Gibson Group News

Our recent article from a special edition of Macro. Rap. Commun. is highlighted in Materials Views magazine.

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The Gibson group's paper "Exploiting Thermoresponsive Polymers to Modulate Lipophilicity: Interactions with Model Membranes" is featured in a special issue of Macromolecular Rapid Communications: " Polymer Science the Next Generation"

Read the issue here

Glycopolymers offer many opportunities for interfacing synthetic materials with biological systems. However, the nature of the interactions between glycopolymers and their biological targets, lectins, and the structural features necessary to obtain high-affinity materials are not fully understood. Here, the enhancement in binding affinity of multivalent glycopolymers to their corresponding lectins is investigated by quartz-crystal microbalance with dissipation monitoring (QCM-d). This technique allows the conformation of the adsorbed polymers to be probed and the direct observation of spanning of multiple binding sites on lectin-functional surfaces. The measured affinity was compared to the anti-adhesion activity of the polymers in solution, and it is shown that increased association constants did not directly correlate with inhibitory activity.

Read the paper here

Matt Gibson (with Remzi Becer) have contributed a chapter entitled "Glycopolymers via Post-Polymerization Modification Techniques" into the edited book "Functional Polymers by Post-Polymerization Modification: Concepts, Guidelines and Applications" published by Wiley-VCH, to be released October 2012. Click here for details.

Devian Patel and Mohammed Sahid join us for the next 5 Months to undertake their AS:MIT research projects. They will be working on understanding how molecular structure affects ice crystal growth/water ordering and on fine-tuning the response of smart materials to external stimuli.

More new equipment in the group! A new Linkam cold stage, capable of rapdi (5000 C/min) cooling and full control of thermal gradients has arrived. This will increase our capacity for ice-growth inhibition work, and compliment out current nanolitre osmometer set up.

Collaborative work with EPFL (Switzerland) and Mainz (Germany) on understanding nano-bio interactions is online now. Read article here

A library-orientated approach is used to gain understanding of the interactions of well-defined nanoparticles with primary human endothelial cells, which are a key component of the vasculature. Fifteen sequentially modified gold nanoparticles (AuNPs) based on three different core sizes (18, 35, 65 nm) and five polymeric coatings were prepared. The synthetic methodology ensured homogeneity across each series of particles to allow sequential investigation of the chemical features on cellular interactions. The toxicity of these nanoparticles, their uptake behavior in primary human dermal microvascular endothelial cells (HDMECs), and quantification of uptake were all investigated. The results of our studies indicated that high concentrations of gold nanoparticles (250 μg/mL) were nontoxic and that the number of internalized nanoparticles was related to nanoparticle size and surface chemistry. In summary, the positive-charged ethanediamine-coated AuNPs were internalized to a greater extent than the negative- or neutral-charged AuNPs. Moreover, differences in the amounts of internalized AuNPs could be shown for the three neutral-charged AuNPs, whereas the uptake of hydroxypropylamine-coated particles was preferred compared with glucosamine-coated or PEGylated AuNPs. Hydroxypropylamine-coated AuNPs were found to be the most efficient neutral-charged particles in overcoming the endothelial cell barrier and entering the cell.

Collaborative work with Ron Unger/Christian Freese at Uni. Mainz (Germany) and Harm-Anton Klok (EPFL, Switzerland) has been accepted for publication in the ACS journal Biomacromolecules. This paper builds on our previous work on designing effecient methods to synthesise libraries of polymer-coated gold nanoparticles (AuNPs). These particles are ideal for studying cellular uptake, as the gold provides a unique 'handle' to allow imaging/detection by TEM or ICP-AES. Here we studied the interactions of the AuNPs with primary human endothelial cells - these are some of the first cells that a drug-delivery system comes into contact with, but there interactions have not been studied in detail. In this work we show the influence of particle size and coating on cytoxicity, biomarker expression and cellular uptake.