lyon, france june 12, 2007 | christophe yamahata electrical & mechanical characteristics of...
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Lyon, France June 12, 2007 | Christophe Yamahata
Electrical & Mechanical characteristics of
DNA bundles revealed by
Silicon Nanotweezers
C. Yamahata, T. Takekawa,
M. Kumemura, M. Hosogi, G. Hashiguchi,
D. Collard & Hiroyuki Fujita
The University of TokyoInstitute of Industrial Science
Kagawa UniversityFaculty of Engineering
Lyon, France June 12, 2007 | Christophe Yamahata
Electrical & Mechanical characteristics of DNA bundlesrevealed by Silicon Nanotweezers
Scope of the research
Working principle & Microfabrication of the Silicon Nanotweezers
DNA trapping by dielectrophoresis
Electrical & Mechanical characterization of DNA bundles
Conclusion & Outlook
Lyon, France June 12, 2007 | Christophe Yamahata
Scope
of the research
Lyon, France June 12, 2007 | Christophe Yamahata
Scope of the research
Biophysical tools used for molecular manipulation
• Optical tweezers • Magnetic tweezers • AFM probes
* D. Collard et al., IEEJ Trans 2: 262–271, 2007
Lyon, France June 12, 2007 | Christophe Yamahata
Scope of the research
Biophysical tools used for molecular manipulation
• Optical tweezers • Magnetic tweezers • AFM probes
* D. Collard et al., IEEJ Trans 2: 262–271, 2007
Lyon, France June 12, 2007 | Christophe Yamahata
Scope of the research
Biophysical tools used for molecular manipulation
• Optical tweezers • Magnetic tweezers • AFM probes
* D. Collard et al., IEEJ Trans 2: 262–271, 2007
Lyon, France June 12, 2007 | Christophe Yamahata
Scope of the research
Biophysical tools used for molecular manipulation
• Optical tweezers • Magnetic tweezers • AFM probes
and
• Silicon nanotweezers
* D. Collard et al., IEEJ Trans 2: 262–271, 2007
Lyon, France June 12, 2007 | Christophe Yamahata
Working principle
& Microfabrication
of the Silicon Nanotweezers
• Working principle• Microfabrication technology
Lyon, France June 12, 2007 | Christophe Yamahata
Working principle of the Silicon Nanotweezers
External dimensions:4.5 mm × 5.5 mm
SOI wafer The different elements are:
• Electrically insulated• Mechanically locked with each other
Lyon, France June 12, 2007 | Christophe Yamahata
Working principle of the Silicon Nanotweezers
Lyon, France June 12, 2007 | Christophe Yamahata
Working principle of the Silicon Nanotweezers
Differential capacitive sensor
Lyon, France June 12, 2007 | Christophe Yamahata
Working principle of the Silicon Nanotweezers
Differential capacitive sensor
MS3110 Universal Capacitive Readout™ (Irvine sensors, CA, USA)
Lyon, France June 12, 2007 | Christophe Yamahata
Working principle
& Microfabrication
of the Silicon Nanotweezers
• Working principle• Microfabrication technology
Lyon, France June 12, 2007 | Christophe Yamahata
(1) Si3N4 deposition (LPCVD) + patterning(2) Silicon etching (RIE)(3) SiO2 oxidation (LOCOS)(3) SiO2 oxidation (LOCOS) + Si3N4 removal(4) KOH anisotropic etching of Silicon <111> facets
Microfabrication technology
(5) HF removal of buried oxide
Si
Si3N4
SiO2
(6) Backside etching by deep-RIE (with Al mask)
SOI wafer
• (100)-Si layer: 25 µm
• Oxide layer: 2 µm
• Handling wafer: 380 µm
Lyon, France June 12, 2007 | Christophe Yamahata
Microfabrication technology
Si
Si3N4
SiO2
(1)
(2)
(3)
(4)
(5)
(6)
SOI wafer
• (100)-Si layer: 25 µm
• Oxide layer: 2 µm
• Handling wafer: 380 µm
Lyon, France June 12, 2007 | Christophe Yamahata
Microfabrication technology
Lyon, France June 12, 2007 | Christophe Yamahata
DNA trapping
by dielectrophoresis
Lyon, France June 12, 2007 | Christophe Yamahata
DNA trapping by dielectrophoresis (DEP)
Droplet:
• λ-DNA: 12 nmol/L• DI water: 5 µL
Dielectrophoresis (DEP):
30 sec @ 1 MHz, 40 Vpp (20 µm gap)
Lyon, France June 12, 2007 | Christophe Yamahata
λ-DNA bundle20 µm gapdiameter ~ 380 nm
DNA trapping by dielectrophoresis (DEP)
Lyon, France June 12, 2007 | Christophe Yamahata
Electrical & Mechanical
characterization
of DNA bundles
• Electrical characterization• Mechanical characterization
Lyon, France June 12, 2007 | Christophe Yamahata
Humidity generator
Ambient air Pump
Gas washing
bottle
Mixer
Temperature and humidity sensor
Glove box
Faraday cage
Keithley 6487 Picoammeter / Voltage Source
chassis
desiccant
saturator
Electrical characterization of DNA bundles
Experimental setup
Lyon, France June 12, 2007 | Christophe Yamahata
Electrical characterization of DNA bundles
~ 20 GΩ
~ 5 TΩ
Measurements for different DNA bundles diameters
Quasi-ohmic behavior
Measurements on “wet” DNA bundles
(various diameters)
T = 25 °C rh ~ 55% humidity
Lyon, France June 12, 2007 | Christophe Yamahata
Measurements on “wet” DNA bundles
(various diameters)
Conductivity bundle section
Electrical characterization of DNA bundles
Measurements for different DNA bundles diameters
Effect of DNA bundle diameter
Lyon, France June 12, 2007 | Christophe Yamahata
Electrical characterization of DNA bundles
Effect of humidity
Exponential dependence with relative humidity
Transient current recording for a 5V step.
Data recorded at 21 °C (1°C overall fluctuation) for different humidity levels (rh 0.2% for each curve)
Lyon, France June 12, 2007 | Christophe Yamahata
Electrical characterization of DNA bundles
Effect of humidity
Exponential dependence with relative humidity
Data extracted from previous measurements (5V step) after 60 sec. (rh was decreased from 75% to 45% in 6 hours)
Lyon, France June 12, 2007 | Christophe Yamahata
Electrical & Mechanical
characterization
of DNA bundles
• Electrical characterization• Mechanical characterization
Lyon, France June 12, 2007 | Christophe Yamahata
Mechanical characterization of DNA bundles
Displacement: ~ 3 µm Cmax 200 fF
Sensitivity: 2 V/pF 150 mV/µm
Error: ε <1 mV
5 nm resolution
Characterization of empty tweezersMeasurements performed with the MS3110 Universal Capacitive Readout™
Lyon, France June 12, 2007 | Christophe Yamahata
Sensitivity of the capacitive sensor enables the measurement of few nN forces
(single DNA ~ 80 pN)
Bundle stretching can be observed
Mechanical characterization of DNA bundles
Measurements after DNA bundle trappingMeasurements performed with the MS3110 Universal Capacitive Readout™
Lyon, France June 12, 2007 | Christophe Yamahata
Conclusion & Outlook
Lyon, France June 12, 2007 | Christophe Yamahata
Conclusion & Outlook
• Efficient trapping of DNA by dielectrophoresis
• Extensive electrical characterization of DNA bundles
• Displacement: 2-3 µm range / few nm resolution
• Force: few nN sensitivity
High potential for biophysical characterization of long macromolecules. e.g.: DNA bundle, microtubules, actin filament, etc.
A new type of biophysical tool has been proposed:
Lyon, France June 12, 2007 | Christophe Yamahata
Acknowledgments
Lyon, France June 12, 2007 | Christophe Yamahata
Swiss National Science Foundation (SNSF)
Japan Society for the Promotion of Science (JSPS)
Japan Science and Technology Corporation (JST)
Centre National de la Recherche Scientifique (CNRS)
Acknowledgments
Lyon, France June 12, 2007 | Christophe Yamahata
Thank you for your attention.Thank you for your attention.