Authors: S. Pathak, M. Davidson, C. Sharp and G. Silva
Affilation: UCSD, United States
Pages: 259 - 262
Keywords: quantum dot characterization, neurosciences
Quantum dot nanocrystals are nanometer sized semiconductor particles, which can be used for labeling biological systems. A critical issue that has not been addressed is determining the number of antibodies bound to nanoparticles. We have previously developed methods to label fixed neurons and neural glial cells. We demonstrated, however, reproducible non-specific artifact labeling if antibody-quantum dot conditions are less than optimal. In order to explain this, we aimed to characterize and quantify the functional antibodies bound to the quantum dots. While other groups have qualitatively characterized antibody functionalized quantum dots using TEM, AFM, UV spectroscopy and gel electrophoresis, and in some cases have reported calculated estimates of the putative number of total antibodies bound to quantum dots, no quantitative experimental results have been reported. In this study, we have developed a technique for quantifying the amount of ligand bound to conjugated quantum dots. Previous attempts to characterize quantum dots never resulted in quantitative information which is necessary to determine the concentration of quantum dots delivered to the system. Using standard gel electrophoresis technology followed by membrane transfer, we have quantified the amount of functional antibody, the amount of antibody available for protein binding, bound to quantum dots from commercially available conjugation kits.