SUREFACE ENHANCED RAMAN SCATTERING BIOSENSORS BASED ON SILVER NANOROD ARRAY

Yiping Zhao

Department of Physics and Astronomy, University of Georgia, Athens, GA 30602

  Recently, nanostructured substrates, especially one dimensional nanostructures such as nanorods and nanowires, have been used extensively to improve the sensitivity and reliability of conventional chemical and biological sensors. In order to make practical devices, the nanofabrication technique should have the ability to fabricate the desired one-dimensional nanorod structures with specific size, shape, alignment, and architectures. In particular, the challenges for the nanostructure fabrication method are: (1) the ability to control the size, aspect ratio, shape of the nanostructures; (2) the ability to grow the desired nanostructure at low temperature and onto a particular substrate geometry, e.g . flat, cylindrical or tapered; (3) the ability to fabricate metallic and dielectric nanostructures with multilayer structures; and (4) the ability to seamlessly integrate the fabrication process with other conventional microfabrication techniques.

We are particularly interested in a surface enhanced Raman spectroscopy (SERS) based sensor. Our preliminary SERS experiments on Ag nanorod samples have shown very promising results. A stepped nanorod sample was deposited onto a Ag-coated glass slide resulting in six different regions, denoted as A, B, C, D, E, and F (Fig. 1). These six regions have randomly aligned Ag nanorod arrays with lengths of l = 0, 190, 218, 300, 366, and 508 nm, respectively. The SEM images in Fig. 1 show representative morphologies of several of the structures. The diameter of the Ag nanorods is about 80-90 nm (see Channey et al, APL).

 

Using these Ag nanorod samples, surface enhanced Raman spectra were acquired using a near-IR confocal Raman microscope at an excitation wavelength of 785 nm. The molecular probe used in this study was trans-1,2-bis(4-pyridyl)ethene (BPE). A representative SERS spectrum of BPE on an Ag nanorod array with a rod length of 366 nm is presented as an insert in Fig. 1. From these spectra, the SERS Surface Enhancement Factor (SEF) was calculated for BPE on the stepped Ag nanorod samples

Figure 1 illustrates the calculated SERS SEF plotted as a function of the length of Ag nanorod. The SEF increased from almost zero for Region A to over 10 5 for a very short Ag nanorod in Region B (l = 190 nm), and then increased another three orders of magnitude ( 108 ) for a nanorod in Region F ( l = 508 nm).

Fig. 1. The Ag nanorod samples for SERS experiments and the enhancement factor as a function of the nanorod length.

This SERS substrate has shown very high enhancement. The fabrication technique is relative simple and the resulting substrate area can be quite large and uniform (Driskell et al, JPCC). It shows strong polarization dependence, and the enhancement factor also depends on the underlying substrate layer (Zhao et al, JPCB). The SERS signal also depends on the incident angle of excitation laser (Liu et al, APL). We have developed a simple model based on a dipole radiation on an nanorod to interpret these effects (Liu et al, PRB). Based on those effects, we could develop an optimal SERS substrate and excitation configuration for a fiber Raman system (Chu et al, OE). The biological sensing capability of this SERS substrate has been tested extensively. We have successfully used the SERS substrates to distinguish different viruses (Shanmukh et al, NL), different virus strains. The sensing of bacteria has also been shown (Chu et al, AS). Recently we have also successfully shown that this technique can be used to differentiate different miRNAs (Driskell et al, BB). Statistic method can be applied to distinguish different bio-agents (Shanmukh et al, ABC). Some more detailed information can be found in two recent reviews: Zhao et al, NanoToday and Driskell et al, IEEE Sensors.

Below please find some of our recent and related work in this area:

Sensing applications:

Qin Zhou, Yuping He, Justin Abell, Zhengjun Zhang, and Yiping Zhao, "Surface-enhanced Raman scattering from helical silver nanorod arrays," Chem Comm., in press.

Suzanne L. Hennigan, Jeremy D. Driskell, Richard A. Dluhy, Yiping Zhao, Ralph A. Tripp, and Duncan C. Krause, “Detection of Mycoplasma pneumoniae in throat swab specimens by nanorod array-surface-enhanced Raman spectroscopy,” PLoS One 5, e13633 (2010).

Qin Zhou, Yongjun Liu, Yuping He, Zhengjun Zhang, and Yiping Zhao, “The effect of underlayer thin films on the surface-enhanced Raman scattering response of Ag nanorod substrates,” Appl. Phys. Lett 97, 121902 (2010).

Xiaobing Du, Hsiaoyun Chu, Yaowen Huang, and Yiping Zhao, "Qualitative and quantitative determination of Melamine by surface enhanced Raman spectroscopy using silver nanorod array substrates," Applied Spectroscopy 64, 781-785 (2010).

Yongjun Liu, Hsiao Chu, and Yiping Zhao, "Silver nanorod array substrates fabricated by oblique angle deposition: morphological, optical and SERS characterizations," J. Phys. Chem. C 114, 8176–8183 (2010).

Jeremy D. Driskell, Yu Zhu, Carl D. Kirkwood, Yiping Zhao, Richard A. Dluhy, and Ralph A. Tripp, "Rapid and sensitive detection of Rotavirus molecular signatures using surface enhanced Raman spectroscopy," PLoS One 5, e10222 (2010).

J.-X. Fu and Y.-P. Zhao, "Au nanoparticle based localized surface plasmon resonancesubstrates fabricated by dynamic shadowing growth," Nanotechnology 21, 175303 (2010).

Y.-J. Liu, Z.-Y. Zhang, R. A. Dluhy, and Y.-P. Zhao, ‘‘The SERS response of semiordered Ag nanorod arrays fabricated by template oblique angle deposition,’’ Journal of Raman Spectroscopy 41, 1112–1118(2010).

J. Driskell, O. Primera-Pedorozo, R. A.Dluhy, Y.-P. Zhao, and R. A. Tripp, ”Quantitative SERS-based analysis of microRNA mixtures,” Applied Spectroscopy 63, 1107-1114 (2009).

J.-X. Fu, B. Park, and Y.-P. Zhao, “Nanorod mediated surface plasmon resonance sensor based on effective medium theory,” Applied Optics 48, 4637–4649 (2009).

J.-X. Fu, B. Park, and Y.-P. Zhao, “Limitation of a localized surface plasmon resonance sensor for Salmonella detection,” Sensors & Actuators B 141, 276–283 (2009).

J. Abell, J. D. Driskell, R. A. Tripp, R. A. Dluhy, and Y.-P. Zhao, “Fabrication and characterization of a multi-well array SERS chip with biological applications,” Biosensors and Bioelectronics 24, 3663–3670 (2009).

Y.-J. Liu, Z.-Y. Zhang, Q. Zhao, R. Dluhy, and Y.-P. Zhao, “The surface enhanced Raman scattering from Ag nanorod array substrate: the site dependent enhancement and layer absorbance effect,” J. Phys. Chem. C 113, 9664–9669 (2009).

Z.-Y. Zhang, Y.-J. Liu, Q. Zhao, and Y.-P. Zhao, “The effect of layer absorbance for complex SERS substrates,” Appl. Phys. Lett. 94, 143107 (2009).

C. L. Leverette, E. Villa-Aleman, S. Jokela, Z.-Y. Zhang, Y.-J. Liu, Y.-P. Zhao, and S. A. Smith, Trace detection and differentiation of Uranyl(VI) ion cast films utilizing aligned Ag nanorod SERS substrates,” Vibrational Spectroscopy 50, 143–151 (2009).

Y.-J. Liu, Z.-Y. Zhang, Q. Zhao, R. A. Dluhy, and Y.-P. Zhao, “The role of the nano-spine in the nanocomb arrays for surface enhanced Raman scattering,” Appl. Phys. Lett. 94, 033103 (2009).

J.-G. Fan and Y.-P. Zhao, “Gold coated nanorod arrays as highly sensitive substrates for surface enhanced Raman spectroscopy,” Langmuir 24, 14172–14175 (2008).

Y.-J. Liu, Z.-Y. Zhang, Q. Zhao, and Y.-P. Zhao,Revisiting the separation dependent surface enhanced Raman scattering,” Appl. Phys. Lett. 93, 173106 (2008).

Y.-J. Liu and Y.-P. Zhao, “Simple model for surface-enhanced Raman scattering from tilted silver nanorod array substrates," Phys. Rev. B 78, 075436 (2008).

J. Driskell, S. Shanmukh, Y. Liu, S. Chaney, X.-J. Tang, Y.-P. Zhao, and R. Dluhy, “The use of aligned silver nanorod arrays prepared by oblique angle vapor deposition,” J. Phys. Chem. C 112, 895–901 (2008).

S.-Y. Chu, Y.-W. Huang, and Y.-P. Zhao, "Silver nanorod array as a SERS substrate for foodborne pathogenic bacteria detection," Applied Spectroscopy 62, 922-931 (2008).

J.-X. Fu, A. Collins, and Y.-P. Zhao, "The optical properties and biosensor application of ultra thin Silver films prepared by oblique angle deposition," J. Phys. Chem. C 112, 16784–16791(2008).

J. D. Driskell, A. G. Seto, L. P. Jones, S. Jokela, R. A. Dluhy, Y.-P. Zhao, and R. A. Tripp, "Rapid microRNA (miRNA) detection and classification via surface-enhanced Raman spectroscopy (SERS)," Biosensors and Bioelectronics 24, 923-938 (2008).

Y.-P. Zhao, R. A. Dluhy, and R. A. Tripp, "Novel nanorod array structures for surface enhanced Raman spectroscopy (SERS) biosensing ," NanoToday 3 , 31-37 (2008).

J.-X. Fu, B. Park, G. Siragusa, L. Jones, R. A. Tripp,Y.-P. Zhao, and Y.-J. Cho, “Au/Si hetero-nanorod-based biosensor for Salmonella detection,” Nanotechnology 19, 155502 (2008).

J. D. Driskell, S. Shanmukh , Y.-J. Liu, S. Hennigan, L. Jones, Y.-P. Zhao, R. A. Dluhy, D. C. Krause, and R. A. Tripp, “Infectious agent detection with SERS-active silver nanorod arrays prepared by oblique angle deposition,” IEEE Sensors 8, 863 - 870 (2008).

S. Shanmukh, L. Jones, Y.-P. Zhao, J. D. Driskell, R. A. Tripp and R. A. Dluhy, “Identification and classification of respiratory syncytial virus (RSV) strains by surface enhanced Raman spectroscopy and multivariate statistical techniques,” Analytical and Bioanalytical Chemistry 390, 1551-1555 (2008).

S. Shanmukh, L. Jones, Y.-P. Zhao, R. A. Dluhy, and R. A. Tripp, “Rapid and sensitive detection of respiratory virus molecular signatures using surface enhanced Raman,” Nano Letters 6, 2630 (2006).

C. L. Leverette, S. A. Jacobs, S. Shanmukh, S. B. Chaney, R. A. Dluhy, and Y.-P. Zhao, “Aligned Silver nanorod arrays as substrates for surface-enhanced infrared absorption spectroscopy (SEIRA),” Appl. Spectroscopy 60, 906 – 913 (2006).

Z.-Y. Zhang and Y.-P. Zhao, “Tuning the optical absorption properties of Ag nanorods by their topologic shapes: A discrete dipole approximation calculation ,” Appl. Phys. Lett. 89, 023110 (2006).

Y.-P. Zhao, Stephen B. Chaney , Saratchandra Shanmukh, and Richard A. Dluhy, “Polarized surface enhanced Raman and absorbance spectra of aligned Silver nanorod arrays,” J. Phys. Chem. B 110, 3153 (2006).

Stephen B. Chaney, Saratchandra Shanmukh , Y.-P. Zhao, and Richard A. Dluhy, “Aligned silver nanorod arrays produce high sensitivity SERS substrates,” Appl. Phys. Lett. 87, 031908 (2005).

Substrate development and physical mechanism study:

Y.-J. Liu, Z.-Y. Zhang, Q. Zhao, and Y.-P. Zhao,Revisiting the separation dependent surface enhanced Raman scattering,” Appl. Phys. Lett. 93, 173106 (2008).

J.-G. Fan and Y.-P. Zhao, “Gold coated nanorod arrays as highly sensitive substrates for surface enhanced Raman spectroscopy,” Langmuir, ASAP.

Y.-J. Liu and Y.-P. Zhao, "Simple model for surface-enhanced Raman scattering from tilted silver nanorod array substrates," Phys. Rev. B 78, 075436 (2008).

Z.-Y. Zhang and Y.-P. Zhao, "Optical properties of U-shaped Ag nanostructure," J. Phys.: Condens. Matter 20, 345223 (2008).

Z.-Y. Zhang and Y.-P. Zhao, "Optical properties of helical and multi-ring Ag nanostructures: the effect of pitch height," J. Appl. Phys. 104, 013517 (2008).

J. Driskell, S. Shanmukh, Y. Liu, S. Chaney, X.-J. Tang, Y.-P. Zhao, and R. Dluhy,"The use of aligned silver nanorod arrays prepared by oblique angle vapor deposition,” J. Phys. Chem. C 112, 895-901 (2008).

Z.-Y. Zhang and Y.-P. Zhao, “Extinction spectra and electrical field enhancement of Ag nanorods with different topologic shapes,” J. Appl. Phys. 102, 113308 (2007).

H. Y. Chu, Y.-J. Liu, Y.-W. Huang, and Y.-P. Zhao, “A high sensitive fiber SERS probe based on silver nanorod arrays,” Optics Express 15 , 12230-12239 (2007).

Z.-Y. Zhang and Y.-P. Zhao, "The optical properties of helical Ag nanostructures calculated by discrete dipole approximation method," Appl. Phys. Lett. 90, 221501 (2007).

Y. Liu, J. Fan, S. Shanmukh, R. A. Dluhy, and Y.-P. Zhao, “Angle dependent surface enhanced Raman scattering obtained from a Ag nanorod array substrate,” Appl. Phys. Lett. 89, 173134 (2006).

Y.-P. Zhao, S. B. Chaney, and Z.-Y. Zhang, “ Absorbance spectra of aligned Ag nanorod arrays prepared by oblique angle deposition,” J. Appl. Phys. 100, 063527 (2006).

S. B. Chaney, Z.-Y. Zhang, and Y.-P. Zhao, “Anomalous polarized absorbance spectra of aligned Ag nanorod arrays,” Appl. Phys. Lett. 89, 053117 (2006).

 

Last updated on February 28, 2011