Genetically Engineered Materials Science

1
Genetically Engineered Materials
Science Engineering Center
NSF-MRSEC at the University of Washington,
Seattle, WA, USA
Protein-Driven Synthesis of Transition
Metal-Doped ZnS Immuno-Quantum Dots
Doping semiconductor nanocrystals with transition
metals is an efficient route to tune emission
color over a broad range of wavelengths. We have
developed a simple and environmentally friendly
process for protein-aided mineralization of
transition metal doped ZnS nanocrystals.
Biofabricated ZnSMn quantum dots (QDs) hold
particular promise for bioimaging and biosensing
applications because (1) they emit bright
yellow-orange light upon excitation with standard
UV sources (2) their core does not incorporate
cadmium ions that persist for long times in
tissues (3) the capping protein shell
incorporates an antibody-binding domain and is
stably tethered to the crystalline core through a
mineralizing ZnS binding peptide and (4) the
antigen-binding valency of the resulting
nanoparticles can be controlled by varying the
molar ratio of antibodies to fusion protein.
(A) Schematic illustration of the QD
biomineralization process mediated by the
BB-TrxACT43 fusion protein. Antibody-binding BB
domain (red), ZnS-binding loop (green) and TrxA
framework (blue) are shown. (B) Influence of Mn2
concentration on fluorescence. Emission (C) and
absorption (D) spectra . The inset shows a HRTEM
image of a ZnSMn nanocrystal. (E) Schematic
illustration of the antibody conjugation process
through the BB domain (red). (F) Agarose gel
analysis of immuno-complexes (a and b) at various
IgG to QD ratios.
RESEARCH
W. Zhou, D. T. Schwartz, F. Baneyx. JACS, 132,
47314738 (2010).
Supported by NSF via GEMSEC, MRSEC at UW
(DMR-0520567)
For more information, visit GEMSEC at
http//www.GEMSEC.washington.edu