Microfluidic Tools for DNA Analysis - DNA Nanotechnology: From Structure to Function - page 122

Fig. 7.8 Integrated microfluidic chip for nanoliter DNA analysis including sample loading,
amplification (strand displacement amplification, SDA ), electrophoresis, and detection (Reprinted
from Ref. [ 38 ] with permission from AAAS)
Early studies focused on the integration of different parts by adopting the inte-
grative innovation modes. A classical work was reported by Burns and coworkers
in 1998 [ 38 ]. They set all necessary procedures for DNA analysis including (1)
precise volume measurement of reagent, enzyme, and DNA-template solutions; (2)
mixing of solutions; (3) controlled thermal reaction of the mixture; (4) loading
of the reaction products onto an electrophoresis device; and (5) detection of
size-fractionated reaction products, in a modular fashion (Fig. 7.8 ). The strand
displacement amplification (SDA), an isothermal amplification which can be per-
formed over a broad temperature range [ 39 ], was carried out to validate the
performance of the device.
To achieve the “sample-in-answer-out” goal, DNA extraction also was
incorporated into microfluidic devices, which allows researchers to perform the
DNA analysis from original specimens directly. Traditionally, DNA extraction and
purification requires multiple steps of centrifugation that are hard to be incorporated
with a stand-alone microchip. We proposed an approach through integrating the
thermal lysis chamber into the upstream of the LAMP reaction channel [ 40 ]. We
separated the lysis chamber from the amplification channel by a screw valve and
controlled the valve by hand (Fig. 7.9 a). The DNA extracted in the sealed chamber