Figure 4.

Basic principle of lateral flow assays. Schematic illustration of different zones of commercially available lateral flow assays for detection of, i.e., β-lactamases. Antigens within the sample migrate along the nitrocellulose membrane by capillary flow. Antigens (e.g., β-lactamase) conjugate with specific dye-labeled antibodies and are captured by immobilized antigen-specific antibodies, resulting in the visualization of the test line. Non-conjugated and unbound antibodies migrate further to the control line and are captured by immobilized anti-IgG antibodies, resulting in the visibility of a control line.