WHOLE BLOOD PLASMAPHERESIS USING ACOUSTIC SEPARATION CHIPS

1
WHOLE BLOOD PLASMAPHERESIS USING ACOUSTIC
SEPARATION CHIPS

• AuthorAndreas Nilsson, Filip Petersson and
  Thomas Laurell
• Dept. of Electrical Measurements, Lund
  University, P.O. Box 118, S-221 00 Lund, SWEDEN
• Reporter Wun-Hao Wu (???)
• 12/26, 2007

2

• Outline
• Introduce
• Theory
• Fabrication
• Result
• References

3
Introduce
The need for pure blood plasma is of interest in
diagnostic applications and in blood banking e.g.
plasmapheresis. Blood plasma is usually generated
by centrifugation or filtration. Plasmapheresis
as realized by centrifugation in blood bank
processes has hitherto not been addressed by µTAS
solutions as throughput is a major issue. This
paper describes a method of extracting pure blood
plasma from whole blood based on previously
reported ultrasonic standing wave separation
technique , offering a potential of up-scaling
throughput to clinically relevant levels.
Figure A single plasmapheresis chip actuated by
a piezoceramic from the backside.
4
Theory
An acoustic standing wave is commonly described
according to eqn. (1).
(1)
If the acoustic field is in the form of a
standing wave, eqn. (1) can be rewritten in terms
of pressure eqn. (2).
(2)
p p0 sin(kx) cos(wt)
According to the acoustic force theory presented
by Yosioka and Kawasima the force on a particle
can be expressed in the following way eqn.(3).
(3)
(4)
Vc is the volume of the particle, p0 is the
pressure amplitude from eqn. (2) and f is
defined by eqn. (4). The density of the medium
and particles are denoted ?w and ?c respectively
and the corresponding compressibilities ßw and
ßc.
5
Theory
F lt 0 ex. lipid particles F ? -0.3
F gt0 ex. Erythrocytes F ? 0.3
6
Fabrication
1.
3.
2.
4.
Glass
bonding
Si
???
7
Result
Fig. a. Cross-type structure with a two band
formation. b. 45-structure with a two
band formation.
Fig. Particle enrichment in the micro channel.
The bands show the enriched particles in
resonance mode, 1st, 2nd and 3rd harmonic with 2,
3 and 4 bands respectively, A) top view
microscope photographs and B) principal separation
channel cross-sections. Channel width 750 µm,
channel depth250 µm.
Received 24th October 2003, Accepted 11th
December 2003 First published as an Advance
Article on the web 9th February 2004
8
Result
Fig. 8 (a) Milk flowing through the 350µm
separation chip with ultrasound turned off. (b)
Milk flowing through the 350 µm separation chip
with ultrasound turned on. (c) A mixture of milk
and blood flowing through the 350 µm separation
chip with ultrasound turned on.
Fig. 11 Lipid particles separated from
erythrocytes at the trifurcation of 350 µm
separation chip with ultrasound turned on.
Received 16th April 2004, Accepted 21st June
2004 First published as an Advance Article on the
web 18th August 2004
9
Result
Figure . Sequential plasma extraction from whole
blood. The plasma fraction from the first step is
the input to the second step and so on.
Figure . The eight channel separator. The
top view to the right shows a channel segment
with ultrasound turned off. The lower right
view shows the acoustically controlled
plasma extraction. White lines have been added
to outline the separator channels.
10
Result
Figure . The diagram shows the removal efficiency
of erythrocytes vs hematocrit (HCT) level. The
HCT after each extraction step is followed by the
step function. The process starts with whole
blood of 40 and end up with a plasma fraction
containing less than 1 erythrocytes.
11
References

• Nilsson, A., et al., Acoustic control of
  suspended particles in micro fluidic chips.
• Lab on a Chip, 2004. 4(2) p. 131-135.
• 2. Petersson, F., et al., Separation of lipids
  from blood utilizing ultrasonic standing
• waves in microfluidic channels. Analyst,
  2004. 129(10) p. 938-943.
• 3. Jonsson, H., et al., Particle Separation Using
  Ultrasound Can Radically Reduce
• Embolic Load to Brain After Cardiac Surgery.
  The Annals of Thoracic Surgery, 2004.78(5) p.
  1572-1577
• 4. K. Yosioka and Y. Kawasima, Acoustic radiation
  pressure on a
• compressible sphere, Acustica, 1955, 5,
  167173.