1. Professor: Cheng-Hsien, Liu Student: Yi-Jou, Lin Date: 2009/11/03
Midterm Report
A HIGH SENSITIVITY CARBON NANOTUBES ENHANCED PZT DIAPHRAM-BASED IMMUNOSENSOR ARRAY
T. Xu1, J.M. Miao1*, Z.H. Wang1, Y.S. Liu2 and C.M. Li2
1Micromachines Centre, Nanyang Technological University, Singapore
2School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
Professor: Cheng-Hsien, Liu
Student: Yi-Jou, Lin
Date: 2009/11/03
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2. Introduction Piezoelectric Biosensors - Micro-machined catilever
- Quartz-Crystal Microbalance System (QCMS)
- Micro-diaphragm
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3. Micro-machined catilever
Introduction
Piezoelectric Biosensors
Transduce different phenomena, such as changes of mass, temperature, heat, or stress, into bending or a change in resonant frequency
High sensitivity
Label-free detection
Low quality merit factor
Fragility of the devices
Micro-machined catilever
Quartz-Crystal Microbalance System (QCMS)
Micro-diaphram
Fig 1. Scheme of the cantilever bending due to a biomolecular interaction between an immobilized receptor and its target. Only the specific recognition causes a change on the surface stress driving to the bending of the cantilever.
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4. Quartz-Crystal Microbalance System (QCMS)
Introduction
Piezoelectric Biosensor
based on quartz crystal resonators, and measured by a resonance frequency decrease, as a result of the superficial mass increase
Good frequency stability and reproducibility
Unable to full fill the requirements as the solid quartz crystal lacks of integration
Micro-machined
catilever
Quartz-Crystal Microbalance System (QCMS)
Micro-diaphram
Fig. 3. Scheme of DNA immobilization and hybridization on golden quartz.
Fig.2 Libra DNA-sensor and piezoelectric quartz.
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5. Introduction Piezoelectric Biosensors High sensitivity
High limit of detection
Micro-machined
catilever
Quartz-Crystal Microbalance System (QCMS)
Micro-diaphram
A HIGH SENSITIVITY CARBON NANOTUBES ENHANCED PZT DIAPHRAM-BASED IMMUNOSENSOR ARRAY
T. Xu1, J.M. Miao1*, Z.H. Wang1, Y.S. Liu2 and C.M. Li2
1Micromachines Centre, Nanyang Technological University, Singapore
2School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
generate stronger output signal
detect the minimum concentration of the analyte
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6. Introduction Piezoelectric Biosensors How to improve the sensitivity?
A HIGH SENSITIVITY CARBON NANOTUBES ENHANCED PZT DIAPHRAM-BASEDIMMUNOSENSOR ARRAY
T. Xu1, J.M. Miao1*, Z.H. Wang1, Y.S. Liu2 and C.M. Li2
1Micromachines Centre, Nanyang Technological University, Singapore
2School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
Introduction
Piezoelectric Biosensors
How to improve the sensitivity?
(1) Gold-nanoparticles (2) Carbon nanotubes (CNTs)
Micro-machined
catilever
Quartz-Crystal Microbalance System (QCMS)
Micro-diaphram
Provide a 3D platform
The high density and weight of the gold might deposit and cause peizoelectric diaphragm deformation
reliability problems during the immobilization process
Extremely high surface area, 400 m2/g theoretically
Enhance the electrochemical reactivity of some molecules
Useful for label-free electrochemical detection
Deposit on the electrodes with applied voltage
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7. Fabrication of piezoelectric diaphragm-based biosensor array
deposit
SOI wafer
Sputtered & patterned
PZT=
Pb(Zr0.52Ti0.48)O3
Deposit
TiO2/Pt
DRIE
Top electrode
bottom electrode
Si3N4
Patterned &etching
Ti/Pt
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8. Fabrication of piezoelectric diaphragm-based biosensor array
-goat IgG
Anti-goat IgG
Fig 5. Sketched immobilization processes for the CNT enhanced PZT biosensor.
Fig. 4. Images of the fabricated biosensor array. (a) Top view of an optical image of the device. (b)Enlarged optical image of the active PZT diaphragm. (c) SEM image of the reaction chamber on the backside of the diaphragm.
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9. Results FSEM & AFM images 82-105 nm 58-66 nm 9/12
Fig 6. FESEM (a, b) and AFM (c, d) micrographs of CNTs. (a) & (c) CNTs were pretreated by SDS. (b) & (d) CNTs after absorbing goat IgGs.
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10. Results High sensitivity High limit of detection 10/12
Figure 5. Relationship between the frequency depression and concentration of the added anti-goat IgG.
High sensitivity
High limit of detection
Figure 4. Detailed frequency shift of the two-sensor array (a)without CNTs, (b) with CNTs after each immobilization processes
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11. References
L.G. Carrascosa, M. Moreno, M. Alvarez, L. M.Lechuga, “Nanomechanical biosensors: a new sensing tool”, Trend Anal. Chem., vol. 25, pp , 2006.
R. Raiteri, M. Grattarola, H. J. Butt, and P. Skladal, “Micromechanical cantilever-based biosensors”, Sens. Actuators B, vol. 79, pp , 2001.
N. Perrot, E. Antoine, and C. Compere, “In situ QCM DNA-biosensor probe modification” Sens. Actuators B, vol. 120, pp , 2006.
Myriam Passamano , Monica Pighini, “QCM DNA-sensor for GMOs detection”, Sens. Actuators B, vol. 118, pp , 2006.
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12. Thank you for your attention!!
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