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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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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
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
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. Global Impact Nature Reviews Microbiology2, 231-240 (2004) DIAGNOSTICS FOR THE DEVELOPING WORLD
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.
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
System Schematic Detection Surfaces/Channels Antibodies Oligos PCR
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
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
Engineering Polymers for Microfluidic Diagnostic Devices PMMA ZEONEX and ZEONOR by ZEON Tg= 85-105C Zeonor 750R, Tg 70C Zeonex 690R Tg 136C Ring Opening Polymerization Polycarbonate Tg= 140-150C 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= 90-110C Addition Polymerization R1,R2,R3; H
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.
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
Completed fluidic card Glass or Si wafer • Photoresist coat • Mask, expose, develop photoresist • Etch glass • Remove photoresist Etched glass plate Electroplate Plastic cover layer Separate Cover and seal Metal electroform Mold or emboss Repeat 1000’s of times Molded plastic card Separate Scale-up Fabrication
Moving Fluid • Pressure • Vacuum • Electroosmotic Flow • Surface Chemistry of Channels • Simultaneous Assay and Device Development
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.