pH-Responsive Amphiphilic Triblock Fluoropolymers as Assemble Oxygen Nanoshuttles for Enhancing PDT against Hypoxic Tumor.

Photodynamic therapy (PDT) is a cancer treatment strategy that utilizes photosensitizers to convert oxygen within tumors into reactive singlet oxygen (1O2) to lyse tumor cells. Nevertheless, pre-existing tumor hypoxia and oxygen consumption during PDT can lead to an insufficient oxygen supply, potentially reducing the photodynamic efficacy. In response to this issue, we have devised a pH-responsive amphiphilic triblock fluorinated polymer (PDP) using copper-mediated RDRP. This polymer, composed of poly(ethylene glycol) methyl ether acrylate, 2-(diethylamino)ethyl methacrylate, and (perfluorooctyl)ethyl acrylate, self-assembles in an aqueous environment. Oxygen, chlorine e6 (Ce6), and doxorubicin (DOX) can be codelivered efficiently by PDP. The incorporation of perfluorocarbon into the formulation enhances the oxygen-carrying capacity of PDP, consequently extending the lifetime of 1O2. This increased lifetime, in turn, amplifies the PDT effect and escalates the cellular cytotoxicity. Compared with PDT alone, PDP@Ce6-DOX-O2 NPs demonstrated significant inhibition of tumor growth. This study proposes a novel strategy for enhancing the efficacy of PDT.

MaDDOSY (Mass Determination Diffusion Ordered Spectroscopy) using an 80 MHz Bench Top NMR for the Rapid Determination of Polymer and Macromolecular Molecular Weight.

Measurement of molecular weight is an integral part of macromolecular and polymer characterization which usually has limitations. Herein, this article presents the use of a bench-top 80 MHz Nuclear Magnetic Resonance (NMR) spectrometer for diffusion-ordered spectroscopy as a practical and rapid approach for the determination of molecular weight/size using a novel solvent and polymer-independent universal calibration.

Hydrolyzable Poly[Poly(Ethylene Glycol) Methyl Ether Acrylate]-Colistin Prodrugs through Copper-Mediated Photoinduced Living Radical Polymerization.

Through the recently developed copper-mediated photoinduced living radical polymerization (CP-LRP), a novel and well-defined polymeric prodrug of the antimicrobial lipopeptide colistin has been developed. A colistin initiator (Boc5-col-Br2) was synthesized through the modification of colistin on both of its threonine residues using a cleavable initiator linker, 2-(2-bromo-2-methylpropanoyloxy) acetic acid (BMPAA), and used for the polymerization of acrylates via CP-LRP. Polymerization proceeds from both sites of the colistin initiator, and through the polymerization of poly(ethylene glycol) methyl ether acrylate (PEGA480), three water-soluble polymer-colistin conjugates (col-PPEGA, having degrees of polymerization of 5, 10, and 20) were achieved with high yield (conversion of ≥93%) and narrow dispersities (D < 1.3) in 2-4 h. Little or no effect on the structure and activity of the colistin was observed during the synthesis, and most of the active colistin can be recovered from the conjugates in vitro within 2 days. Furthermore, in vitro biological analyses including disk diffusion, broth microdilution, and time-kill studies suggested that all of the conjugates have the ability to inhibit the growth of multidrug-resistant (MDR) Gram-negative bacteria, of which col-PPEGA DP5 and DP10 showed similar or better antibacterial performance compared to the clinically relevant colistin prodrug CMS, indicating their potential as an alternative antimicrobial therapy. Moreover, considering the control over the polymerization, the CP-LRP technique has the potential to provide an alternative platform for the development of polymer bioconjugates.

Comb Poly(Oligo(2-Ethyl-2-Oxazoline)Methacrylate)-Peptide Conjugates Prepared by Aqueous Cu(0)-Mediated Polymerization and Reductive Amination.

The controlled synthesis of poly(oligo(2-ethyl-2-oxazoline)methacrylate) (P(OEtOxMA)) polymers by Cu(0)-mediated polymerization in water/methanol mixtures is reported. Utilizing an acetal protected aldehyde initiator for the polymerization, well-defined polymers are synthesized (>99% conversion, Ð < 1.25) with subsequent postpolymerization deprotection resulting in α-aldehyde end group containing comb polymers. These P(OEtOxMA) are subsequently site-specifically conjugated, via reductive amination, to a dipeptide (NH2 -Gly-Tyr-COOH) as a model peptide, prior to conjugation to the functional peptide oxytocin. The resulting oxytocin conjugates are evaluated in comparison to poly(oligo(ethylene glycol) methyl ether methacrylate) combs synthesized in the same manner for potential effects on thermal stability in comparison to the native peptide.

Stability Enhancing N-Terminal PEGylation of Oxytocin Exploiting Different Polymer Architectures and Conjugation Approaches.

Oxytocin, a cyclic nine amino acid neurohypophyseal hormone therapeutic, is effectively used in the control of postpartum hemorrhaging (PPH) and is on the WHO List of Essential Medicines. However, oxytocin has limited shelf life stability in aqueous solutions, particularly at temperatures in excess of 25 °C and injectable aqueous oxytocin formulations require refrigeration (<8 °C). This is particularly problematic in the hot climates often found in many developing countries where daytime temperatures can exceed 40 °C and where reliable cold-chain storage is not always achievable. The purpose of this study was to develop N-terminal amine targeted PEGylation strategies utilizing both linear PEG and polyPEG "comb" polymers as an effective method for stabilizing solution formulations of this peptide for prolonged storage in the absence of efficient cold-chain storage. The conjugation chemistries investigated herein include irreversible amine targeted conjugation methods utilizing NHS ester and aldehyde reductive amination chemistry. Additionally, one reversible conjugation method using a Schiff base approach was explored to allow for the release of the native peptide, thus, ensuring that biological activity remains unaffected. The reversibility of this approach was investigated for the different polymer architectures, alongside a nonpolymer oxytocin analogue to monitor how pH can tune native peptide release. Elevated temperature degradation studies of the polymer conjugates were evaluated to assess the stability of the PEGylated analogues in comparison to the native peptide in aqueous formulations to mimic storage conditions in developing nations and regions where storage under appropriate conditions is challenging.

Well-Defined Protein/Peptide-Polymer Conjugates by Aqueous Cu-LRP: Synthesis and Controlled Self-Assembly.

The synthesis of well-defined protein/peptide-polymer conjugates with interesting self-assembly behavior via single electron transfer living radical polymerization in water is described. A range of protein/peptides with different physical and chemical properties have been modified to macroinitiators and optimized polymerization conditions ensure successful polymerization from soluble, insoluble, and dispersed protein/peptide molecules or protein aggregates. This powerful strategy tolerates a range of functional monomers and mediates efficient homo or block copolymerization to generate hydrophilic polymers with controlled molecular weight (MW) and narrow MW distribution. The polymerizations from bovine insulin macroinitiators follow surface-initiated "grafting from" polymerization mechanism and may involve a series of self-assembly and disassembly processes. Synthesized insulin-polymer conjugates form spheres in water, and the self-assembly behavior could be controlled via thermal control, carbohydrate-protein interaction, and protein denaturation.

Organic arsenicals as efficient and highly specific linkers for protein/peptide-polymer conjugation.

The entropy-driven affinity of trivalent (in)organic arsenicals for closely spaced dithiols has been exploited to develop a novel route to peptide/protein-polymer conjugation. A trivalent arsenous acid (As(III)) derivative (1) obtained from p-arsanilic acid (As(V)) was shown to readily undergo conjugation to the therapeutic peptide salmon calcitonin (sCT) via bridging of the Cys(1)-Cys(7) disulfide, which was verified by RP-HPLC and MALDI-ToF-MS. Conjugation was shown to proceed rapidly (t < 2 min) in situ and stoichiometrically through sequential reduction-conjugation protocols, therefore exhibiting conjugation efficiencies equivalent to those reported for the current leading disulfide-bond targeting strategies. Furthermore, using bovine serum albumin as a model protein, the trivalent organic arsenical 1 was found to demonstrate enhanced specificity for disulfide-bond bridging in the presence of free cysteine residues relative to established maleimide functional reagents. This specificity represents a shift toward potential orthogonality, by clearly distinguishing between the reactivity of mono- and disulfide-derived (vicinal or neighbors-through-space) dithiols. Finally, p-arsanilic acid was transformed into an initiator for aqueous single electron-transfer living radical polymerization, allowing the synthesis of hydrophilic arsenic-functional polymers which were shown to exhibit negligible cytotoxicity relative to a small molecule organic arsenical, and an unfunctionalized polymer control. Poly(poly[ethylene glycol] methyl ether acrylate) (PPEGA480, DPn = 10, Mn,NMR = 4900 g·mol(-1), D = 1.07) possessing a pentavalent arsenic acid (As(V)) α-chain end was transformed into trivalent As(III) post-polymerization via initial reduction by biological reducing agent glutathione (GSH), followed by binding of GSH. Conjugation of the resulting As(III)-functional polymer to sCT was realized within 35 min as indicated by RP-HPLC and verified later by thermodynamically driven release of sCT, from the conjugate, in the presence of strong chelating reagent ethanedithiol.

In situ conjugation of dithiophenol maleimide polymers and oxytocin for stable and reversible polymer-peptide conjugates.

The in situ one-pot synthesis of peptide-polymer bioconjugates is reported. Conjugation occurs efficiently without the need for purification of dithiophenol maleimide functionalized polymer as a disulfide bridging agent for the therapeutic oxytocin. Conjugation of polymers was demonstrated to be reversible and to significantly improve the solution stability of oxytocin.

Cast Titanium for Obturator Framework Construction in Maxillofacial Prosthodontics.

A 37 year old male presented with the complaint of a loose and bulky acrylic obturator prosthesis. He had previously tried to using a different acrylic obturator prostheses as well as both cobalt chromium and titanium framework obturators. The most successful previous prosthesis was a titanium based obturator which had performed well prior to a fractured clasp. Accordingly, following an exploration of the available surgical and prosthodontic treatment options, a further tooth borne partial maxillary obturator was provided successfully. The case highlights the relative merits and limitations of the use of cast titanium as a denture base material in partial denture and obturator construction.

Aqueous copper-mediated living radical polymerisation of N-acryloylmorpholine, SET-LRP in water.

The polymerisation of N-acryloylmorpholine in water is reported utilising Cu(0)-mediated living radical polymerisation (SET-LRP). The inherent instability of [Cu(I) (Me6-Tren)Br] in aqueous solution is exploited via rapid disproportionation to prepare Cu(0) particles and [Cu(II) (Me6-Tren)Br2 ] in situ prior to addition of monomer and initiator. Quantitative conversion is attained within 30 min for various degrees of polymerisation (DPn = 20-640) with SEC showing symmetrical narrow molecular weight distributions (D < 1.18) in all cases. Optimised conditions are subsequently applied for the preparation of a diblock copolymer poly(NIPAm)-b-(N-acryloylmorpholine), illustrating the versatility of this approach.

The impact of devolution on local health systems: Evidence from Greater Manchester, England.

Devolution and decentralisation policies involving health and other government sectors have been promoted with a view to improve efficiency and equity in local service provision. Evaluations of these reforms have focused on specific health or care measures, but little is known about their full impact on local health systems. We evaluated the impact of devolution in Greater Manchester (England) on multiple outcomes using a whole system approach. We estimated the impact of devolution until February 2020 on 98 measures of health system performance, using the generalised synthetic control method and adjusting for multiple hypothesis testing. We selected measures from existing monitoring frameworks to populate the WHO Health System Performance Assessment framework. The included measures captured information on health system functions, intermediatory objectives, final goals, and social determinants of health. We identified which indicators were targeted in response to devolution from an analysis of 170 health policy intervention documents. Life expectancy (0.233 years, S.E. 0.012) and healthy life expectancy (0.603 years, S.E. 0.391) increased more in GM than in the estimated synthetic control group following devolution. These increases were driven by improvements in public health, primary care, hospital, and adult social care services as well as factors associated with social determinants of health, including a reduction in alcohol-related admissions (-110.1 admission per 100,000, S.E. 9.07). In contrast, the impact on outpatient, mental health, maternity, and dental services was mixed. Devolution was associated with improved population health, driven by improvements in health services and wider social determinants of health. These changes occurred despite limited devolved powers over health service resources suggesting that other mechanisms played an important role, including the allocation of sustainability and transformation funding and the alignment of decision-making across health, social care, and wider public services in the region.

Aqueous copper-mediated living polymerization: exploiting rapid disproportionation of CuBr with Me6TREN.

A new approach to perform single-electron transfer living radical polymerization (SET-LRP) in water is described. The key step in this process is to allow full disproportionation of CuBr/Me6TREN (TREN = tris(dimethylamino)ethyl amine to Cu(0) powder and CuBr2 in water prior to addition of both monomer and initiator. This provides an extremely powerful tool for the synthesis of functional water-soluble polymers with controlled chain length and narrow molecular weight distributions (polydispersity index approximately 1.10), including poly(N-isopropylacrylamide), N,N-dimethylacrylamide, poly(ethylene glycol) acrylate, 2-hydroxyethyl acrylate (HEA), and an acrylamido glyco monomer. The polymerizations are performed at or below ambient temperature with quantitative conversions attained in minutes. Polymers have high chain end fidelity capable of undergoing chain extensions to full conversion or multiblock copolymerization via iterative monomer addition after full conversion. Activator generated by electron transfer atom transfer radical polymerization of N-isopropylacrylamide in water was also conducted as a comparison with the SET-LRP system. This shows that the addition sequence of l-ascorbic acid is crucial in determining the onset of disproportionation, or otherwise. Finally, this robust technique was applied to polymerizations under biologically relevant conditions (PBS buffer) and a complex ethanol/water mixture (tequila).

Conjugation-induced fluorescent labeling of proteins and polymers using dithiomaleimides.

Dithiomaleimides (DTMs) with alkyl substituents are shown to be a novel class of highly emissive fluorophores. Variable solubility and further functionalization can easily be tailored through the choice of N and S substituents. Inclusion of a DTM unit into a ROP/RAFT initiator or insertion into the disulfide bond of salmon calcitonin (sCT) demonstrates the utility for fluorescent labeling of polymers and proteins. Simultaneous PEGylation and fluorescent labeling of sCT is also demonstrated, using the DTM unit as both a linker and a fluorophore. It is anticipated that DTMs will offer an attractive alternative to commonly used bulky, planar fluorophores.

A composite approach to the management of worn maxillary first molar teeth.

A lady with extrinsic acid erosion was referred to the restorative department at Bristol Dental Hospital by her General Dental Practitioner (GDP) for restoration of worn maxillary first molar teeth. These teeth were both causing symptoms of dentinal sensitivity and two attempts had been made to restore them with composite by her GDP. The restorations failed because there was insufficient space to bond the composite in place, which was due to dento-alveolar compensation of the first molars into the space created by the wear. Following relevant preventive advice, the maxillary first molar teeth were restored with 'high' direct composite resin, which allowed for adequate strength in bulk for retention while acting as fixed intrusion devices. These cured the patient's sensitivity and within four months her occlusion compensated for the composites and had re-established.

Calcium-Alginate Tissue Gels (CATG): Proof-of-concept biomaterial development.

Hydrogels are desirable materials to the field of forensic science and offer many advantages for use as tissue simulants in research and training scenarios. In this work, we demonstrate a proof-of-concept study for our biomaterial described as the Calcium-Alginate Tissue Gel (CATG). CATG biomaterials integrate functional DNA strands designed to amplify with known human primer sets for genetic profiling. Our range of CATG materials demonstrate successful DNA extraction, PCR amplification and genotyping when both fresh and aged for 21 days. The rheological properties of the CATGs were measured and the incorporation of DNA into the CATGs was assessed. Overall, the CATGs demonstrated increased viscoelastic behavior with the addition of DNA. In addition, two methods of sampling were considered, where it was found that cutting a sample of the dried CATG produced higher allele peak heights in the genotype compared to swabbing. Overall, our CATG biomaterials can be designed for multiple applications in forensic science with tunable properties for various training and research needs.

Oro-facial rehabilitation of cancer patients: 'Zygomatic 2019'-1-2 March 2019, London, UK.

This first truly global conference on the use of zygomatic implants for the oral reconstruction of patients with compromised or deficient maxillae was held at the Museum of London from 1 to 2 March 2019. It attracted over 200 clinicians and academics from 24 nations and reviewed over 25 years' experience and research in this field. This conference presented concepts heralding new opportunities for the oro-facial rehabilitation of doctor-induced osteonecrosis of the jaw (ONJ), both osteonecrosis radiation-induced (ORN) and medication-induced ONJ (MRONJ) in oncology patients.

Self-Assembling Protein-Polymer Bioconjugates for Surfaces with Antifouling Features and Low Nonspecific Binding.

A new method is demonstrated for preparing antifouling and low nonspecific adsorption surfaces on poorly reactive hydrophobic substrates, without the need for energy-intensive or environmentally aggressive pretreatments. The surface-active protein hydrophobin was covalently modified with a controlled radical polymerization initiator and allowed to self-assemble as a monolayer on hydrophobic surfaces, followed by the preparation of antifouling surfaces by Cu(0)-mediated living radical polymerization of poly(ethylene glycol) methyl ether acrylate (PEGA) performed in situ. By taking advantage of hydrophobins to achieve at the same time the immobilization of protein A, this approach allowed to prepare surfaces for IgG1 binding featuring greatly reduced nonspecific adsorption. The success of the surface modification strategy was investigated by contact angle, XPS, and AFM characterization, while the antifouling performance and the reduction of nonspecific binding were confirmed by QCM-D measurements.

A Hydrogel-Based Localized Release of Colistin for Antimicrobial Treatment of Burn Wound Infection.

There is an urgent unmet medical need for new treatments for wound and burn infections caused by multidrug-resistant Gram-negative "superbugs," especially the problematic Pseudomonas aeruginosa. In this work, the incorporation of colistin, a potent lipopeptide into a self-healable hydrogel (via dynamic imine bond formation) following the chemical reaction between the amine groups present in glycol chitosan and an aldehyde-modified poly(ethylene glycol), is reported. The storage module (G') of the colistin-loaded hydrogel ranges from 1.3 to 5.3 kPa by varying the amount of the cross-linker and colistin loading providing different options for topical wound healing. The majority of the colistin is released from the hydrogel within 24 h and remains active as demonstrated by both antibacterial in vitro disk diffusion and time-kill assays. Moreover and pleasingly, the colistin-loaded hydrogel performs almost equally well as native colistin against both the colistin-sensitive and also colistin-resistant P. aeruginosa strain in the in vivo animal "burn" infection model despite exhibiting a slower killing profile in vitro. Based on this antibiotic performance along with the biodegradability of the product, it is believed the colistin-loaded hydrogel to be a potential localized wound-healing formulation to treat burn wounds against microbial infection.

A traceless reversible polymeric colistin prodrug to combat multidrug-resistant (MDR) gram-negative bacteria.

Colistin methanesulfonate (CMS) is the only prodrug of colistin available for clinical use for the treatment of infections caused by multidrug-resistant (MDR) Gram-negative bacteria. Owing to its slow and variable release, an alternative is urgently required to improve effectiveness. Herein we describe a PEGylated colistin prodrug whereby the PEG is attached via a cleavable linker (col-aaPEG) introducing an acetic acid terminated poly (ethylene glycol) methyl ether (aaPEG) onto the Thr residue of colistin. Due to the labile ester containing link, this prodrug is converted back into active colistin in vitro within 24h. Compared to CMS, it showed a similar or better antimicrobial performance against two MDR isolates of Pseudomonas aeruginosa and Acinetobacter baumannii through in vitro disk diffusion, broth dilution and time-kill studies. In a mouse infection model, col-aaPEG displayed acceptable bacterial killing against P. aeruginosa ATCC 27853 and no nephrotoxicity was found after systemic administration, suggesting it to be a potential alternative for CMS.