Distance-Dependence Study of Plasmon Resonance Energy Transfer with DNA Spacers

Plasmon resonance energy transfer (PRET) in hybrid plasmonic-molecular systems has a broad range of applications from catalysis to analytical/biochemical/biophysical imaging and sensing. Herein, we experimentally and theoretically probed the influence of the distance (d) between the plasmonic nanoparticle and the conjugated molecules on the PRET efficiency (η_PRET) using two PRET systems, which involved tetramethylrhodamine (TAMRA) or Cy3 molecules as acceptors and single spherical gold nanoparticles (AuNPs) as donors. The double-stranded DNA (dsDNA) sequences precisely adjusted within 12.0 nm were utilized as a donor-acceptor spacer. Then, the η_PRET of the two systems under varied d-values was available from the reduction of the scattering intensity of AuNPs. Both experimental and quasi-static approximation data show that η_PRET displays a d-value-dependent decay function. This study would provide new insights into optimal PRET-based chemical/biochemical sensors.