Activity

Eight-armed A4B4-type hetero-arm star-shaped PCL-PLA polymers ((PCL)4-POSS-(PLA)4, SPLA30) with POSS core were successfully prepared via combination of the “arm-first” approach utilizing ring-opening polymerization (ROP) and click chemistry techniques. Firstly, alkyne-functional PLA and PCL polymers having arms with 30 repeating units were synthesized via ROP with utilizing propargyl alcohol as initiator and stannous octoate (Sn(Oct)2) as catalyst. Then, the obtained hetero-armed star-shaped polymers were prepared by Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC) click reaction between alkyne functional polymers (11 PCLPLA) and azido functional polyhedral oligomeric silsesquoxane (POSS-(N3)8) molecules. Finally, these obtained star-shaped SPLA30 was blended with neat PLA at different PLA/SPLA30 ratios (95/5 and 90/10 wt%) via melt blending by utilizing micro-compounder (a lab-scale) to enhance thermal, morphological, and mechanical properties of neat PLA. Also, different diisocyanates (1,4-phenylene diisocyanate (PDI), isophorone diisocyanate (IPDI), methylene diphenyl diisocyanate (MDI), and toluene 2,4-diisocyanate (TDI)) at constant ratio (1 wt%) were used as a chain extender bonding terminal group of polymers. It was found that addition of SPLA30 and SPLA30+ diisocyanates provided improvements in mechanical properties (especially in elongation at break and impact strength) of neat PLA. Proteasome inhibitor When the thermal properties were examined, it was seen that the decomposition temperatures of the blends decreased significantly compared to neat PLA and that there was a significant increment in the Tg and Tm values. In addition, it has been found that especially the diisocyanates added to provide good interfacial adhesion with polymer blends and show a homogeneous distribution on the surface.In present work, a LiP enzyme producing bacterium was isolated form textile wastewater and sludge sample and identified as Bacillus albus by 16S rRNA gene sequencing analysis. This bacterium decolorized 99.27 % MB dye and removed 83.87 % COD within 6 h at 30 °C, pH 7, 100 rpm and 100 mg/l of dye concentration in presence of glucose and yeast extract as carbon and nitrogen source, respectively. The bacterium also produced LiP enzyme of molecular weight ∼48 kDa, characterized by SDS-PAGE analysis. Different metabolites like monomethylthionine, thionin, (E)-2-(3-Oxopropylidene)-2H-benzo[b][1,4] thiozine-3-carboxylic acid, N-(3,4-dihydroxyphenyl)-N-methylformamide, ethylamine, water and carbon dioxide produced during treatment process were characterized by FT-IR and LC-MS analysis. Further, the toxicity assessment results showed that the toxicity of bacteria treated dye solution was reduced significantly allowing 90 % seed germination indicating that the isolated bacterium B. albus has high potential to decolorize and detoxify MB dye for environmental safety.Zwitterionic polymers play an attractive role in the application of stealthy nanocarriers for their excellent antifouling property. Herein, a zwitterionic nanogel with temperature sensitivity and redox-responsive degradability prepared by copolymerization of N-vinylcaprolactam (VCL) and 2-(methacryloyloxy) ethyldimethyl-(3-sulfopropyl) ammonium hydroxide (DMAPS) via aqueous precipitation polymerization. The prepared nanogels own ultra-high colloidal stability and non-specific protein adsorption resistance as a result of the incorporation of zwitterionic groups. Meanwhile, they exhibit sensitive temperature-induced swelling/collapse transition in aqueous solution and excellent redox-degradability ascribed to the presence of disulfide bonds. The nanogels loaded with anticancer drug doxorubicin (DOX) exhibit low leakage of DOX under physiological conditions (merely 23.8 % within 24 h), whereas striking release amount of DOX under reducing conditions combined with elevated temperature (93.4 % within 24 h). The measurement of cell viability showed that the cytotoxicity of blank nanogels to tumor cells (HeLa cells) was negligible, while the nanogels loaded with DOX had a prominent inhibitory impact on tumor cells.Peroxidase-like activity of MoS2 quantum dots (QDs) can be reversibly regulated by means of Fe3+/alendronate sodium (ALDS)-induced aggregation/disaggregation of the QDs in solution. Specifically, Fe3+ can selectively aggregate the MoS2 QDs and thus greatly enhance their peroxidase-like activity, while such enhancement can be inhibited in the presence of ALDS owing to the competitive coordination of ALDS with Fe3+. By regulating the enzyme-like activity of MoS2 QDs, different colorimetric signal of a typical substrate of horseradish peroxidase, 3,3΄,5,5΄-tetramethylbenzidine, can be measured in the presence of H2O2. Based on this mechanism, we develop a colorimetric approach for the determination of ALDS and further applied in quality control of pharmaceutical products, utilizing either smartphone or UV-vis spectrometer as a readout. This detection method is rapid and selective, where derivatization of ALDS before detection is not needed. Such a smartphone-based colorimetric detection platform is promising to be applied in point-of-care testing at home, small clinics, or underdeveloped regions.Escherichia coli is one of the most common commensal aerobic bacteria in the gut microbiota of humans (and other mammals). Nevertheless, if left free to proliferate, it can induce a large range of diseases from diarrhoea to extra-intestinal diseases. In recent years, this bacterium had become increasingly resistant to antibiotics. It is therefore essential to implement new approaches able to maintain both bacterial viability and to control their proliferation. In this context, we developed a process to encapsulate Escherichia coli in polymer shells. We took advantage of the fact that this bacterium has a negatively charged surface and modified it via a layer-by-layer process, i.e. with oppositely charged polyelectrolyte pairs (namely chitosan as the polycation and alginate or dextran sulfate as polyanion). We successfully demonstrate the controlled coating of the bacterial surface via zeta potential measurement, the viability of the encapsulated bacteria and a delay in growth due to the multilayer coating. This delay was dependent on the number of polyelectrolyte layers.