Title: Disposable molecular diagnostics: Microfluidic laboratories for the field
1Disposable 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
2Microfluidics 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
3Global 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
4State 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.
5MicroTAS 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
6System Schematic
Detection Surfaces/Channels Antibodies Oligos PC
R
7Device 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
8Materials 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
9Engineering 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
10Advantages 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.
11Rapid 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
12Scale-up Fabrication
13Light-directed Processing in Formed Channels
14In Situ Filter and Column Formation
15Nucleic Acid Extraction
16Moving Fluid
- Pressure
- Vacuum
- Electroosmotic Flow
- Surface Chemistry of Channels
- Simultaneous Assay and Device Development
17Immobilized Surface Chemistries for Detection
18Jessica 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.