by Scatchard formula. Moreover, the quenching fluorescence was further restored by H2S both in tube and live cells along with the releasing of AIEE molecular 1. That is, a reversible process between AIEE, self-assembly and disaggregation can be found in the model compound.

Quantum material accompanied nonenzymatic cascade amplification for ultrasensitive photoelectrochemical DNA sensing.

A novel cascade photoelectrochemical (PEC) signal amplification sensing strategy was designed and applied in target DNA detection by introducing quantum dots (QD) as the accompanying tag. The CdTe QD was labeled onto a designed sequence of single stranded DNA forming S-QD, which could be further hybridized with another magnetic bead labeled conjugate, leading to a metastable structure. In the presence of the detecting target, the S-QD could be released from the metastable structure via toehold strand displacement. With the help of the designed strand (H), the target could be released and triggered the cascade amplification. In the magnetic field, the S-QD could be easily separated from the reaction mixture and coated on the F-doped tin oxide (FTO) electrode leading to the "signal on" PEC response. The designed cascade amplification photoelectrochemical strategy exhibited a detection limit of 0.76 pM target DNA, and a linear range from 1 pM to 50 nM, indicating promising application in DNA or related analysis. Moreover, compared with other tags such as fluorescent dye, the quantum material leads to less unspecific adsorption and better sensing reproducibility, due to the appropriate nano size and high quantum efficiency.

Enhanced Photoelectrochemical Proximity Assay for Highly Selective Protein Detection in Biological Matrixes.

This work proposes the first photoelectrochemical proximity assay (PECPA) method via the sensitization of CdTe quantum dots (QDs) on photoelectrochemical response of ITO/TiO2/CdS electrode for highly selective and sensitive detection of proteins. This detection was performed on a sensing interface formed via the hybridization of capture DNA immobilized on ITO/TiO2/CdS electrode with labeled antibody-DNA (DNA-Ab1). Upon the recognition of Ab1 to target protein, the immunocomplex of DNA-Ab1, target, and the detection antibody-DNA (DNA-Ab2) was formed, which led to the proximity hybridization of the DNA in DNA-Ab2, capture DNA, and signal DNA-CdTe QDs, and brought CdTe QDs to the ITO/TiO2/CdS electrode to produce a sensitized photocurrent. The photocurrent intensity increased with the increasing concentration of the specific target protein. Using insulin as a target, this sensitized method showed a detectable range of 10 fM to 10 nM and a detection limit of 3.0 fM without the need of a washing step. It possessed high selectivity and good accuracy for detection of proteins in biological matrixes. This method is extremely flexible and can be extended to varieties of protein targets.

Ultrasensitive photoelectrochemical immunoassay through tag induced exciton trapping.

The development of photoelectrochemical (PEC) sensors with novel principles is of significance in realizing sensitive and low-cost detection. This work uses CuO NPs labeled antibody to construct a simple and sensitive sandwich-type immunobiosensor for the detection of protein. The detection signal is produced by dissolving the CuO NPs to release copper ions, which are then added on a quantum dots (QDs) modified F-doped tin oxide to quench the photocurrent of QDs via copper ion-induced formation of exciton trapping. The formed exciton trapping blocks the escape of photoelectron and thus leads to a "signal off" PEC method for sensitive immunoassay. The proposed method shows a detectable range from 0.05 to 500 ng/mL for α-fetoprotein (AFP) with a detection limit (LOD) of 0.038 ng/mL. This work further extends the application of exciton trapping-based PEC biosensing strategy in bioanalysis. The sensitive analytical performance of the designed route implies a promising potential of the PEC sensing in clinical diagnosis.

Anatomic study of selective neurectomy of gastrocnemius muscle for calf reduction in Chinese.

BACKGROUND: Selective neurectomy of the innervating nerves of the gastrocnemius muscle is a popular method employed for calf reduction. However, accidental injury to the untargeted adjacent nerves could happen. This study aims to provide detailed morphometry of the motor branches from the tibial nerve innervating the gastrocnemius muscle, the soleus and the medial sural cutaneous nerve in the popliteal fossa. METHODS: 23 lower legs from female cadavers were dissected to explore the origin, length of and the spatial relationship between the four branches given off from the tibial nerve in the popliteal fossa. RESULTS: Our study showed there were seven origin patterns existing among the four nerve branches; the origin of the branches to the medial and lateral heads of the gastrocnemius muscle was located ranging from -16 mm to 22 mm away from the midpoint of the line between the lateral and medial condyles of the femur; In 95% of the specimens, the location of the origin of the nerve branch to the medial head was proximal to its lateral counterpart. The nerve to the medial head was often given off from the medial aspect or the posteromedial aspect of the tibial nerve, while the other three often from the lateral aspect. CONCLUSIONS: A variety of origin patterns among the nerves to the lateral and medial gastrocnemius muscle, the nerve to the soleus muscle and the sural cutaneous nerve exist, necessitating the formulation of diversifying surgical strategies preoperatively and the meticulous and sequential dissection intra-operatively to ensure the lowest level of accidental injury.