title: A compact functional quantum Dot-DNA conjugate: preparation, hybridization, and specific label-free DNA detection.
abstract: In this letter, we report the preparation of a compact, functional quantum dot (QD)-DNA conjugate, where the capturing target DNA is directly and covalently coupled to the QD surface. This enables control of the separation distance between the QD donor and dye acceptor to within the range of the Förster radius. Moreover, a tri(ethylene glycol) linker is introduced to the QD surface coating to effectively eliminate the strong, nonspecific adsorption of DNA on the QD surface. As a result, this QD-DNA conjugate hybridizes specifically to its complementary DNA with a hybridization rate constant comparable to that of free DNAs in solution. We show this system is capable of specific detection of nanomolar unlabeled complimentary DNA at low DNA probe/QD copy numbers via a "signal-on" fluorescence resonance energy transfer (FRET) response.
authors.affiliation: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom.
authors.forename: Dejian
authors.initials: D
authors.lastname: Zhou
authors.forename: Liming
authors.initials: L
authors.lastname: Ying
authors.forename: Xin
authors.initials: X
authors.lastname: Hong
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Hall
authors.forename: Chris
authors.initials: C
authors.lastname: Abell
authors.forename: David
authors.initials: D
authors.lastname: Klenerman
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000032:analysis / Q000737:chemistry*; D018736:DNA Adducts / Q000737:chemistry*; D015342:DNA Probes / Q000737:chemistry; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D045663:Quantum Dots; D013050:Spectrometry, Fluorescence
chemical_list: D018736:DNA Adducts; D015342:DNA Probes; D004247:DNA