Chapter One gives a broad introduction to the research described herein, initially discussing the reasons for morphology control, polymerisation techniques and self- assembly methods. A general introduction to solution crystallisation of polymers is given, with a focus on block copolymers with a crystalline core-forming block. Chapter Two discusses the use of various poly(L-lactide) based amphiphiles to propose a unimer solubility-based shape selectivity mechanism for the formation of 1D and 2D nanostructures, leading to a single component solution phase protocol for the preparation of uniform diamond-shaped platelets. Chapter Three considers the use of three different morphologies, namely spheres, cylinders and platelets, as nanocomposites in calcium alginate hydrogels, where a greater shear strength is measured for platelet-composite hydrogels. Chapter Four utilises the proposed unimer solubility approach to create 2D diamond-shaped platelets of controlled size and shape. The use of different size platelets as water-in-water Pickering emulsifiers is explored, where larger plates are shown to give more stable emulsions. Chapter Five employs the use of a poly(ɛ-caprolactone) crystallisable core-forming block for the preparation of 1D cylindrical structures of controlled length and dispersity. Direct epitaxial growth in water is shown, leading to the preparation of strong hydrogel materials. Chapter Six summarises the research presented, giving general conclusions as well as discussing the scope for future investigations in this area of research.

This thesis aims to explore the applicability of Electron Paramagnetic Resonance (EPR) spectroscopy in the pharmaceutical field. EPR is a powerful biophysical tool that allows the detection and characterisation of paramagnetic species, such as free organic radicals and metal complexes. EPR is widely used across all disciplines but to date has been much underutilised in the pharmaceutical industry. In the first part of this work, EPR techniques were applied to characterise the degradation products originating from irradiation sterilization of two common excipients, L-histidine and D-mannitol. Radicalic degradants can form as a result of several degradation pathways and industrial processes, including γ-radiation sterilization. A quantification of the radical species formed upon γ-irradiation was performed, indicating a much higher radical concentration for D-mannitol compared to L-histidine at pharmaceutically relevant irradiation doses. Cold irradiation analysis allowed the study of the low temperature stable species and their evolution into the r.t. stable ones. Three low temperature persistent radical species of D-mannitol were identified for the first time. The reactivity of the radicals in solution was also investigated. Spin trapping experiments allowed trapping of radicals from both L-histidine and D-mannitol. An unusual, and potentially hazardous, radical regeneration mechanism was observed for L-histidine, which was suggested to be due to the sterile metal needles used for transferring the sample solution in the EPR tubes. The second part of this work was concerned with the investigation of the radicalic mechanism of action of a promising photo-activable platinum(IV) anticancer complex. It has been previously suggested that the cytotoxicity of the said compound is associated to the photo-release of azidyl radicals, which can be quenched in the presence of the amino acid L-tryptophan. By the use of the spin trapping methodology, an intermediate indole radical was isolated and identified from photo-activation of the anticancer complex in the presence of both L-tryptophan and melatonin. The same photo-protective effect was observed also in the presence of a tryptophan-containing peptide. Thus, this work contributed to the overall understanding on photo-irradiated platinum anticancer complexes and their generated photo-products.

This thesis explores the synthesis and self-assembly of nucleobase-containing acrylamide amphiphiles and investigates their self-assembly behaviors and potential applications in aqueous solutions. In Chapter 1, the synthesis and self-assembly of block copolymers are briefly introduced. Then the effect of H-bonding interactions on self-assembly behaviours is highlighted. Finally, an overview of the synthesis, self-assembly and applications of synthetic nucleobase-containing polymers is presented. Chapter 2 investigates the effect of complementary nucleobase interactions within micellar cores on the morphologies of self-assemblies in aqueous solutions. Self-assemblies with different core sizes of thymine are fabricated and their morphological transitions with introducing complementary copolymers are studied as well. Chapter 3 systematically explores the pathway-dependent and complementary chain-selective morphological transitions of micelles with a thymine core. In addition, the complementary H-bonding within micellar cores is utilized to prepare a series of worms with different lengths and widths in aqueous media. Chapter 4 builds on the knowledge obtained in the previous Chapters. A series of mixed corona micelles are fabricated through a simple supramolecular ‘grafting-to’ approach. By introducing protein ligands and environment-sensitive fluorophores at the end of corona, the reveal and concealment of functional groups on the micelle surface through heating and cooling are investigated. Chapter 5 reveals the synergetic H-bonding and thymine photodimerization give a novel polymer fluorescent dots. A number of factors are investigated on the observed fluorescent properties, including the effect of blocking H-bonding interactions and changing the degree of core-crosslinking. Finally, Chapter 6 summarizes the conclusions of Chapters 2-5 and provides some insights and outlines for the future work.

Within this thesis we explore the synthesis of novel colloidal particles for the use as both a thermochromic indicator and opacifiers. Initially in Chapter 1 we describe the synthesis of polystyrene copolymers and the effect the co-monomers have upon the phase transitional temperature within dioctyl phthalate. Co-polymers containing varying mol% of copolymers led to a decrease in the transitional temperatures for the systems. Following the determination of the phase transitions, we touched upon the potential to encapsulate the oils and use them within both a soft fibre and a waterborne latex binder as a thermochromic pigment. In Chapter 2 we looked into the synthesis of hollow non-spherical silica particles and their potential use within both ultrasound imaging and films as an opacifying agent. In Chapter 3 we expand upon the use of the silica shells by dispersing them within a PMMA nanocomposite to determine the effect on the mechanical properties. In Chapter 4 we explored further into the UCST systems shown in Chapter 1 with the addition of specialised dye tagging of the polystyrene chains to obtain a fluorescent changes upon phase transition.

The aim of the work presented in this thesis was to explore the structural and molecular features of a filamentous bacteriophage for incorporation in biosensing platforms. To tune the bacteriophage surface as a scaffold for molecular recognition, chemical and biological protocols aimed at controlling and enhancing its intrinsic properties were developed. A key part of the work was aimed at anchoring bacteriophage particles by one-end to surfaces, and on labelling its viral capsid with dyes, antibodies and DNA molecules. The tolerance of the bacteriophage for modifications, as well its simplicity and robustness, makes it an attractive probe for biosensors. Furthermore, the filamentous structure of the bacteriophage was demonstrated to be a valuable feature in both microscopy- and spectroscopy-based biosensors. The ability of the bacteriophage to align under flow was considered as a simple, yet efficient approach for the detection of wall shear stress and pathogenic bacteria. A novel method to detect wall shear stress (WSS) was developed by using a fluorescently decorated bacteriophage particle anchored by one-end to a surface. The response of this filamentous nanosensor to flow variations was tracked under a microscope, and gave valuable information on the shear flow of a fluid passing over a surface. Using a custom-made analysis tool and an algorithm, we were able to derive the wall shear stress on the point of attachment of the nanosensor, using endothelial cells as a model system. The proof-of-concept to this work highlighted how a simple bacteriophage construct can be use as a nanosensor for imaging and mapping flow. Linear dichroism (LD) spectroscopy also explores the high aspect ratio of the filamentous bacteriophage. Linear Diagnostics Ltd., a startup company in Birmingham, exploits the natural LD properties of the bacteriophage and integrated it with a biosensing platform targeting pathogenic bacteria. The work reported in this thesis mainly focused on developing alternative approaches that could improve the biosensor sensitivity and simplicity, by modifying the bacteriophage scaffold, further demonstrating its versatility.

Platinum complexes, e.g. cisplatin, oxaliplatin, carboplatin, have been used for near 40 years in clinic as potent anticancer drugs. However, these drugs can cause severe side effects, and hence there is an urgent need to develop other metal based antiproliferative agents. For example, organometallic Ru II/III complexes possess potent anticancer activity but low cytotoxicity towards normal cells, which makes them promising alternatives to currently used anticancer drugs. In this thesis, a series of neutral pseudo-octahedral Ru II-sulfonamidoethylenediamine complexes [(η6-arene)Ru(N,N’)X] where η6-arene is p-cym, biph and benzene, N,N’ is ethylenediamine chelating ligands with sulfonyl substituents (e.g. Ts or Nb) on one terminal N and various functional groups (e.g. Me, Me2, Et, benzyl, 4-fluorobenzyl or naphthalen-2-ylmethyl) on the other terminal N were synthesized and fully characterized, including X-ray crystal structures. These complexes catalyse the reduction of NAD+ regioselectively to 1, 4-NADH using sodium formate as hydride source under biologically relevant conditions. The catalytic efficiency depends markedly on the steric and electronic effects of the N-substituent, with turnover frequencies (TOFs) increasing with the enhancement of bulkiness and electron withdrawing of the substituents, achieving a highest TOF of 12.9 h−1 for complex 10 [(η6-biph)Os(TsEnBz)Cl]. These complexes exhibited antiproliferative activity against A2780 human ovarian cancer cells. Co-administration with sodium formate (2 mM) increased their potency significantly towards A2780 cells. Substituted Ru II sulfonylethylenediamine complexes can also interact rapidly with glutathione (GSH) and N-acetyl-L-cysteine (NAC) to form S-bridged [(η6-arene)2Ru2(GS)3]2+ or [(η6-arene)2Ru2(NAC)3]+ dimers, and the presence of GSH can effectively hamper the catalytic reduction of NAD+ to NADH. Next, a series of neutral organometallic tethered [Ru(η6-benzene-N-R-ethylenediamine)Cl] complexes was synthesized and characterized, where R = methylsulfonyl (Ms), toluenesulfonyl (Ts), trifluorobenzenesulfonyl (Tf) and 4-nitrobenzenesulfonyl (Nb), including their X-ray crystal structures. In general, these complexes also exhibited potent catalytic activity in the transfer hydrogenation of NAD+ to NADH with formate as hydride donor (310 K, pH 7), but with moderate antiproliferative activity towards human ovarian, lung, liver and breast cancer cell lines. Tethered Ru II complexes showed preferential binding to 9-ethylguanine (9-EG) over adenosine 5’-monophosphate (5’-AMP). However, DNA appears not to be the target, as little binding of complex 17 [Ru(η6-benzene-N-Ts-ethylenediamine)Cl] to ct-DNA or bacterial plasmid DNA was observed. Also, the tethered complexes bind rapidly to GSH, which might again hamper the transfer hydrogenation reactions in cells. Interestingly, these tethered Ru II complexes can induce a dose-dependent G1 cell cycle arrest and high level of reactive oxygen species (ROS) generation, which is likely to contribute to their antiproliferative activity. Diseases caused by bacterial infections, especially by multidrug-resistance bacteria, are the major cause of deaths worldwide. Traditional clinical drugs cannot cope with the rapid rise of drug resistance. In this thesis, a new class of organometallic antimicrobial complexes of the type [(arene/Cpx)Ir(Big)Z]Z (where arene is para-cymene or biphenyl, Cpx = Cp* (tetramethylcyclopentadienyl), Cp*ph or Cp*biph, Big = biguanide ligands and functional sulfonyl substituted biguanide ligands, Z = Cl, Br and I) were synthesized and characterized by NMR, ESI-MS, elemental analysis and X-ray crystallography. These complexes not only have promising antibacterial activity against Gram-negative bacteria and excellent potency against Gram-positive bacteria, but also exhibit high antifungal potency towards C. albicans and C. neoformans. Most of the complexes have low cytotoxicity towards mammalian cells (HEK-293 human red blood cells and HaCaT keratinocyte cells), indicating a high selectivity. These Ir III complexes have a high stability in both medium even at high temperature (315 K). A mutant generation study suggests that S. aureus exhibits a low tendency to generate mutants in response to these complexes. Ir biguanide complexes 27 [(η5-CpXbiph)Ir(PhBig)]Cl, 30 [(η5-CpXbiph)Ir(TolBig)Cl]Cl and 33 [(η5-CpXbiph)Ir(TsTolBig)Cl] exhibited synergy with clinical drug vancomycin when co-administered in vancomycin-resistant Enterococci (VRE), with the MIC 256× lower at sub-MIC complex concentration. These complexes also exhibited potent anti-biofilm activity against biofilms generated by S. aureus. Potent antimicrobial activity against various microbes might provide an alternative pathway to treat drug resistant nosocomial pathogens.

Lignocellulose is an abundant natural polymer on earth that contains renewable resource of aromatic compound, the lignin. Many industrially valuable chemicals can be developed from lignin and this can reduce the dependency on petrochemicals. Wheat straw contains ferulic acid as one of its building blocks, which can be accumulated as a major metabolite from growth with Rhodococcus jostii RHA1, a known lignin degrading bacteria in minimal media. Using the enzyme phenolic acid decarboxylase (PAD) in engineered E.coli, ferulic acid was converted into 4-vinylguaiacol (3-methoxy-4-hydroxystyrene). The substituted monostyrene was then enzymatically polymerised by laccase to form a polymer that showed an adhesive property. This enzymatically generated polymer can potentially provide an alternative to synthetic process, besides providing renewable option to generate environmental friendly material in ambient conditions.

This thesis explores the self-assembly and responsive behavior of block copolymer amphiphiles in aqueous solution. In Chapter 1, an overview of the modern synthetic methods used for preparing such materials will be given, as well as the parameters governing block copolymer self-assembly in solution. An introduction into polymerization-induced self-assembly will be given, as well as an overview of stimuli- responsive polymers and polymer self-assemblies. Finally, an outline of the analytical techniques used throughout this thesis for studying polymer self-assemblies will be given. Chapter 2 will introduce thermoresponsive polymers, which can respond to changes in temperature, before investigating the solution behavior of a series of thermoresponsive polymer self-assemblies. These micelles have a tunable average number of chains per particle and will used as a platform to investigate the thermoresponsive behavior of the system using a range of complementary solution-based characterization techniques. Chapter 3 will build on the knowledge gained in the previous chapter and will explore the effects of factors such as the glass transition temperature and hydrogen bonding ability on the thermoresponsive behavior of such systems. This will give an insight into the reversibility of thermoresponsive phase transitions, more generally, and provide a unique tool with which to probe structure-property relationships in stimuli-responsive self- assemblies. Chapter 4 will uncover the differences between the two initiation pathways for polymerization-induced self-assembly, thermally and photoinitiated, discussed in this Chapter. Isothermal non-equilibrium phase diagrams will be constructed using thermally initiated and photoinitiated polymerization-induced self-assembly. The effects of light intensity on the formed nano-objects will be investigated as well as the effect of post synthetic light irradiation, both are aspects that have not been widely explored in the literature. Chapter 5 will explore the use of polymerization-induced self-assembly to prepare selectively permeable biohybrid vesicular nanoreactors. Functional proteins with fluorescent or enzymatic capabilities will be encapsulated inside hollow polymersomes and the selective permeability of the membrane will be demonstrated. A clinically relevant therapeutic protein will also be investigated as the encapsulated species and the formed nanoreactors’ ability to prevent cancer cell proliferation will be validated. The non-covalent, yet protective nature of this protein compartmentalization will also provide several distinct advantages over covalent attachment of poly(ethylene glycol), the current state-of-the-art for this clinical therapeutic. Finally, Chapter 6 will summarize the conclusions gained from the research herein, as well as offer some insights into possible areas of new research directed by the findings detailed in this thesis.

Introduction of antimicrobial chemotherapy in the 20th century was an invaluable achievement of medicine. The efficacy of currently available antibiotics, however, is decreasing due to the global spread of antibiotic-resistant strains of pathogens. Especially Gram-negative bacteria pose a serious threat as there are fewer possible treatment options. The innovation gap in antibiotics discovery severely reduced the number of novel antibacterial drug candidates. Penicillin-binding proteins (PBPs) are enzymes responsible for the final steps of cell wall synthesis in bacteria. Due to their uniqueness, essentiality and interspecific conservation, they are important drug targets, yet there is only one class of compounds in clinical use that can directly inhibit them. As the need for new antibiotics increases, alternative approaches to penicillin-binding proteins’ inhibition should be scrutinised. The aim of this thesis was to investigate new biochemical methods to monitor enzymatic activities of class A penicillin-binding proteins, in particular E. coli PBP1b, and their amenability to the high-throughput drug screening. Two distinct assays were developed and optimised for target-based drug screening in a high-throughput manner. The assays complement each other as they are designed to measure two different activities of the same enzyme. The methods rely on the use of tailored substrates in the presence of the natural PBP1b cofactor, lipoprotein B. The assays were tested against chemical libraries of over 150,000 diverse compounds yielding over 2,700 primary hits. The post-screening selection process has decreased the number of compounds, and now 11 of them are available for further investigation. The assay development process provided additional insight into the PBP1b biology and natural products inhibiting its activity. Supplementary applications were found for the bespoke substrate used in the assay. The methods presented in the thesis can become the foundation of a cell wall inhibitors discovery platform and identify new chemical matter for medicinal chemistry.

This thesis is in two distinct sections. In the first section, novel diketopiperazines are synthesised and incorporated as chain extenders into thermoplastic polyurethane elastomers and the resulting mechanical, thermal and degradative properties are analysed. In the second section, hyperbranched chain terminating agents are synthesised from 1,1’-carbonyldiimidazole in a one-pot process and the potential applications of fluorinated hyperbranched chain terminating agents are investigated. Chapter 1 has three parts. First, the synthesis and applications of polyurethanes are introduced and the current market trends and growth projections are discussed. Secondly, an overview of current literature covering biodegradable polymers focusing on the incorporation of amino acids into polyurethanes and their potential applications is presented. Thirdly, hyperbranched polymers are introduced and a focus is made on the synthesis of isocyanate and non-isocyanate polyurethanes and polyureas. In chapter 2, the use of the dipeptides of tyrosine and glutamic acid as chain extenders in polyurethane synthesis is explored. The dipeptide of glutamic acid is modified to incorporate a higher content of ester and amide degradable linkages with aromatic character that form comparable chain extenders to tyrosine dipeptide. Their use in the organocatalysed step-growth polymerisation of novel thermoplastic polyurethane elastomers is described. In chapter 3, the resulting tyrosine and glutamic acid-derived thermoplastic polyurethane elastomers are utilised to explore the variation of thermal, mechanical and degradative properties of a range of polymer compositions. In chapter 4, the synthesis of novel hyperbranched materials polymerised in a one-pot, temperature-controlled sequential synthesis incorporating aromatic or fluorinated functional chain ends from both carbonylbiscaprolactam and 1,1’-carbonyldiimidazole precursors is described. In chapter 5, 1,1’-carbonyldiimidazole derived hyperbranched polymers are incorporated into an existing thermoplastic polyurethane formulation and the surface properties are studied by varying polymer composition. In chapter 6, the significant findings and conclusions are summarised. In chapter 7, the experimental methods used are set out.