Quantum Dots for Multicolor Tumor Pathology and Multispectral Imaging

Quantum dots (QDs) are new nanocrystal semiconductor fluorophores consisting of a cadmium selenide core and zinc sulfide or cadmium sulfide shell. They have many advantages over conventional fluorophores including prolonged signal because of photostability, and reinforcement of weak positive reactions. In this study, we have used QDs to intensify fluorescent signals in immunohistochemistry for pathology diagnostics. In addition, we introduce a new confocal laser scanning microscopy analysis method called the META system (Carl Zeiss, Jena, Germany) in which a dye spectrum is utilized. This system ensures optimum specimen illumination and efficient collection of reflected or emitted light and uses an innovative way of separating fluorescent emissions. Our results suggest that very weak immunoreactions seen by traditional immunohistochemical techniques can be greatly intensified, a useful feature for pathology diagnostics.