Affiliations: [a] Bioengineering Center, Chongqing University, Chongqing, Sichuan 630044, P.R. China | [b] Department of Biological and Chemical Engineering, Faculty of Technology, Gunma University, Kiryu City, Gunma 376, Japan
Correspondence:
[*]
Address correspondence to: Dr. Mian Long, Bioengineering Center, Chongqing University, Chongqing, Sichuan 630044, P. R. China, Fax: +86-811-966656.
Abstract: We measured the volume fraction dependence of erythrocyte sedimentation for human red cells in autologous plasma while the volume fraction, Hct, ranges from 0.220 to 0.650. A modified electrophoretic instrument was employed to investigate the electric effect of an upward DC field on erythrocyte sedimentation at a constant source supply of Vs=60.0±0.5V. The sedimentation curves all coincided well with the sigmoidal type equation,
l=lmax/{1+(t50/t)n},
at VS=0, or 60.0 V. Here, lmax is the length of plasma level, l, when the time, t, tends to infinity; t50 is the elapsed time when the plasma level falls to lmax/2, and n is a constant (n > 0). A non-linear least-squares method was employed to fit experimental data. It was found that lmax decreased and t50 increased with the increase of Hct while n ranged from 1.53 to 3.95. The volume fraction dependence of sedimentation velocity, vmax, defined as the maximum slope of the sedimentation curve, fits well with an exponential-type curve, both at VS=60.0V and at VS=0V:
vmax=vS(1−Hct)exp(−BHct),
where vs is the velocity at infinite dilution and B is a phenomenological parameter. In the range of Hct=0.220–0.650, vS and B are 326.1 mm/hr and 4.30, respectively, at VS=60.0V, while they are 130.4 mm/hr and 2.46, respectively, at VS=0V.
Keywords: Erythrocyte sedimentation rate, volume fraction dependence, human red cell, plasma, DC electric field
DOI: 10.3233/BIR-1994-31306
Journal: Biorheology, vol. 31, no. 3, pp. 287-295, 1994
