Spiral inertial microfluidic devices and methods to remove contaminants

A process for separating larger particles from smaller particles comprising:

• (i) flowing a fluid comprising the larger particles and the smaller particles into a device comprising:
• a spiral microfluidic channel on a support, the spiral microfluidic channel having an inlet in a center of the spiral microfluidic channel and an outlet at the outer end of the spiral microfluidic channel, the outlet at the outer end of the spiral microfluidic channel being bifurcated to yield a first outlet for fluid from an inner wall of the spiral microfluidic channel and a second outlet for fluid from an outer wall of the spiral microfluidic channel;
• wherein the device further comprises a first reservoir for the fluid, the first reservoir being fluidly connected to the inlet of the spiral microfluidic device;
• wherein the fluid flows into the inlet in the center of the spiral microfluidic channel;
• and
• (ii) continuously adding a volume of a wash fluid medium into the first reservoir during the flowing of step (i) sufficient to maintain the population density of the larger particles in the fluid and provide for a log reduction value (LRV) of the smaller particles from the fluid by at least a value of 4 following steps (i) and (ii), as compared to the fluid prior to step (i).