Advancing Nanostructured Porous Si-Based Optical Transducers for Label Free Bacteria Detection
Optical label-free porous Si-based biosensors for rapid bacteria detection are introduced. The biosensors are designed to directly capture the target bacteria cells onto their surface with no prior sample processing (such as cell lysis). Two types of nanostructured optical transducers based on oxidized porous Si (PSiO2) Fabry-Pérot thin films are synthesized and used to construct the biosensors. In the first system, we graft specific monoclonal antibodies (immunoglobulin G’s) onto a neat electrochemically-machined PSiO2 surface, based on well-established silanization chemistry. The second biosensor class consists of a PSiO2/hydrogel hybrid. The hydrogel, polyacrylamide, is synthesized in situ within the nanostructured PSiO2 host and conjugated with specific monoclonal antibodies to provide the active component of the biosensor. Exposure of these modified-surfaces to the target bacteria results in “direct-cell-capture” onto the biosensor surface. These specific binding events induce predictable changes in the thin-film optical interference spectrum of the biosensor. Our studies demonstrate the applicability of these biosensors for the detection of low bacterial concentrations, in the range of 103–105 cell/ml, within minutes. The sensing performance of the two different platforms, in terms of their stability in aqueous media and sensitivity, are compared and discussed. This preliminary study suggests that biosensors based on PSiO2/hydrogel hybrid outperform the neat PSiO2 system.
KeywordsPorous Si Biosensor Bacteria detection Optical transducer Hydrogel Hybrid
This work was supported by Marie Curie European Reintegration Grant, The Israel Science Foundation (grant No. 1118/08). E.S gratefully acknowledges the generous financial support of the Technion and the Russell Berrie Nanotechnology Institute.
- Archer, M., Christophersen, M., Fauchet, P. M., Persaud, D., & Hirschman, K. D. (2004). Electrical porous silicon microarray for DNA hybridization detection. Micro- and Nanosystems, 782, 385–391.Google Scholar
- Bonanno, L. M., & Delouise, L. A. (2009a) Design of a hybrid amine functionalized polyacrylamide hydrogel-porous silicon optical sensor. Proceedings of SPIE, 7167, 71670F1-11.Google Scholar
- Bonanno, L. M., & Delouise, L. A. (2009b). Optical detection of polyacrylamide swelling behavior in a porous silicon sensor. Materials Research Society Symposium. Proceeding., 1133, 1133-AA01-05.Google Scholar
- D’Auria, S., de Champdore, M., Aurilia, V., Parracino, A., Staiano, M., Vitale, A., Rossi, M., Rea, I., Rotiroti, L., Rossi, A. M., Borini, S., Rendina, I., & de Stefano, L. (2006). Nanostructured silicon-based biosensors for the selective identification of analytes of social interest. Journal of Physics. Condensed Matter, 18, S2019–S2028.CrossRefGoogle Scholar
- Janshoff, A., Dancil, K. P. S., Steinem, C., Greiner, D. P., LIN, V. S. Y., Gurtner, C., Motesharei, K., Sailor, M. J., & Ghadiri, M. R. (1998). Macroporous p-type silicon Fabry-Perot layers. Fabrication, characterization, and applications in biosensing. Journal of the American Chemical Society, 120, 12108–12116.CrossRefGoogle Scholar
- Kilian, K. A., Boecking, T., & Gooding, J. J. (2009). The importance of surface chemistry in mesoporous materials: Lessons from porous silicon biosensors. Chemical Communications, 630–640.Google Scholar
- Sailor, M. J., & Link, J. R. (2005). “Smart dust”: Nanostructured devices in a grain of sand. Chemical Communications, 1375–1383.Google Scholar
- Somasundaran, P. (2006). Encyclopedia of surface and colloid science. Boca Raton: CRC Press.Google Scholar
- Sundararaj, S., Guo, A., Habibi-Nazhad, B., Rouani, M., Stothard, P., Ellison, M., & Wishart, D. S. (2004). The CyberCell Database (CCDB): A comprehensive, self-updating, relational database to coordinate and facilitate in silico modeling of Escherichia coli. Nucleic Acids Research, 32, D293–D295.PubMedCrossRefGoogle Scholar
- Taylor, A. D., Ladd, J., Homola, J., & Jiang, S. (2008). Surface plasmon resonance (SPR) sensors for the detection of bacterial pathogens. In Z. Mohammed, E. Souna, & T. Anthony (Eds.), Principles of bacterial detection: Biosensors, recognition receptors and microsystems. New York: Springer.Google Scholar
- Yoon, M. S., Ahn, K. H., Cheung, R. W., Sohn, H., Link, J. R., Cunin, F., & Sailor, M. J. (2003). Covalent crosslinking of 1-D photonic crystals of microporous Si by hydrosilylation and ring-opening metathesis polymerization. Chemical Communications, 680–681.Google Scholar