The present invention provides a filtration chamber comprising a microfabricated filter enclosed in a housing, wherein the surface of said filter and/or the inner surface of said housing are modified by vapor deposition, sublimation, vapor-phase surface reaction, or particle sputtering to produce a uniform coating； and a method for separating cells of a fluid sample, comprising: a) dispensing a fluid sample into the filtration chamber disclosed herein； and b) providing fluid flow of the fluid sample through the filtration chamber, wherein components of the fluid sample flow through or are retained by the filter based on the size, shape, or deformability of the components.
