Abstract: Biotin-trap compositions are disclosed that contain particles having an inner polymer coating layer disposed on at least a portion of an outer surface thereof and a biotin-specific binding partner conjugated to the inner polymer coating layer. The biotin-trap compositions may further include an outer polymer coating layer disposed about the biotin-specific binding partner. The biotin-trap compositions specifically bind to free biotin but do not substantially bind to biotin conjugated to other moieties, such as biotinylated assay reagents. Also disclosed are kits and microfluidics devices that include the biotin-trap compositions, as well as methods of producing and using the biotin-trap compositions.