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Chen, Yeng-LongPolymer Physics and Flow - TheoryDNA / Polymer physics in nanoslits and nanochannels

Macromolecules, 2010, 2011, 2012

4 mM7.5 mM15 mM30 mM250 mM

CircularLinearCircularLinear20nm65nm110nm192nm465nmI = 35 mMh =104 nm2 mm

Fractionation of cells by elasticity and size by cell deformation and inertial flow physics

RBC and plateletsHealthy and diseased cellsJ. Chem. Phys. 2010Hou et al, Lab Chip (2010)

Re ~ O(1)Chen, Yeng-Long

Biophysics, Polymer Physics, and MicroflowChou, Chia-Fu

Entropy-driven polymer dynamics at the nanoscale is fundamentally important in biological systems but the dependence of the entropic force on the nanoconfinement remains elusive. Here, we established an entropy-driven single molecule tug-of-war (TOW) at two micronanofluidic interfaces bridged by a nanoslit (Fig. 2), performed the force analysis from a modified wormlike chain in the TOW scenario and the entropic recoiling process, and determined the associated scalings on the nanoconfinement (Fig. 1). Our results provide a direct experimental evidence that the entropic forces in these two regimes, though unequal, are essentially constant at defined slit heights, irrespective of the slit lengths and the DNA segments within. Our findings have the implications to polymer transport at the nanoscale, device design for single molecule analysis, and biotechnological applications.

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