Immuno-fluorescence detection of snake venom by using single bead as the assay platform

By using micro-scale polystyrene beads as a platform, a rapid and sensitive method for the detection of snake venom was established. In the method, anti-venom antibody or BSA was covalently fixed onto the microsbead to form the capture-bead or control bead. In first step of the experiment, the venom binds to the capture-bead to form the complex through the antibody-antigen interaction. The Qdot conjugated second antibody was then added. The second antibody targeted the Qdot to the capture-bead/antigen complex and form Qdot-second antibody-antigen-capture-bead complex. This complex can be directly observed under UV-microscope. The system was applied to the testing of Naja kaouthia venom and the detection limit of this method was 5–10 ng/ml.