SPP1 and cancer: Another nanocomposite material for the aptamer anchoring, a hybrid of zirconium oxide nanoparticles and graphene-like nanofiber (ZrO2@GNF), did not improve LOD (then 4.76 fg mL−1 or 7.5 × 10−17 M), but allowed from 0.01 pg mL−1 to 2.0 ng mL−1 (from 1.6 × 10−16 M to 3.2 × 10−11 M) OPN detection in spiked human plasma samples, with a negligible interference from some other cancer biomarker proteins and IgG [136].