The interface of biology and photonics reresents a promising and rapidly growing area of research. We work on a number of projects, combining our experience in photonics with biologists to better understand biological processes and systems.

Developing and Applying Novel Light Sources for the Treatment of Cancer

Photodynamic therapy (PDT) uses light to treat skin cancer.

Photodymanic Therapy involves the topical application of a light sensitive drug, such as Metvix from Galderma, followed by irradiation with red light. The drug is selectively taken up by tumour cells, such as basal cell carcinoma or squamous cell carcinoma, which are destroyed upon light activation. The laser is the traditional choice in a clinical setting, but for time and cost reasons treatment with a laser requires a short treatment time and consequently a high dose. To address this issue, wearable Organic Light Emitting Diode light sources are being developed at St Andrews which allow longer treatment times with smaller doses. Trials are ongoing in collaboration with Ninewells Hospital, Dundee, to apply custom light sources to the treatment not only of cancer, but also diseases such as actinic keratosis, chronic wounds, acne, dermatitus, and even wart and wrinkle removal. This innovation has been brought to market by the spin-out company Ambicare Health Ltd.

Assaying protein-protein interaction by FRET

Fluorescence resonant energy transfer (FRET) is used to observe protein interactions in biological samples.

While FRET is often used visually in vivo, it may also be used as a quantitative screening assay for protein interaction. In this work, we study the small ubiquitin-like modifier SUMO1 and its interactions with further proteins of the SUMO cycle, including enzymes (Ubc9), substrate (RanGAP1) and proteases (SENP1), which are important in many biological processes. In this example, complexes of CFP-SUMO and YFP-Ubc9 were expressed and purified, and steady state FRET measurements of the binding of Ubc9 to SUMO1 were performed. This provides a real-time conjugation and protease cleaving assay, with a sensitivity and simplicity novel to biomolecular science.