期刊
BIOSENSORS & BIOELECTRONICS
卷 44, 期 -, 页码 191-197出版社
ELSEVIER ADVANCED TECHNOLOGY
DOI: 10.1016/j.bios.2013.01.038
关键词
Biosensor; High pressure sputtering; Microorganisms; Sub-10-nm nanogaps; Surface enhanced Raman scattering
类别
资金
- National Natural Science Foundation of China [50871028]
- Fundamental Research Funds for the Central Universities [N100702001, N110610001]
Nanoscale gaps in noble metal films can produce intense electromagnetic enhancement. When Raman-active molecules are positioned in these regions, their surface-enhanced Raman scattering (SERS) signals can be dramatically enhanced. However, the lack of convenient and reliable fabrication methods with ultrasmall nanogaps (< 10 nm) severely block the application of SERS. Here, we propose a cost-effective and reproducible technique to fabricate the large-area Ag SERS-active substrates which are full of the high-density, sub-10-nm nanogaps by high pressure sputtering, and the enhancement factor (EF) is testified to improve by 10(3) times compared to the continuous Ag film with a smooth surface (the roughness is 0.5 nm) and without nanogaps. Since there are no chemicals used during fabrication, this substrate has a clean surface, which is crucial for acquiring reliable SERS spectra. This SERS-active substrate has then been applied to identify a series of microorganisms, and excellent, reproducible SERS spectra were obtained. Finally, a set of piecewise-linear equations is provided according to the correlation between SERS intensity and rhodamine 6G (R6G) concentration, and the detection limit is calculated to be 0.2 x 10(-8) M. These results suggest that the high pressure sputtering is an excellent, reliable technique for fabricating sub-10-nm plasmonic nanogaps, and the SERS-based methodology is very promising for being used in biological sensing field. (c) 2013 Elsevier B.V. All rights reserved.
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