Lipid cubic phases: sustainable nanomaterials to immobilize membrane proteins for biocatalysis and biosensors

The Centre for Sustainable Chemical Technologies (CSCT) at the University of Bath has launched a joint PhD programme with Monash University, Australia.

This project is one of a number that are in competition for up to four funded studentships. More details are available here: http://www.csct.ac.uk/study-with-us/

Home institution: Bath University
Supervisor at Bath: Adam Squires (lead)

Supervisor at Monash: Leonie van ‘t Hag

Context

The project will investigate the use of lipid cubic phases to immobilize membrane proteins. The end goal is to harness membrane-bound enzymes in devices for biotechnological applications including sensing and catalysis.

Enzymes have value as highly specific chemical catalysts, especially when immobilised onto a solid support, for a range of new technologies, both in industrial processing (eg flow reactors) and in diagnostics (eg electrochemical biosensors for healthcare). However, achieving this immobilisation is a major challenge, especially for the significant proportion of proteins that are associated with cell membranes.

This project will investigate the use of nanomaterials known as “lipid cubic phases” (LCPs) – artificial membrane-mimicking “glues” within which membrane proteins can maintain their activity. Both supervisors have researched LCPs extensively, for membrane protein crystallization, and as templates for metal electrodeposition. LCP nanostructures form spontaneously when a lipid-coated substrate is exposed to water. They form a stable functional film under water, and can be removed after use by dissolving in ethanol. They therefore offer a sustainable route to device fabrication using low-cost, industrially compatible materials and processes, and green solvents and conditions (ethanol / water, room temperature). Furthermore, we anticipate that the morphology of the cubic phase – a continuous curved lipid bilayer extending in 3 dimensions– will allow incorporation of much more membrane protein, and therefore provide considerable signal amplification, compared with a single flat bilayer.

The project will build in complexity, as follows:

1) (Bath, months 1-12) Incorporate model proteins (eg porin OmpF) and peptides (eg gramicidin) into lipid cubic phases on electrodes, establishing fundamental thermodynamics of protein incorporation into substrates pre-coated with lipids. Studies with UV/Vis spectroscopy and small-angle x-ray scattering

2) (Monash, months 13-27) Synthesise designer functional membrane-bound peptides. Study protein structure upon immobilisation using circular dichroism spectroscopy and Fourier transform infrared spectroscopy (including using AFM-IR in the department and infrared microspectroscopy at the Australian Synchrotron). Additionally, fluorescence recovery after photobleaching (FRAP) experiments using a confocal microscope will be used to quantify peptide and protein diffusion in the film.

3) (Bath, months 28-43) Investigation of electrochemistry of redox-active membrane enzymes immobilized in lipid cubic phases (eg Cytochrome C Oxidase); device fabrication.

The student will learn biophysical sample preparation methods associated with lipids and membrane proteins, and physical chemistry techniques including x-ray and neutron scattering, electrochemistry and spectroscopy.



Application process

We invite applications from Science and Engineering graduates who have, or expect to obtain, a first or upper second class degree and have a strong interest in Sustainable & Circular Technologies.

You MUST express interest for three projects in order of preference – you can see all projects here: https://www.csct.ac.uk/bath-monash-global-phd-programme/ . Please submit your application at the Home institution of your preferred project (‘Home’ institution details can be found in the project summary). However, please note that you are applying for a joint PhD programme and applications will be processed as such.


University of Bath

Please submit your application through the following link: https://www.csct.ac.uk/bath-monash-global-phd-programme/
Please make sure to mention in the “finance” section of your application that you are applying for funding through the joint Bath/Monash PhD programme for your specified projects.
In the “research interests” section of your application, please name the three projects you are interested in and rank them in order of preference. Please also include the names of the Bath lead supervisors.

Monash University

Expressions of interest (EoI) can be lodged through https://www.monash.edu/science/bath-monash-program. The EoI should provide the following information:
CV including details of citizenship, your Official Academic Transcripts, key to grades/grading scale of your transcripts, evidence of English language proficiency (IELTS or TOEFL, for full requirements see: https://www.monash.edu/graduate-research/faqs-and-resources/content/chapter-two/2-2), and two referees and contact details (optional). You must provide a link to these documents in Section 8 using Google Drive (Instructions in Section 8).