Silica-polydopamine hybrids as light-induced oxidase mimics for colorimetric detection of pyrophosphate.

In this study, silica-polydopamine hybrids (SPDA) were fabricated by a facile and one-step heating method using dopamine and (3-aminopropyl)triethoxysilane (APTES) as the reaction reagents. It was firstly found that light illuminated-SPDA could oxidize colorless 3,3',5,5'-tetramethylbenzidine (TMB) to produce blue ox-TMB. The coloration process was quenched very efficiently via the addition of Cu2+. The presence of pyrophosphate ion (PPi) in the solution of light-illuminated SPDA-Cu2+-TMB induced the recovery of the coloration process. The recovery occurred because PPi coordinated with Cu2+, effectively sequestering the ion from SPDA. A calibration curve was developed that is related to the extent of absorption recovery to [PPi], making the SPDA-Cu2+-TMB system a sensitive and selective turn-on sensor for PPi detection. The limit-of-detection (LOD) for PPi was 0.06 µmol L-1 (S/N = 3) with a linear dynamic range of 0.1-30 µmol L-1 and the calibration curve of linear equation is given as: y = 0.00146x + 0.05096 (r = 0.9974). The proposed method has been successfully applied to the detection of PPi in human serum with satisfactory recovery. The simplicity, low cost, high sensitivity, good reproducibility and excellent selectivity of the PPi detection platform based on the light-induced oxidase mimicking property of SPDA makes it promising for further applications of SPDA in chemo/biosensing.

Micelle-mediated chemiluminescence of 6-aza-2-thiothymine-protected gold nanoclusters for carbazochrome sodium sulfonate detection.

Chemiluminescence (CL) intensity of luminol-H2O2 system was dramatically enhanced by cetyltrimethylammonium bromide (CTAB) micelle-mediated 6-aza-2-thiothymine-protected gold nanoclusters (ATT-AuNCs). It is proved that spherical micelles of CTAB in aqueous solution improved the dispersity of ATT-AuNCs, thus enhancing their catalytic activity, which brought in the increased CL intensity of luminol-H2O2 system. Carbazochrome sodium sulfonate (CSS) with a hemostatic containing tetrahydroindole structure broke the spherical micelles and notably quenched the CL intensity of luminol-H2O2-CTAB-ATT AuNCs system. Based on these results, a simple, fast, and sensitive CL method has been developed for the detection of CSS with a linear range of 0.25-25 µM and a detection limit of 0.11 µM. The method has also been successfully applied to the determination of CSS in serum with satisfied recoveries in the range of 89.6 % to 103.7 %. This study not only provides an effective approach for CSS detection but also paves the way for AuNCs-based CL applications.

Effects of transplantation of umbilical cord blood mononuclear cells into the scrotum on sexual function in elderly mice.

Aim: This study investigated the effect of allografting umbilical cord blood mononuclear cells (UCBMCs) into the scrotum on sexual function in male elderly mice. Methods: UCBMCs were injected once into the scrotal sheath cavity of elderly mice. Results: The transplanted UCBMCs survived in the scrotal sheath cavity for 1 month. The mice had significantly increased blood testosterone concentrations, cyclic guanosine monophosphate (cGMP) levels and total nitric oxide synthase (T-NOS) activity in the corpus cavernosum and an increase in the number of mouse matings within 30 min (all p = 0.000). Conclusion: Scrotum-implanted UCBMCs improve the sexual function of male elderly mice through testosterone production and the NOS/cGMP pathway, which may provide an innovative transplantation approach for the treatment of erectile dysfunction.

A sensitive biosensor for glucose determination based on the unique catalytic chemiluminescence of sodium molybdate.

Chemiluminescent (CL) reaction between hydrogen peroxide (H2O2) and luminol was dramatically enhanced by sodium molybdate (Na2MoO4) for 284-fold. CL mechanism investigation indicated that Na2MoO4 increased the production of hydroxyl radical (•OH) and superoxide anion (•O2-) in the H2O2-luminol system, which could attribute to the enhanced-CL intensity and gave us new insights into the CL-enhanced property of Na2MoO4. The CL intensity of Na2MoO4-H2O2-luminol system increased with the concentration of H2O2, based on which, a convenient and sensitive CL determination method could be developed for H2O2 in the concentration ranging from 0.5 to 60 µmol/L, with a detection limit of 0.25 µmol/L. Combining with glucose oxidase, the Na2MoO4-H2O2-luminol system could also be applied for glucose detection. Glucose in human serum has been successfully detected with satisfied recoveries in the range of 96.7 % to 105.4 %.

A facile route for constructing Cu-N-C peroxidase mimics.

Nanozymes have emerged as enzyme-mimicking nanomaterials to overcome the low stability and high cost of some natural enzymes. The design and fabrication of nanozymes with superior performance to natural enzymes are in urgent demand. Single-atom catalysts offer the unique characteristics of maximum atomic utilization, and are an excellent candidate for nanozymes. However, most of the reported synthesis methods for single-atom catalysts require the preparation of supports for single-atom catalysts in advance, which requires multiple steps and calcination in a high temperature atmosphere. Herein, Cu-N-C single-atom nanozymes (Cu-N-C SAzymes) were successfully designed via a one-pot solvothermal method. Cu-N-C SAzymes exhibited excellent peroxidase-mimicking activity that is superior to some other related nanoparticles. The mechanism study revealed that H2O2 was catalyzed by Cu-N-C SAzymes to generate reactive oxygen species. Furthermore, based on the excellent peroxidase-mimicking activity of the Cu-N-C SAzymes, a simple and sensitive detection method for H2O2 and glucose has been developed.

Delicaflavone induces ROS-mediated apoptosis and inhibits PI3K/AKT/mTOR and Ras/MEK/Erk signaling pathways in colorectal cancer cells.

Colorectal cancer (CRC) is one of the most common malignant tumors worldwide and tends to have drug resistance. Delicaflavone (DLF), a novel anticancer agent of biflavonoid from Selaginella doederleinii Hieron, showed strong anti-CRC activities, which has not yet been reported. In this study, we investigated the effects and possible anti-CRC mechanism of DLF in vitro and in vivo. It was shown that DLF significantly inhibited the cells viability and induced G2/M phase arrest, apoptosis, the loss of mitochondrial membrane potential (Δψm), generation of ROS and increase of intracellular Ca2+ in HT29 and HCT116 cells by MTT assay, TEM, flow cytometry and inverted fluorescence microscope. Western blot and qPCR assays results further confirmed DLF induced caspase-dependent apoptosis and inhibited PI3K/AKT/mTOR and Ras/MEK/Erk signaling pathways in CRC cells. Meanwhile, DLF significantly suppressed the tumor growth via activation of Caspase-9 and Caspase-3 protein and decrease of ki67 and CD34 protein without apparent side effects in vivo. In summary, these results indicated DLF induced ROS-mediated cell cycle arrest and apoptosis through ER stress and mitochondrial pathway accompanying with the inhibition of PI3K/AKT/mTOR and Ras/MEK/Erk signaling cascade. Thus DLF could be a potential therapeutic agent for CRC.

Delicaflavone induces apoptosis via mitochondrial pathway accompanying G2/M cycle arrest and inhibition of MAPK signaling cascades in cervical cancer HeLa cells.

BACKGROUND: Cervical cancer (CCa) represents the fourth most common cause of cancer-related death in women worldwide. CCa therapy is still a major clinical challenge worldwide. Finding and developing new anti-CCa chemotherapeutic drugs is a very significant issue. Delicaflavone is a rare biflavonoid from Selaginella doederleinii Hieron, which has shown strong anti-cancer activities in our preliminary screening. PURPOSE: The present study aimed to investigate the apoptotic effect and mechanism of delicaflavone against CCa. METHODS: In this study, the effect and potential mechanism of delicaflavone against CCa were investigated in vitro and in vivo by MTT assay, TEM, flow cytometry, western blot assay, qPCR assay, immunofluorescence assay and the mouse xenograft tumor model. RESULTS: It was confirmed that delicaflavone inhibited the proliferation of human CCa HeLa cells, and induced morphological changes, G2/M phase arrest and apoptosis in a dose- and time-dependent manner. HeLa cells treated with delicaflavone showed the loss of mitochondrial membrane potential, release of Cytochrome c, activation of caspases, alteration of Bax/Bcl-2 balance, and the inhibition of MAPK signaling cascades. Furthermore, delicaflavone significantly decreased tumor growth in a dose-dependent manner without apparent side effects in a xenograft tumor model of HeLa cells. Immunohistochemistry analysis confirmed the up-regulation of Caspase-9, Caspase-3, Bax protein and down-regulation of Bcl-2 protein in the xenografts tumors, which was consistent with the results in vitro. CONCLUSION: The results of the current study show that apoptosis is induced by the mitochondrial pathway accompanying with G2/M cycle arrest and inhibition of MAPK signaling cascades in human CCa HeLa cells, which can be used as a promising therapeutic drug for CCa.

Simultaneous quantification of five biflavonoids in rat plasma by LC-ESI-MS/MS and its application to a comparatively pharmacokinetic study of Selaginella doederleinii Hieron extract in rats.

Selaginella doederleinii Hieron is a widely used as folk Chinese medicine for treatment of different cancers. Our previous investigations have confirmed that the total biflavonoids in ethyl acetate extract from S. doederleinii (SDEA) have favorable anticancer potentials. However, the in vivo process of its bioactive ingredients remains unknown. In this paper, a sensitive and reliable method was developed for simultaneous quantification of main five biflavonoids, including amentoflavone, robustaflavone, 2″,3″-dihydro-3',3″-biapigenin, 3',3″-binaringenin and delicaflavone in the ethyl acetate extract of S. doederleinii (SDEA extract) in rat plasma by high-performance liquid chromatography with electrospray ionization-mass spectrometry (HPLC-ESI-MS/MS). Chromatographic separation was performed using an Ultimate® XB-C18 (100×2.1mm, 3.5µm) with gradient elution of water (0.5% acetic acid) and acetonitrile at 0.2mL/min. All analytes with internal standard (chrysin) were detected using selective reaction monitoring (SRM) in negative ionization mode. The method showed a good linearity over a wide concentration range (r2>0.99). The limits of quantification for the biflavonoids were less than 10ng/mL. The developed method was applied to the comparatively pharmacokinetic study of the five biflavonoids after oral or intravenous administration of SDEA extract in rats. In addition, in silico assessments of permeability and solubility of these biflavonoids were also performed to understand their poor bioavailability. It is the first time to report the in vivo process profiles of the biflavonoids of SDEA extract in rats.

[Sample pretreatment for the measurement of phthalate esters in complex matrices].

Sample pretreatment methods for the measurement of phthalate esters (PAEs) by gas chromatography-mass spectrometry (GC-MS) in various complex matrices, including sediment, soil, suspended particle matter, urban surface dust, Sinonovacula Constricta, cosmet- ic, leather, plastic and coastal/estuarine seawater, were proposed. The pretreatment which was appropriate for GC-MS detection was focused on the investigation and optimization of oper- ating parameters for the extraction and purification, such as the extraction solvent, the eluant and the adsorbent of solid phase extraction. The results of the study of pretreatment for various complex matrices showed that methylene chloride was the best solvent for the ultrasonic extraction when solid-liquid extraction was used; silica gel was the economical and practical adsorbent for solid-phase extraction for purification; C18 was the most commonly adsorbent for preconcentration of PAE in coastal/estuarine seawater sample; the mixed solution of n-hexane and ethyl acetate with a certain proportion was the suitable SPE eluent. Under the optimized conditions, the spiked recoveries were above 58% and the relative standard deviations (RSDs) were less than 10.5% (n = 6). The detection limits (DL, 3σ) were in the range of 0.3 µg/kg (dibutyl phthalate)--5.2 µg/kg ( diisononyl phthalate) for sediment, and 6 ng/L (dipropyl phthalate)--67 ng/L (diisodecyl phthalate) for costal/estuarine seawater. The pretreatment meth- od for various complex matrices is prominent for the measurement of the 16 PAEs with GC-MS.