Functionalization of carbon nanomaterials by evolutionary molecular engineering: potential application in drug delivery systems.

By virtue of the progress made in evolutionary molecular engineering, peptide aptamers that specifically recognize target molecules are now routinely created using a peptide phage display system. The system was originally developed for isolating peptides that specifically recognized biomacromolecules (e.g. proteinous receptors), but are now also being used to acquire peptide motifs that bind to inorganic materials, such as semiconductors, metals and carbon nanomaterials. We have created the peptide aptamer against carbon nanohorns, a vesicular carbon nanomaterial whose size is 80-100 nm in diameter. By combining the peptide motif that has affinity to the surfaces of carbon nanohorns with peptide aptamers that can target specific organs, we can functionalize the carbon nanomaterial to provide novel types of carriers for drug delivery systems.