TY - JOUR
T1 - Calorimetric biosensors with integrated microfluidic channels
AU - Zhang, Yuyan
AU - Tadigadapa, Srinivas
N1 - Funding Information:
This work is supported by a grant from the National Science Foundation, ECS-0097468.
PY - 2004/7/15
Y1 - 2004/7/15
N2 - A microfluidic device capable of measuring real-time enthalpy changes of biochemical reactions and thermal properties of biological fluids is presented in this paper. The device consists of a freestanding microthermopile integrated with a glass microfluidic reaction chamber. The p-type polysilicon/gold microthermopiles fabricated on a 2 μm thick thermally isolated membrane showed a sensitivity of 0.94 V/W and a thermal time constant of less than 100 ms. Although the device is not restricted to enzymatic reactions, in this paper measurements of the heat of reaction from the catalytic action of glucose oxidase, catalase, and urease on glucose, hydrogen peroxide, and urea, respectively, are reported. Reactions were performed in open air using liquid batch testing and in enclosed fluidic reaction chamber by continuous flow experiments. A sensitivity of 53.5 μV/M for glucose, 26.5 μV/M for hydrogen peroxide and 17 μV/M for urea was obtained. Detection limit for glucose in the continuous flow mode is ∼2 mM (30 pmol). The aim of this work is to demonstrate the potential of the integrated calorimetric microfluidic device for fundamental thermodynamic studies in biochemical reactions. Using arrays of such devices with immobilized enzymes multi-analyte detection can be accomplished and the effects of interferents from competing substrates can be compensated. This paper presents the design, fabrication and initial testing results from such a microthermopile-based thermal biosensor.
AB - A microfluidic device capable of measuring real-time enthalpy changes of biochemical reactions and thermal properties of biological fluids is presented in this paper. The device consists of a freestanding microthermopile integrated with a glass microfluidic reaction chamber. The p-type polysilicon/gold microthermopiles fabricated on a 2 μm thick thermally isolated membrane showed a sensitivity of 0.94 V/W and a thermal time constant of less than 100 ms. Although the device is not restricted to enzymatic reactions, in this paper measurements of the heat of reaction from the catalytic action of glucose oxidase, catalase, and urease on glucose, hydrogen peroxide, and urea, respectively, are reported. Reactions were performed in open air using liquid batch testing and in enclosed fluidic reaction chamber by continuous flow experiments. A sensitivity of 53.5 μV/M for glucose, 26.5 μV/M for hydrogen peroxide and 17 μV/M for urea was obtained. Detection limit for glucose in the continuous flow mode is ∼2 mM (30 pmol). The aim of this work is to demonstrate the potential of the integrated calorimetric microfluidic device for fundamental thermodynamic studies in biochemical reactions. Using arrays of such devices with immobilized enzymes multi-analyte detection can be accomplished and the effects of interferents from competing substrates can be compensated. This paper presents the design, fabrication and initial testing results from such a microthermopile-based thermal biosensor.
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U2 - 10.1016/j.bios.2004.01.009
DO - 10.1016/j.bios.2004.01.009
M3 - Article
C2 - 15142608
AN - SCOPUS:2442442807
SN - 0956-5663
VL - 19
SP - 1733
EP - 1743
JO - Biosensors and Bioelectronics
JF - Biosensors and Bioelectronics
IS - 12
ER -