Calibration Method of Biochip Temperature Sensors

Abstract

Currently, a microanalysis technology is employed in detection sys- tems in fields such as medical science, food safety, and environmental monitor- ing, and it is being developed in the form of a lab-on-a-chip. However, the re- producibility and sensitivity of biochips are essential factors for its commercial- ization. Because this requires accurate temperature control, there should be no errors in the temperature sensor used for the biochip. This paper proposes a method that can calibrate the temperature sensor in an accurate and efficient manner. Biochips can obtain information regarding multiple genes within a short period of time, and this enables the analysis of the gene. Further, biochips are used to diagnose various diseases based on reactions with components inside the body of a target per- son to be examined. The commercialization of biochips requires them to be reliable in terms of their re- producibility and sensitivity, and therefore, accurate temperature control and calibra- tion of the biochip's temperature sensor are required. To realize temperature control, a heater and a temperature sensor are usually attached to the surface on which the DNA is amplified (1-4). For this, the biochip is equipped with various temperature sensors such as a metal film, a thermistor, and a thermocouple; however, a calibration method has not yet been reported. An example of a calibration method that can be employed for the biochip temperature sensor involves placing the biochip in a constant- temperature water bath and measuring the resistance and voltage of the temperature sensor against fundamental temperatures in each application. However, in the case involving the constant-temperature water bath, there is a problem with the long cali- bration time required by the biochip temperature sensor as the temperature of the constant-temperature water bath changes slowly. Therefore, in this paper, we propose a calibration system and a method that calibrates the biochip temperature sensor by measuring the surface temperature of the biochip using a biochip temperature sensor and a precision temperature sensor.