Description:
Researchers at
Princeton University have developed three new methods for manipulation of DNA
and other large macromolecules in microfluidic environments.
The 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 100kbp.
The 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.
The 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
distributions.
It is
anticipated that these methods will be useful in any application
using
microfluidics or
lab-on-a-chip technologies. Patent
protection is pending.