Gibson Group News

Our latest work on developing 'smart' materials has been published in RSC Polymer Chemistry. We are very interested in antifreeze protein mimetics - polymers which can slow the rate of ice growth (know as Ice recrystalisation inhibition - IRI) which have huge potential in cryopreservation of donor cells/tissue. An underlying challenge with these materials is understanding why they work. As part of our major reserach program to investigate this, we have developed polymers with essentially zero IRI activivty - but when we apply Fe 3+ ions, the polymers activity is activated. This was acheived by installation of a catechol group at the chain end (using RAFT polymerization) which promotes the formation of star-shaped polymers are higher molecular weight, triggering activity. We believe this, or similar, tools will enable us to gain more detailed understanding of the underlying mechanisms of action. This is also an analogy to how Nature works; if more protein is needed, Arctic fish up-regulate the protein synthesis. We cannot do this in chemistry, so really on the supramolecular trigger.

Read the paper here

Our latest work on new cryopreservation methods has been featured in the leading chemistry journal, Angewandte Chemie.

Donated cells and tissue are crucial for regenerative medicine but there is a core challenge in that the cells have short life times necessitating freezing. Current methods of cryopreservation require the addition of large amounts of organic solvent, which is non ideal and can lead to processing/toxicity challenges. In our latest paper, in collaboration with Steve Armes at Sheffield, we use self-assembled polymer micelles to provide a hydrated matrix around red blood cells. Alone, these offer little protection, but in combination with ice-growth inhibiting polymers (pionneered in our group) we get remarkable levels of recovery. Furthermore, post thawing, the micelles become worm-like and form a hydrogel. This provides a new method for direct, post-thaw 3-D tissue culture and will have many applications

Read the paper here

Combining Biomimetic Block Copolymer Worms with an Ice-Inhibiting Polymer for the Solvent-Free Cryopreservation of Red Blood Cells

http://onlinelibrary.wiley.com/wol1/doi/10.1002/ange.201511454/abstract

Highlighted as a 'hot' paper by the journal and also a press released issued

Matt was today interviewed on BBC Coventry/Warwickshire about the the importance of maintaining blood stocks and the need for new innnovations to help this. In particular the use of cryopreservation methods being developed in the group were discussed.

Read some of our papers on this;

Deller, RC, Vatish, M, Mitchel, D., Gibson, MI., 2015. 1 789–794, ACS Biomaterials Science and Enginneering. "Glycerol Free Cryopreservation of Red Blood Cells Enabled by Ice Recrystallization Inhibiting Polymers"

Mitchell, DE., Cameron, NR., Gibson, MI, 2015, 51, 12977-12980 Chemical Communications Rational, yet simple, design and synthesis of an antifreeze-protein inspired polymer for cellular cryopreservation

A recent paper by the GibsonGroup has been highlighted in RSC Chemistry World, and also selected as a 'hot' article in Molecular Biosystems. This work, in collaboration with the FullamGroup, describes a new method for identfiying bacteria, by creating 'barcodes' describing how bacteria bind to different sugars. In the work, the team assembled small arrays of simple sugars onto a surface, and then mapped how different bacteria bind to them. This allowed a trianing matrix to be developed, so unknown bacteria could then be identified. The key to this is its simplicity and scalable to a range of different biosensory surfaces. In this preliminary work, a range of Gram Negative and Gram Postive Mycobacteria were tested and identified. This included surrogates for Mycobacterium Tubuculosis. It is hoped that this will translate to easy point of care biosensors, and to enable more effecient use of antibiotics.

Read the paper here.

Discrimination between bacterial species by ratiometric analysis of their carbohydrate binding profile

Our latest paper, in collaboration with the FullamLab (Life Sciences) has been published in Molecular Biosystems. In this work we demonstrate a new, easy, concept to the identification of Bacterial species. Recently, much interest has been placed on identifying bacteria using sequencing techniques - these are excellent, but need a culturing step and bio-film forming species are a problem. They also need signifcant infrastructure, which is a challenging in the developing world. There is also the growing problem of antibiotic resistance in developed countries.

To address this we have profiled how bacteria bind to carbohohydrates (sugars). Using a simple microwell plate, we could type the bacteira based on their profile, in essence creating a barcode. We could then use this to assign blind samples. We hope to translate this to clinically relevant strains, and also to more realistic (and cheap) detection systems.

Read the paper here (open access)

Otten, LC, Fullam, E, Gibson, M.I. Molecular Biosystems, 2016, 'Discrimination between Bacterial Species by Ratiometric Analysis of their Carbohydrate Binding Profile'

Lucienne Otten passed her PhD viva today, examined by Manuella Tosin (internal) and Ed Yates (Liverpool). Her Thesis was entitled 'Pathogen Detection Based on Carbohydrate Adhesion' and funded by the Systems Biology CDT. In short, Lucienne used 'simple' sugars and accesible chemsitry to make arrays which we used to interrogate pathogens (toxins, bacteria, viruses and parasites) and to create mathematical models of how they bound - in essence we made barcodes. USing this we could then use the arrays to rapidly discriminate between different toxins and species.

Read some of Luciennes papers!

Otten, LC, Fullam, E, Gibson, M.I. Molecular Biosystems, 2016, 'Discrimination between Bacterial Species by Ratiometric Analysis of their Carbohydrate Binding Profile' link

Richards, SJ, Otten, LC, Gibson, MI, J. Mater. Chem. B., 2016, Glycosylated Gold Nanoparticle Libraries for Label-Free Multiplexed Lectin Biosensing, Accepted Link

Otten, L.C., Gibson, MI. RSC Advances, 2015, 5, 53911 - 53914,. 'Discrimination between Lectins with Similar Specificities by Ratiometric Profiling of Binding to Glycosylated Surfaces; A Chemical ‘Tongue’ Approach' Accepted. Link

Jones, M. W., Otten, L, Richards, S-J, Lowery, R., Phillips D. J., Haddleton D. M., and Gibson MI. Chem. Sci., 2014, 5, 1611 - 1616 "Glycopolymers with secondary binding motifs mimic glycan branching and display bacterial lectin selectivity in addition to affinity"

Otten, L., Richards,S-J., Fullam, E., Besra, G.S., Gibson, M,I. , J.Mater. Chem. B, 2013, 1, 2665 - 2672, "Gold Nanoparticle-Linked Analysis of Carbohydrate-Protein Interactions, and Polymeric Inhibitors, using Unlabelled Proteins; Easy Measurements Using a ‘Simple’ Digital Camera" Link

Daniel Mitchell has become the most recent PhD to graduate from the lab. He defended his Thesis, examined by Daniell Mitchel (Warwick Medical School) and Vitaly Khutoryanskiy (Reading). Dan's Thesis was on the design of new antifreeze protein mimetic polymers and their translation to cell cryo-storage applications.

Read some of his papers, below;

Mitchell, D. E., et al. (2014). "Quantitative study on the antifreeze protein mimetic ice growth inhibition properties of poly(ampholytes) derived from vinyl-based polymers." Biomaterials Science. 2014, 2 (12), 1787 - 1795Mitchell, D.E, et al. (2015).

"Rational, yet simple design of an antifreeze protein inspired polymer for cellular cryopreservation". Chemical Communications. 2015, DOI: 10.1039/C5CC04647E.

Our contribution the the Book 'Macro-Glycoligands' has been published in Methods in Molecular Biology. Our chapter is a protocol (as with the series in general) describing how to obtained well-defined polymer coated gold nanoparticles with a corona of glycans. This shares our expertise and experience in this area including trouble-shooting to enable others to make these versatile materials. In particular, the use of these to probe lectin-binding is discussed.

Read the chapter here.

Methods in Molecular Biology; Macro-Glycoligands. "Multivalent Glycopolymer-coated Gold Nanoparticles