A device for segregating smaller and larger particles, the device comprising: a body and a cover that define a void therebetween, the void containing a separation element that segregates an inlet region and an outlet region of the void, the separation element defining, together with a surface of the void, a channel that fluidly connects the inlet and outlet regions by way of a separating portion, the channel having an overall width at the separating portion and a height defined by the distance between the separation element and the surface of the void, at least one of the body, the cover, and the separation element bearing a segregating step disposed within and having a leading edge extending completely across the separating portion of the channel, whereby the channel is divided into an upstream portion on the inlet side of the leading edge and a lamellar downstream portion on the outlet side of the leading edge, the height of the upstream portion being sufficient to facilitate passage therethrough of both larger and smaller particles, the height of the downstream portion being sufficiently large to facilitate passage therethrough of the smaller particles and sufficiently small to inhibit passage therethrough of the larger particles, and the length of the leading edge being at least 20 times greater than the overall width of the channel at the separation region, wherein the upstream portion of the channel is lamellar in a region between the inlet region and the separation element, and wherein the leading edge has an undulating shape, whereby the particles can be segregated by passing them through the channel, and recovering particles based on their ability to traverse the segregating step. a body and a cover that define a void therebetween, the void containing a separation element that segregates an inlet region and an outlet region of the void, the separation element defining, together with a surface of the void, a channel that fluidly connects the inlet and outlet regions by way of a separating portion, the channel having an overall width at the separating portion and a height defined by the distance between the separation element and the surface of the void, at least one of the body, the cover, and the separation element bearing a segregating step disposed within and having a leading edge extending completely across the separating portion of the channel, whereby the channel is divided into an upstream portion on the inlet side of the leading edge and a lamellar downstream portion on the outlet side of the leading edge, a separation element that segregates an inlet region and an outlet region of the void, the separation element defining, together with a surface of the void, a channel that fluidly connects the inlet and outlet regions by way of a separating portion, the channel having an overall width at the separating portion and a height defined by the distance between the separation element and the surface of the void, at least one of the body, the cover, and the separation element bearing a segregating step disposed within and having a leading edge extending completely across the separating portion of the channel, whereby the channel is divided into an upstream portion on the inlet side of the leading edge and a lamellar downstream portion on the outlet side of the leading edge, an overall width at the separating portion and a height defined by the distance between the separation element and the surface of the void, the height of the upstream portion being sufficient to facilitate passage therethrough of both larger and smaller particles, the height of the downstream portion being sufficiently large to facilitate passage therethrough of the smaller particles and sufficiently small to inhibit passage therethrough of the larger particles, and the length of the leading edge being at least 20 times greater than the overall width of the channel at the separation region, wherein the upstream portion of the channel is lamellar in a region between the inlet region and the separation element, and wherein the leading edge has an undulating shape,