Last week brought excitement and disappointment in approximately equal measures for my research on tracking nanoparticles [see ‘Slow moving nanoparticles‘ on December 13th, 2017 and ‘Going against the flow‘ on February 3rd, 2021]. The disappointment was that our grant proposal on ‘Optical tracking of virus-cell interaction’ was not ranked highly enough to receive funding from Engineering and Physical Sciences Research Council. Rejection is an occupational hazard for academics seeking to win grants and you learn to accept it, learn from the constructive criticism and look for ways of reworking the ideas into a new proposal. If you don’t compete then you can’t win. The excitement was that we have moved our apparatus for tracking nanoparticles into a new laboratory, which has been set up for it, so that we can start work on a pilot study looking at the ‘Interaction of bacteria and viruses with cellular and hard surfaces’. We are also advertising for a PhD student to start in September 2021 to work on ‘Developing pre-clinical models to optimise nanoparticle based drug delivery for the treatment of diabetic retinopathy‘. This is an exciting development because it represents our first step from fundamental research on tracking nanoparticles in biological media towards clinical applications of the technology. Diabetic retinopathy is an age-related condition that threatens your sight and currently is managed by delivery of drugs to the inside of the eye which requires frequent visits to a clinic for injections into the vitreous fluid of the eye. There is potential to use nanoparticles to deliver drugs more efficiently and to support these developments we plan that the PhD student will use our real-time, non-invasive, label-free tracking technology to quantify nanoparticle motion through the vitreous fluid and the interaction of nanoparticles with the cells of the retina.