Microfluidics and Biosensors for Point-of- Care Diagnostics Xuanhong Cheng Materials Science and Engineering Bioengineering Lehigh University November 24, 2014
Microfluidics for Basic Medicine Water Supply Micronit.com
Advantage of Microfluidic Systems Small sample volume Small reagent volume Low production cost Portable, potential for integration and automation High surface to volume ratio Laminar flow, predictable transport property
POC Diagnostics
Micro-scale Fabrication Master
HIV Diagnostics 1000 WHO Stage 2 and 3: Symptomatic HIV infection CD4 200-500 Mild infections Weight loss, fatigue TB, Thrush CD4 Count 350 200 WHO Stage 1: Asymptomatic HIV infection CD4 >500 WHO Stage 4 AIDS CD4 < 200 TB, infections Death ~18 months 2 Time (years) 4 6
Impact of Treatment Begin ART CD4 Viral load (HIV RNA level) Weeks time Years
Clinical Indicators Basic Water Supply 10 Viral load 7 HIV RNA level 10 8 10 6 10 5 10 (copies/ 4 ml plasma) 10 3 10 2 10 1 900 800 700 CD4 cell count 600 (cells/µl blood) 500 400 300 200 100 10 0 Weeks 1 2 3 4 5 6 7 8 0 Years
State of the Art Technologies Basic Water Supply BD FACSCalibur CD4-count start treatment < 200 cells/ul Viral load count measure resistance to treatment RT PCR
Lab Diagnostics Basic in Resource Water Supply Poor Settings
What is Needed Low cost Easy to use Rapid and Robust Portable Sensitive and specific
Microchip Technology Basic Water for Medicine Supply
Portable CD4 Counter Cl - Cl - K + Cl - Cl - K + Na + K +
Microfluidic Cell Counting Chip CD4 counting microchip Daktari Diagnostics Inc. Cheng, X. et. al, Lab on a Chip, 2007
Nanoporous Membrane for Viral Processing and Sensing Controllable pore size High porosity Bio-functionality Tight pore size distribution Thin membranes
Embedded Nanoporous Membranes for Virus Capture PDMS membrane
Embedded Nanoporous Membranes for Virus Staining
Optically Forced Cytometry for Nanoparticle Counting
Detection of Bacteria Viability Cell Staining Flow Cytometer Molecular Markers Significant in clinical diagnosis, biohazard surveillance, food safety monitoring, etc. Contemporary approaches require laboratory access Electrical test can be fast, compact, sensitive and label free
Broadband Electrical Sensing Dielectric Constant Cellular Proper:es Subcellular Proper:es Molecular Proper:es Conduc:vity (ms/cm) Frequency (Hz) HP Schwan (1985): Hypothesis based on :ssue measurement
Broad Band Electrical Sensing 22
Experimental Setup RF In Cells In Micro- Chamber Syringe Pump Inverted Microscope Signal Generator High- Speed Oscilloscope Network Analyzer
RF In Cells In Input Reflec2on RF Connector Cells in μ- Chamber RF Connector Transmission
Modeling to Extract Cell Information Sample Volume = 20 cubes of 10μm 10 μm 10 μm
Cell Immobilized by Dielectrophoresis
Differentiating Live vs Dead HEK Cells 2 S 11 Disp. (10 10 db/hz) 1.5 1 0.5 0 S 11 Live S 11 Dead 0 5 10 15 20 No. of Cells Trapped
Differentiating Dead HEK and Jurkat Cells 1 HEK Jurkat S 11 Disp. (10 10 db/hz) 0.75 0.5 0.25 0 S 11 Dead HEK S 11 Dead Jurkat 0 5 10 15 20 No. of Cells Trapped
Differentiating Live and Dead E. coli Number of bacteria average delta S 11 (db) 0-0.1-0.2-0.3-0.4-0.5-0.6-0.7 0 500 1000 1500 2000 Live Dead
Biofilm Monitoring on a Chip Culture Absorbance 1.6 1.4 CM1 19 h 1.2 LB 19h 1 0.8 0.6 0.4 0.2 0 0.01 1 100 Log scale Conduc:vity (ms) Next Steps Monitor biofilm growth on chip Screen anti-biofilm reagents
Acknowledgments Collaborators Fil Bartoli Arthur Chiou (Yangming U, Taiwan) Tim Friel (LVHN) MarJn Hirsch (MGH) Jim Hwang Jim Gilchrist Sabrina Jedlicka Yaling Liu Alp Oztakin Daniel Ouyang William Rodriguez (MGH) Olga LaJnovic (IHV) Peikuen Wei (Academia Sinica, Taiwan) Frank Zhang Students Caroline Multari Krissada Surawathanawises Bu Wang Chao Zhao
Nanoporous Membrane for Viral Processing and Sensing Controllable pore size High porosity Bio-functionality Tight pore size distribution Thin membranes
Embedded Nanoporous Membranes for Viral Processing 120 Percentage of Virions (%) 100 80 60 40 20 200nm Pores 20nm Pores Filtrate Absorbed on membrane Suspended above membrane 0 Viral Concentration (/ml) 8e+7 6e+7 4e+7 2e+7 0 Original Sample 1mL filtration + 10µL Wash % of Virions Captured on Membranes 70 60 50 40 30 20 10 0 Bare PEG AntiCD44
Community-based Care Care takes place in the community. Reinforced in the clinic.