Bioconjugates of Luminescent CdSe-ZnS Quantum Dots with Engineered Recombinant Proteins: Novel Self-Assembled Tools for Biosensing

Colloidal semiconductor quantum dots (QDs) are luminescent nanoparticles with size- dependent emission spectra spanning a wide range of wavelengths in the visible and near IR. This property, as well as their higher resistance to photo-degradation compared to organic dye labels, makes QDs potentially suitable for certain biomolecule tagging and multiplexing applications. We describe an electrostatic self-assembly approach for conjugating highly luminescent colloidal CdSe-ZnS core-shell QDs with engineered two-domain recombinant proteins to form conjugates for sensing and imaging applications. The design, preparation, and characterization of high quantum yield IgG antibody-binding protein G bioconjugates using luminescence, electrophoretic gel shift, and affinity assays is reported.