Continued advances in the design of prosthetic devices will demand increasingly smaller and more precise connections. We are developing a single cell device capable of specific molecular interactions using semiconductor quantum dots (qdots). The qdots are placed in direct proximity to individual cellular receptors using biorecognition molecules. These molecules may be incorporated into the passivation layer of the quantum dot or may be presented as an external molecule. In this manner, we have successfully created qdot-nerve cell interfaces utilizing both peptides and antibodies. Ultimately, the qdots will be excited optically, eliciting a change in the nerve cell membrane potential. The change in nerve cell membrane potential will be measured using a microelectrode array currently under development. These devices will allow researchers to determine the effect of electrical excitation on individual nerve-cell receptors and enhance development of molecular neuroprosthetics.