Published online by Cambridge University Press: 01 February 2011
Nerve cells communicate by passing electrical signals through extensions from their cell bodies. Micron-scale devices such as microelectrode arrays and field effect transistors have already been used to externally manipulate these signals. However, these devices are almost as large as the cell body of the neuron. In order to make functional electrical connections to nerve extensions or their component ion channels that propagate signals, it will be necessary to utilize increasingly smaller components. We propose the use of semiconductor quantum dots, which can be optically activated, as a potential means of perturbing the nerve membrane potentials. As a first step, we have created qdot-neuron interfaces with cadmium sulfide quantum dots. The qdots may be attached to cells either non-specifically or through selected interactions exploiting biorecognition molecules attached to the qdot particle surface. We have investigated the effect of altered synthesis conditions including pH, concentration, reactant ratio, ligand length, ligand R group, and ligand concentration on the nature and quality of qdot-cell binding. We discuss the effect of these altered synthesis conditions on particle fluorescence intensity and color. Additionally, we studied the interaction of these particles with cells and determined that larger particles are more likely to bind non-specifically than smaller particles produced with the same amount of passivating ligand. It is possible this results from reduced surface area coverage of passivating chemical. Finally, we have produced particles passivated with the biorecognition peptide CGGGRGDS in the absence of other chemical stabilizers and characterized their surfaces using NMR and IR.
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