Peer-Reviewed Journal Details
Mandatory Fields
Dinca, MP, Gheorghe, M, Aherne, M, Galvin, P;
Journal of Micromechanics and Microengineering
Fast and Accurate Temperature Control of A Pcr Microsystem With A Disposable Reactor
Optional Fields
The paper presents a micro polymerase chain reaction (PCR) device consisting of a miniature thermal cycler incorporating Pt thin layers used as heater and temperature sensors, screen-printed on a ceramic plate and a disposable PDMS part with a 1 mu l chamber. Using a heating power of only 0.3 W at 95 degrees C and 1.5 W during heating transitions, the device can provide a 7.7 degrees C s(-1) heating rate. For temperature control, a two-degree-of-freedom proportional-integral-derivative controller in conjunction with an anti-windup algorithm was designed and implemented. The obtained performances (such as the use of the maximum/minimum power level during almost all of the transition time, overshoots and undershoots below 0.1 degrees C, very short settling time with no oscillation, steady error less than +/- 0.05 degrees C and excellent robustness against the process changes) exceed those published so far. In addition, the proposed controller is much simpler to implement and tune in comparison to other previously described controllers. A dynamical correction of the difference between the sensor and chamber temperatures is introduced and several profiles for set-point shaping are proposed and compared. The delayed preshaped profile, based on the inverse of the corresponding transfer function, was found to give the best results. Forced convection cooling is handled as a heat switch providing a cooling rate of 6.6 degrees C s(-1) while preserving the low power requirement for heating. With the device described cycle times of 12 s (if the dwell times are not considered) are possible. PCR amplification with 32 cycles was successfully carried out in less than 25 min..
DOI 10.1088/0960-1317/19/6/065009
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