A Multichannel Calorimetric Simultaneous Assay Platform Using a Microampere Constant-Current Looped Enthalpy Sensor Array.
Calorimetric biochemical measurements offer various advantages such as low waste, low cost, low sample consumption, short operating time, and labor-savings. Multichannel calorimeters can enhance the possibility of performing higher-throughput biochemical measurements. An enthalpy sensor (ES) array is a key device in multichannel calorimeters. Most ES arrays use Wheatstone bridge amplifiers to condition the sensor signals, but such an approach is only suitable for null detection and low resistance sensors. To overcome these limitations, we have developed a multichannel calorimetric simultaneous assay (MCSA) platform. An adjustable microampere constant-current (AMCC) source was designed for exciting the ES array using a microampere current loop measurement circuit topology. The MCSA platform comprises a measurement unit, which contains a multichannel calorimeter and an automatic simultaneous injector, and a signal processing unit, which contains multiple ES signal conditioners and a data processor. This study focused on the construction of the MCSA platform; in particular, construction of the measurement circuit and calorimeter array in a single block. The performance of the platform, including current stability, temperature sensitivity and heat sensitivity, was evaluated. The sensor response time and calorimeter constants were given. The capability of the platform to detect relative enzyme activity was also demonstrated. The experimental results show that the proposed MCSA is a flexible and powerful biochemical measurement device with higher throughput than existing alternatives.
Department of Bio-Industrial Mechatronics Engineering, National Taiwan University, Taipei 10617, Taiwan. d94631001@ntu.edu.tw.
Hsien-Chin
HC
Wei
Department of Biotechnology, Asia University, Taichung 41354, Taiwan. shhuang@asia.edu.tw.
Su-Hua
SH
Huang
Department of Bio-Industrial Mechatronics Engineering, National Taiwan University, Taipei 10617, Taiwan. jajiang@ntu.edu.tw.|Education and Research Center for Bio-Industrial Automation, National Taiwan University, Taipei 10617, Taiwan. jajiang@ntu.edu.tw.|Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 40447, Taiwan. jajiang@ntu.edu.tw.
Joe-Air
JA
Jiang
Department of Bio-Industrial Mechatronics Engineering, National Taiwan University, Taipei 10617, Taiwan. yclee@ntu.edu.tw.
Yeun-Chung
YC
Lee
adjustable microampere constant current loop; catalase; enthalpy sensor array; multichannel calorimeter; relative enzyme activity; simultaneous assay