Active grip filter plug for sample collection devices

A system for collecting a biological sample, comprising:

• a collection device comprising a cylindrical wall defining a bore extending therethrough and a filter membrane disposed at one end thereof;
• a filter plug having a cylindrical insert sized and configured for insertion into the bore of the collection device, the filter plug having a flanged proximal end extending radially outward from an exterior surface of the filter plug insert;
• a cylindrical collar concentrically mounted about, and movable relative to, the exterior surface of the filter plug insert, the collar sized and configured for insertion into an annular space defined by the exterior surface of the filter plug insert and an interior surface of the collection device;
• and
• a compressible annular gasket disposed about the exterior surface of the filter plug insert between a proximal end of the collar and the flanged proximal end of the filter plug insert, such that movement of the collar towards the flanged proximal end of the filter plug insert compresses and expands the gasket radially outward from the exterior surface of the filter plug insert, so as to form a seal between and thereby engage the the filter plug insert to the collection device.