# 형광상관분광법을 이용한 광세기에 따른 유효 초점 부피 변화에 대한 연구

• Accepted : 2013.04.19
• Published : 2013.04.25

#### Abstract

Using fluorescence correlation spectroscopy, we analyzed the change of effective focal volume of a confocal system with light intensity. The fluorescence correlation spectroscopy system was home-built in accordance with the He-Ne laser with a wavelength of 632.8 nm, and two kinds of samples (AlexaFluor657 and Quantum dot655) suitable for the wavelength of the laser beam were used. For each sample, we analyzed and compared the correlation functions obtained while changing the intensity of the light source in a range of 1~50 ${\mu}W$. The result shows that the radius of the focal area increases linearly through the increase of particle number and diffusion time in response to an intensity change in weak light below 10 ${\mu}W$. In the higher intensity region (>10~15 ${\mu}W$), the increasing rate of particle number and diffusion time keep increasing but at a much slower rate. Through this result, it was also found that the radius increasing rate of the focal area was reduced however, the radius still increased slightly.

#### Acknowledgement

Supported by : 한국연구재단

#### References

1. P. Kask, P. Piksarv, M. Pooga, T. Mets, and E. Lippmaa, "Separation of the rotational contribution in fluorescence correlation experiments," Biophys. J. 55, 213-220 (1989). https://doi.org/10.1016/S0006-3495(89)82796-1
2. J. A. Hodgdon and F. H. Stillinger, "Stokes-Einstein iolation in glass-forming liquids," Phys, Rev. E 48, 207-213 (1993). https://doi.org/10.1103/PhysRevE.48.207
3. D. R. Lide, CRC Handbook of Chemistry and Physics (CRC Press, 1994), Chapter 6, p. 205.
4. K. Jacobson, E. D. Sheets, and R. Simson, "Revisiting the fluid mosaic model of membranes," Science 268, 1441-1442(1995). https://doi.org/10.1126/science.7770769
5. J. B. Pawley, Hand book of Biological Confocal Microscopy, 3rd ed. (Springer, New York, USA, 2006), p. 506.
6. K. Wang, X. Qiu, C. Dong, and J. Ren, "Single-molecule technology for rapid detection of DNA hybridization based on resonance light scattering of gold nanoparticles," Chem BioChem 8, 1126-1129 (2007).
7. J. Enderlein, I. Gregor, D. Patra, T. Dertinger, and U. B. Kaupp, "Performance of fluorescence correlation spectroscopy for measuring diffusion and concentration," ChemPhysChem 6, 2324-2336 (2005). https://doi.org/10.1002/cphc.200500414
8. J. Mertz, Introduction to Optical Microscopy (Robertand Company Publishers, Colorado, 2010), p. 269.
9. A. Cooper, Biophysical Chemistry (RSC, Cambridge, UK, 2005), Chapter 4.
10. S. H. Kim, T. Shin, and D. Kim, "Particles size measurement of silole nano-clusters by fluorescence correlation spectroscopy," J. Korean Phys. Soc. 56, 1264-1268 (2010). https://doi.org/10.3938/jkps.56.1264
11. P. Schwille, U. Haupts, S. Maiti, and W. W. Webb, "Molecular dynamics in living cells observed by fluorescence correlation spectroscopy with one- and two-photon excitation," Biophys. J. 77, 2251-2265 (1999). https://doi.org/10.1016/S0006-3495(99)77065-7
12. M. Ehrenberg and R. Rigler, "Rotational brownian motion and fluorescence intensify fluctuations," Chem. Phys. 4, 394(1974)
13. D. Magde, E. Elson, and W. W. Webb, "Thermodynamic fluctuation in a reacting system-measurement by fluorescence correlation spectroscopy," Phys. Rev. Lett. 29, 705-708 (1972). https://doi.org/10.1103/PhysRevLett.29.705
14. E. L. Elson and D. Magde, "Fluorescence correlation spectroscopy. I. conceptual basis and theory," Biopolymers 13, 1-27 (1974). https://doi.org/10.1002/bip.1974.360130102
15. J. R. Lakowicz, Principles of Fluorescence Spectroscopy, 3rd ed. (Springer Science+Business Media, New York, USA, 2006), p. 797.
16. O. Krichevsky and G. Bonnet, "Fluorescence correlation spectroscopy: the technique and its applications," Rep. Prog. Phys. 65, 251-297 (2002). https://doi.org/10.1088/0034-4885/65/2/203