Staphylococcus aureus regulates virulence and biofilm formation through the agr-mediated quorum sensing (QS) system, making it an attractive target for anti-virulence therapies. In this study, we design and evaluate β-amino acid-containing peptides as potential QS inhibitors. The QS inhibition efficacy is assessed in vitro using a bioluminescence reporter system, where fluorescence intensity serves as an indicator of QS activity. Our results demonstrate that β-amino acid peptides exhibit remarkable enzymatic stability, significantly enhancing their in vivo half-life. Furthermore, even when β-amino acid residues are incorporated into an α-amino acid peptide backbone, they provide substantial protection to adjacent peptide bonds against enzymatic degradation. This work highlights the potential of β-amino acid-modified peptides as stable and effective QS inhibitors for combating antibiotic-resistant S. aureus infections.
Aqueous polyurethanes (PU) offer a low-volatile organic compound route to environmentally friendly, high-performance coatings. For effective product development, it is necessary to understand and control the morphologies of the dispersions. This study investigates how variations in hard block content and thermomechanical processing influence the final paint performance. By employing small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM), we aim to analyse the particle structures both in dispersion and in films, establishing key correlations to enhance formulation strategies.
Artificial photosynthesis (AP) is at the forefront of solar chemistry research. Pt(II) donor-bridge-acceptor complexes hold potential as AP systems due to their extensive electron transfer pathways upon irradiation with light. The nature and lifetime of the excited states formed can be modified through variation of both the strength of the donor/acceptor moieties and also the extent of electronic coupling to the Pt(II) bridge. A particular state of interest is the charge separated state (CSS) due to its high potential energy. The aim of this project is to design and synthesise complexes that could exhibit the CSS, investigate their electron transfer pathways using ultrafast spectroscopic techniques, and externally control the lifetime of the desirable states. Control is applied via specific infrared laser perturbation which, when applied to specific vibrations within the molecule, can selectively increase or decrease the yield of a certain electron transfer pathway.
The detection and analysis of trace gases are crucial in environmental and industrial monitoring, particularly for mitigating the impact of global warming and ensuring air quality. This thesis explores advanced photoacoustic spectroscopy (PAS) techniques for the detection of key atmospheric gases, including carbon dioxide (CO₂) and hydrogen sulfide (H₂S). Focusing on Near-Infrared (NIR) applications, this work evaluates the performance of different PAS systems, such as Resonant Photoacoustic Spectroscopy (RPAS), Quartz-Enhanced Photoacoustic Spectroscopy (QEPAS), and Cavity Enhanced Resonant Photoacoustic Spectroscopy (CERPAS). The study also incorporates Distributed Feedback (DFB) lasers to improve detection sensitivity and specificity. The experimental analysis includes a comparative assessment of these PAS techniques and investigates their detection limits and sensitivity when applied to trace gases in both air and natural gas environments.
Per- and polyfluoroalkyl compounds (PFAS) are substances that are widely used in textiles, surfactants, food packaging, non-stick coatings and firefighting foams etc. due to their many advantages such as durability and stability. However, PFAS can enter the human body through inhalation, skin contact, ingestion of food and drinking water where they can potentially lead to cancer, immune system suppression and hormonal disruption.1,2
Adsorption is a common method for removing perfluorinated and polyfluorinated alkyl compounds (PFAS) from wastewater. In this study, hypercrosslinked polymers with good adsorption uptakes are investigated. A batch of hypercrosslinked polymers (HCPs) with high surface areas were synthesised using 1,4-bis(chloromethyl)-benzene and 4,4'-bis(chloromethyl)-1,1'-biphenyl, polystyrene, etc.
The results of the adsorbents for PFOA adsorption will be discussed, and the adsorption process of PFOA by these HCPs will be described using isothermal adsorption modelling.
Heterocyclic boronic acids are essential building blocks for creating complex molecules, with significant applications in medicinal chemistry and material science. Since many small-molecule pharmaceuticals contain saturated heterocycles, having access to saturated heterocyclic boron-based building blocks is highly desirable. However, current commercial availability of these building blocks is limited.
In this project, we developed a method to prepare boronic ester lactams using a conjugate borylation-cyclisation strategy using amino enoates. Initially, we used SIMes as an achiral ligand, producing racemic boronic esters. Later, we employed (S,S)-FOXAP as a chiral ligand, successfully obtaining enantiomerically enriched boronic esters in good to excellent yield. The reactivity of the boronic esters has been explored to demonstrate their potential as chemical building blocks.
Pyrrolidine is a N-heterocyclic ring. Much like all ring systems, they are present in drugs to dictate various molecular properties such as bioavailability. N-Heterocycles tend to be more useful than other ring systems as nitrogen can form interactions with binding sites and receptors. However, whilst drugs benefit from high geometric/structural diversity, most ring systems in drugs are aromatic (and planar). Usage of pyrrolidines as pharmaceutical building blocks is typically performed via reactions such as the Suzuki-Miyaura coupling, which would require a boronic ester function. Unfortunately, there are few synthetic routes which construct borylated pyrrolidine ring systems and some routes exhibit narrow substrate scopes. In this work, the reaction of β-aminoethyl pinacol boronates with diphenylvinylsulfonium triflate triggers a conjugate addition/cyclisation/1,2-borate rearrangement cascade, providing a simple route to borylated pyrrolidine ring systems.
It is well-established that polymer adsorption at a model planar interface can be studied using a quartz crystal microbalance (QCM). Normally, this technique reports both the adsorbed mass of polymer chains plus any bound or entrained solvent molecules. Thus the total adsorbed amount significantly exceeds that reported by other methods such as optical reflectometry or adsorption isotherms obtained for colloidal substrates using a supernatant depletion assay. Herein we report a new approach whereby the dry adsorbed amount, Γdry, is obtained directly from the wet (solvated) adsorbed amount, Γwet, by switching from liquid flow to a flow of nitrogen gas after the initial conventional QCM analysis. The latter conditions lead to complete removal of the solvent, leaving only the desolvated adsorbed polymer chains.
A major challenge in the aviation industry is the significant carbon footprint produced by traditional jet fuels, which contribute heavily to greenhouse gas emissions. In response, the industry is actively seeking ways to achieve net-zero emissions by 2030. One promising near-term alternative is Sustainable Aviation Fuel (SAF), which closely resembles the composition of conventional jet fuel. However, the widespread adoption of SAF faces a key hurdle: the certification process. This process, required for SAF to meet strict ASTM standards, is both expensive and time-consuming. This research focuses on developing a practical and efficient method for predicting the properties of SAF. By providing producers with accurate predictions about their SAF's properties, this approach could streamline the certification process, saving both time and cost.
Emulsions, which consist of oil droplets dispersed in water, are widely used in a range of industries, from agricultural chemicals to medical and personal care products. Traditional surfactant-stabilised emulsions often suffer from drawbacks such as lack of long term stability and biocompatibility. These issues can be mitigated by the use of particle stabilised emulsions, known as Pickering emulsions. Micron-sized platelet particles can be synthesised in aqueous media, with a degradable poly(L-lactide) core and inert poly(dimethylacrylamide) corona, via an approach combining reverse sequence polymerisation-induced self-assembly (rsPISA) and crystallisation-driven self-assembly (CDSA). In this work, these biocompatible and hydrolytically degradable platelet particles are examined as Pickering emulsifiers for oil-in-water emulsions. The high surface area and large size of these platelets should, in theory, enable the formation of relatively stable emulsions at low concentrations.
The vast consumption of energy, from predominantly non-renewable sources, heavily contributes to one of the biggest challenges of this century: climate change. Renewable energy is a well-recognised alternative. Transition metal complexes can access notably long lived excited states. Enabling promising applications in dye-sensitised solar cells (DSSC), to harness energy. Copper(I) complexes have been studied since the late 1970s, due to their interesting electron dynamics and structural distortions. With the primary focus on Copper(I) complexes, to utilise a cost effective, abundant metal. This research utilises ultra-fast spectroscopy and spectroelectrochemical techniques, located at X-ray free electron lasers (XFELs). These XFELs give a unique opportunity to directly address the questions of electronic, spin and structural change. The analysis will allow for a deeper understanding of transition metal complexes, to extend our knowledge on how to improve DSSC and PDT.
AAA+ ATPases hydrolyze ATP to generate mechanical force used to disassemble macromolecular assemblies, which function for diverse cellular processes. We are interested in understanding how the activity of these AAA+ ATPase is regulated by post-translational modifications, which remains largely unknown. We focus on VPS4, a member of the meiotic clade of AAA+ ATPases family, is crucial for disassembling the membrane-remodelling ESCRT-III protein polymers, facilitating endosomal sorting of transmembrane receptors, organelle membrane repair and completing cell division. We explore how phosphorylation in the linker that joins substrate-binding and ATPase domain impact on the structure and activity of the enzyme. The unstructured linker sequence contains several identified phosphosites, some of which appear conserved. Using phosphomimetic mutants, we examine how modifications in the linker affects VPS4 activity in vitro and at cellular membranes.
Interstrand cross links (ICLs) are covalent linkages between the two polynucleotide strands of the DNA double helix structure, they are highly toxic due to their ability to impede DNA transcription and replication. Fanconi anaemia (FA) patients are deficient in ICL repair and are therefore cancer-prone. FA arises from mutations in FANC genes, disrupting the FA pathway which repairs ICLs via DNA excision. Recent work has highlighted a secondary, excision-free, ICL repair pathway that remains undefined.
4-Hydroxynonenal (4-HNE), a lipid peroxidation product, forms both native (imine, carbinolamine and pyramidopurinone forms in equilibrium) and reduced ICLs. This work aims to synthesize DNA duplexes containing 4-HNE-derived ICLs to study their structure and repair, potentially involving the non-FA pathway. Progress includes the synthesis of several key compounds, including O6 protected 2-fluoro-2’-deoxyinosine for use in DNA synthesis as well as a 4-HNE derived aminodiol linker compound.
Drug discovery research is heavily reliant on library synthesis to uncover new small molecule ‘hits’ that can be further developed into lead compounds. The availability of multifunctional small molecule scaffolds underpins this activity, as these offer a platform for the generation of libraries of distinct compound sets for downstream biological assays. Moreover, it is essential that such scaffolds have relatively low molecular weight profiles so that they can be elaborated without going over the limits set by Lipinski’s guidelines. In this context, this project entails the synthesis of pyrazolylmethyl trifluoroborate salts, potential precursors of N-benzyl pyrazole derivatives – a privileged class of bioactive small molecules in medicinal chemistry.
Streptonigrone is a natural product derived from Streptomyces, belonging to the same class of compounds as streptonigrin, which has been definitively established as an axially chiral molecule. However, naturally isolated streptonigrone does not exhibit circular dichroism, raising uncertainty as to whether it is an achiral compound or a racemic mixture. Given the crucial role of chirality—particularly atropisomerism—in modern drug discovery, where different stereoisomers often exhibit significantly distinct pharmacological properties such as efficacy and toxicity, determining streptonigrone’s chiral nature is important. However, the synthesis of single atropisomers remains a considerable challenge. To address these challenges, this study aims to develop an efficient and stereocontrolled route to streptonigrone using dynamic resolution of boronic esters. This poster will provide an update on our progress towards the synthesis of this natural product.
We have recently developed a new class of thermoresponsive amphiphilic diblock copolymers that can reversibly switch between up to four copolymer morphologies in aqueous media. A new exemplar of this unique self-assembly behaviour is poly(N,N’-dimethyl acrylamide)-poly(4-hydroxybutyl acrylate) (PDMAC-PHBA).Thermal transitions are sensitive to the precise copolymer composition but typically spheres are formed below 5°C, worms are obtained at around 12.5-17.5°C, vesicles are produced at 25°C and lamellae are formed above 30°C for PDMAC43-PHBA180
This project is focused on two key parts. Firstly, the rigorous analysis using Small Angle X-Ray Scattering of the various shapes that can be specifically targeted to build up a large data set which may be used to develop machine-learning algorithms to assist users. Secondly, the analysis of these polymers using Small Angle Neutron Scattering to determine the exact mechanism of the thermoresponsive behaviour.
Self-assembled nanostructures of β (beta) and α (alpha) stereoisomer amino acids have garnered significant attention in drug delivery and other applications due to their unique properties. These amino acids, the fundamental building blocks of proteins, are capable of self-organizing into nanostructures at the molecular level. The distinct structural and functional characteristics of the β and α forms influence their interactions within biological systems. When applied to drug delivery, these nanostructures can improve the stability, targeting, and controlled release of therapeutic agents. Moreover, their biocompatibility and versatility make them well-suited for a wide range of applications, including tissue engineering, biosensing, and regenerative medicine, thus presenting promising avenues for advanced medical treatments.