pH-Responsive hollow particles prepared by co-solvent assisted solvent evaporation: From dispersions to gel composites

Stimulus responsive microcapsules attract considerable interest in the polymer science and biomaterials communities because of the varied applications they can provide. At Manchester we developed a cosolvent assisted solvent evaporation approach to prepare pH-responsive hollow particles (Fig. 1a – c). A cosolvent blend was used to dissolve the linear pH-responsive copolymer and subsequent emulsification resulted in hollow particle formation. The morphology of the hollow particles was strongly dependent on copolymer composition[1] and morphologies that mimicked red blood cells could be produced. The relationships between linear copolymer composition and hollow particle morphology are discussed. Concentrated hollow particle dispersions could form injectable physical gels when the pH was increased (Fig. 1d) and gels could be prepared that were redox degradable[2]. The gels could also be converted into covalently inter-linked hollow particle gels (Fig. 1e) that were also pH-responsive. The hollow particles were well suited to gel composite formation (Fig. 1f) and the mechanical properties of these systems could be varied by including shell-crosslinking[3] which was found to strongly affect their pH-responsive behaviours. The potential for application of these scalable systems is discussed. Please click Additional Files below to see the full abstract

Endoscopy : an evolving speciality

The practice of endoscopy has been rapidly changing due to new emerging technologies and novel techniques. There has been more focus on colonoscopy training with the development of structured programmes including simulators. Chromoendoscopy and magnification endoscopy have enabled improved diagnosis of small neoplastic lesions and will be important for the success of colorectal cancer screening programmes. The small bowel is now accessible to diagnostic modalities like capsule endoscopy and to therapeutic tools through the double balloon enteroscope. Endoscopic therapy has also become more sophisticated with endoscopic therapy of reflux disease now possible. Excision of large colorectal adenomatous polyps by endoscopic mucosal resection and dissection of submucosal tumours may reduce the need for surgical intervention. The practice of endoscopy has rapidly changed over the past few years. What was once a simple diagnostic procedure made possible by the development of fibre optics has become a speciality in its own right. This article will highlight some aspects of endoscopic practice that have undergone major changes over the past few years and that will shape endoscopy practice in the future.peer-reviewe

.Multi-gram preparation of pH-responsive DX MG colloidsomes by a scalable approach

Biodegradable pH-responsive hollow polymer particles have excellent potential for preparing high performance biomaterials. Recently, we reported that pH-responsive microgel-colloidosomes was prepared using microgel particles as the building blocks and macro-crosslinker [1]. Our method used covalent inter-linking of vinyl-functionalised microgel particles adsorbed to oil droplets to form shells of doubly crosslinked microgels (DX MGs). Unfortunately, this method is unsuitable for scale up. Here, we greatly expand and extend that work by investigating pH-responsive hollow particle systems based on poly(EA-co-MAA) (ethyl acrylate and methacrylic acid) using a scalable thermal crosslinking route (Scheme 1). The hollow polymer particles were crosslinked by covalent inter-linking of vinyl-functionalised microgel particles and gave micrometer-sized colloidosomes that were pH-responsive (Fig. 1). This is the first time we have obtained more than 1 g of pH-responsive DX MG colloidosomes. The properties of these microgel-colloidosomes dispersions imply they have good potential for future application as injectable gels for regenerative medicine. Further, the work indicates that the size of the colloidosomes can be controlled simply by preparation conditions. Please click Additional Files below to see the full abstract

A New Climate Movement?:Extinction Rebellion’s Activists in Profile

Extinction Rebellion set out to mobilise a new generation of activists. As our data shows, they have in part succeeded: participants in Extinction Rebellion's two major actions in London in 2019 had notably little prior experience of protest action, and we encountered many first-time activists. At the same time, however, our socio-demographic profile of XR's activists in the UK reveals a broadly familiar kind of environmentalist: XR's activists are typically highly-educated and middle-class (and though our survey did not explicitly ask this, white); they identify politically on the Left; and they consciously adopt multiple pro-environmental behaviours in the course of their everyday lives. XR's strength has been to create a new public agency amongst people who are not 'natural' protesters, and perhaps even less so natural law-breakers, but who were already persuaded of the rightness of the climate cause, and frustrated with the inability of both 'politics as usual' and lifestyle environmentalism to bring about the kind of transformative political change that the climate emergency demands. Mobilising this group enabled XR to significantly expand the numbers of people willing to engage in environmental direct action, broadening its age profile, and bringing non-violent direct action on climate change into the centre of political life in the UK