INTRODUCTION. Understanding the hematological behavior of near-infrared (NIR) responsive plasmonic nanoparticles is crucial for their medical applications. Despite low concentrations, their nature may cause toxicity in biological environments through interactions with biomolecules. Especially interactions with plasma proteins have implications for hemostasis, thrombosis, and inflammatory responses. This study focuses on the interactions of isotropic and anisotropic silver nanoparticles (AgNPs) with bovine serum albumin (BSA) and their effects on red blood cells (RBCs)and clotting time.

METHOD. Specific localized resonant surface plasmon AgNPs were synthesized and exposed to protein. The protein solution was prepared within normal blood plasma limits (35-50 mg mL-1). UV-Vis and fluorescence spectroscopy were used to study the interaction, while transmission electron microscopy (TEM) was used to analyze changes in particle size and morphology. Fresh blood incubated with AgNPs was used to assess cell morphology changes. RBC content release, specifically lactate dehydrogenase (LDH) activity, was measured using UV–vis-NIRspectrophotometry to indicate membrane rupture. AgNPs' impact on blood coagulation times was investigated using a test kit after incubation.

RESULTS. UV-Vis was used to study the chemical environment of interface AgNPs/BSA. The results did not show changes in the prism-shaped particles at different concentrations, but the sphere-shaped particles showed decreased intensity. Fluorescence revealed that nanoparticles can induce the enhancement and quenching of protein emission, possibly due to conformational changes in the protein structure. By TEM, the aggregated state of the systems' AgNPs/BSA was confirmed. AgNPs showed minimal a impact on the RBC morphology and LDH release. The isotropic AgNPs increased LDH release compared to the anisotropic ones. Interaction with BSA may activate the coagulation cascade, but AgNPs showed no impact on coagulation time.

CONCLUSIONS. AgNPs interacted with BSA at lower than reported. Isotropic nanosilver distributes throughout the protein network, exerting reactivity. In addition to the effect on BSA organization, isotropic nanoparticles caused some RBCs disruption compared to the NIR-sensitive anisotropic AgNPs, which showed no negative effects on hemocompatibility. These results aid in developing devices loaded with NIR- light responsive nanosilver, ensuring safe use.