Label-free C-reactive protein SERS detection with silver nanoparticle aggregates

摘要: In this work, we report a qualitative approach for detecting the adsorption of C-reactive protein on phosphocholine-terminated self-assembled monolayers without use any labels. An amplified plasmon concentration-induced silver nanoparticle aggregates located ∼4.0 nm away from via monolayer linker is considered to be source robust electromagnetic enhancement. The high level (109 1010 M−1) apparent binding constant (KA) suggests that immobilized surface was well-oriented extreme random stacking. A Raman sensitivity toward around 2800–3000 cm−1 noted, which gradually increased upon addition successive layers up approximately 6–7 phosphocholine-coated aggregates, with minimum detection amounts ∼0.01 ng mL−1 in buffer and ∼0.1 1% serum. cross-reactivity test confirmed excellent selectivity specificity measured signals. computational study based finite-difference-time-domain method successfully demonstrated enhanced (∼1.1 × 106) field 2-D as compared isolated particles, congruent analytical enhancement factor (1.7 105).