Described herein is a multiplex platform that uses ultrasmall nanoparticles (e.g., C dots and C dots) to graphically differentiate specific nerves (e.g., sensory nerves vs. motor nerves) for nerve transplants and other surgeries. Also described herein is a multiplex platform that uses ultrasmall nanoparticles (e.g., C dots and C dots) to graphically differentiate between different types of lymph nodes and/or lymphatic pathways, e.g., to safely and effectively perform vascularized lymph node transplantation in the treatment of lymphedema. Also described herein is a multiplex platform that uses ultrasmall nanoparticles (e.g., C dots and C dots) to graphically differentiate parathyroid tissue.