Albumin−CdTe Nanoparticle Bioconjugates:  Preparation, Structure, and Interunit Energy Transfer with Antenna Effect

Conjugates of bovine serum albumin and CdTe nanoparticles capped with l-cysteine have been synthesized via a one-pot glutaric dialdehyde cross-linking procedure. Diads (1:1) with some amount of 2:1 albumin−nanoparticle assemblies preferably form in this reaction, as evidenced by gel electrophoresis. Circular dichroism spectroscopy demonstrates that the tertiary structure of the protein remains largely intact after the conjugation. Attachment of protein moieties result in a significant increase of CdTe emission, which is attributed to the resonance energy transfer from the tryptophan moieties of albumin to CdTe nanoparticles acting as receptors for the protein antennae.