NRGN and Alzheimer disease: Innovative aptamer-based surface-enhanced Raman scattering (SERS) biosensors integrated with a multiwell glass chip enabled a selective, sensitive (atto-molar blood levels), dynamic and quantitative correlation with some biomarkers for early-stage AD diagnosis and progression, such as neurogranin (Nrgn), angiopoietin-2 (Angio-2), PRDX3, lactate dehydrogenase (L-LDH), and Tau τ-441 [138].