on-chip ph sensing with gel microbead positioned by optical tweezers
DESCRIPTION
PME MAPS. On-Chip pH Sensing with Gel Microbead Positioned by Optical Tweezers. Hisataka Maruyama 1 , Fumihito Arai 2 and Toshio Fukuda 1 1 Department of Micro-Nano Systems Engineering, Nagoya University, Japan 2 Department of Bioengineering and Robotics, Tohoku University, Japan. - PowerPoint PPT PresentationTRANSCRIPT
On-Chip pH Sensing with Gel Microbead Positioned by Optical Tweezers
Hisataka Maruyama1, Fumihito Arai2 and Toshio Fukuda1
1Department of Micro-Nano Systems Engineering, Nagoya University, Japan2Department of Bioengineering and Robotics, Tohoku University, Japan
9633584 黃紫郁Ref: μTAS2006
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Outline
• Introduction
• Gel-Tool Contained a pH Indicator
• Experimental
• Conclusions
• References
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Introduction
• Environment measurement in a microchip is important to the on-chip experiment.
• Conventionally, microsphere’s surface is modified by fluorescent reagents and indicators.
• A local pH sensing method in a microchip using a functional gel-tool was developed.
• Gel-tools are UV curing and adhere to the glass, but we can manipulate them by the optical tweezers.
• Measure pH value locally from the color of gel-tool using calibrated color information in YCrCb color.
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Gel-Tool Contained a pH Indicator• Gel-tool is made by salting-out of ENT-3400 (polyet
hyleneglycol, PEG) which is hydrophilic resin.
• Manipulate gel-tool by optical tweezers in a water because the relative refractive index of PEG (1.42) is higher than that of water (1.33).
Fig.1 Optical tweezerFig.2 Active pH sensing Fig.3 pH sensing gel-tool pattern
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Gel-Tool Contained a pH Indicator
Fig.4 A schematic of generation of pH sensing gel-tool
Gel-tool
Fig.5 Photograph of salting-out gel-tool
20 wt% KCl
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Gel-Tool Contained a pH Indicator• Fabrication of gel-tools takes a few minutes and is
shorter than that of the surface modification.
• Gel-tools can be used as a carrier of cells because the tool adheres to cells by attaching.
• Color information on gel-tools acquired by CCD camera is converted from RGB to YCrCb by eq(1).
Y = 0.299R + 0.587G + 0.114BCr = 0.5000R - 0.419G - 0.081B (1)Cb = -0.169R - 0.419G + 0.500B
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Experimental
• Applied Cr value for calculating pH value and pH value is calculated by eq.(2).
pH = - 0.17 × Cr + 7.1 (2)pH = 0.13 × Cb + 8.0 (3)
• Adhered gel-tools did not removed from glass even by 894 mm/s flow speed.
Fig.6 Relation between pH and Cr Fig.7 Relation between pH and Cb
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Experimental
Fig.8 A schematic of active pH sensing Fig.9 Change of pH value
(d) Return to start point
Fig.10 Active pH sensing
(a) Start point (b) 100 μm moved (c) 200 μm moved
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Fig.10 On-chip pH sensing using pH sensing gel-tool
Experimental
(b) Size adjustment(a) Manipulation of gel -tool
(d) Gel-tool pattern (pH 6)
(c) Fixation of gel-tool
(e) pH 7 (f) pH 9
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Conclusions
• Proposed the pH sensing gel-tool for local environ-ment sensing in a microchip.
• Demonstrate active pH sensing and arrangement of pH sensing gel-tool pattern.
• Make the on-chip measurement easy.
• Make great contributions for cell biology.
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References
[1] H. Maruyama, F. Arai, and T. Fukuda, Proc. of μTAS2006, pp. 1247-1249, 2006
[2] H. Maruyama, F. Arai, and T. Fukuda, Proc. of IEEE2007, pp. 806-811, 2007
[3] 林世傑 , 光學嵌住之技術探討
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