ABS Global, Inc. and Genus plc - Ex. 1012, cover 1
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`ABS Global, Inc. and Genus plc - Ex. 1012, cover 2
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`ABS Global, Inc. and Genus plc - Ex. 1012, cover 3
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`ABS Global, Inc. and Genus plc - Ex. 1012, cover 4
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`PARTICLE-SHAPE SENSING-ELEMENTS FOR
`
`INTEGRATED FLOW CYTOMETER
`
`J.H. Nieuwenhuis1, S.S. Lee1, J. Bastemeijer1, M.J. Vellekoop2
`1Electronic Instrumentation Laboratory — DIMES, Delft University of Technology,
`Mekelweg 4, 2628 CD Delft, The Netherlands
`2Vienna University of Technology, Faculty EE&lT, Institute lEMW
`J.H.Nieuwenhuis@|TS.TUDelft.nl
`
`Abstract
`
`Two particle-shape sensing-elements are presented that directly measure absolute shape.
`Measurement results show that without lenses shape is accurately registered when the object is
`close to the sensor. Finite element simulations show that this condition can be created with a
`double sheath flow.
`
`Keywords: particle/cell shape, integrated cytometer
`1. Introduction
`
`
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`Two different particle-shape sensing—elements have been
`developed for application in an integrated flow cytometer.
`These elements are to be placed on the bottom of a
`transparent micro flow-channel
`that
`is illuminated from
`above (see Fig. 1). When a particle passes over these
`elements it will partially block the light. One line of this
`shadow is
`registered by the sensing—element and by
`repeatedly reading out
`the sensor a two-dimensional
`projection ofthe particle is obtained.
`In a number of applications, particle or cell shape is an
`important parameter. Sample enrichment is one of these
`applications; here rare cells are separated from a larger
`population for further analysis. In contrast to the current
`light scattering analysis systems,
`the proposed system
`yields absolute shape information, which allows for far
`more accurate determination.
`
`2. The Elements
`
`Fig 1. The “Wing element 0” the
`bottom of a transparentflow channel
`that is illuminatedfrom above
`
`The first sensing-element consists of a miniature double one—dimensional array of photodiodes
`(see Fig. 2). There is a small offset between the upper and the lower part of the array such that by
`combining the data of the two parts a virtual one-dimensional array is formed with a pitch of only
`2.5 micron.
`
`The second sensing-element consists of an elongated photodiode-structure (see Fig. 4). When a
`particle passes over this strip photodiode the drop in photocurrent will be proportional to the width
`ofthe particle. To be able to uniquely reconstruct the particle shape a cut is placed in the middle as
`a reference.
`
`3. Comparison
`
`To compare the performance of the two elements images were obtained by manually moving a
`gold bonding wire (diameter 27 mm) with a small bump (diameter 67 mm) over the two elements.
`357
`
`J.M. Ramsey and A. van den Berg (eds), Micro Total Analysis Systems 2001, 357—358.
`© 2001 Kluwer Academic Publishers. Printed in the Netherlands.
`
`ABS Global, Inc. and Genus plc - Ex. 1012, p. 357
`ABS Global, Inc. and Genus plc - EX. 1012, p. 357
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`The results are depicted in Fig. 2 and Fig. 4, along with a photo ofthe bonding wire (Fig. 3). Both
`sensing-elements deliver an adequate image of the object but there are some differences. The main
`advantage
`of
`the
`array
`1
`sensing-element is that it can
`be used for
`all kinds of
`
`_F'-.
`
`semi-
`including
`particles,
`transparent and non-uniform
`transparent ones. However, it
`generates a lot of data that
`needs
`to be processed in
`real-time. The strip sensing-
`element has the advantage
`that
`it only requires
`two
`readouts
`for
`every image
`line. A disadvantage is that
`without
`any
`a
`priori
`knowledge of the particles it
`is only suitable for non-
`transparent
`particles.
`A
`calibration measurement can
`.
`.
`allevtate.
`this
`drawback
`substantially.
`
`
`
`
`
`L'—
`
`array
`The
`2,
`Fig.
`sensing element (top)
`and the image made
`with
`this
`element
`(bottom)
`
`Fig.3, Aphoto of
`the bonding wire
`
`strip
`The
`4,
`Fig.
`sensing element (top)
`and the image made
`with
`this
`element
`(bottom)
`
`iiiztatlhx
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`Sample inlet
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`
`
`4. Feasibility
`
`The small projection distance is critical for the functioning of the device to avoid serious
`diffraction distortion of the image. This
`
`is realized by the application of a sheath
`flow [1], a proven technique in flow
`cytometry. A flow channel
`can be
`formed with
`a
`simple
`two-wafer
`structure.
`The
`finite
`element
`simulations in Fig.
`5 show that
`the
`position of
`the
`sample
`inside
`the
`channel can be controlled over
`the
`
`
`
`_n
`
`
`5mg"
`OUUE‘
`requirement of the small projection
`Fig, 5, Finite element simulations showing that the height
`distance can be fulfilled.
`ofthe sample can be controlled
`5. Conclusions
`In this paper two particle—shape sensing-elements are presented for application in an integrated
`flow-cytometer. Measurements show that both elements work well and the choice for either one
`depends on the application. This approach is unique in the fact that absolute particle shape
`information is obtained without any lenses or other optical equipment. To avoid optical diffraction
`the object should pass close to the sensing-element. Finite element simulations show that this
`condition can be created in a flow channel with a double sheath flow that can be realized with a
`two-wafer structure.
`
`complete height ofthe channel, so the
`
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`References
`
`1. Z. Darzynkiewicz, H.A. Crissman, J.P. Robinson, Methods in Cell Biology, Volume 63
`Cytometry, 2001, pp. 26-33
`
`358
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`ABS Global, Inc. and Genus plc - Ex. 1012, p. 358
`ABS Global, Inc. and Genus plc - EX. 1012, p. 358
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