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Proceedings Paper

A new approach for detection and analysis of urinary proteins: dynamic light scattering
Author(s): Shaoxin Li; Da Xing; Shichi Tan
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Paper Abstract

Using a modified dynamic light scattering (DLS) apparatus we had measured and analyzed the Human Serum Albumin (HSA), a main composition of human urinary proteins when people suffer from nephropathy. The HSA radius had been examined by measuring diffusion coefficient of HSA for different concentrations and pH values. The designed and established experimental setup for DLS consists of a high-stability Ti:Sapphire ring laser, a single photon counting module with a high-sensitive avalanche tube and a gradient-index lens coupled single-mode fiber at 90° geometry for collecting scattering photons. The results of diffusion coefficient of HSA at different concentrations and pH values indicated that, the first, Coulomb interaction between the charged proteins acted as a main contribution to the diffusion coefficient; the second, at the isoelectric point (pH 5.2) the Coulomb effect vanished and the diffusion coefficient of protein reached its minimum. At the isoelectric point the diffusion coefficient linearly decreased with the escalation of the protein concentration. The main reason was that, the Coulomb interactions among the proteins become decrease; and the attractive potential increased relatively. Within the concentration range of 5 mg/ml-40mg/ml, and at wavelength of 532 nm, it was found mutual diffusion coefficient Dm = D0[1-(0.00194 ± 0.00008)C], where D0 = (6.74 ± 0.01)x10-7 cm2/s extrapolated to zero concentration at 23°C and C is in units of mg/ml. The measured radius of HSA is 3.44 ± 0.01 nm. Furthermore, with a multi-particle analysis cord, we can examine the dimension and content of different species proteins in urinary solution. This technique may potentially provide a new means for early diagnosis of nephropathy.

Paper Details

Date Published: 29 July 2004
PDF: 6 pages
Proc. SPIE 5486, ALT'03 International Conference on Advanced Laser Technologies: Biomedical Optics, (29 July 2004); doi: 10.1117/12.572445
Show Author Affiliations
Shaoxin Li, South China Normal Univ. (China)
Da Xing, South China Normal Univ. (China)
Shichi Tan, South China Normal Univ. (China)

Published in SPIE Proceedings Vol. 5486:
ALT'03 International Conference on Advanced Laser Technologies: Biomedical Optics
Ruikang K. Wang; Jeremy C. Hebden; Alexander V. Priezzhev; Valery V. Tuchin, Editor(s)

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