Our latest work has been published in ACS Macro Letters. In this work we describe a new mehtod to covalent attached synthetic polymers to cell surfaces, enabling us to bring new functionality to them, without resorting to genetic methods. There already exist many chemistry for targetting cell surfaces, such as simple NHS esters, or lipid insertion, but we wanted to form a directed, covalent bond. Glycan metabolic labelling was exploited, whereby we added an azido-functional ManNac (a sugar) to the cells, which can be processed such that it presented an azide on the cell surface as a sialic acid. We then made telechelic polymers used RAFT, adding an azide reactive strained alkyne at one end, and a fluorophore or biotin at the other. We would able to show selective conjugation and coating of the cells using these polymers, with no evidence of cytoxocity nor of morphological changes (i.e. the cells looked happy). To show that we can use this method to change the functionality of the cells, we were able to recruit strepavidin to the cell surfaces, targetting the biotin units on the polymer, which did not occur without the polymer. We think this method could be broadly used to add synthetic polymers to cell surfaces to modify their function, which may have application in therapies, cell tracking and also to ask fundamental questions about how this modification affects cell function.

Read the paper here

Engineering Cell Surfaces by Covalent Grafting of Synthetic Polymers to Metabolically-Labeled Glycans

Our latest work has been published in Langmuir, as part of a special issue focussed on Mechano- and Cryo-biology, which we were very proud to be invited to contributed too. In this work, we ask the question of 'do our antifreeze-protein mimetic polymers function the same in nanoparticle form, as in solution'. This might seem straightforward, as we know that increasing the molecular weight of our polymers, increases their activity, hence when immobilised on a nanoparticle they might be more active. We actually saw that there was no enhancement, but also no decrease (which again is a surprise as the nanoparticles have a lower molar concentration than free polymers). We made use of RAFT/MADIX polymerization to make thiol-terminated poly(vinyl alcohol) to coat gold nanopartices for this particular work, as model nanoparticle systems, which were tunable in terms of size and composition.

Read the paper here;

Multivalent Presentation of Ice Recrystallization Inhibiting Polymers on Nanoparticles Retains Activity

Professor Gibson spoke at the Glycobiotechnology 2018 event hosted at Manchester University. This was an event to celebrate and showcase UK Glycoscience research. Professor Gibson showed new research from the group in the design of dynamic glycomaterials, where we exploit polymer chemistry to contorl the presentation of specfic glycans in response to external stimuli. He also highlgihted the role of the RSC Carbohydrate Group, of which he is the present chair.

On 29th September, Professor Gibson gave the keynote lecture in the Biomaterials Stream of the 7th EuChems international Confernece in Liverpool. In this he discusssed the groups latest research into using polymers to transform the Biologic Cold Chain. This included how to target ice crystals with polymers, and the cryopreseration of mammalian and bacterial cells as well as protein drugs.

Our latest work into developing non-traditional antimicrobial agents has been published in Chemistry: A European Journal. This continues our research into cationic polymers as antimicrobial agents. In this new work, we demonstrate a semi-automated synthesis platform, which can use robotics to speed up the liquid handling, alongside exploiting photo-chemical polymerization to enable this to take place in 'open air'; this is a key step as it removes the need for sealed vials and allowed us to polymerise directly in 96 well plates. 96 well plates are industry-standard for biological screening, which enabled us to rapidly screen ~ 100 polymers for antimicrobial activity, as well as blood compatability. Using this high-throughoput approach a surprising 'hit' was found, where including 15 mol % of oligopropyleneglycol methacrylate lead to a dramatic enhancement in bacteriostatic activity, but without introducing bacteriocidal activity.

Read the paper here

Photochemical 'In-Air' Combinatorial Discovery of Antimicrobial Copolymers

The paper was also featured in the media, and highlighted by the reviewers as being a 'hot' paper.

Our latest cryopreservation work has been published in Biomacromolecules. This work describes the development of an 'all-polymer' cryopreservation formulation for bacteria. Bacteria are used routinely in all molecular and structural biology labs around the world, and are key in many biotechnology and food processes (e.g. 'friendly bacteria' in yoghurts). The bacteria are not kept continously growing, but are stored as stocks, using glycerol to reduce ice-induced damage in freezers. In this work, we were inspired by antifreeze proteins which let extreomphile species survive in the coldest places on earth, but used synthetic polymers, which are cheaper, more scalable and practical for daily use. We have previously shown that polymer mimics of antifreeze proteins can protect mammalian cells in DMSO-mediated cryopreservation, but the mechanisms of stress (and recovery) from cold are very different in bacteria. Here we simply used precise ratios of PEG and PVA (both are food-safe, low cost commodity polymers) and show we can match, or outperform, glycerol in several bacteria storage scenarios.

Read the paper here;

Ice Recrystallization Inhibiting Polymers Enable Glycerol-Free Cryopreservation of Microorganisms

Ben Graham, a PhD student in the group, won a prize for his poster on designing antifreeze-protein inspired polymers at the 2018 MacroGroupUK Young Researchers Conference

Alice Fayter, a PhD in the group won best poster prize at the KTN Bioformulation conference. Her poster detailed her work on new polymeric cryopreservation agents for storing micro-organisms and proteins.