Work performed and overview of the results
Biocompatible and biodegradable lasers in the form of solid microbeads and liquid microdroplets were demonstrated. The spherical lasers were fabricated from biocompatible materials that are already used for medical implants. The lasers were manufactured in the form of microspheres with sizes ranging from 10 µm to 25 µm containing a fluorescent dye, with all the materials approved for use in humans. The operation of these lasers was demonstrated inside the eye (cornea), skin tissue and blood. Microlasers are typically pumped by an external light source, which limits their ability to operate deep inside tissues. In InjectableLasers the microcavities were pumped using bioluminescence, for the first time, to generate a laser-like emission, without the use of any external light source. Bioluminescence is the generation of light in living organisms by the chemical reaction of luciferin (“fuel” that provides energy) and luciferase (the enzyme that catalyses the reaction). The main advantage of bioluminescence is that there is no need for an external source of light, thus ending the limit relating to light penetrating the tissue. A biocompatible Bragg onion laser was made out of cholesterols, which are naturally occurring in living organisms, making the laser naturally biocompatible and biodegradable. A mixture of cholesterols forms a liquid-crystal cholesteric phase, which has a periodic structure and therefore acts as a photonic crystal, selectively reflecting the light. The Bragg onion laser is a unique source of light, since it is single mode, coherent, the light radiates in all directions and therefore could be used for biomedical purposes as a source of light for imaging, sensing, therapy and holography. Furthermore, the emission wavelength from cholesteric liquid-crystal lasers is highly temperature dependent, so remote temperature sensing within biological tissue could be demonstrated.
Exploitation and dissemination
The results of the action were published in two peer-reviewed articles in the following journal articles: Optica and Optics express. The work has been also presented on 9 international invited conference talks including prestigious conferences such as Gordon Research Conference and SPIE Photonic West. Apart from invited talks, the work was presented at 5 talks at various local events, seminars, invited talks at universities and schools. The results of this action are very interesting to the general public. The fellow took part in 6 news items on radio, in newspapers and a half-hour science show about biolasers on national TV. He was sharing his work on Facebook and the laboratory website. There were also regular visits to his laboratory, including students as well as prominent scientists from all over the world.
