CD63 and central nervous system cancer: Qiu et al. introduced a titanium nitride (TiN)-based SPR platform functionalized with biotinylated antibodies (BAF-TiN) for the sensitive detection of glioma-derived exosomal proteins, achieving detection limits of 4.29 × 10−3 μg/mL for CD63 and 2.75 × 10−3 μg/mL for the epidermal growth factor receptor variant-III (EGFRvIII), a glioma-specific mutant protein [70].