Quantum dots have already proven themselves as powerful imaging probes that can enable researchers to track disease-related molecules inside cells and even within the body.
In response to illumination with near infrared light, these semiconductor nanocrystals shine so brightly it is possible to spot individual quantum dots inside cells.
Now, however, investigators at the Center for Cancer Nanotechnology Excellence (CCNE) Focused on Therapy Response, based at Stanford University, have developed a self-illuminating quantum dot that can reveal its presence without an external light source. This team was able to create this novel quantum dot using a new method they developed for adding proteins to the quantum dot surface. This work was reported in the journal Angewandte Chemie International Edition.
Jianghong Rao, Ph.D., a member of the Stanford CCNE, and Sanjiv Gambhir, M.D., Ph.D., principal investigator there, led the team that developed a generalized method for creating a uniform protein coating on the surface of quantum dots. This method uses a commercially available, genetically engineered enzyme known as a HaloTag protein, that forms a strong chemical bond between itself and a small organic molecule – the HaloTag ligand – that is easily coated onto a quantum dot surface. Furthermore, the HaloTag protein itself can be linked to other proteins, providing an easy method for adding such proteins to a quantum dot surface.