Methods of particle manipulation and analysis

Abstract

Methods described herein, in some embodiments, permit extraction of particle structural and/or surface charge data from gradient induced particle motion in channels. In one aspect, a method of manipulating particle motion comprises introducing a fluid into a channel, the fluid comprising particles, and driving particle accumulation to a preselected location in the channel by setting advective velocity of the fluid to offset diffusiophoretic mobility of the particles at the preselected location.

1 . A method of determining zeta potential of channel walls comprising:
 establishing a solute concentration gradient to induce a wall slip boundary condition in the channel;   measuring pressure drop over the channel length;   determining channel wall diffusiophoretic mobility of the slip boundary condition from the measured pressure drop; and   deriving the zeta potential of the channel walls from the wall diffusiophoretic mobility.   
     
     
         2 . The method of  claim 1 , wherein the wall diffusiophoretic mobility is derived from a relation between the measured pressure drop and wall slip velocity of the boundary condition. 
     
     
         3 . A zeta potentiometer comprising:
 at least one flow channel;   at least one light source for illuminating the flow channel;   an imaging device positioned to observe the illuminated flow channel; and   a sample storage location adapted to provide sample to the at least one flow channel.   
     
     
         4 . The zeta potentiometer of  claim 3 , wherein the imaging device comprises a microscope.