Integrated PCR amplification and detection processes on a Lab-on-Chip platform: A new advanced solution for molecular diagnostics

Background: Several microdevices have been developed to perform only a single step of a genotyping process, such as PCR or detection by probe hybridization. Here, we describe a Lab-on-Chip (LoC) platform integrating a PCR amplification microreactor with a customable microarray for the detection of sequence variations on human genomic DNA. Methods: Preliminary work was focused on developing the single analytical steps including PCR and labeling strategies of the amplified product by conventional reference systems. The optimized protocols included a 1:4 forward:reverse primer ratio for asymmetric PCR, and Cy5-dCTP multiple incorporation for the generation of a labeled PCR product to be hybridized to complementary probes bound to the chip surface. Results: Final conditions were applied to the fully integrated LoC platform for the detection of the IVSI-110 G>A mutation in the human β-globin (HBB) gene associated with β-thalassemia, used as a model of genetic application, allowing for correct genotyping of 25 samples that were heterozygous, homozygous or wild-type for this mutation. Conclusions: The overall results show that the present platform is very promising for rapid identification of DNA sequence variations in an integrated, cost effective and convenient silicon chip format.