Surface Enhanced Raman Scattering-based Tumor Immunoassay Using PS@Ag Nano-probes and Si@Ag Array Substrate

Recent Advances in Sandwich SERS Immunosensors for Cancer Detection

“…A large group of proposed substrates includes glass, quartz, or silicon slides with a layer of nanoparticles, usually gold or silver, of various shapes (e.g., spherical, nanorods) [34][35][36][37][38][39][40][41]. To improve the intensity and repeatability of the SERS signal, substrates with a layer of silver or gold nanoparticles on microarray chips were also developed [42][43][44][45]; the most interesting case in this group was the use of ordered gold nanohoneycomb arrays [46].…”

“…To give the reader an idea of the number of modified nanoparticles proposed also with nonmetallic materials/substances, we decided to mention a few such cases. This group includes; e.g., nanotags with hybrid multilayered nanoshells prepared by the layerby-layer assembly of small AgNPs at the surface of silica (SiO 2 ) particles [53] also using poly(ethyleneimine) [74]; AuNP-coated acid-based resin microspheres [32]; silica-coated Ag nanorods [36]; core-shell SiO 2 @Ag [52]; SiO 2 -coated Si NPs [48]; AuNPs with polydopamine resin [33]; ZnO and CoFe 2 O 4 nanocomplexes with Au [39]; AgNPs deposited on graphene oxide [64]; Ag-covered polystyrene spheres [41]; silica-coated gold/silver core-shell nanostars [66]; nanospheres with a silver coating core, an ultrathin continuous silica shell, and high coverage of gold nanospheres satellites [67]; MoS 2 nanoflower@AuNPs [57]; Au-coated 'stellate' mesoporous SiO 2 @Au nanoprobes [49]; Au seeds on Fe 3 O 4 @TiO 2 core-shell NPs [50]; nano-Ag polydopamine nanospheres [68]; and gold-graphene hybrid nanotags [72].…”

“…The authors assessed the linear range (3 pg mL −1 -3 mg mL −1 ) and the limit of detection (0.72 pg mL −1 ) toward the AFP. Zhe and coworkers presented a sandwich-type immune structure with Ag-covered polystyrene sphere probes and a Si@Ag substrate [41]. To prepare an immune probe, they immobilized 4-mercaptobenzoic acid and anti-AFP antibodies on the Ag-covered polystyrene sphere.…”