An automated micro-solid phase extraction device involving integrated \high-pressure microvalves for genetic sample preparation

This paper presents an automated micro-SPE device for DNA extraction using monolithically integrated high-pressure microvalves. The automated micro-SPE device was fabricated through glass-to-glass thermal bonding and microfluidic system interface technologies. To increase the DNA extraction efficiency, silica beads were packed in the extraction microchannel involving two weir structures. Experimental results show that the DNA extraction efficiency using the automated micro-SPE device containing bare silica beads was 75.87% in the first 8 mu l of solution eluted by automated SPE procedure. In addition, the reproducibility of the DNA extraction was evaluated by ten successive measurements. Genomic DNA extracted from human WBCs had an absorbance ratio of DNA to protein (A(260)/A(280)) of 1.56. The applicability of this automated micro-SPE device to genetic sample preparation was verified by PCR amplification of a beta-globulin gene using the genomic DNA extracted from WBCs. Consequently, we demonstrated that the proposed automatic micro-SPE device can extract nucleic acids from biological samples, thereby facilitating its integration with downstream genetic analyses in a micro format.