Ricerc@Sapienza

This paper presents the fabrication and testing of a lab-on-chip system suitable for treatment of DNA. It includes two main modules: a system-on-glass (SoG) and a disposable microfuidic chip. The SoG integrates, on the same glass substrate, thin film metal heaters and amorphous silicon temperature sensors to achieve a uniform temperature distribution (within 1°C) in the heated area. Two polydimethylsiloxane microfluidic chips have been developed: a PCR-Chip for DNA amplification and a dsDNA-Chip for separation and selective isolation of a ssDNA from a dsDNA.

This work combines a lab-on-chip device with an electronic system for the achievement of a small-scale and low-cost thermal treatment of biomolecules. The lab-on-chip is a 1.2 mm-thick glass substrate hosting thin film resistor acting as heater and, on the other glass side, amorphous silicon diodes acting as temperature sensors. The electronic system controls the lab-on-chip temperature through a Proportional-Integral-Derivative algorithm.

This work reports on the characterization of stability of amorphous silicon diodes used as temperature sensors in lab-on-chip systems. We found that under constant forward current injection, the voltage drop over the diode changes depending on the values of current and injection time. The optimized operating conditions for practical applications have been established on the base of the obtained experimental data.