New force-field for organosilicon molecules in the liquid phase

In this paper, we present a new molecular model that can accurately predict thermodynamic liquid state and phase-change properties for organosilicon molecules including several functional groups (alkylsilane, alkoxysilane, siloxane and silanol). These molecules are of great importance in geological processes, biological systems and material science, yet no force field currently exists that is widely applicable to organosilicates. The model is parameterized according to the recent Polarization-Consistent Approach (PolCA), which allows for polarization effects to be incorporated into a non-polarizable model through post facto correction terms, and is therefore consistent with previous parameterizations of the PolCA force field. Alkyl groups are described by the United-Atom approach, bond and angle parameters were taken from previous literature studies, dihedral parameters were fitted to new quantum chemical energy profiles, point charges were calculated from quantum chemical optimizations in a continuum solvent, and Lennard-Jones dispersion/repulsion parameters were fitted to match the density and enthalpy of vaporization of a small number of selected compounds. Extensive validation efforts were carried out, after careful collection and curation of experimental data for organosilicates. Overall, the model performed quite well for the density, enthalpy of vaporization, dielectric constant and self-diffusion coefficient, but slightly overestimated the magnitude of self-solvation free energies. The modular and transferable nature of the PolCA force field allows for further extensions to other types of silicon-containing compounds

Multi-purpose gel: From supramolecular envirogel to high-value applications

Dibenzylidene-D-sorbitol (DBS) has remained a well-known low molecular weight gelator of organic solvents for over 100 years. As such, it constitutes a very early example of supramolecular gels. It has found widespread applications such as personal care products and high-tech applications. Despite the versatility of DBS as an organogelator and industrial feedstock, none of its existing derivatives could gel water. Herein, functionalization of the aromatic ‘wings’ with various functionalities and their gelation profiles were described. None of the synthesized derivatives but DBS-COOH and DBS-CONHNH2 could undergo gelation in water. DBS-COOH formed a stable hydrogel by pH-switching while the DBS-CONHNH2 formed stable hydrogels across a wide range of pH values by a heat-cool cycle. CD spectroscopy and SEM were used to show that these functionalities control the aggregation mode of the parent DBS. DBS-COOH and DBS-CONHNH2 hydrogels demonstrated a significant uptake of dyes from model polluted water and hence we call them supramolecular envirogels. DBS-COOH demonstrated higher affinity towards methylene blue at ambient conditions but DBS-CONHNH2 demonstrated a pH-dependent selectivity towards various dyes. Lead, cadmium and mercury were significantly adsorbed by DBS-CONHNH2 .The maximum metal loading of 1:1 molar ratio was obtained at neutral ambient pH condition and 2:1 molar ratio at basic pH. The adsorption processes fit pseudo-second-order kinetic and the Langmuir isotherm models. DBS-CONHNH2 were used to recover precious metals from a model mine tailing with greater selectivity towards precious metals than earth-abundant metals. The adsorbed precious metals were reduced in situ to nanoparticulate form. Interestingly, the hydrogel–NPs exhibited higher conductance and electrocatalytic activities than bare gels and/or carbon electrodes. Solubility of the APIs in water was enhanced by forming complexes with the DBS-CONHNH2 while the mechanical stability and morphology of the native hydrogel was influenced by the presence of APIs. APIs were released under basic pH conditions in a controlled-manner

Biophysical Chemistry

Biophysical chemistry is one of the most interesting interdisciplinary research fields. Some of its different subjects have been intensively studied for decades. Now the field attracts not only scientists from chemistry, physics, and biology backgrounds but also those from medicine, pharmacy, and other sciences. We aimed to start this version of the book Biophysical Chemistry from advanced principles, as we include some of the most advanced subject matter, such as advanced topics in catalysis applications (first section) and therapeutic applications (second section). This led us to limit our selection to only chapters with high standards, therefore there are only six chapters, divided into two sections. We have assumed that the interested readers are familiar with the fundamentals of some advanced topics in mathematics such as integration, differentiation, and calculus and have some knowledge of organic and physical chemistry, biology, and pharmacy. We hope that the book will be valuable to graduate and postdoctoral students with the requisite background, and by some advanced researchers active in chemistry, biology, biochemistry, medicine, pharmacy, and other sciences

Treatment of Micropollutants in Water and Wastewater

Treatment of Micropollutants in Water and Wastewater gives a comprehensive overview of modern analytical methods and will summarize novel single and hybrid methods to remove continuously emerging contaminants - micropollutants from the aqueous phase. New trends (e.g. sensor technology, nanotechnology and hybrid treatment technologies) are described in detail. The content of the book is divided into chapters that present current descriptive and analytical methods that are available to detect and measure micropollutants together with detailed information on various chemical, biological and physicochemical methods that have evolved over the last few decades. The provides an understanding of why and how micropollutants must be removed from water sources, and what are the most appropriate and available techniques for providing a cost and technologically effective and sustainable solutions for reaching the goal of micropollutant-free water and wastewater

Development of a dual sensor polymer-based system for antibiotic detection in water samples

Ph. D. ThesisIn April 2019, the UN issued a warning that the overuse of antibiotics could lead to 10 million fatalities annually by 2050. It would also be a significant financial burden as there can be losses of €1.6 billion per single strain of antimicrobial resistant (AMR) bacteria, occurring primarily but not limited to the costs of medical care, hospitalisation, and patient care. Infiltration of antibiotics into groundwater arises from multiple sources; agriculture, highly populated residential areas and pharmaceutical effluents. These leached antibiotics journey to river systems cause selective pressure, thereby giving rise to accelerated AMR development. One route for aiding this issue is to slow the growth rate the emergence of AMR by controlling the levels of antibiotics that gain entry to water systems. To monitor this, a low-cost and reliable sensor platform is needed that can rapidly and on-site identify contaminated areas. Molecularly Imprinted Polymers (MIPs) are synthetic receptors that have potential for specific detection of contaminants in complicated matrices but have found limited commercial applications. The work within this thesis will explore the rational design of MIPs, their optimisation for a plethora of targets and the investigation of various applications to exploit their favourable characteristics when deployed as sensor platforms. Looking at how these imprinted polymers have been developed and utilised in recent times (primarily 2010-2020) and assessing any limitations encountered. These limitations have holstered MIP use, giving rise to the need for the critical review, which has been carried out in this thesis, on what development is needed to boost their applications to convert them into a mainstream commercial tool. Most MIP-based sensor systems focus primarily on a single analysis technique. Chapter 3 sees a novel, dual detection system developed which facilitates direct validation of the results and therefore can realise reliable detection of antibiotics in aqueous samples. Fluorescent monomers have been incorporated into the MIP complex allowing for fluorescent analysis as well as thermal, producing a dual sensor platform thus vastly enhancing the reliability of the biosensor. 3 Two applications of MIPs, that have been deployed as sensors, have been experimentally assessed. A focus on mounting these polymers onto Screen Printed Electrodes (SPEs) and the subsequent thermal analysis will be describe in chapter 4. This work comprised of a comparison of two techniques was carried out to determine the most appropriate method for attaching the polymers to the surface of the SPE, direct polymerisation onto the SPE against dropcasting of MIP particles synthesized by free radical polymerisation on the SPE surface. The direct polymerisation proved to afford MIP-modified SPEs to have higher levels of binding affinity. Chapter 5 explores an investigation into the evolution from small molecule targets to large macromolecules including whole bacteria. This proof-of-concept study saw a yeast mixture used as a target for MIP detection since yeast resembles bacteria in size and shape but does not need to be handled in a certified biosafety lab. A full evaluation of the work carried out concludes the thesis with an aim to gauge how the work undertaken will contribute to the development of a new division of quantitative sensor platforms. Secondly, the work produced will construct foundations for what is still needed to push the use of MIPs into commercial use to combat the rise in AMRManchester Metropolitan Universit