Gibson Group » Gibson Group News (tag [Group News])

Identification of Protein Glycoforms using Nanoparticles is Published!

Wed, 18 Jan 2023 10:34:00 GMT

In the diagnosis of disease, proteins are common biomarkers. These are typically detecting using antibodies which specifically target protein sequences, such as those used in lateral flow devices (LFDs). However, there is a challenge in that any given protein sequence can have many different post-translational modifications - phosphorylation, lipidation and many more including glycosylation - the addition of glycans. The presence of a particular protein (detected by antibodies) does not always indicate disease and the exact glycoform is an important parameter not detected by current biosensing strategies, requiring complicated methods or technologies such as mass spectrometry. In this work, we show a hybrid detection based on antibodies and lectins - glycan 'reading' proteins. We use the antibody on the surface of a biolayer interferometry sensor to first capture 'all proteins which match' the antibody, but they use lectin-coated gold nanoparticles as the signal generators, so that we only detect a single glycoform. We demonstrate this with prostate specific antigen (PSA), where the different glycoforms, not just protein concentration, are important markers of disease.

Read the paper here, published in Nanoscale Horizons

Discrimination between protein glycoforms using lectin-functionalised gold nanoparticles as signal enhancers

A Bottlebrush-Shaped Polymer Which Can Nucleate Ice Published

Tue, 29 Nov 2022 08:31:54 GMT

We have a major research interest in understanding, and deploying, ice binding protein mimetics. Whilst we have made huge progress with polymers which can slow the rate of ice growth, the question of how to make ice nucleate remains a challenge. Ice nucleating proteins form complex assemblies and isolated proteins are poor nucleators. To address this, we have synthesised dense bottlebrush polymers with poly(vinyl alcohol) side chains. These side chains are known to bind ice and when presented as very high molecular weight (100's of kg/mol) we show they can nucleate ice. This is the first report of a bottom-up designed polymeric nucleator which we can now use as a tool to probe ice nucleation.

Read the paper here

Poly(vinyl alcohol) molecular bottlebrushes nucleate ice

2023 PhD vacancies now open

Fri, 21 Oct 2022 07:27:00 GMT

We are not beginning to advertise our (fully funded) PhD openings for 2023 start. These span polymer chemistry, glycobiology, cryobiology and diagnostics. We apply these tools in important areas of sustainability, new healthcare materials and more.

More here

https://warwick.ac.uk/fac/sci/chemistry/research/gibson/gibsongroup/vacancies/

Glycoprotein Corona Formation on Nanoparticles Published in Nanoscale

Mon, 05 Sep 2022 13:28:51 GMT

Nanoparticles have found widespread use in diagnostics and have been suggested for e.g. drug delivery. Chemists can now fine tune the nanoparticle surface to e.g target cell types. However, what a cell 'sees' is not what is made, but is the particle surface plus any proteins which adhere to it in blood - the protein corona. There has been extensive research into the proteins which make up the corona, but the glycans on these proteins have received less attention. In our latest work, we investigate the impact of the glycoprotein corona on how polymer-coated nanoparticles bind lectins. We show that serum proteins bring significant sialic acids to the particle surface. The impact of this, is that the particles can bind additional lectins (which were not intended) as well as those which are intended. Finally, we show that 'blocking' the surface does reduce the amount of protein, but sufficient glycans remain to cause off-target binding. These results will help guide the next generation of nanoparticle sensing and delivery agents.

Read the paper here:

Polymer-Tethered Glycosylated Gold Nanoparticles Recruit Sialylated Glycoproteins into their Protein Corona, Leading to Off-Target Lectin Binding

Cell Monolayer Storage, with Cryologyx, Published

Wed, 17 Aug 2022 12:59:00 GMT

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 here

Environmental sustainability success! Bronze LEAF awards for the Gibson Group Labs

Wed, 17 Aug 2022 11:25:00 GMT

The Gibson Group labs in Chemistry and The Medical School have been awarded with a Bronze LEAF award for the 2021/22 academic year.

Following a successful portfolio submission and inspection we were provided with the following feedback "The Gibson lab is a fantastic example of a lab that is working with the support of the PI to consider sustainability across every aspect of their work. During the audit it was great to hear that LEAF has encouraged lab users to implement some of the sustainability practices that have been discussed before but never implemented. There are some great examples of best practice, which could be shared with others outside of the lab, including the successful annual inventory check."

In recognition of our success at implementing environmentally friendly protocols, Caroline Biggs has been invited to speak the the University-Wide LEAF promotion and celebration event on 11th October.

Find out more about the LEAF initiative and how to get involved here https://warwick.ac.uk/sustainability/environment/gettinginvolved/sustainablelabs/

Sulphoxide side-chain polymers and impact on cryopreservation published!

Mon, 08 Aug 2022 09:28:25 GMT

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.

Read the paper here

https://pubs.acs.org/doi/10.1021/acspolymersau.2c00028

Clickable anti-tubercular agents imaged at cell surface, published

Tue, 02 Aug 2022 16:18:00 GMT

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,

Photo-chemical 'easy and better' synthesis of PVA published in Polymer Chemistry

Fri, 29 Jul 2022 10:49:53 GMT

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

Read the paper here!

Review on Glycan-Based Diagnostics Published in ChemSoc Rev!

Wed, 27 Jul 2022 16:30:44 GMT

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 Flow