Izvorni znanstveni članak

https://doi.org/10.5772/61094

Single-molecule Detection in Nanogap-embedded Plasmonic Gratings

Biyan Chen ; Department of Electrical and Computer Engineering, 139 and 141A Engineering Building West, University of Missouri, Columbia, MO, USA
Avinash Pathak ; Department of Electrical and Computer Engineering, 139 and 141A Engineering Building West, University of Missouri, Columbia, MO, USA
Keshab Gangopadhyay ; Department of Electrical and Computer Engineering, 139 and 141A Engineering Building West, University of Missouri, Columbia, MO, USA; Nanos Technologies LLC, Business Incubator Center, Columbia, MO, USA
Peter V. Cornish ; Department of Biochemistry, 117 Schweitzer Hall, University of Missouri, Columbia, MO, USA
Shubhra Gangopadhyay ; Department of Electrical and Computer Engineering, 139 and 141A Engineering Building West, University of Missouri, Columbia, MO, USA

Sažetak

We introduce nanogap-embedded silver plasmonic gratings for single-molecule (SM) visualization using an epifluorescence microscope. This silver plasmonic platform was fabricated by a cost-effective nano-imprint lithography technique, using an HD DVD template. DNA/RNA duplex molecules tagged with Cy3/Cy5 fluorophores were immobilized on SiO2-capped silver gratings. Light was coupled to the gratings at particular wavelengths and incident angles to form surface plasmons. The SM fluorescence intensity of the fluorophores at the nanogaps showed approximately a 100-fold mean enhancement with respect to the fluorophores observed on quartz slides using an epifluorescence microscope. This high level of enhancement was due to the concentration of surface plasmons at the nanogaps. When nanogaps imaged with epifluorescence mode were compared to quartz imaged using total internal reflection fluorescence (TIRF) microscopy, more than a 30-fold mean enhancement was obtained. Due to the SM fluorescence enhancement of plasmonic gratings and the correspondingly high emission intensity, the required laser power can be reduced, resulting in a prolonged detection time prior to photobleaching. This simple platform was able to perform SM studies with a low-cost epifluorescence apparatus, instead of the more expensive TIRF or confocal microscopes, which would enable SM analysis to take place in most scientific laboratories.

Ključne riječi

single-molecule detection; DNA/RNA duplex; plasmonic gratings; nanogaps; epifluorescence microscope

Hrčak ID:

157684

URI

https://hrcak.srce.hr/157684

Datum izdavanja:

1.1.2015.

Posjeta: 751 *