Photophysics of (CdSe)ZnS colloidal quantum dots in an aqueous environment stabilized with amino acids and genetically-modified proteins.
Using a combination of two amino acids, histidine and N-acetyl-cysteine, to replace the original organic capping groups of (CdSe)ZnS quantum dots, water-soluble and highly luminescent (CdSe)ZnS quantum dots have been successfully prepared at pH 8. Characterization by steady-state and time-resolved photoluminescence spectroscopy, and transient absorption spectroscopy, demonstrate that the electronic properties of these quantum dots exceed those of the original as-synthesized samples dissolved in a more-conventional organic solvent. Furthermore, these amino acid-stabilized quantum dots have been assembled onto a cellulose substrate via cellulose binding proteins that specifically bind to cellulose and was genetically engineered to harbor dual hexahistidine tags at the N- and C-termini to confer binding with the zinc(II) on the quantum dot surface. The spectroscopic measurements show that the protein-bound quantum dots continue to retain their desirable electronic properties when bound on the substrate. Meanwhile, the specific and very selective binding properties of the proteins have remained effective.
Ai
Xin
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National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, CO 80401-3393, USA.
Xu
Qi
Q
Jones
Marcus
M
Song
Qing
Q
Ding
Shi-you
SY
Ellingson
Randy J
RJ
Himmel
Mike
M
Rumbles
Garry
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D000596:Amino Acids / Q000235:genetics / Q000378:metabolism*; D019187:Cadmium Compounds / Q000737:chemistry*; D002480:Cellulase / Q000235:genetics / Q000378:metabolism*; D003102:Colloids; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D010777:Photochemistry; D045663:Quantum Dots; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D018036:Selenium Compounds / Q000737:chemistry*; D017967:Zinc Compounds / Q000737:chemistry*
D000596:Amino Acids; D019187:Cadmium Compounds; D003102:Colloids; D011994:Recombinant Proteins; D018036:Selenium Compounds; D017967:Zinc Compounds; C058667:cadmium selenide; D002480:Cellulase