Nanothermometer with Temperature Induced Reversible Emission for Evaluation of Intracellular Thermal Dynamics.

Temperature dynamics reflect the physiological state of cells, and accurate measurement of intracellular temperature helps to understand the biological processes. Herein, we report a novel nanothermometer by conjugating a fluorescent probe 3-ethyl-2-[4-(1,2,2-triphenylvinyl)styryl]benzothiazol-3-ium iodide (TPEBT) with a thermoresponsive polymer poly(N-isopropylacrylamide-co-tetrabutylphosphonium styrenesulfonate) [P(NIPAM-co-TPSS)]. The derived nanoprobe TPEBT-P(NIPAM-co-TPSS) self-assembles into micelles with TPEBT as hydrophobic core and PNIPAM as hydrophilic shell. It exhibits aggregation-induced emission (AIE) at λex/λem = 420/640 nm in aqueous medium with a quantum yield of ΦF 11.9%. The rise in temperature transforms PNIPAM chains from linear to compact spheres to serve as the core of micelles, and meanwhile converts TPEBT from the state of aggregation to dispersion and redistributes in the micellar shell. Temperature-driven phase transition of P(NIPAM-co-TPSS) mediates the reversible aggregation and disaggregation of TPEBT and endows the nanothermometer with temperature-dependent AIE features and favorable sensitivity for temperature sensing in 32-40 °C. TPEBT-P(NIPAM-co-TPSS) is taken up by HeLa cells to distribute mainly in lysosomes. It enables quantitative visualization of in situ thermal dynamics in response to stimuli from carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone, oligomycin, genipin, and lipopolysaccharide. The real-time monitoring of photothermal-induced intracellular temperature variation is further conducted.

A miniaturized analytical method based on molecularly imprinted absorbents for selective extraction of (S)-1,1'-binaphthyl-2,2'-diamine and combinatorial screening of polymer precursors by computational simulation.

Chiral resolution of binaphthylamine is often a toilful conundrum in the field of analytical chemistry and biomedicine. The work puts forward a selective, sensitive, and miniaturized analytical method based on molecularly imprinted polymers (MIPs) as adsorbent for miniaturized tip solid-phase extraction (MTSPE) in the separation of binaphthylamine enantiomer. This method combines the advantages of MIPs (high selectivity), MTSPE (low consumption), and high-performance liquid chromatography (HPLC, high sensitivity). A simple synthesis methodology of MIP (P2) was conducted through bulk polymerization with (S)-(-)-1,1'-binaphthyl-2,2'-diamine (S-DABN) as template together with methacrylic acid monomer, and ethylene glycol dimethacrylate as cross-linker in proper porogen, realizing a selective recognition and efficient enrichment for S-DABN. The method exhibited appreciable linearity (0.06-1.00 mg ml-1 ), low quantification limit (0.056 mg ml-1 ), good absolute recoveries (45.70%-69.29%), and high precision (relative standard deviations ≤ 3.54%), along with low consumption (0.50 ml sample solution and 25.0 mg adsorbent). Based on the density functional theory, computational simulation was used to make a preliminary prediction for rational design of MIPs and gave a reasonable elaboration involving the potential mechanism of templates interacting with functional monomers. The adsorption kinetics and thermodynamics were investigated to evaluate the recombination process of substrates. In addition, the selectivity of MIPs for S-DABN was obtained by MIP-MTSPE coupled with HPLC, which supports the feasibility of this convenient design process. The proposed method was employed for selective extraction of S-DABN and exhibited promising potential in the application of chiral analysis.

High performance isolation of circulating tumor cells by acoustofluidic chip coupled with ultrasonic concentrated energy transducer.

The isolation of circulating tumor cells (CTCs) from whole blood is a challenging task. Although various studies on the separation of CTCs by acoustofluidic devices have been reported, difficulties still persist, such as the complicated equipment, high cost, and difficult operation. Those problems should be resolved urgently. Herein, we developed an acoustofluidic chip separation system coupled with an ultrasonic concentrated energy transducer (UCET) system for efficient separation of CTCs. In the separation system, the acoustically sensitive particles were pre-focused by inertial forces of the PDMS chip channel structure. Then, the particles with different sizes were separated by acoustic radiation forces (ARF). In this study, the circulating tumor cells was simulated (CTCs-like particles) by aminated mesoporous acoustically sensitive particles (MSN@AM) encapsulated carboxylate polystyrene microspheres (PS-COOH). Subsequently, efficient CTCs-like particles separation was achieved by the acoustofluidic chip coupling system. This study effectively separated polystyrene microspheres carrying acoustically sensitive particles (MSN@AM@PS-COOH). However, the MSNs agglomerates and PS microspheres without acoustically sensitive particles did not show phenomenon of separation. This method allows to efficiently separate 2 µm MSNs agglomerates，8.0-8.9 µm PS microspheres and 10-10.5 µm MSN@AM@PS-COOH particles. It is demonstrated that the CTCs-like particles show more sensitive response, longer moving distance, and more obvious separation effect at the condition of the low frequency traveling wave sound field (20 kHz from UCET). This system can maintain the same separation with reduced amount of reagents used for cancer detection. It may provide a reliable basis for sorting out CTCs efficiently from the whole blood of cancer patients.

[Study on osteogenesis and angiogenesis of Pluronic F-127 composite gel loaded with transforming growth factor ß 3 and bone marrow mesenchymal stem cells in rabbit maxillary sinus lift].

OBJECTIVE: To prepare Pluronic F-127 composite gel loaded with transforming growth factor ß 3 (TGF-ß 3) and bone marrow mesenchymal stem cells (BMSCs) and observe its osteogenesis and angiogenesis effects in vivo and in vitro. METHODS: BMSCs were isolated from the tibial and femoral bone marrow of New Zealand white rabbits and passaged, and the 3rd generation cells were used for subsequent experiments after identification of osteogenic and adipogenic induction. Pluronic F-127 powder and TGF-ß 3 were dissolved in L-DMEM medium to prepare Pluronic F-127 gel, TGF-ß 3+Pluronic F-127 gel, BMSCs+Pluronic F-127 gel, and TGF-ß 3+BMSCs+Pluronic F-127 gel. The 3rd generation of BMSCs were cultured with L-DMEM medium (group A), osteogenic induction medium (group B), osteogenic induction medium containing Pluronic F-127 gel (group C), and osteogenic induction medium containing TGF-ß 3+Pluronic F-127 gel (group D), respectively. After 14 days of culturing, alkaline phosphatase (ALP) staining and Alizarin red staining were used to observe the osteogenesis. In addition, the BMSCs were cultured with L-DMEM medium containing Pluronic F-127 gel (experimental group) and L-DMEM medium (control group) for 1, 2, 3, and 4 days, respectively. And the cell proliferation was detected by MTT assay. Ten New Zealand white rabbits were taken to prepare the maxillary sinus lift models, and Pluronic F-127 gel (group A), TGF-ß 3+Pluronic F-127 gel (group B), BMSCs+Pluronic F-127 gel (group C), and TGF-ß 3+BMSCs+Pluronic F-127 gel (group D) were injected into the bone defects, respectively. On the 8th week, imaging examination and HE staining were used to observe the formation of new bone, immunohistochemical staining was used to observe the expression of vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2) in bone tissue, and Western blot was used to detect the relative expressions of VEGF, oncostatin M (OSM), and BMP-4 proteins in bone tissue. RESULTS: Osteogenic and adipogenic induction identified the isolated and cultured cells as BMSCs. In vitro staining showed that ALP activity and Alizarin red concentration in group D were significantly higher than those in other groups ( P<0.05). MTT assay showed that the absorbency ( A) value of the two groups increased gradually, and there was no significant difference between the groups at each time point ( P>0.05). In vivo experimental imaging examination showed that the bone mineral density and osteogenic continuity of group D were the best, and the proportion of new bone volume was superior to other groups ( P<0.05). HE staining showed that compared with other groups, bone trabeculae in group D were dense and arranged regularly, on which a large number of osteoblasts and osteoclasts were distributed, and a large number of new bone formation could be seen. Immunohistochemical staining showed the strong positive expressions of BMP-2 and VEGF in group D ( P<0.05); Western blot detection showed that the relative expressions of VEGF, OSM, and BMP-4 proteins in group D were significantly higher than those in other groups ( P<0.05). CONCLUSION: The BMSCs in Pluronic F-127 composite gel loaded with TGF-ß 3 and BMSCs can be induced to differentiate into osteoblasts, and the composite gel has no toxic effect on cells, and has obvious osteogenesis and angiogenesis in the maxillary sinus of rabbits.

Colorimetric assay for heterogeneous-catalyzed lipase activity: enzyme-regulated gold nanoparticle aggregation.

Lipase is a neglected enzyme in the field of gold nanoparticle-based enzyme assays. This paper reports a novel colorimetric probe to rapidly visualize lipase activities by using Tween 20 functioned GNPs (Tween 20-GNPs) as a reporter. The present strategy hence could overcome the limitations caused by the heterogeneous interface in lipase assay. Catalytic hydrolytic cleavage of the ester bond in Tween 20-GNPs by lipase will trigger the rapid aggregation of GNPs at a high salt solution. The color change from red to purple could be used to sense the activity of lipase. The detection limit (3σ) is as low as 2.8 × 10-2 mg/mL. A preliminary enzyme activity screening was carried out for seven commercially purchased lipase samples. It also has been successfully applied to detecting lipase in fermentation broth of Bacillus subtilis without any pretreatment.

Cosolvent or antisolvent? A molecular view of the interface between ionic liquids and cellulose upon addition of another molecular solvent.

Ionic liquids (ILs) are promising nonderivatizing solvents for the dissolution of cellulose and lignin in biomass pretreatment processes, which are, however, retarded by sluggish dynamics. Recent investigations showed that cosolvents such as dimethyl sulfoxide (DMSO) can accelerate the dissolution dramatically. On the other hand, water is used as a common antisolvent to regenerate cellulose from solutions. To understand the co-/antisolvent effects in dissolving cellulose by ILs, we performed molecular dynamics simulations of the interfaces between an Iß cellulose crystal and different solvent systems, including ILs, DMSO, water, and mixed solvent systems. The density profiles and pair energy distributions (PEDs) show that the anions interact much more strongly with the cellulose surface than the cations, which is responsible for the dissolution of cellulose. It was found that the number of chloride ions in contact with cellulose does not cause the co-/antisolvent effect. In contrast, the cellulose-chloride PEDs are sensitive to the addition of molecular solvents, such as DMSO and water. Detailed analyses show that multiple hydrogen-bond (HB) patterns are formed between chloride and the hydroxyl groups of cellulose that are noticeably changed in the presence of DMSO or water. A combined analyses of both the PEDs and HB patterns can provide valuable information about the enhancement of cellulose dissolution. The simulation results in this work present useful knowledge for the design of solvent systems for dissolving cellulose or other types of biomass.