5
Rochish Thaokar Department of Chemical Engg IIT Bombay [email protected] www.che.iitb.ac.in/faculty.html Nanomachines: A DNA Miniplasmid Theoretical analysis of nanomachines and biological motors Intrinsic curvature and anisotropy for asymmetry in potential A Thermal ratchet can cause it move at around 50 nm/s A potential ratchet can make it move at 10 micros/s Switching times is Smoluchowski times and so very fast

Rochish Thaokar Department of Chemical Engg IIT Bombay Nanomachines: A DNA

Embed Size (px)

DESCRIPTION

Electrohydrodynamic instability in Microfluidics and Charged membranes and deformation of vesicles and dielectric drops Electrohydrodynamic instability in Perfect and Leaky dielectrics due to destabilising Maxwells stresses The long and short wave instability undergo supercritical bifurcation under flow due to nonlinear effects, making it useful in pumping fluids in microfluidics A charged membrane is predicted subcritical by the Debye Huckel theory while the the Poisson Boltzmann’s theory predicts supercritical bifurcation AC electrokinetics and drop deformation under electric field

Citation preview

Page 1: Rochish Thaokar Department of Chemical Engg IIT Bombay  Nanomachines: A DNA

Rochish ThaokarDepartment of Chemical Engg

IIT [email protected]

www.che.iitb.ac.in/faculty.html

Nanomachines: A DNA Miniplasmid Theoretical analysis of nanomachines and biological motors

Intrinsic curvature and anisotropy for asymmetry in potential

A Thermal ratchet can cause it move at around 50 nm/s

A potential ratchet can make it move at 10 micros/s

Switching times is Smoluchowski times and so very fast

Page 2: Rochish Thaokar Department of Chemical Engg IIT Bombay  Nanomachines: A DNA

Force Extension curves: DNA loops and deflections

A semiflexible chain which is looped or non-straight can be expressed by a WLC model

The persistence length is re-normalized

The renormalisation is due to enthalpic effects

The theory explains discrepancies in the force-extension curves of semiflexible polymers, looped and kinked DNAs and DNA protein complexes

Page 3: Rochish Thaokar Department of Chemical Engg IIT Bombay  Nanomachines: A DNA

Electrohydrodynamic instability in Microfluidics and Charged membranes and deformation of vesicles and dielectric drops

Electrohydrodynamic instability in Perfect and Leaky dielectrics due to destabilising Maxwells stresses

The long and short wave instability undergo supercritical bifurcation under flow due to nonlinear effects, making it useful in pumping fluids in microfluidics

A charged membrane is predicted subcritical by the Debye Huckel theory while the the Poisson Boltzmann’s theory predicts supercritical bifurcation

AC electrokinetics and drop deformation under electric field

Page 4: Rochish Thaokar Department of Chemical Engg IIT Bombay  Nanomachines: A DNA

Swimming at Low Reynolds number: Three celled animal

Stability of Oscillatory flows over flexible surfaces

A torus represents a force free torque free swimmer

Swimming velocity proportional to rotational velocity and square of the slenderness

Reversal of direction with the thickness of “Guide rails”

A purely oscillatory instability found for time periodic flow of fluids over viscoelastic gels

Theory and experiments show qualitative agreement

The instability should be relevant in biological systems

Page 5: Rochish Thaokar Department of Chemical Engg IIT Bombay  Nanomachines: A DNA

Nanomachines: A DNA Miniplasmid ● Igor M Kulic, RochishThaokar, Helmut Schiessel, Europhysics Letters, 72,527-533, 200

● I.M.Kulic, Rochish Thaokar, Helmut Schiessel, J Phys Cond Matt, 17, S3965, 2005

● Force Extension curves: DNA loops and deflections● Igor Kulic, H Mohrbach, V Lobaskin, Rochish Thaokar, Helmut Schiessel, Physical Review E, 72, 041905-1-5,2005

● Igor Kulic, H Mohrbach, Rochish Thaokar, Helmut Schiessel, “Equation of state of a looped DNA”, Physical Review E

(Under Review)

● Electrohydrodynamics ● Thaokar R, Kumaran V, Physics of Fluids, 17,084104, 2005

● Thaokar, R. Kumaran V, Physical Review E,66,051913, 2003

● Stability of Oscillatory flows over flexible surfaces● Thaokar R, Shankar, V. and Kumaran V, EPJB, 23, 533, 2001

● Thaokar, R. Kumaran V, Journal of Fluid Mechanics,66,051913, 2003

● Thaokar, R., Kumaran V, EPJB, 41,135