PROJECT SUMMARY. We have recently developed a label-free biological and chemical sensing system knownas a frequency locked optical whispering evanescent resonator (FLOWER) that integrates microtoroid opticalresonators with frequency locking feedback control which aids the suppression of noise. FLOWER is currentlycapable of highly sensitive and rapid (under 30 seconds) label-free detection down to the single macromoleculelevel as demonstrated by the detection of single human interleukin-2 (IL-2) molecules. To date FLOWER hasachieved a signal-to-noise ratio of 5 using an anti-IL-2 antibody layer immobilized on a microtoroid to specificallycapture IL-2. In addition to its high sensitivity FLOWER has an advantage over other nanoscale sensingplatforms such as cantilevers or nanowires in that it possesses a relatively large capture area increasing theprobability of analyte detection. We propose (1) using FLOWER to target a large number of current biomedical problems which wouldbenefit from a rapid sensitive and accurate means to identify key microscopic nanoscopic or molecularmarkers specific to the problem; (2) miniaturizing and multiplexing FLOWER and making it part of a self-contained compact portable device to quickly establish the prognosis of various conditions; and (3) furtherincreasing FLOWERs sensitivity and selectivity making it capable of detecting even smaller molecules withsocietal interest such as insulin or more capable of detecting the small signal changes mentioned in (1). As suchFLOWER may be used to understand the process of olfaction in synthetic optical noses or disease progressionin Alzheimers. FLOWER is a new method that has not been applied to these questions before and with proofof concept has great potential to advance several fields. If successful this project would allow for a robust extremely sensitive and portable device that could begiven to an EMT or a solider in order for them to rapidly detect diseases or viruses and bacteria in drinking wateror food. These devices could empower citizen scientists to monitor their drinking supply or breathing air.Furthermore these devices could be easily translatable to other labs enabling robust assays for drug libraryscreening cell signaling studies and clinical assays. Eventually we envision these devices to be prevalent indrug stores throughout the country creating a convenient inexpensive routine accessible and non-invasivemeans to impact the diagnosis and treatment of many diseases including Alzheimers cancer pain from multiplesclerosis diabetes addiction and depression.