PhD: Real-time nanoscale imaging in live cells - High Speed Single Molecule Localisation Microscopy

Lead Research Organisation: University of Cambridge
Department Name: Chemistry

Abstract

Background: Single-molecule based super-resolution microscopy is a recently developed family of optical imaging techniques that allow for imaging at spatial scales far smaller than the diffraction limit (~250 nm). These techniques have seen a great deal of success in recent years, particularly in investigating important biological questions (Nobel Prize Chemistry 2014). The basis of these techniques relies on gaining higher spatial resolution by trading off temporal information, therefore they remain relatively slow. Although whole-cell imaging has been achieved to ~20 nm resolution, this can typically take 10s of minutes and is clearly not compatible with a dynamic living systems.

Aims: This project will aim to overcome the limitations of low-speed single-molecule based super-resolution microscopy for dynamic living systems by developing a novel high-speed Single-Molecule Localisation Microscope (hsSMLM). The primary aim of the PhD will be to develop both the physical microscope used for hsSMLM and the data analysis techniques necessary to extract the fluorescence signal from the background when imaging at high speed.

Methodology: This work will build upon existing SMLM techniques, substituting the high sensitivity cameras used in existing microscopes for a lower sensitivity high speed camera. Our initial goal is to achieve real-time (~25 Hz) cellular imaging with 50 nm resolution. Once this is achieved, there is further potential to transfer established techniques in traditional SMLM to hsSMLM versions, such as 3D Double helix point spread function imaging[1] spectrally resolved[2,3] and polarisation resolved[4] super-resolution microscopy to enable novel biological investigations.

This project will deliver multidisciplinary training where the student will develop skills in photonics, biology, microscopy, signal processing and novel probe development. This project allows for both method-led and application-led development, providing the best possible opportunity for an engaging and highly successful PhD.

Application: Once developed, a new frontier of numerous biological questions will be accessible. The primary biological interests pertain to human health and include:
(1) real-time imaging and direct visualisation of synaptic transmission in human induced pluripotent stem cell derived cortical neurons, important in neurodegenerative conditions such as Alzheimer's and Parkinson's disease. Synaptic transmission occurs across time scales of milliseconds and length scales of nanometres, and as such have never been imaged. hsSMLM would enable the first direct observation of this established mechanism.
(2) The molecular basis of adaptive immunity, in receptor clustering in T cells, important in auto immune diseases such as rheumatoid arthritis. At present whole-cell imaging is extremely lengthy: imaging a T cell with 22 nm isotropic resolution currently takes ~4 hours. hsSMLM would reduce this to less than a second.

Industrial Engagement: The project will involve a collaboration with Dr Owen Richards, an applications scientist at the microscopy company and industrial partner 3i. 3i have an excellent track-record in both licencing and commercialising academic discoveries.

Planned Impact

The impact of the CDT in Integrated Photonic and Electronic Systems is expected to be wide ranging and include both scientific research and industry outcomes. In terms of academia, it is envisaged that there will be a growing range of research activity in this converged field in coming years, and so the research students should not only have opportunities to continue their work as research fellows, but also to increasingly find posts as academics and indeed in policy advice and consulting.

The main area of impact, however, is expected to be industrial manufacturing and service industries. Industries involved will include those involved in all areas of ICT, together with printing, consumer electronics, construction, infrastructure, defence, energy, engineering, security, medicine and indeed systems companies providing information systems, for example for the financial, retail and medical sectors. Such industries will be at the heart of the digital economy, energy, healthcare, security and manufacturing fields. These industries have huge markets, for example the global consumer electronics market is expected to reach $289 billion in 2014. It should also be noted that the photonics sector itself represents a huge enterprise. The global photonics market was $385B in 2010 and is growing with a CAGR of >10%. The Photonics 21 pan-European industry group estimates that the European photonics industry generated revenues of Eu 58B in 2010 and employed 290,000 people. They recognised that photonics is deployed in many industries and has an impact on markets with > Eu 3.6 trillion and 30 M jobs (about 14% of the total) in Europe.

Rightly highlighted by the Technology Strategy Board (TSB), the wider UK EPES (Electronics, Photonics and Electrical Systems) manufacturing sector turned over £42.4B in 2006, and employed over 330,000 people in 14,500 enterprises, with particular strengths in defence, imaging, displays, components, communications, lighting and solar energy. As well as involving large companies, such as BAE Systems, Arm and QinetiQ, there are over 10,000 UK SMEs in the EPES manufacturing sector, according to the TSB. Evidence of the entrepreneurial culture that exists and the potential for benefit to the UK economy from establishing the CDT includes the founding of companies such as Smart Holograms, Light Blue Optics, recent recipients of $26M venture funding, Zinwave, Eight19 and Photon Design by staff and our former PhD students. Indeed, over 20 companies have been spun out in the last 10 years from the groups proposing this CDT.

Centre research activities will contribute very strongly to research impact in the ICT area (computer interconnects, next generation access technologies, cellular network backhaul, converged photonic/electronic integration, quantum information processing etc), underpinning the Digital Economy theme, and contributing strongly to the themes of Energy (low energy lighting, low energy large area photonic/electronics for e-posters and window shading, photovoltaics, energy efficient displays), Manufacturing the Future (integrated photonic and electronic circuits, smart materials processing with photonics), Next Generation Healthcare (optical coherence tomography, discrete and real time biosensing, personalised healthcare), Global Uncertainties and Living with Environmental Change (advanced sensing systems incorporating electronics with photonics).

Publications

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