TY - JOUR
T1 - Increased resonance energy transfer between fluorophores bound to DNA in proximity to metallic silver particles
AU - Malicka, Joanna
AU - Gryczynski, Ignacy
AU - Fang, Jiyu
AU - Kusba, Jozef
AU - Lakowicz, Joseph R.
N1 - Funding Information:
This work was supported by NIH National Center for Research Resources, RR-08119. We thank Dr. Badri P. Maliwal for his help in suggesting the DNA sequence and preparation of samples.
PY - 2003/4/15
Y1 - 2003/4/15
N2 - We examined the effects of metallic silver particles on resonance energy transfer (RET) between fluorophores covalently bound to DNA. A coumarin donor and a Cy3 acceptor were positioned at opposite ends of a 23-bp double helical DNA oligomer. In the absence of silver particles the extent of RET is near 9%, consistent with a Forster distance R0 near 50Å and a donor to acceptor distance near 75Å. The transfer efficiency increased when the solution of AMCA-DNA-Cy3 was placed between two quartz plates coated with silver island films to near 64%, as determined by both steady-state and time-resolved measurements. The apparent R0 in the presence of silver island films increases to about 110Å. These values of the transfer efficiency and R0 represent weighted averages for donor-acceptor pairs near and distant from the metallic surfaces, so that the values at an optimal distance are likely to be larger. The increased energy transfer is observed only between two sandwiched silvered slides. When we replaced one silvered slide with a quartz plate the effect vanished. Also, the increased energy transfer was not observed for silvered slides separated more than a few micrometers. These results suggest the use of metal-enhanced RET in PCR, hybridization, and other DNA assays, and the possibility of controlling energy transfer by the distance between silver surfaces.
AB - We examined the effects of metallic silver particles on resonance energy transfer (RET) between fluorophores covalently bound to DNA. A coumarin donor and a Cy3 acceptor were positioned at opposite ends of a 23-bp double helical DNA oligomer. In the absence of silver particles the extent of RET is near 9%, consistent with a Forster distance R0 near 50Å and a donor to acceptor distance near 75Å. The transfer efficiency increased when the solution of AMCA-DNA-Cy3 was placed between two quartz plates coated with silver island films to near 64%, as determined by both steady-state and time-resolved measurements. The apparent R0 in the presence of silver island films increases to about 110Å. These values of the transfer efficiency and R0 represent weighted averages for donor-acceptor pairs near and distant from the metallic surfaces, so that the values at an optimal distance are likely to be larger. The increased energy transfer is observed only between two sandwiched silvered slides. When we replaced one silvered slide with a quartz plate the effect vanished. Also, the increased energy transfer was not observed for silvered slides separated more than a few micrometers. These results suggest the use of metal-enhanced RET in PCR, hybridization, and other DNA assays, and the possibility of controlling energy transfer by the distance between silver surfaces.
UR - http://www.scopus.com/inward/record.url?scp=0037446252&partnerID=8YFLogxK
U2 - 10.1016/S0003-2697(02)00710-8
DO - 10.1016/S0003-2697(02)00710-8
M3 - Article
C2 - 12689825
AN - SCOPUS:0037446252
SN - 0003-2697
VL - 315
SP - 160
EP - 169
JO - Analytical Biochemistry
JF - Analytical Biochemistry
IS - 2
ER -