7^th World Congress on Biopolymers and Polymer Chemistry June 4-6, 2018 Osaka, Japan

An enantiomeric pair imprinted polymeric film, with embedded functionalized multiwalled carbon nanotubes, was developed following the ‘surface grafting from’ approach onto a gold nanoparticles decorated pencil graphite electrode. Double imprinting of chiral molecules in a single polymer motif, as a sensory platform, for the one-by-one evaluation of individual components of a racemic mixture, is a challenging task. The underlying state-of-art proposed for this purpose is novel and if this works well, any two simple molecules could be used as templates. In this work, a pencil graphite electrode was first dipped for the overnight in the aqueous suspension of gold nanoparticles. The electrode was then subjected to spin coating with a pre-polymerization mixture consisting a monomer (N-acryloyl-pyrrolidine-2,5-dione) , templates (D- and L-Aspartic acid) , a cross-linker (ethylene glycol dimethacrylate) in the presence of an initiator (α,α’-azoisobutyronitrile). As aspartic acid isomers have been found to be electro-inactive, their evaluation was feasible indirectly with the help of a potassium ferricyanide probe. The quantitation ability of the proposed sensor, with differential pulse anodic stripping voltammetric transduction, was found to be in the tune of 4.08 ng mL−1 (S/N=3) for both the enantiomers in the real samples, which reportedly manifest several chronic diseases at their stringent limits.

Present study was consisted in the chemical treatment of raw timber sawdust (TS-OH)r by chemical agents (acid and base) for the comparative removal of two anionic dyes, namely, Thiazole Yellow (TY) and Bright Yellow (BY), from aqueous solutions. Batch experiments were performed to evaluate the influence of various operating conditions viz., pH, contact time, temperature, etc. on dyes removal efficiency. This results obtained from the Adsorption of the two dyes, was found to be endothermic with second-order rate kinetics, who followed the Langmuir isotherm. The monolayer saturation capacities are 1408.4507 and 140.845 mg g-1 for Thiazole Yellow and Bright Yellow respectively. Adsorption was favorably influenced by an increase in the temperature of the operation. The positive values of the change in entropy (DS0) and heat of adsorption (DH0); and the negative value of change in Gibbs free energy (DG0) indicate feasible and spontaneous adsorption of (TY and BY) on adsorbent. Desorption experiments with 1 M aqueous NaCl put into evidence that anionic dyes were completely desorbed from the matrices and the reusability of the (TS-OH)r chemically modify after three repeated cycles led to just a slight attenuation in its performance. These results show that chemical treatment of a low value by-product of the timber industry leads to an effective adsorbent

I have done my undergraduate and MSc studies in the Materials Science with the focus on electrochemical sensors. Then, I have started my PhD at 2015 in the Professor Justin Gooding group at the School of Chemistry, UNSW. My PhD project is a broad study on polyelectrolyte brushes and their responsive behaviors and characterizations. The aim of study is to tailor and rationally design these polymer brushes to achieve dynamic biocompatible surfaces that can mimick biological processes that happen in our body.

Smart surfaces have recently aroused interest because of their wide applications in different fields of science and technology. In such surfaces, the surface properties are altered by applying stimuli- such as pH, light and electrical potential- and regenerated by removing it or applying an alternative trigger. One of the interesting applications of these surfaces is developing substrates that can mimic the dynamic properties of biological systems in response to applied stimuli. Electrical potentials and ionic strength have been shown as an active stimulus that triggers specific conformational transitions in the surface-bound molecules to facilitate rapid and reversible switching. The idea these switchable surfaces is modifying an electrode surface with a polymer brush which is anchored to the surface via “grafting to” method which contains charged all over its polymeric backbone. Then, applying the same or opposite polarity of the potential or different ionic strength causes the polymer to repel or attract to the surface respectively. This concept has been previously used successfully to switch the cell adhesion on the surface using GRGDS peptides in the monolayer [1]. In this current work, we promoted the idea to be able to mimic and use larger biological components using polymer as a switching element. Also, gold nanoparticles are being used as platforms for putting down the receptors of interest on the surface. So, this surface will ultimately is able to mimic different biological events like T cells activation by choosing the right size of the polymer and gold nanoparticles.

Nadiia Velychkivska received her BSc and MSc from Lviv Polytechnic National University in the field of chemical technology of fuel and carbon materials in 2012. In 2013, she joined the Department of NMR Spectroscopy at the Institute of Macromolecular Chemistry, Prague. As a UNESCO/IUPAC student, she worked with temperature-sensitive polymers. Since 2014, Mrs. Velychkivska has been a PhD student and her overall scientific interest lies in the investigation of temperature-sensitive macromolecular and supramolecular systems by means of high-resolution NMR spectroscopy, which can be used in drug delivery, cosmetics or photodynamic therapy. During 11.2016-01.2017 Mrs. Velychkivska participated in NIMS internship program, were she investigated supramolecular water soluble porphyrin systems.

Statement of the Problem: Porphyrin derivatives are group of compounds with ability to form molecular complexes with metals, charged or uncharged organic molecules, supramolecular aggregates (J-, H-aggregates) and exhibit reversible protonation. A large number of such porphyrins were used for enantiomeric detection, selective detection of anions, water trace detection in organic solvents, naked-eye discrimination of methanol from ethanol, as sensors of toxic metal ions using nanostructured cage materials, etc. But a huge drawback for those systems was that all these valuable properties were achieved only in organic solvents (CHCl3, DMSO, THF). In order to come closer to biological application, novel water soluble porphyrins with PNIPAM chains were synthesized (Figure 1a). Methodology & Theoretical Orientation: In order to provide qualified physicochemical analysis of these systems means of high-resolution NMR spectroscopy, Small angle X-ray Scattering, Differential Scanning Calorimetry were used. Findings: Obtained porphyrins exhibit reversible phase separation (LCST) and their phase separation temperature (Tp) depends on: sample concentration and on the length of PNIPAM. Size and form of the nanoparticles before and after the phase separation was determined (Figure 1b). Conclusion & Significance: Physicochemical analysis for newly synthesized porphyrin derivatives was conducted. These systems can be potentially used in heterogeneous catalysis, drug delivery or as photosensitizers in photodynamic therapy, as well as for cloud point separation of acids/anions/chiral molecules and temperature sensing.