TY - JOUR
T1 - Label-free fluorescent functional DNA sensors using unmodified DNA
T2 - A vacant site approach
AU - Xiang, Yu
AU - Wang, Zidong
AU - Xing, Hang
AU - Wong, Ngo Yin
AU - Lu, Yi
PY - 2010/5/15
Y1 - 2010/5/15
N2 - A general methodology to design label-free fluorescent functional DNA sensors using unmodified DNA via a vacant site approach is described. By extending one end of DNA with a loop, a vacant site that binds an extrinsic fluorophore, 2-amino-5,6,7-trimethyl-1,8-naphthyridine (ATMND), could be created at a selected position in the DNA duplex region of DNAzymes or aptamers. When the vacant site binds ATMND, ATMNDs fluorescence is quenched. This fluorescence can be recovered when one strand of the duplex DNA is released through either metal ion-dependent cleavage by DNAzymes or analyte-dependent structural-switching by aptamers. Through this design, label-free fluorescent sensors for Pb2+, UO22+, Hg2+, and adenosine have been successfully developed. These sensors have high selectivity and sensitivity; detection limits as low as 3 nM, 8 nM, 30 nM, and 6 μM have been achieved for UO22+, Pb2+, Hg2+ and adenosine, respectively. Control experiments using vacant-site-free DNA duplexes and inactive variants of the functional DNAs indicate that the presence of the vacant site and the activity of the functional DNAs are essential for the performance of the proposed sensors. The vacant site approach demonstrated here can be used to design many other label-free fluorescent sensors to detect a wide range of analytes.
AB - A general methodology to design label-free fluorescent functional DNA sensors using unmodified DNA via a vacant site approach is described. By extending one end of DNA with a loop, a vacant site that binds an extrinsic fluorophore, 2-amino-5,6,7-trimethyl-1,8-naphthyridine (ATMND), could be created at a selected position in the DNA duplex region of DNAzymes or aptamers. When the vacant site binds ATMND, ATMNDs fluorescence is quenched. This fluorescence can be recovered when one strand of the duplex DNA is released through either metal ion-dependent cleavage by DNAzymes or analyte-dependent structural-switching by aptamers. Through this design, label-free fluorescent sensors for Pb2+, UO22+, Hg2+, and adenosine have been successfully developed. These sensors have high selectivity and sensitivity; detection limits as low as 3 nM, 8 nM, 30 nM, and 6 μM have been achieved for UO22+, Pb2+, Hg2+ and adenosine, respectively. Control experiments using vacant-site-free DNA duplexes and inactive variants of the functional DNAs indicate that the presence of the vacant site and the activity of the functional DNAs are essential for the performance of the proposed sensors. The vacant site approach demonstrated here can be used to design many other label-free fluorescent sensors to detect a wide range of analytes.
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U2 - 10.1021/ac100244h
DO - 10.1021/ac100244h
M3 - Article
C2 - 20465295
AN - SCOPUS:77952504417
SN - 0003-2700
VL - 82
SP - 4122
EP - 4129
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 10
ER -