Quantum dots combined with antibodies as a method for studying cells

To understand cell function, we need to be able to study them in their native environment, in vivo. While there are many techniques for studying cells in vitro, or in the laboratory setting, in vivo studies are much more difficult. 

A new study by a team of researchers at the Massachusetts Institute of Technology and Harvard Medical School used a unique quantum dot-antibody conjugate to facilitate in vivo studies of bone marrow stem cells in mice.

Typically, to study a cell in vivo involves making invasive modifications to the cell or the organism that disrupt the cell's native environment. Additionally, many in vivo studies involve studying groups of cells, rather than tracking a single cell. Prior techniques involved manipulating the cells by immunohistochemistry, genetic engineering, or irradiation of the organism.

All of these techniques either create substantial changes to the native environment, or they are only able to look at a "snapshot" of the cell interacting with its environment. It cannot study the movement of the cell throughout the body.

Quantum dots are semi-conductor-like nanoparticles with optical properties that can be finely tuned for a wide range of optical-based studies, including infrared and fluorescence. Han, et al. targeted a particular cell type by combining quantum dots with antibodies matched to the cell's surface receptors, so that they would combine like a lock and key.