Crystal engineering approaches for the design of novel delivery systems for nutrients and nutraceuticals

Supervisor(s)

Contact Dr Elena Simone to discuss this project further informally.

Project description

Finely mixed multiphase systems made up of two or more immiscible entities, such as foams or emulsions, are commonly used for many pharmaceutical and food applications. For example, topical medications can be formulated in the form of oil and water emulsions with the active pharmaceutical ingredients dissolved in one of the two phases, or as aerated foams for improved drug penetration and reduced sense of greasiness after application.

Countless examples of multiphase systems can also be found in the food sector including ice cream, whipped cream and salad dressings. Emulsions and foams are often thermodynamically unstable and the immiscible phases will tend to separate with time, reducing considerably the shelf life of these products with a clear economical loss and increased generation of waste. Surfactants or solid particles (Pickering effect) can be added to multiphase formulations in order to prevent phase separation and increase product stability.

Pickering particles have many advantages over surfactants since:

  1. They provide better stability as a result of stronger interfacial adsorption;
  2. Food grade particles that do not have the side effects often associated with surfactants (e.g., irritancy) can be used;
  3. A wider range of dispersity can be achieved via tuning the particle properties;
  4. Nutraceuticals can be used as solid particles and be incorporated in food or pharmaceutical formulations for increased health benefits for consumers.

To date particles for Pickering stabilization have been selected semi-empirically, considering only basic physical and chemical properties of the desired molecule in relation to the immiscible phases (e.g., wettability, solubility), as well as basic particle attributes such as size and aspect ratio. However, most studies do not consider the complex, anisotropic nature of faceted crystals. Such nature is strongly related to the intermolecular interactions within the crystalline structure, and it can dramatically affect the ability of a particle to stabilize curved interfaces.

The PhD candidate will mainly conduct experimental work, studying how particle morphology and polymorphism (internal molecular arrangement within a crystal) affect the interfacial behaviour of faceted crystals at curved surface. The project will involve:

  1. the design of crystallization experiments to obtained target crystal shape and size distributions of a selected polymorph.
  2. the characterization of both particle population and single crystals
  3. the characterization of three dimensional multiphase structures containing the produced crystals.

At the end of the PhD the candidate will have acquired a strong background in crystallization from solution and process control, as well as a good understanding of colloidal and interfacial science. Examples of the techniques that will be used during the project are: x-ray scattering and tomography, x-ray photoelectron spectroscopy, confocal and electron microscopy (both room temperature and cryo), differential scanning calorimetry and laser diffraction.

Entry requirements

Applications are invited from candidates with or expecting a minimum of a UK upper second class honours degree (2:1), and/or a Master's degree in a relevant science subject such as (but not limited to) food science, chemistry, physics or chemical engineering.

If English is not your first language, you must provide evidence that you meet the University's minimum English Language requirements.

How to apply

Formal applications for research degree study should be made online through the university's website. Please state clearly in the research information section that the PhD you wish to be considered for is 'PhD in Crystal engineering approaches for the design of novel delivery systems for nutrients and nutraceuticals' as well as Dr Elena Simone  as your proposed supervisor.
 
We welcome scholarship applications from all suitably-qualified candidates, but UK black and minority ethnic (BME) researchers are currently under-represented in our Postgraduate Research community, and we would therefore particularly encourage applications from UK BME candidates. All scholarships will be awarded on the basis of merit.

If you require any further information please contact the Graduate School Office e: maps.pgr.admissions@leeds.ac.uk