This document discusses quantum dots (QDs) and their use in biomedical imaging. It notes that QDs can emit fluorescent light across the UV-infrared spectrum depending on their size. The document then discusses using polymer-encapsulated QDs conjugated to targeting ligands and drugs for cancer cell imaging in living animals. It finds the QD probes accumulate in tumors through enhanced permeability and retention, as well as antibody binding to cancer cells. However, concerns are raised about QD toxicity if their surface is degraded, but polymer coatings can make QDs essentially nontoxic and prevent core exposure.