Abstract
The optical spectra of yeast cells in phosphate buffer saline (PBS) were analyzed with an optical UV-vis sensor based on a shallow p + n junction realized in a low doped n-type epitaxial silicon layer grown on a strongly doped n + substrate. The presence of the n/n + interface allows a significantly enhanced sensitivity, due to an increased collection of carriers photogenerated both by short and large wavelengths in the range 250...800 nm. In our experiments the optical absorption of yeast cells was investigated in the wavelength range 250...500 nm as a function of the cells concentration in PBS in the range of 6 × 106–2 × 108 cells/ml. The main absorption peaks were found at 310, 350, 400 and 427 nm, respectively. A significant red shift of the wide absorption band at 427 nm has been observed when increasing cell concentration. This red shift behaviour was nonlinear, with saturation observed for yeast concentrations larger than 5 × 107 cells/ml. The half-peak bandwidth of this peak also showed a most significant nonlinear variation. These findings suggest that monitoring the parameters of the absorption band at 427 nm versus cells concentration could be used, e.g. using a dedicated integrated spectrometric microsystem, for fast quantitative measurements of yeast cell concentrations in various bio-samples, with possible applications in the food industry.
Similar content being viewed by others
References
C. Bercu, T. Oncescu, L. Lupan, R. Bandula, M. Vasilescu, and T. Sandu, Fresenius J Anal Chem 355, 753 (1996).
A. Biber, P. Seitz, and H. Jackel, Sensors and Actuators A90, 82–88 (2001).
J.H. Correia, G. de Graaf, S.H. Kong, M. Bartek, and R.F. Wolffenbuttel, Sensors and Actuators A82, 191–197 (2000).
P.B. Dengis, L.R. Nellissen, and P.G. Rouxhet, Applied and Environmental Microbiology 61, 718–728 (1995).
E.H. van Hamersveld, R.G.J.M. van der Lans, and K.C.A.M. Luyben, Biotechnology and Bioengineering 56, 190–200 (1997).
K. Husimi, S. Ohkawa, C. Kim, S. Osada, and F. Shiraishi, Nuclear Instruments and Methods 196, 131–136 (1982).
A. Katz and R.R. Alfano, Proceedings of SPIE 3931, 223–226 (2000).
D. Libkind, P. Perez, R. Sommarunga, M.C. Dieguez, M. Ferraro, S. Brizzio, H. Zagarese, and M. van Broock, Photochemical & Photobiological Science 3, 281–286 (2004).
S. Martic, J. Campbell, M. Bercu C. Atik, and M. Scarlet, Canadian Journal of Analytical Science and Spectroscopy 48, 1–8 (2003).
J.M. Meinders, H.C. van der Mei, and H.J. Busscher, Journal of Colloid and Interface Science 176, 329–341 (1995).
P.N. Prasad, Introduction to Biophotonics, Willey Interscience 2003.
C. Ruggiero, M. Mantelli, and A. Curtis, European Cells and Materials 4 (Suppl.2), 115–117 (2002).
M.H. Straver, P.C.V.D. Aar, G. Smit, and J.W. Kijne, Yeast 9, 527–532 (1993).
A. Touhami, B. Hofmann, A. Vasella, F. Denis, and Y. Dufrene, Langmuir 19, 1745–1751 (2003).
P.S. Tuminello, E.T. Arakawa, B.N. Khare, J.M. Wrobel, M.R. Querry and M.E. Milham, Applied Optics 36, (no.13), 2828–2824 (1997).
J. Vitte, A.M. Benoliel, A. Pieres and P. Bongrand, European Cells and Materials 7, 52–63 (2004).
D. S. Yaney, J.T. Nelson, and L.L. Vanskike, IEEE Transactions On Electron Devices ED-26, 10–16 (1979).
C. F. Williamson, J. R. Boujot, J. Picard, in “Silicon Surface-Barrier and Ion Implanted Detectors for Charged Particles”, Ortec Incorporated, Oak Ridge TN, (1976).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Bercu, M., Zhou, X., Lee, A.C. et al. Spectral characterization of yeast cells with an epitaxy-based UV-Vis optical sensor. Biomed Microdevices 8, 177–185 (2006). https://doi.org/10.1007/s10544-006-7713-7
Issue Date:
DOI: https://doi.org/10.1007/s10544-006-7713-7