Midterm Report Professor: Cheng-Hsien, Liu Student: Yi-Jou, Lin Date: 2009/11/03 A HIGH SENSITIVITY CARBON NANOTUBES ENHANCED PZT DIAPHRAM-BASED IMMUNOSENSOR ARRAY T. Xu 1 , J.M. Miao 1 *, Z.H. Wang 1 , Y.S. Liu 2 and C.M. Li 2 1 Micromachines Centre, Nanyang Technological University, Singapore 2 School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 1/1 2
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Midterm Report Professor: Cheng-Hsien, Liu Student: Yi-Jou, Lin Date: 2009/11/03 A HIGH SENSITIVITY CARBON NANOTUBES ENHANCED PZT DIAPHRAM-BASED IMMUNOSENSOR.
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Midterm Report
Professor: Cheng-Hsien, Liu
Student: Yi-Jou, Lin
Date: 2009/11/03
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. Li21Micromachines Centre, Nanyang Technological University, Singapore
2School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
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Introduction
Piezoelectric Biosensors
- Micro-machined catilever
- Quartz-Crystal Microbalance System (QCMS)
- Micro-diaphragm
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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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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.2 Libra DNA-sensor and piezoelectric quartz.
Fig. 3. Scheme of DNA immobilization and hybridization on golden quartz.
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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. Li21Micromachines Centre, Nanyang Technological University, Singapore
2School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
A HIGH SENSITIVITY CARBON NANOTUBES ENHANCED PZT DIAPHRAM-BASEDIMMUNOSENSOR ARRAYT. 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
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 6/12
Fabrication of piezoelectricdiaphragm-based biosensor array
SOI wafer
PZT=Pb(Zr0.52Ti0.48)O3
TiO2/Pt
Si3N4
Ti/Pt
deposit
Deposit
Patterned &etching
Sputtered & patterned
DRIETop electrode
bottom electrode
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Fabrication of piezoelectricdiaphragm-based biosensor array
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.
Fig 5. Sketched immobilization processes for the CNT enhanced PZT biosensor.
-goat IgG
Anti-goat IgG
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Results
FSEM & AFM images
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.
58-66 nm
82-105 nm
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Results
Figure 4. Detailed frequency shift of the two-sensor array (a)without CNTs, (b) with CNTs after each immobilization processes
Figure 5. Relationship between the frequency depression and concentration of the added anti-goat IgG.
High sensitivity
High limit of detection
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References
L.G. Carrascosa, M. Moreno, M. Alvarez, L. M.Lechuga, “Nanomechanical biosensors: a new sensing tool”, Trend Anal. Chem., vol. 25, pp. 196-206, 2006.
R. Raiteri, M. Grattarola, H. J. Butt, and P. Skladal, “Micromechanical cantilever-based biosensors”, Sens. Actuators B, vol. 79, pp. 115-126, 2001.
N. Perrot, E. Antoine, and C. Compere, “In situ QCM DNA-biosensor probe modification” Sens. Actuators B, vol. 120, pp. 329-337, 2006.
Myriam Passamano , Monica Pighini, “QCM DNA-sensor for GMOs detection”, Sens. Actuators B, vol. 118, pp. 177-181, 2006.