Synthesis and Evaluation of Novel Functional Polymers Derived from Renewable Jasmine Lactone for Stimuli-Responsive Drug Delivery

Instances of synthetic polymers obtained from renewable feedstock with the possibility of post-synthesis functionalization are scarce. Herein, the first ever synthesis and drug delivery application of amphiphilic block copolymer (mPEG-b-PJL) derived from renewable jasmine lactone with free allyl groups on the backbone is presented. The polymer is synthesized via facile ring-opening polymerization and subsequently, UV mediated thiol-ene click chemistry is utilized for post-functionalization. The introduction of hydroxyl, carboxyl, and amine functionality to mPEG-b-PJL polymer is successfully established. As a proof-of-concept demonstration, doxorubicin (DOX) is conjugated on hydroxyl-terminated polymer (mPEG-b-PJL-OH) via redox responsive disulfide linkage to obtain PJL-DOX. PJL-DOX is readily self-assembled into micelles with an average hydrodynamic size of ≈ 150 nm and demonstrates reduction-responsive DOX release. Micelles are evaluated in vitro for cytocompatibility and selective drug release in cancer cells (MDA-MB-231) using 10 mm glutathione as a reducing agent. Cytotoxicity and microscopy results confirm a redox-triggered release of DOX, which is further confirmed by flow cytometry. The introduction of these novel functional polymers can pave the way forward in designing polymer-drug conjugate-based smart nano-carriers.     

Influence of shallow and deep cryogenic treatment on the corrosion behavior of Ti6Al4V alloy in isotonic solution

This study investigated the corrosion behavior of cryogenically treated Ti6Al4V alloys in an isotonic solution. Samples were subjected to shallow or deep cryogenic treatment, and some samples then underwent an aging procedure. They were characterized by microstructural analysis, an open circuit potential test, an electrochemical impedance method, and a potentiodynamic test. The polarization tests demonstrated that the deep cryogenic treatment shifted the corrosion potential to more anodic values compared to the untreated sample. For all treated samples, it was found that the corrosion current densities were lower than those in the untreated sample, and the lowest current densities were registered for the sample subjected to deep cryogenic treatment for 36 hr. The shallow cryogenic treated samples and the sample aged without cryogenic treatment showed semicapacitive loops with poor corrosion impedance compared to the untreated sample, whereas deep cryogenic treatment produced Warburg impedance with diffusion in the solid phase.     

Synthesis,Characterization, and Thermoelectric Properties of Electrospun Boron-Doped Barium-Stabilized Bismuth-Cobalt Oxide Nanoceramics

In this study, the boron-doped barium-stabilized bismuth cobalt oxide thermoelectric nanocrystalline ceramic powders were produced by the polymeric precursor technique. The powders were characterized by X-ray diffraction, scanning electron microscopy, and the physical properties measurement system. The X-ray diffraction results showed that these patterns have mixture of two phases as face-centered cubic and body-centered cubic. Values of the crystallite size, the dislocation density, and the microstrain were calculated by the Scherrer equation. According to these values, the crystallite size decreased from 60 to 51 nm with the boron addition in the boron-undoped and boron-doped samples, respectively. The scanning electron microscope results showed that nanograins are rarely seen in the boron-undoped samples, but nanograins turn into needle-like and layered structures with boron addition. The diameters distribution of nanofibers was calculated. The average diameter of the boron-doped sample is smaller than the boron-undoped sample. The physical properties measurement system values showed that the electrical and thermal conductivity, the Seebeck coefficient, and the figure of merit increased with the temperature rise for both samples. The boron-doping effect increased the electrical and thermal conductivity, decreased the Seebeck coefficient, and decreased the figure of merit.     

Application of GC, GC-MSD, ICP-MS and Spectrophotometric Methods for the Determination of Chemical Composition and In Vitro Bioactivities of Chroogomphus rutilus: The Edible Mushroom Species

Chemical composition of Chroogomphus rutilus, the edible mushroom species, was analyzed by using gas chromatography (GC), gas chromatography mass spectrometry (GC-MSD) and inductively coupled plasma mass spectrometry (ICP-MS). The silylated extract affords 19 components. Xylitol (56.28 %), glucitol (11.08 %), fumaric acid (10.92 %) and mannitol (6.79 %) were identified as the major compounds. The methylated extract possessed 13 fatty acids, and linoleic acid (41.61 %) and oleic acid (35.87 %) were the majors. In addition, the mineral and the heavy metal contents were tested for nine minerals and 12 heavy metals by using ICP-MS. In addition, the extracts were evaluated for cholinesterase inhibitory effects against acetyl-cholinesterase and butyrylcholinesterase which are the chief enzymes of Alzheimer’s disease. The antioxidative effect of the extracts was also determined by using five complimentary assays. Moreover, the hexane extract (IC₅₀, 2.22?±?0.13 μg/ml) and the ethyl acetate extract (IC₅₀, 2.28?±?0.18 μg/ml) exhibited a good lipid peroxidation inhibitory activity while the methanol extract demonstrated good butyrylcholinesterase inhibitory activity (IC₅₀, 45.5?±?1.1 μg/ml). In addition, total phenol and flavonoid contents of the extracts were also determined as pyrocatechol and quercetin equivalents, respectively. Because of its high antioxidant activity, C. rutilus might protect people against lipid peroxidation and free radical damage when consumed. It can be also used in food industry as preservative agents or extension of the shelf-life of foods. Since methanol extract indicated remarkable inhibitory activity being close to that of galantamine, it may be also useful as moderate cholinesterase inhibitory agents, particularly against butyrylcholinesterase.