Gibson Group News
Latest Work Published In J.A.C.S !
In our latest publication we describe an entirely new approach to mimicing antifreeze protein (AFP) function, using self-assembled metal complexes, in place of helical peptides. This work also provides insight into the fundemental design principles to mimic AFP function.
It is often assumed that the desirable property of IRI (ice recrystalisation inhibition), associated with AFPs, requries a specific 'match' or structure to interact with growing ice crystals. We have hypothesised that, in fact, key macromolecular features, rather than 'binding motifs' are what are required. Here we used self-assembled metal complexes which have similar dimensions and pitch to short helical antifreeze proteins as potent IRI's. Crucially, the ligands themselves are not water soluble, but the produced metal complexes are. Modelling showed that the active 'metallohelices' had 'patchy amphiphilicity'; in short, segregated domains of hydrophobic and hydrophilic character. There are not obvious ice-binding sites, and few hydrogen bond donors, confirming that amphipathicity (not amphiphilicity) is the crucial feature.
These results are exciting for both fundamental studies of ice/water interface, but to help us develop new cryoprotectants for low-temperature applications, especially cell/tissue cryopreservation.
The work was conducted in collaboration with the Scott and Fox groups, and can be found here;
Antifreeze Protein Mimetic Metallohelices with Potent Ice Recrystallization Inhibition Activity
Prof Gibson gives his Inauguration lecture at Warwick Medical School
On 26th June, Professor Matthew Gibson gave his inuagral ('leading lights') lecture at Warwick Medical School. This is a celebration of his promotion to a personal chair (professorship) joint between Warwick Medical School and the Department of Chemistry. After introductions by Prof Sudhesh Kumar (WMS Dean) and Prof Martin Wills (HoD of Chemistry) Matt introduced his career path on his way to Warwick, sharing success (and failures!) along the way. He then described two areas of research where his group actively works with his Medical School (and Life Sciences) colleagues; Glycoscience to study infection and new cell cryo-storage methods.
Following this, the Group had a Cocktail night to celebrate this, and future group successes!
Review Article in ChemSocRev
We have published our latest review, with the O'Reilly Group. This review article discussed the effects of disperstiy on polymer self assembly processes, and applications. This covers the length scales from monomer sequence dispersity to the final self-assembled particles. This provides crucial discussion on if 'narrow dispersity' is needed, and how narrow is needed. The impact of the above on developments in controlled polymerizations is also made.
Read the article here in Chem. Soc. Rev.
Dispersity effects in polymer self-assemblies: a matter of hierarchical control
Group attend APME 2017
7 Members of the group attended the APME (Advanced polymers via macromolecular engineering) conference in Gent. The group presented posters cover a diverse range of topics from bacterial biosensors, synthesis of poly(ampholytes), near antifreeze-protein mimetic polymers and glycopolymers for anti-adhesion therapy. Matt gave an invited lecture discussing the synthesis and most importantly activity of glycomaterials for infection. Our new approaches to make this process more high-throughput was also introduced.
Paper Published in Polymer Chemistry
In this paper, two initiation methods in polymerization-induced self-assembly PISA were studied in depth in order to compare the morphological phase diagram outcomes of these processes.This is part of our ongoign interest in creating polymers and nanomaterials to mimic Nature's complexitiy - in this case, self assembly. The first process was light-mediated initiator-free PISA and the second was thermal initiation with the use of an azo- initiator. We found that light-mediated PISA (photo-PISA) formed structures that were generally of higher order to those formed by thermal initiation. The influence of the light intensity was studied as was the end group retention of the resulting polymers from each process. It was found that the end group fidelity decreased as a function of light intensity and irradiation time. The differences between the phase diagrams obtained by the two original processes were therefore attributed to a combination of the reaction kinetics and the degree of end group fidelity. Irradiating pre-formed nano-objects for extended periods of time was able to induce a worm-to-vesicle morphology transition by removal of the trithiocarbonate end group. It is anticipated that this work will further the understanding of photo-PISA in relation to thermal PISA, both of which have gained tremendous interest in recent years.
Read the paper here
Sucessful Launch of Polymers to Near-Space!
Our collaboration with Edgecombe Community College, NC, USA, funded by a Nasa outreach grant resulted in the high-altitude balloon launch on Saturday. Our polymers were sent up added to several biological samples. Due to the polymers ability to mimic the function of natural antifreeze proteins, the cells (blood and algae) were protected from teh extreme cold stress and survived the (bumpy) journey.
Anti-Bacterial Polymers Published in Biomacromolecules
Our latest work, in collaboration with the Fullam group at the School of Life Sciences has been published in ACS Biomacromolecules. This is part of our larger collaboration, including an Innovation grant from the MRC, into new methods for addressing the challenge of antimicrobial resistance. Traditional antimicrobials function by targetting a specific enzyme/pathway, which often enables resistance to develop. We are interested in moving from single target/small molecule paradigm to more innovative targets. In this work, we wanted to evaluate cationic polymers as anti-mycobacterial agents. Cationic polymers are extremely well studied, but mostly against pathogenic gram-negative organisms. Mycobacteria, which are a unique class of gram positive micro-organisms, which include Mycobaterium Tuberculosis have not been studied. We found that poly(dimethyl aminoethyl methacrylate) was particularly potent against a non-pathogenic mycobacterium (M. smegmatis). Interestingly, the polymer did not appear to lyse the cell membranes, which is the assumed mode of action, but less active cationic polymers did. Electron microscopy analysis suggested the cell-walls were being stressed. We are currently investigating this in more detail.
Read the full paper here
GibsonGroup in Space; Live 8th April
On Saturday, 8th April, a high altitidue balloon will be launched to over 60,000 ft, containing an experiment designed in collaboration with the GibsonGroup. This is part of a NASA-sponsered program, being undertaken by students at Edgecombe Community College, in Carolina, USA. The balloon will contain equipment for monitoring the external environment and also cameras; the Balloon will be high enough for the curvature of the Earth to be clearly visible. A secondary payload will also be included, enabling an additional science experiment. Jilian Leary, a student at the College contacted Professor Gibson to see if our cryo-protective polymers, inspired by antifreeze proteins could be included in an experiment to see how cells (blood) survive in the harsh conditions.
The launch will be live on facebook on 8th April (evening, UK time),
https://www.facebook.com/pg/EdgecombeCC/posts/?ref=page_internal
Read more here
https://www.edgecombe.edu/news/students-preparing-high-altitude-balloon-launch/
The photograph shows the lead student Jillian, preparing the samples.