a device for immunological techniques is prepared containing a macroporous hydrophobic synthetic polymer cloth having antibodies or antigens directly adsorbed therein and directly absorbed and immobilized thereon . the cloth has a thickness of more than about 200 μm and has spaces between fibres exceeding about 20 μm in diameter , and preferably has a frazier air permeability , in cfm / ft 2 at 0 . 5 &# 34 ; h 2 o of from about 215 to about 750 for thickness of from about 11 to about 40 mils such that it can accommodate a large volume of liquid per surface area , that it has a large surface area , and that it has minimum flow resistance . in immunoassays antibodies may be directly adsorbed therein and directly absorbed and immobilized thereon , and specific antigens from a selected test sample , may then be captured by the antibodies , to be detected conventionally . alternatively antigens may be directly adsorbed therein and directly absorbed and immobilized thereon , and specific antibodies from a selected test sample , may be captured by the antigens , to be detected conventionally . this device can also be used for extraction and concentration of lipopolysaccharide antigens and for preparing biotinylated , affinity - purified antibodies .