Most cell biology, biomaterials and associated research is conducted on cells attached to tissue culture plastic in multiwell plates - such as high throughput drug discovery and toxicity, to viral plaque assays. However, there is a disconnect that the cells are stored frozen in suspension, not in the format ‘ready to use’. This is because conventional cryoprotectants do not protect the cells when in monolayer format. The GibsonGroup, and UoW Spin-Out Cryologyx have worked together to solve this problem using macromolecular cryoprotectants. In this later paper, the team demonstrate reproducible and robust recovery of cell monolayers out of the freezer. This is shown for common cell lines, including HepG2 and Caco-2, commonly used in drug screening. This is a revolutionary technology as it shows researchers could stop wasting time culturing cells, and just order them, remove from freezer and within 24 hours begin data collection with no of the traditional culturing steps. Cryologyx are deploying these findings to commercialise assay ready cells, and trial plates are available!

Read the paper hereLink opens in a new window

We have a major interest in developing macromolecular cryoprotectants to enable new cell based therapies and to simplify and support cell-based assay development and use. We have previously shown that polyampholytes, with mixed cationic/anionic side chains, are very potent cryoprotectants, but exactly how they function is under investigation. There have been reports that DMSO-like side chains (sulphoxides) may introduce cryoprotective properties, so we synthesised a panel of sulphoxide methacrylates. The sulphoxide side chain is often draw S=O but is actually highly polarised, and can be represented as S+O-, and hence we asked if this charge separation can help, as it does with ampholytes. We also used N-oxides for similar reasons. Overall, these are not as potent as polyampholytes, but a crucial observation was that over-oxidation of the sulphoxide lead to increase toxicity.

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https://pubs.acs.org/doi/10.1021/acspolymersau.2c00028Link opens in a new window

In collaboration with the Fullam group (Life Sciences) we have previously demonstrated that Mycobacterium Tuberculosis can be killed if its cell surface glycans are cross-linked, removing the need for traditional targeting of a protein, and crucially the compounds do not have to permeate into the bacteria. In this latest work the team synthesised ‘clickable’ dimeric boronic acids which allow visualisation of the active compounds at the bacteria cell surface, providing key evidence for their mechanism of action. This approach is very distinct from traditional drug mechanisms, considering the glycome rather than the proteome and removing traditional limits associated with anti-tubercular drug discovery

Read the paper here in ChemComm

Imaging of antitubercular dimeric boronic acids at the mycobacterial cell surface by click-probe capture,Link opens in a new window

We have a large interest in biomimetic polymers which can control ice growth, inspired by ice-binding ‘antifreeze’ proteins. We have previously shown that poly(vinyl alcohol), PVA, is remarkably potent at reproducing the ice recrystallisation inhibition of PVA. However, PVA synthesis is not easy, and gives low yields. Here the team used a photo-chemical method allow PVA to be obtained open to air (no degassing) to high conversion (no wastage of monomer) and removing the need for messy oil baths! This method really simplifies the process, and using a photo reactor is also less energy intensive and does not need azo-initiators. Our team then showed that these polymers retain their function to slow ice growth over 100 freeze/thaw cycles. This is a crucial, if they are to be used in e.g infrastructure applications, where materials like concrete are exposed to many freeze/thaw cycles over several years. It has been previously suggested that PVA aggregation (as PVA is known to cryo-gelate at concentrations above ~ 50 mg/mL) would de-activate it, but in the concentration range for IRI activity (< 1 mg/mL) this was not a problem

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We have a long standing interest in how we can use biomaterials to probe, understand and exploit glycans (sugars) for a range of applications. During infection glycans are often the first thing a pathogen encounters and binds to. Hence there is an opportunity to use this binding event as a tool to sense or diagnose the presence of pathogens. In this review, written with Prof Rob Field (Manchester) and Simone Dedola (Iceni Glycoscience) we review the state of the art for using glycans in diagnostics and in particular how they can be used in lateral flow devices. Lateral flow devices have been widely used during COVID-19 pandemic, but typically rely on antibodies on gold nanoparticles (which give the red colour). We show how glycans have potential to be used alongside these.

Read the review here

Glycosylated Gold Nanoparticles in Point of Care Diagnostics: From Aggregation to Lateral FlowLink opens in a new window

We, along with Dr Tom Whale, have an interest in developing and discovering new disruptive tools for biologic cryopreservation. In our latest paper, led by Dr Kat Murray and Dr Tom Whale, we show that macromolecules extracted from pollen can enhance cell cryopreservation, in particular for challenging 2-D monolayers. Common sense, says that water turns to ice at zero, but in fact in low volumes, water can super-cool to below - 30 C. This is a huge problem when freezing cells. IN this work we used pollen extracts which nucleate ice at - 10 C, and can increase the recovery cell yield dramatically. This adds to our growing evidence base that thinking beyond 'just re-fomulating DMSO' and using chemical probes/tools, can transform how biologics are stored, transported and eventually delivered to patients/users.

Read the paper here

Pollen derived macromolecules serve as a new class of ice-nucleating cryoprotectants

https://www.nature.com/articles/s41598-022-15545-4Link opens in a new window

Our team is developed next generation (macro-)molecular tools to improve the cryopreservation of biologics (cells/protein therapies). In our latest review article, in Nature Reviews Chemistry, we discuss the role of chemistry-driven approaches to this challenge. This summarises the key challenges in cryopreservation - the need to cool material to stop it degrading, whilst minimising the damage caused by the freezing process. The review tries to highlight how consideration of the physical , as well as biochemical, damage pathways together offers a route to improving cryopreservation and that a 'med-chem' like approach could be taken.

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Chemical Approaches to CryopreservationLink opens in a new window

Free to read linkLink opens in a new window

We have previously developed maromolecular cryoprotectants, based on polyampholytes (polymers with cationic/anionic groups) which are remarkable cryoprotectants - they protect cells from damage during freezing, leading to more, healthier cells being recovered. However, our previous work has been focussed on all-carbon backboned polymers which are not intrinsically degradable. In our latest work, we collaborated with Prof Julien Nicolas (Paris) to develop polyampholytes containing ester bonds in their backbone, which can be hydrolysed. This was achieved using radical ring-opening copolymerization, enabling convention controlled radical methods to introduce esters (instead of the normal C-C bonds). The resulting polymers were shown to enhance the cryopreservation of cell monolayers - a very challenging cryopreservation scenario.

Read the paper here:

Degradable Polyampholytes from Radical Ring-Opening Copolymerization Enhance Cellular CryopreservationLink opens in a new window