The focus of our project is to develop a fast and efficient process to detect the presence of mast cells in dogs. Mast cells promote tumor growth and histamine development, which are known as Mast Cell Tumors (MCTs). Our solution is to create a cost-effective, fluorescence biosensor to detect the target miRNA-21, found in saliva, which increases inflammation of mast cells. We will apply Lambert iGEM’s Rolling Circle Amplification (RCA) technique to amplify the miRNA-21. The RCA technique utilizes Padlock Probes to target and amplify the miRNA-21 sequence.