Correlative Light Electron Microscopy (CLEM) is one of the most powerful imaging technologies as it combines the advantages of live cell imaging from light microscopy (LM) with the sub-nanometer spatial resolution of electron microscopy (EM). Using this technology, key biological questions have been answered [1].
CLEM is, however, seriously hampered by the availability of robust probes. It is highly questionable whether most bimodal probes, using a fluorophore (for LM) and an electron-dense gold nanoparticle (for EM) attached to the protein of interest, actually show the same protein pool. This is due to limitations such as photobleaching or quenching of the fluorophore, and/or detachment of the probes while trafficking inside the cell or after sample processing for EM. These are serious drawbacks that need to be addressed.
To do so, the aim of this project is to develop a novel CLEM method where a gold nanoparticle (AuNP) is used as the same probe for both LM and EM. AuNP will be visualised in LM in living cells using a novel nonlinear optical microscopy technique developed at Cardiff University. The technique uses electronically-resonant Four Wave Mixing (FWM) and exploits the strong and photostable absorption and scattering of light of a AuNP at the localised surface plasmon resonance (LSPR). Using a combination of short optical pulses to generate and detect changes in the AuNP transmission or scattering at the LSPR, the technique is uniquely sensitive to single small AuNPs which are detected background free with high spatial resolution in 3D [2]. Notably, the technique is also uniquely sensitive to the AuNP shape, which opens up the prospect of probe multiplexing via shape recognition.
In this project, spherical AuNPs and gold nanorods of various sizes will be conjugated to proteins of interest (for example the iron-binding protein transferrin) and internalised in mammalian cell lines. The aim will be to demonstrate the full CLEM workflow starting from imaging living cells with FWM (at Cardiff), to fixation, sectioning and correlative imaging of the same AuNP within the cell ultrastructure revealed by EM (at Bristol).
The project will also explore the pioneering concept of assembling AuNPs directly inside living cells using proteins expressed in the cytoplasm which have the capability to bind metals and concentrate these to form electron dense particles. This could open the way to genetically tag cytoplasmic proteins with metallic NPs.
*Please note that in their first year of the 4-year programme, DTP students will undertake taught units and rotation projects*
Eligibility Criteria
Applicants for a studentship must have obtained, or be about to obtain, a First or Upper Second Class UK Honours degree, or the equivalent qualifications gained outside the UK, in an appropriate area of science or technology. Applicants with a Lower Second Class degree will be considered if they also have a Master’s degree or have significant relevant research or non-academic experience.
In addition, due to the strong mathematical component of the taught course in the first year and the quantitative emphasis in our projects, a minimum of a grade B in A-level Maths or an equivalent qualification or experience is required (this includes a Physics A-level (grade B and above) or having undertaken units as part of your degree that have a significant mathematical component such as maths, statistics, bioinformatics. Applicants must ensure they highlight their Maths background within their application and to upload any supporting evidence.
To support PhD training opportunities, these studentships are only available to applicants that have not previously obtained or about to obtain a PhD degree (or equivalent).
If your first language is not English, you will need to meet the minimum English requirements for the programme (IELTS must be 6.5 overall and 6.5 in all sub-skills). Please note that the English Language requirement is stipulated by the University of Bristol, because of the first year taught elements, which is higher than is standard for Cardiff. We ask that the language requirements are met by 1st June at the latest, to allow adequate time to obtain any necessary documentation to allow you to study in the UK.
For more information about eligibility requirements, please visit: Eligibility – SWBiosciences Doctoral Training Partnership
How to Apply
To submit a formal application via Cardiff University’s online application service, click the 'Institution Website' button on this advert; in the ‘Apply’ box at the top-right of the page, select Qualification (Doctor of Philosophy), Mode of Study (Full Time) and Start Date (October 2022). This will take you to the application portal.
To apply for BBSRC SWBio studentships, candidates must submit the following:
Two references
Academic transcripts / degree certificate(s)
Personal statement. Please include supporting evidence for your Maths background.
Curriculum Vitae (CV)
English language certificates (where applicable)
NB: It is essential that students submit all the application elements required, as these will be needed for the shortlisting and interview processes.
In the research proposal section of the application, specify the project title and supervisors of the project. In the funding section, select “I will be applying for a scholarship/grant” and specify advertised funding from BBSRC SWBio DTP. If you are applying for more than one Cardiff University project, please note this in the research proposal section as the form only allows you to enter one title.
For more details on how to apply, visit the SWBio DTP website.
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