AOAC SPIFAN Stakeholder Panel Meeting Book (September 7, 2019)

Immunoassay - ELISA

X ELISA: Enzyme Linked Immuno Sorbent Assay X Antibody-antigen (sample) interaction X Varieties: Direct, Indirect, Sandwich, Competitive

X Sandwich ELISA:

X (1) Capture antibody (CA) bound to plate X (2) Sample (antigen) added, binds to (CA) X (3) 1° detection antibody (DA) added, binds to antigen also X (4) 2° DA added with linked enzyme, binds to 1° DA X (5) Wash then add substrate for enzyme linked to 2°antibody Æ Activate -> Detect signal using a plate reader

By Jeffrey M. Vinocur, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=770729

X MULTIPLE options available for lactoferrin analysis: different species, etc. X Kits can be expensive, some specialized instrumentation required

Immunoaffinity - Biosensor

Biosensor: A device that monitors and transmits information about a life process Especially : a device consisting of a biological component (such as an enzyme or bacterium) that reacts with a target substance and an electrochemical or optical component that detects the resulting products or by-products and emits a signal “biosensor." Merriam-Webster.com . 2019. https://www.merriam- webster.com (8 Aug 2019). X Various types of detection (signal) and equipment: X Electrochemical detection of various types: Antibody/antigen trigger X Surface plasmon resonance detection: Change in the angle of polarized light due to bound/unbound target molecules on a light reflective surface. X Microarrays X Quantum dots X Many more novel setups X Indyk, H. E., Filonzi, E. L., & Gapper, L. W. (2005). Determination of lactoferrin in bovine milk, colostrum and infant formulas by optical biosensor analysis. International Dairy Journal , 15 (3), 429–438. https://doi.org/10.1016/j.idairyj.2004.09.003