Centre for Sustainable Chemical Technologies

Scientists and engineers working together for a sustainable future

Research update: Responsive nanocapsules

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📥  Research updates

Responsive nanocapsules for detection and treatment of infection

Responsive nanocapsules for detection and treatment of infection

This research fits under the "pharmaceutical and wellbeing" theme in the CSCT.  In paediatric patients, the immune response to burn trauma is similar to that observed in infection, making infections in burns difficult to diagnose. Burns have the potential to kill the patient, through infection with a toxin producing strain of staphylococcus aureus resulting in toxic shock syndrome. Importantly, this outcome is unrelated to the size of the burn. To prevent scarring and promote healing, a ‘Biobrane’ silicone-collagen dressing must be left on for 12 days. Removal prior to this results in scarring for life. However, if infection is present the patient could die in less than 24 hours.

This project focuses on the development and stabilisation of responsive nanocapsules for detection and treatment of bacterial infections in paediatric burns. As shown in the image, a stable nanocapsule containing an antimicrobial and/or dye is attached to a scaffold;  in the presence of non-pathogenic ‘friendly’ bacteria the nanocapsule does not respond, however, in the presence of pathogenic ‘unfriendly’ bacteria the nanocapsule is broken open and the antimicrobial and/or dye is released.  This response will allow the released antimicrobial to attack the bacteria, and the dye signal the changes in the wound environment, allowing appropriate intervention, before infection takes hold.

Serena Marshall is in the first year of her PhD, studying "Responsive vesicles in an aqueous cream emulsion for dermatological applications". She is supervised by Dr Toby Jenkins in the Department of Chemistry.


Research update: Biodiesel production in fixed bed catalytic reactors

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📥  Research updates

Biodiesel has the potential to be an environmentally sustainable alternative fuel source for diesel engines.  It is made by the transesterification of triglycerides, which are the main components in fats and oils.  Transesterification is a chemical reaction which, in the case of biodiesel, leads to the long fatty acid chain being removed from the glycerol backbone of a triglyceride (fat) molecule and being replaced by an alkyl group from a short chain alcohol, such as methanol, as shown in Figure 1.  This has historically been done with the aid of a dissolved or liquid catalyst, either an acid or a base.  Unfortunately, this leads to increased wastewater production, as the catalyst must be washed out of the fuel before being neutralised.  Additionally, the faster basic catalysts are extremely sensitive to both water and free fatty acids (FFA), resulting in the formation of soap from the latter.  If these catalysts can be replaced with a solid, water and FFA tolerant catalyst, the production of biodiesel can be made much cleaner and more economical.

Figure 1. Reaction scheme for biodiesel production

Figure 1. Reaction scheme for biodiesel production

My project is focused on developing a solid catalyst anchored on a support structure, which will allow the catalyst to be fixed inside a reactor while the oil and methanol are pumped through it. The main aims for the catalyst are that it:

  • Does not dissolve (leach) into the reaction mixture
  • Stays active for a prolonged period of time
  • Is tolerant of FFA and water

Previous work at the University had focused on a zinc-amino acid complex, but this was ultimately shown to leach. Thus, focus has shifted to catalysts that can be physically incorporated into a coating layer, such as a sol-gel. Currently, strontium oxide is being examined as a candidate, as it is a very effective catalyst when used as a powder.

About the author

Ben Firth is in the first year of his PhD, studying "Biodiesel production in fixed bed catalytic reactors". He is supervised by Prof Stan Kolaczkowski in the Department of Chemical Engineering.

Further reading

KNOTHE, G., VAN GERPEN, J. & KRAHL, J. 2005. The biodiesel handbook, Urbana, Ill., AOCS Press.

Whorrod Prize in Sustainable Chemical Technologies announced


📥  Prizes & awards

The Whorrod Prize in Sustainable Chemical Technologies for the student achieving the best credit rated average in the first year (MRes) of the Integrated PhD in Sustainable Chemical Technologies was awarded to Tom Forder in the academic year 2009/10. While Tom's prize was announced at a graduation ceremony in December 2010, he has to wait until the Summer Showcase in July 2011 to actually receive his certificate and cash prize. (more…)