Researchers at Princeton University
have developed three new methods for manipulation of DNA and other large
macromolecules in microfluidic environments.
first method permits fractionation of DNA continuously on micro or
nano-fabricated support materials.
Current methods to fractionate larger (greater than 30kb) DNA molecules
by size use pulsed gel electrophoresis and typically take several days to
fractionate one set of samples.
This new method uses micro or nano fabricated environments to accurately
control the motion of the DNA molecules, allowing continuous fractionation with
very high resolution in a matter of seconds, even for DNA molecules larger than
second method permits generation of a wide variety of electrical field
distributions in the electrolyte layer of micro-fabricated electrophoretic
devices. Pulsed field gel
electrophoresis, which is currently used to fractionate large DNA molecules,
requires a uniform, homogeneous alternate electric field. This is performed in standard
electrophoresis setups using multiple electrodes, however, this method is not
practical in microfluidic applications as it requires a multitude of electrodes,
electrolyte reservoirs, complex driving circuits, and can create undesirable
bubbles at the electrode/electrolyte interface. This new method permits the
generation of many types of electrical fields, while minimizing bubble
generation and the number of electrodes, thereby increasing the reliability of
such microfluidic devices.
third method allows the generation of a wide variety of flow distributions of a
layer of liquid in micro-fluidic devices.
Current methods require the use of numerous pressure regulators to
control the flow distribution in a layer of liquid, and may not be practical in
microfluidic applications, due to complexity, instability and cost. This new method employs pressure sources
in series with microfluidic channels to generate two-dimensional flow
is anticipated that these methods will be useful in any application
lab-on-a-chip technologies. Patent
protection is pending.