SERS of Human Red Blood Cells in Non-Resonant Conditions: Benefits, Limitations, and Complementary Tools (CytoViva and GFAAS)

Herein, Raman and surface-enhanced spectroscopies (SERS) were successfully employed to establish the chemical interactions of citrate-capped silver nanoparticles (AgNPs, 10–15 nm) with human red blood cells (RBCs). The Raman/SERS spectra offered spectral evidence for cellular uptake AgNPs subsequent change in conformation most abundant component, hemoglobin (Hb), from oxyhemoglobin deoxyhemoglobin. characterization AgNPs’ other RBC biomarkers (membrane proteins lipids) was impeded by dominant Hb bands, even non-resonant conditions. CytoViva hyperspectral imaging graphite furnace atomic absorption spectroscopy (GFAAS) served as complementary tools effectively address challenges related a single excitation line (632.8 resolution confocal microscope (0.5–1.0 µm). confirmed RBC-AgNP through signatures facilitated label-free localization extracellularly intracellularly. Irreversible agglutination RBCs noted after 24 h exposure, raising concerns about toxicity biocompatible citrate coatings. GFAAS validated results quantifying proportion absorbed RBCs, which significant (~48% mass), mostly at membrane (60% RBCs), size dependent (no large or AgNP-aggregates 12–24 h).