Patent ID: 11944967
Assignee: ARIZONA BOARD OF REGENTS ON BEHALF OF ARIZONA STATE UNIVERSITY
Field: Measurement (Instruments)
Classification: CPC B  G | IPC B  G

Claim 17:
18. A method of separating sub-micrometer bioparticles by size utilizing ratchet migration using a system including
a microfluidic channel,
a structure configured within the microfluidic channel, the structure comprising an array with rows, the array including posts arranged in the rows, wherein some rows in the array are shifted in a lateral direction relative to other rows in the array,
a reservoir disposed at each of two opposite ends of the microfluidic channel, and
an electrode positioned in each of the reservoirs,
the method comprising:
introducing a fluid into the microfluidic channel, the fluid containing the sub-micrometer bioparticles, wherein the introduced fluid immerses the electrodes; and
applying a biased alternating electrical potential via the electrodes in each of the reservoirs, the biased alternating electrical potential comprising
a first waveform with a first frequency that induces electro-kinetic flow of sub-micrometer bioparticles in the microfluidic channel alternatingly in a first direction during a high period of the first waveform and in a second direction during a low period of the first waveform, and
a second waveform with a second higher frequency superimposed on the first waveform only during one selected from a group consisting of the high period of the first waveform and the low period of the first waveform, wherein the second waveform selectively induces a dielectrophoretic trapping force to selectively restrict migration of larger sized bioparticles during application of the second waveform,

wherein applying the biased alternating electrical potential causes bioparticles of a first size to migrate towards a first reservoir at a first end of the microfluidic channel and causes bioparticles of a second larger size to migrate towards a second reservoir at a second opposite end of the microfluidic channel.