Patent ID: 8142631

Claim:
A method for focusing particles by using a three-dimensional particle focusing apparatus, the method comprising: forming a single sufficiently-extended straight channel having first and second ends, the channel not having an intersection with a branch channel; fixing the first and second ends of the channel respectively, via connecting a first fixing portion of a fixing member to the first end of the channel and connecting a second fixing portion of the fixing member to the second end of the channel, the first fixing portion and the second fixing portion being separately formed from each other and being spatially isolated from each other; feeding fluid having particles into the channel at a predetermined pressure, through a fluid feeding portion passing through the first fixing portion to be connected to the first end of the channel; and generating a voltage difference between first and second terminals of a power supply, via connecting the first terminal of the power supply to a positive electrode of the power supply and connecting the second terminal of the power supply to a negative electrode of the power supply, the first terminal passing through the first fixing portion to be connected to the first end of the channel, the second terminal passing through the second fixing portion to be connected to the second end of the channel, wherein the channel has a cross section of a circle, wherein the three-dimensional particle focusing apparatus focuses the particles along a central point of the circle of the channel without sheath flows, and wherein the channel is only supported by the first fixing portion and the second fixing portion at the first and second ends of the channel.