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. Nieuwenhuis", S.S. Lee’, J. Bastemeijer", M.J. Vellekoop”
`‘Electronic Instrumentation Laboratory — DIMES,Delft University of Technology,
`Mekelweg 4, 2628 CD Delft, The Netherlands
`"Vienna University of Technology, Faculty EE&IT, Institute IEMW
`J.H.Nieuwenhuis@ITS.TUDelft.n!
`
`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
`
`
`
`+ ace
`Particle
`Shadow<a pe
`Sensor| oo
`i
`
`—
`Silicon
`
`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 ofthis
`shadow is
`registered by the sensing-element and by
`repeatedly reading out
`the sensor a two-dimensional
`projection of the particle is obtained.
`In a numberofapplications, 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
`
`Chann
`
`3
`
`/, The sensing element on the
`‘ig.
`bottom of a transparentflow channel
`that is illuminaiedfrom 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 lowerpart 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 overthis strip photodiode the drop in photocurrentwill be proportional to the width
`of the 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
`
`JM. 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 Genusple - Ex. 1012, p. 357
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`The results are depicted in Fig. 2 and Fig. 4, along with a photoof the 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
`J
`sensing-elementis that it can
`be used for
`all kinds of
`particles,
`including
`semi-
`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 a__prioriany
`
`knowledge of the particles it
`is only suitable for non-
`transparent
`particles.
`A
`calibration measurement can
`.
`.
`alleviate
`this
`drawback
`substantially.
`
`array
`The
`2,
`Fig.
`sensing element (top)
`and the image made
`with
`this
`element
`(bottom)
`
`Fig.3,Aphotoof
`the bonding wire
`
`strip
`The
`4,
`Fig.
`sensing element (top)
`and the image made
`with
`this
`element
`(bottom)
`
`—:
`
`a
`
`
`
`
`Hydrodynamic
`
`4, Feasibility
`
`The small projection distance is critical for the functioning of the device to avoid serious
`diffraction distortion of the image. This
`
`Sample inlet
`is realized by the application of a sheath|jpjer ; ae
`Sheathinlet 2
`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
`
`Re
`
`:“
`
`liquid
`cross- AMso
`
`complete height ofthe channel, so the
`
`
`Sheath
`liquid
`i
`
`Sample
`:
`
`set ot
`
`requirement of the small projection
`Fig. 5, Finite element simulations showing that the height
`distance can befulfilled.
`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.
`
`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 Genusple - Ex. 1012, p. 358
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