Templated self-assembly of quantum dots from aqueous solution using protein scaffolds

Short, histidine-containing peptides can be conjugated to lysine-containing protein scaffolds to controllably attach quantum dots (QDs) to the scaffold, allowing for generic attachment of quantum dots to any protein without the use of specially engineered domains. This technique was used to bind quantum dots from aqueous solution to both chicken IgG and cowpea mosaic virus (CPMV), a 30 nm viral particle. These quantum dot–protein assemblies were studied in detail. The IgG–QD complexes were shown to retain binding specificity to their antigen after modification. The CPMV–QD complexes have a local concentration of quantum dots greater than 3000 nmol ml −1 , and show a 15% increase in fluorescence quantum yield over free quantum dots in solution.