Comparison of glass etching to xurography prototyping of microfluidic channels for DNA melting analysis

Two microchannel manufacturing methods-xurography of double-sided tape and glass etching (lithography and wet etching)-were compared using DNA melting analysis. A heterozygous mutation (3 base-pair deletion) was distinguished from wild type (normal) DNA in 10 nL (xurography and glass etching) and 1 nL (xurography) volumes. The results of the 10 nL and 1 nL melting curves were compared to results using commercial high-resolution instrumentation with 10 mu L volumes. These 1000-fold and 10000-fold volume reductions reduced the signal-to-noise ratio (SNR) only 29-fold and 40-fold for xurography (10 nL and 1 nL, respectively,) and 39-fold for 10 nL glass etched microchannels, still providing adequate discrimination for mutation detection. The reduced SNR of the glass etched microchannels compared to the tape microchannels was due to the in-house bonding process which gave poor optical quality on the surface of the microchip. Xurography of double-sided tape reduces the cost by 20 fold and is four times faster to manufacture than glass etching. Microchips created using the rapid prototyping technique of xurography are a reasonable prototyping alternative to channels created using traditional glass etching for DNA mutation detection.