Disposable molecular diagnostics: Microfluidic laboratories for the field

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Disposable molecular diagnostics Microfluidic
laboratories for the field

• Catherine Klapperich, Ph.D.
• Biomedical Microdevices and Microenvironments
  Laboratory
• www.klapperichlab.org
• Biomedical and Manufacturing Engineering
  Departments
• Boston University
• 3 October 2006

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Microfluidics Applications

• Diagnostics/Management
• Point of Care
• Disease Surveillance
• Detection
• Homeland Security
• Fighting Force Protection
• High Throughput Screening
• Drug Discovery/Development
• Cell Based Assays
• Research Bench Applications
• Micro-Reactions
• Combinatorial Methods
• Living Tissue Arrays
• Drug Development

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Global Impact

• Case finding
• Case management
• Surveillance
• 24 of the current burden of disease could be
  averted if 80 of the population of low income
  countries received the following
  prenatal/delivery care, family planning,
  treatment of TB, management of sick children and
  case management of STDs.
• Implementation would cost 8/person per year.

Nature Reviews Microbiology 2, 231-240 (2004)
DIAGNOSTICS FOR THE DEVELOPING WORLD
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State of the Art

• Microscopy
• Parasitic and mycobacterial infections
• Requires well trained technician
• Cell Culture
• EIA
• Nucleic acid amplification
• All require specialized equipment and/or
  technicians.

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MicroTAS for Diagnostics

• Sample introduction
• Cell sorting/separation
• Mixing
• Lysis
• Separation/concentration
• Detection
• Waste stream capture

Sample Preparation
Fluidics
Detection
Input
Output
Control and Signal Processing
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System Schematic
Detection Surfaces/Channels Antibodies Oligos PC
R
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Device Design Constraints

• Inexpensive materials
• Rapid prototyping
• Scale up/mass production
• Shelf life of 1 year or more
• Ease of use
• On-board reagents
• Disposable
• Little sample preparation off chip
• Low power or no power

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Materials Requirements

• Optical properties
• UV transparent (for quantifying proteins, DNA and
  RNA)
• Transparent to excitation and detection
  wavelengths (488 nm, FITC)
• Thermal properties
• For PCR (95 degrees Celsius)
• For dimensional stability
• Surface chemistry
• Hydrophilic/hydrophobic
• Non-binding
• Binds specific molecules
• Shelf life issues

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Engineering Polymers for Microfluidic Diagnostic
Devices
PMMA
ZEONEX and ZEONOR by ZEON
Tg 85-105?C
Zeonor 750R, Tg 70?C Zeonex 690R Tg 136?C
Ring Opening Polymerization
Polycarbonate
Tg 140-150?C
ZEON Polymers are obtained by ring-opening
metathesis polymerization (ROMP) of norbornene
derivatives monomers followed by complete
hydrogenation of double bonds.
Polystyrene
TOPAS by TICONA and APEL by Mitsui
Tg 90-110?C
Addition Polymerization
R1,R2,R3 H
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Advantages of Thermoplastic Chips

• Feature size is identical to PDMS but with long
  term dimensional stability.
• Surface treatments are robust and do not age as
  on PDMS devices.
• Permeability is low.
• Thermoplastics can be purchased in grades that
  are certified non-pyrogenic (do not contain DNA
  or RNA destructive enzymes).
• The per device material cost is low.
• The plastic chips can be easily manufactured
  in-house using rapid prototyping techniques in
  production materials to test and optimize new
  chip layouts and chemistries quickly.
• Internal structures (filters, valves, detection
  patches) can be fabricated in situ by
  light-directed processes.
• Acrylics and cyclic polyolefins have low
  autofluorescence for high detection signal to
  noise ratios.
• Acrylics and cyclic polyolefins are transparent
  to UV, which enables light directed processing of
  internal structures and UV detection of nucleic
  acid concentrations and integrity through the
  chip.

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Rapid Prototyping

• A cyclic polyolefin (Zeonex 690R) was used as
  chip material
• Microchip fabricated by hot-embossing with a
  silicon master

Photoresist
Pressure and Heat Applied
Si Wafer
Polymer pellets
UV light
Mask
Embossed substrate
DRIE
Thermally bonded channels
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Scale-up Fabrication
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Light-directed Processing in Formed Channels
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In Situ Filter and Column Formation
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Nucleic Acid Extraction
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Moving Fluid

• Pressure
• Vacuum
• Electroosmotic Flow
• Surface Chemistry of Channels
• Simultaneous Assay and Device Development

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Immobilized Surface Chemistries for Detection
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Jessica Kaufman Arpita Bhattacharyya Justyn
Jaworski Nathan Spencer Dominika Kulinski Dave
Altman Amy VanHove Dr. Cassandra Noack Coulter
Foundation Whitaker Foundation CIMIT NSF MUE Pria
Diagnostics, Inc.