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POINT-OF-CARE
INFECTIOUS DISEASE TEST
BASED ON CMOS TECHNOLOGY
Bernhard E. [email protected]
Berkeley Sensor & Actuator CenterDept. of Electrical Engineering and Computer SciencesUniversity of California, Berkeley
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INFECTIOUS DISEASE - MORTALITY
Source: WHO/wikipedia
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HIV PROBLEM
Worldwide 33 million people are infected1 in 4 people who have HIV in the US are unaware and are responsible for up to 75% of new infectionsThe CDC recommends routine testing of everyone between the ages of 13 and 64
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DIAGNOSING HIV
1st Appt Venu-puncture
Manage Sample
ELISA*
2nd Appt Counseling
1st Appt Rapid Test Counseling
Current Procedure :
Procedure using Rapid Tests:
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INFECTIOUS DISEASE TESTING:CURRENT SOLUTION
Beckman Coulter UniCel DxC 880i400 immunoassay tests per hour
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DEVELOPING WORLD
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STRIP TESTS
Simple, low cost, rapidLow sensitivity
Control Line
Test Line
Sample
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STRIP TEST READOUT
An example of a weakly positive results that is difficult to read
Control Line
Test Line
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BASIS FOR INFECTIOUS DISEASE TESTS:ANTIGEN – ANTIBODY INTERACTIONS
Antibody-Antigen Complex
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ANTIBODY-ANTIGEN TESTSELISA (ENZYME-LINKED IMMUNOSORBENT ASSAY)
Antibody specific to target analyte (e.g. HIV virus)
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ADD ANALYTE(E.G. BLOOD SERUM)
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INCUBATE
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WASH
Captured target No target
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ADD SECONDARY ANTIBODY
Molecular label
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INCUBATE
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WASH
Label bound to analyte No labels present
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ADD SUBSTRATE
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QUANTIFY COLOR CHANGE
Substrate activated by label
Color change
No color change
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MICROFLUIDICS/LAB-ON-CHIP
Reproduce laboratory protocols on a disposable cartridgeIntegration of valves, pumps, filters and mixersRequires external support to evaluate assay results
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MAGNETIC “ELISA”
1
Hall Sensor
Antibodies coatedon surface of
Hall sensor Array
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Hall Sensor
Non-specificantigen
Targetantigen
1. Retain antibody-antigen chemistry2. Optical magnetic label3. Hydrodynamic electromagnetic separation4. Electronic detection
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Magnetic
Label
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Magnetic
Separation
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Magnetic
Detection
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IMMUNOSENSOR
Blood from finger stick is placed on filterCartridge is agitated and slotted into reader10-20 minutes later, digital, quantitative results are displayedOffers ELISA sensitivity
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TECHNOLOGY
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OPERATION
Sensor Sensor
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Biotinylated monoclonal antibody
Streptavidin coated 4.5μm magnetic bead
Antigen (Human IgG)
GoldSiO2
Passively adsorbedmonoclonal antibody
MAGNETIC BEADS AS IMMUNO-LABELS
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MAGNETIC BEADS AS IMMUNO-LABELS
ImmunoSensorFlorescu et al., “On-chip magnetic washing of super-paramagnetic beads for integrated assay applications”, Journal of Applied Physics, In Press (2009)
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y (m)
x (m)
Bbead,z (T)Magnetic Bead
Sensor Plane
BBead
BApplied
BBead,z
zr
INTEGRATED MAGNETIC BEAD DETECTION
( ) ( )5
34 r
o beadbeadbead
mrrrmrB
⋅−⋅⋅=
πμ
zBV appliedbb /zmbead χ=
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Top View
W=4um
L=6um
Contacts inton-well
Bbead,z
n-well
INTEGRATED MAGNETIC BEAD DETECTION
zbeadHallHH BLWGV ,μ=
zbeade BqvF ,×=
A B dlqFV
B
A
eH ∫=
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INTEGRATED MAGNETIC BEAD DETECTION
Icoil = 10mA
Bapplied= 800uT
Bbead,z= 10uT
SHall= 1.7%/T
HALL SENSOR
COIL
MAGNETICBEAD
CHIP SURFACE
2.8 μm
1.75 μm
1.8 μm
a)
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POST CMOS PROCESSING: EXPOSE SENSORS
Hall Sensor
Micro-coil (Metal 1)
Metal 2
Current Line
Top Metal
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POST CMOS PROCESSING: PROTECT PADS
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POST CMOS PROCESSING: ETCH
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POST CMOS PROCESSING: REMOVE METAL
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POST CMOS PROCESSING: GOLD COATING
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Low NoisePreampG ≈ 7
2 AC Coupled Amplifiers G = 150
12-Bit ADC and DSP
INTEGRATED MAGNETIC BEAD DETECTION
Matching < 5%, before auto-zeroing
Matching < 0.05%, after auto-zeroing
Bn= 300nT/√Hz
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INTEGRATED MAGNETIC BEAD DETECTION
10010 (kHz)
0.1
1
10
(uT)
0.1
1
10(uT)
A single 2.8um magnetic bead was detected with 35dB of SNR for a 1Hz noise bandwidth
No Bead
Bead
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Florescu et al., “Fully integrated detection of single magnetic beads in complementary metal-oxide-semiconductor”, Journal of Applied Physics, Volume 103, Issue 4, pp. 046101-046101-3 (2008)
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Hall Sensor
IntegratedCoils
8umBackend Amplifier
INTEGRATED MAGNETIC BEAD DETECTION
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INTEGRATED MAGNETIC BEAD CONCENTRATION
( ) washwash BB ∇⋅=o
beadbeadmag
VF
μχ
3
2
3 bead
washbeadbeadomag x
IrF
πχμ ⋅⋅⋅
=
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INTEGRATED MAGNETIC BEAD CONCENTRATION
t = 30s t = 60s t = 90s t = 120s t = 150st = 0s
Iconcentrate = 2mA
Fmag = 0.2pN from 4um away
60% of beads land in center of trench
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INTEGRATED MAGNETIC BEAD WASHING
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INTEGRATED MAGNETIC BEAD WASHING
Lrbead
Fmag
Au
SiO2
Ftether
Lr
FF beadmagtether 2
=
L = 20nm
rbead = 2.5μm
Amplification = 8
Ftether = 9pN from 18μm away
Iwash = 50mA
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Cth,fluid= 0.17 J/K
Rth1,SiO2= 385 K/W
Rth2,SiO2= 769 K/W
Rth,Si= 0.1 K/W
Pin= 25mW
INTEGRATED MAGNETIC BEAD WASHING
T=Pin(Rth2,SiO2+Rth,Si)
=(Rth2,SiO2 + Rth2,SiO2+Rth,Si)Cth,fluid
( )τ/1 teTT −−=Δ
τ
∆T = 2.7oC after 30 seconds of washing
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0ng/mlBW AW
1ng/mlBW AW
10ng/mlBW AW
INTEGRATED MAGNETIC BEAD WASHING
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INTEGRATED MAGNETIC BEAD WASHING
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Florescu et al., “On-chip magnetic washing of super-paramagnetic beads for integrated assay applications”, Journal of Applied Physics, In Press (2009)
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0123456789
Sample 1 Sample 2 Sample 3
Num
ber
of B
eads
Clinical Sample
Dengue Assay Results
On-chip Assay
ELISA
0.5
1
1.5
2
0.5
1
1.5
2
Opt
ical
Den
sity
INTEGRATED MAGNETIC BEAD WASHING
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INTEGRATED ASSAY PLATFORM
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INTEGRATED ASSAY PLATFORM
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MEMBRANE FILTRATION
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35μm
2.5μm
.25mm
• Hydrophilic polymeric membrane – Combination of
PVP/PES– No hemolysis– No non-specific
protein binding• Graduated pore size
– 35μm – 2.5μm– ~250μm thick
MEMBRANE FILTRATION
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Filtration vs. Centrifugation
0
0.5
1
1.5
2
2.5
3
3.5
1/1000 1/4000 1/16000 1/64000
Dilution
ELIS
A O
.D.
ELISA fromcentrifuged wholeblood
ELISA from wholeblood filtrate
FILTRATION VS. CENTRIFUGATION
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0.00
0.50
1.00
1.50
2.00
2.50
3.00
Dengue Positive Serum Dengue Spiked Whole Blood
ELIS
A O
.D.
Filtration Admittance of Dengue Antigen
FILTRATION VS. CENTRIFUGATION
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BEAD ASSAYS ON WHOLE BLOOD FILTRATE
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BEAD ASSAYS ON WHOLE BLOOD FILTRATE
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LIFE SCIENCE PROBLEMS
POC Diagnostics
Developing World Dx
Low Cost Assay Kits
Wireless IntegrationEpidemic Monitoring
POC PCR Multiplexed Assays
Proteomics/GenomicsMars Trip Dx
ImmunoSensor Commercialization plan provided by Silicon BioDevices, Inc.
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ACKNOWLEDGEMENTS
Collaborators:Octavian FlorescuDr. Turgut AyturDr. Mekhail AnwarTomohiro IshikawaJonathan FoleyKevan WangPaul DierMoritz MattmanProf. Robert BeattyProf. Eva HarrisSilicon BioDevices, Inc.
Funding from:Berkeley Sensor & Actuator CenterAcumen foundationTrans-NIH Genes, Environment and Health Initiative grant U54 ES016115-01Pacific Southwest RCE NIH award AI065359
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