This image is part of a project developing a chemical imaging catheter for in-situ bladder cancer diagnostics. It shows a three-dimensional chemical image detecting Nuclear Matrix Protein 22 (NMP-22), an FDA-approved biomarker for bladder cancer. A standard medical catheter was transformed into an annular nanosensor array and internally probed with a rotating ball lens. The heat map represents fluorescence signals generated when nanosensors grafted onto the catheter surface selectively interact with protein efflux from cancer cells.