SWOPT aims to solve one of the great challenges in visualising biology: break through the penetration limits of optical microscopy and image cells and their function in vivo at depths of several millimetres to centimetres, while retaining high resolution and sensitivity of single cells. The ability to visualize few cells in a live organism is important because many biological phenomena, especially in the immune system, the onset of tumours, or fundamental developmental biology, rely on a small number of cells.
SWOPT will achieve this by combining the principles of photoswitching with optoacoustic imaging. Optoacoustic imaging is a method that relies on reading out ultrasound signal generated by light. It already has the power to deliver a combination of higher penetration depth, higher resolution, and larger fields of view than other imaging technologies. However, for many research questions, optoacoustic needs tools like genetically encoded reporters and sensors. Photoswitchable label proteins can help here. These proteins can change their state upon illumination, like a tiny switch that changes the state of the protein from ON to OFF and with that, the signal it generates. In optoacoustic, we use the light switchable signal to make the label blink, which enables the visualization of small numbers of cells against a strong background of other signals, which shows a constant signal. One can imagine the effect, like the blinking of a lighthouse in a stormy dark night at sea.
SWOPT will enable examination of whole tissues in vivo with the same ease, flexibility and, eventually, abundance of tools, paralleling fluorescence microscopy, thus bringing research and understanding of living organisms to the next level. As an affordable imaging technology, SWOPT aspires to become routine in life science and bio-medical research.
The overall objective of SWOPT is to create a technology based on optoacoustic imaging and photoswitching. To this aim, a new imaging instrumentation will be developed, and SWOPT-tailored contrast agents (protein-based and synthetic) will be created. SWOPT’s abilities will be benchmarked by visualizing cells and their anatomical and chemical environment in vivo in whole tumours and in 3D models based on spheroids and organoids.
