Nanofiber near-field light-matter interactions for enhanced detection of molecular level displacements and dynamics.
Nano Lett
; 13(4): 1440-5, 2013 Apr 10.
Article
em En
| MEDLINE
| ID: mdl-23517010
ABSTRACT
We experimentally demonstrate that plasmonic nanoparticles embedded in the evanescent field of subwavelength optical waveguides (WGs) are highly sensitive to distances normal to the propagation of light, showing an ~10× increase in spatial resolution compared to the optical field decay of the WG. The scattering cross-section of the Au nanoparticle is increased by the plasmon-dielectric coupling interaction when the nanoparticle is placed near the dielectric surface of the WG, and the decay of the scattering signal is enhanced, showing angstrom level distance sensitivity within 10 nm from the WG. Numerical studies with the finite-difference time-domain (FDTD) method correlate well with the experimental results. To demonstrate real-time monitoring of a single molecule stretching in the evanescent field, we linked individual single-stranded DNA molecules between the WG and plasmonic nanoparticles and pushed on the nanoparticles with fluidic forces. The simple design and ease of obtaining optical feedback on molecular displacements makes our approach ideal for new in situ force sensing devices, imaging technologies, and high-throughput molecular analysis.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
DNA de Cadeia Simples
/
Nanopartículas
/
Nanofibras
Tipo de estudo:
Diagnostic_studies
Idioma:
En
Revista:
Nano Lett
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Estados Unidos