Comparative Anti-Cancer Properties of Quantum Dots and Gold Particles Conjugated to Chemotherapeutic Agents

Nanoparticles are being increasingly used as delivery vehicles for anti-cancer drugs. They improve drug delivery to and retention in tumors, decrease damage to normal tissues, and may provide active anti-tumor effects due to photosensitization or radiosensitization. However, the optimal methods of synthesis, conjugation, and delivery of anti-cancer nanoparticles remain to be determined. Their precise mechanisms of anti-cancer activity are not fully understood, and the advantages of active over passive targeting have not been established. Furthermore, there are essentially no studies that directly compare different types of nanoparticles for anti-cancer efficacy. In this chapter we review the literature on the use of two common types of nanoparticles, gold nanoparticles and quantum dots, for anti-cancer applications. The properties of cadmium-free indium phosphide (InP) quantum dots are discussed. We then present some original data directly comparing the efficacy of gold versus InP conjugates to the chemotherapeutic drug doxorubicin, using doxorubicin-resistant B16 melanoma cells as a target.