Synthesis of Starch-Based Amphiphilic Fluorescent Nanoparticles and Their Application in Biological Imaging.

Due to the extensive source, good biocompatibility and biodegradability, the starch of carbohydrates has been extensively investigated for application in biological field. Recently, the development of fluorescent organic nanoparticles (FONs) on the basis of aggregation induced emission (AIE) dyes has attracted great research interest. In this article, novel starch-based S-TPEV polymers with AIE property were successfully fabricated by atom transfer radical polymerization (ATRP) of TPEV dye into water-soluble starch for the first time, subsequently, their structure and properties were detailedly investigated by 1H NMR, TEM, UV-vis, FL and FTIR. The characterization results confirmed the successful synthesis of S-TPEV polymers, and the molar fraction of TPEV and C6H10O5 ring in the starch polymers could be respectively calculated as approximate 5.8% and 94.2%. In aqueous solution, the as-prepared S-TPEV polymers will tend to self-assemble into FONs with 100-200 nm diameters, and their fluorescence intensity increased with the increase of the concentration of water in the mixed solution of water and DMSO, indicative of the obvious AIE property. More importantly, owing to their high water dispersity, good fluorescence and excellent biocompatibility, the S-TPEV FONs can be uptaken by HepG2 cells and show promising application in biological imaging field.

The Hydrogen Sulfide Donor NaHS Delays Programmed Cell Death in Barley Aleurone Layers by Acting as an Antioxidant.

H2S is a signaling molecule in plants and animals. Here we investigated the effects of H2S on programmed cell death (PCD) in barley (Hordeum vulgare L.) aleurone layers. The H2S donor NaHS significantly delayed PCD in aleurone layers isolated from imbibed embryoless barley grain. NaHS at 0.25 mM effectively reduced the accumulation of superoxide anion (·O2 (-)), hydrogen peroxide (H2O2), and malondialdehyde (MDA), promoted the activity of superoxide dismutase (SOD), guaiacol peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), and decreased those of lipoxygenase (LOX) in isolated aleurone layers. Quantitative-PCR showed that NaHS treatment of aleurone tissue led to enhanced transcript levels of the antioxidant genes HvSOD1, HvAPX, HvCAT1, and HvCAT2 and repressed transcript levels of HvLOX (lipoxygenase gene) and of two cysteine protease genes HvEPA and HvCP3-31. NaHS treatment in gibberellic acid- (GA-) treated aleurone layers also delayed the PCD process, reduced the content of ·O2 (-), and increased POD activity while decreasing LOX activity. Furthermore, α-amylase secretion in barley aleurone layers was enhanced by NaHS treatment regardless of the presence or absence of GA. These data imply that H2S acted as an antioxidant in delaying PCD and enhances α-amylase secretion regardless of the presence of GA in barley aleurone layers.

[Slow-release recombinant human bone morphogenetic protein-2 suppresses chromium wear particle-induced osteolysis in rats].

OBJECTIVE: To observe the effect of a slow-release recombinant human bone morphogenetic protein-2 (rhBMP-2) formulation on the expressions of receptor activator of nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG) in a murine air pouch model of bone implantation. METHODS: A cranial bone allograft was implanted in the air pouch induced on the back of the recipients. The rat models were then randomized into 5 groups, including a blank control group, chromium particle group, and 3 rhBMP-2 groups receiving 50, 100 or 200 µg/L slow-release rhBMP-2 in addition to chromium particles. Three weeks later, the expressions of RANKL and OPG in the air pouch was detected using Western blotting and RT-PCR, and the positively stained area for osteoclasts in the bone graft was determined with TRAP staining for drug effect assessment. RESULTS: RANKL and OPG expressions were found in the air pouches in all the 5 groups. RANKL and OPG protein and mRNA expressions, RANKL/OPG ratio and osteoclast staining area in the bone graft were the highest in chromium particle group (P<0.05), but were significantly decreased by treatment with the slow-release rhBMP-2 formulation (P<0.05); the measurements showed no significant differences between the blank control group and 200 µg/L rhBMP-2 group (P>0.05). CONCLUSION: Chromium particles can cause osteolysis by increasing the RANKL/OPG ratio in rats, and intervention with slow-release rhBMP-2 can significantly promote bone formation and suppress bone resorption by decreasing RANKL/OPG ratio.

A new piezochromic fluorescence and aggregation-induced emission compound containing tetraphenylethylene and triphenylamine moieties with morphology-alterable property.

A novel piezochromic fluorescent (PCF) compound with aggregation-induced emission (AIE) effect and morphology-alterable emission property was developed. The amorphous and crystalline aggregates were obtained, and their spectroscopic properties and morphological structures were reversibly and repeatedly exhibited upon pressing (fuming) or annealing. The piezochromic fluorescent nature was generated through crystalline-amorphous phase transformation. It was proposed that AIE compounds existing a twisted propeller-shaped conformation will exhibit PCF activity. The common relationship betweeen AIE and PCF established will guide researchers in identifying and synthesizing more piezochromic fluorescent materials.

Synthesis and characterization of triphenylethylene derivatives with aggregation-induced emission characteristics.

New aggregation-induced emission (AIE) compounds derived from triphenylethylene were synthesized. The thermal, photophysical, electrochemical and aggregation-induced emissive properties were investigated. All the compounds had strong blue light emission capability and good thermal stability. Their maximum fluorescence emission wavelengths were between 443 to 461 nm in solid states, while their glass transition temperatures ranged from 86 to 129 °C. The decomposition temperatures of the synthesized compounds were in the range of 432-534 °C. The synthesized compounds possessed aggregation-induced emission properties, namely exhibited enhanced fluorescence emission in aggregated states. The highest occupied molecular orbital (HOMO) energy levels estimated from the oxidation potentials were between 5.61 and 5.66 eV and the lowest unoccupied molecular orbital/highest occupied molecular orbital (LUMO/HOMO) energy gap values were found to be in the range of 3.18-3.22 eV. The compounds 4-(4-(2,2-bis(4-(naphthalen-1-yl)phenyl)vinyl)phenyl) dibenzothiophene [(BN)(2)Bt] and 4-(4-(2,2-di(biphenyl-4-yl)vinyl)phenyl) dibenzothiophene [(BB)(2)Bt] exhibited vibronic fine-structure photoluminescence spectra when the water fraction was less than 70%.

Comparison of responsive behaviors of two cinnamic acid derivatives containing carbazolyl triphenylethylene.

Two cinnamic acid derivatives (CPA and CPC) containing carbazolyl triphenylethylene moiety have been synthesized and characterized. The two derivatives possessed aggregation-induced emission property. They exhibited different and interesting responsive behaviors to solvents, water and metal ions. Considering the structural differences between the two derivatives resulting in different interactions between their molecules and the various media was proposed as a possible explanation for these observations. The intermolecular interactions of CPC were much stronger than those of CPA, which promoted molecular association through intermolecular hydrogen bonding to form multimers. It was found that CPC and CPA exhibited high sensitivity to K(+) and Mn(2+), respectively. It is suggested that the derivatives have potential technological applications in chemosensor fields.

Synthesis and properties of diphenylcarbazole triphenylethylene derivatives with aggregation-induced emission, blue light emission and high thermal stability.

New aggregation-induced emission materials derived from diphenylcarbazole triphenylethylene were prepared. The thermal, photophysical, electrochemical and aggregation-induced emissive properties were investigated. All the compounds had strong blue light emission capability and excellent thermal stability. Their maximum fluorescence emission wavelengths were between 450 to 460 nm in TLC plates, while their glass transition temperatures ranged from 162.2 to 182.4 °C. The decomposition temperatures of the synthesized compounds were all well over 500 °C. The synthesized compounds possessed aggregation-induced emission (AIE) properties, which exhibited enhanced fluorescence emissions in aggregation states or in solid states. The HOMO energy levels estimated from the oxidation potentials were found in the range from 5.49 to5.52 eV. The lowest unoccupied molecular orbital/highest occupied molecular orbital (LUMO/HOMO) energy gaps (ΔEg) for the compounds were estimated from the onset absorption wavelengths of UV absorption spectra and ranged from 3.04 to 3.20 eV.