Microfluidic-based DNA amplification by microwave heating for forensic applications.

Pierre-Alain Auroux1, Javier Atencia2, Jayna Shah1,

James Booth3, Michael Gaitan1

 

1 EEEL, Semi-Conductor Electronics Division, MicroElectroMechanical Systems Group

2 Advanced Chemical Science Laboratory, Analytical Chemistry Division, Microanalytical Metrology Group

3 EEEL, Electromagnetics Division, Radio Frequency Electronics Group

Contact: Pierre-Alain Auroux, pauroux@nist.gov, tel: (301) 975-3095, Building 225, Room B310

Category: Biotechnology

 

 

 

 

 

The emergence of the microfluidic field in the 1990's has lead to state-of-the-art applications. In particular, driven by the need to circumvent intrinsic limitations, new devices have been engineered and optimized to surpass their macro-scale equivalents. In this poster we will present a new concept to amplify DNA by microwave heating for the purpose of forensic applications.

 

 

DNA amplification is conventionally performed by Polymerase Chain Reaction (PCR). Although PCR is a very efficient method, it is also highly prone to contamination. Additionally volumes typically used are prone to wasting expensive reagents. Furthermore conventional thermocyclers are bulky and therefore ill suited for point-of-care analysis. DNA amplification is also rendered very time-consuming due to the thermal inertia of the heating/cooling blocks incorporated into the apparatus.

 

 

The micro-total-analysis system that is currently under development in our laboratory is based on a polymeric device engineered to perform microfluidic operations. Such a microchip will integrate sample preparation, DNA amplification and sample analysis for forensic applications. Cross-contamination is minimized as the device is a closed system and no external intervention is required between operational steps. Additionally, reagent volumes are reduced due to an adequate interface between each step. Furthermore, microwave heating enables targeted sample heating based on frequency-dependent absorption of the delivered energy, therefore enhancing heat transfer and minimizing thermal inertia.

 

 

Our current set-up comprises customized microfluidic chips. Each prototype is manufactured using an in-house prototyping milling/drilling machine, the ProtoMat S62. The channels/reservoirs are then closed following an optimized laminating protocol. Whilst miniaturized microwave-based integrated heaters are being developed, a microwave transmission line is used to characterize the heat exchange during thermocycling. Although this system is currently under development, preliminary results are very encouraging and microwave-heated PCR should be performed within the next few months.