Polyhistidine fusion proteins can nucleate the growth of CdSe nanoparticles.

A (His-Asn)6 domain fused to fatty acid binding protein provides the low-temperature assembly of CdSe nanoparticles starting with common inorganic salt precursors. This observation is significant, since fusion proteins with this protein domain are common for affinity purification. While not optimized, this domain readily provides CdSe nanoparticles from room-temperature solutions. The nanoparticles are soluble and do not precipitate during standard biochemical purification procedures. High-resolution transmission electron microscopy demonstrates that the CdSe nanoparticles are crystalline. Surface defects on these nanoparticles are presumed, as weak emission was observed. This report presents a straightforward method to produce protein-attached semiconducting nanoparticles that can be used for biological assays.