Nanoparticle鈥揊ilm Plasmon Ruler Interrogated with Transmission Visible Spectroscopy
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- 作者：Ryan T. Hill ; Klaudia M. Kozek ; Angus Hucknall ; David R. Smith ; Ashutosh Chilkoti
- 刊名：ACS Photonics
- 出版年：2014
- 出版时间：October 15, 2014
- 年：2014
- 卷：1
- 期：10
- 页码：974-984
- 全文大小：578K
- ISSN：2330-4022
文摘
The widespread use of plasmonic nanorulers (PNRs) in sensing platforms has been plagued by technical challenges associated with the development of methods to fabricate precisely controlled nanostructures with high yield and characterize them with high throughput. We have previously shown that creating PNRs in a nanoparticle鈥揻ilm (NP鈥揻ilm) format enables the fabrication of an extremely large population of uniform PNRs with 100% yield using a self-assembly approach, which facilitates high-throughput PNR characterization using ensemble spectroscopic measurements and eliminates the need for expensive microscopy systems required by many other PNR platforms. We expand upon this prior work herein, showing that the NP鈥揻ilm PNR can be made compatible with aqueous sensing studies by adapting it for use in a transmission localized surface plasmon resonance spectroscopy format, where the coupled NP鈥揻ilm resonance responsible for the PNR signal is directly probed using an extinction measurement from a standard spectrophotometer. We designed slide holders that fit inside standard spectrophotometer cuvettes and position NP鈥揻ilm samples so that the coupled NP鈥揻ilm resonance can be detected in a collinear optical configuration. Once the NP鈥揻ilm PNR samples are cuvette-compatible, it is straightforward to calibrate the PNR in aqueous solution and use it to characterize dynamic, angstrom-scale distance changes resulting from pH-induced swelling of polyelectrolyte (PE) spacer layers as thin as 1 PE layer and also of a self-assembled monolayer of an amine-terminated alkanethiol. This development is an important step toward making PNR sensors more user-friendly and encouraging their widespread use in various sensing schemes.