Continuous threat of terrorist attack with chemical (CWA) or biological warfare agents (BWA) has been stimulating research on development of rapid and sensitive methods for their detection for many years [1]. The development of such methods for the detection of bioagents is also important for medical diagnostics of infectious diseases. Traditionally, PCR method has been used for bacterial identification. However, despite the recent advances, it still requires relatively long time of analysis [3,4]. Among other methods for detecting bioagents, spectroscopic methods, such as fluorescence or Raman spectroscopy, have been shown to be applicable for biological detection. Recently, one of the Raman spectroscopy techniques, Surface-Enhanced Raman Spectroscopy (SERS), based on enhancement of scattering on plasmonic nanostructures have been shown as a great tool for spectroscopic detection of bacteria [2,4]. However, the key challenge is the development of sensitive and stable SERS substrates as well as methodology of SERS measurements in case of bacteria.

In this work we present results of studies on the surface enhanced Raman spectroscopy of Bacillus Atrophaeus (Bacillus globigii, BG) – simulant to Bacillus Anthracis [4]. The SERS spectra of BGs were obtained using various types of nanostructures – drop-deposited layers of gold, silver and SiO₂@Au/Ag core-shells nanoparticels and assembled monolayers of noble metal nanoparticles [5]. The example of SERS spectra of BGs is presented in Figure 1. Preliminary studies have shown that the signal enhancement is strongly dependent on type and morphology of SERS substrates, as well as the way sample for SERS measurement is prepared.

Figure 1. SERS spectrum of BGs obtained with use of silver nanoparticles.

The financial support from NCBiR under grant No. O N507 282540 and NCN under Grant No. 2011/03/D/ST5/06038 is greatly appreciated.

References

[1]  J.P. Jones, T. Alexander, N.F. Fell Jr., A.W. Fountain III, Characterization of Photonic Nanostructures used as Surface-Enhanced Raman Substrates for Bacterial Spores, P SPIE  5617 (2004), 323-333.

[2]  H.W. Cheng, S.Y. Huan, R.Q. Yu, Nanoparticle-based substrates for surface-enhanced Raman scattering detection of bacterial spores,  Analyst 137 (2012), 3601-3608.

[3]  H.W. Cheng, Y.Y. Chen, X.X. Lin, S.Y. Huan, H.L. Wu, G.L. Shen, R.Q. Yu, Surface-enhanced Raman spectroscopic detection of Bacillus subtilis spores using gold nanoparticle based substrates, Anal Chim Acta 707 (2011), 155-163.

[4]  J.A. Guicheteau, S.D. Christesen, Surface Enhanced Raman Immunoassay (SERIA): Detection of bacillus globigii in ground water, P SPIE  5585 (2004), 113-121.

[5] B. Bartosewicz, M. Gajda-Rączka, B. J. Jankiewicz, Chemical approach to fabrication of semicontinuous Au nanolayers for SERS applications, Photonics Let. Pol. 5 (2013), 48-50.

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1. Application of silica-metal core-shell nanostructures for Surface Enhanced Raman Spectroscopy