A new type of silver nanoparticle agglomerates induced by hydrophobic interaction in SERS practice

Abstract

This study describes a novel type of nanostructure complexes – silver nanoparticle agglomerates stabilized by the hydrophobic interactions. These complexes differ in size, morphology, and zeta potential from known agglomerates stabilized by an electrostatic interaction. The key property of these novel type agglomerates is their ability to amplify electromagnetic field intensity at nanoparticle contact points, leading to a significant SERS signal enhancement due to the formation of hot spots. Notably, the albendazole SERS signal enhancement factor is nearly identical for both types of agglomerates, suggesting a fundamental similarity in the mechanisms driving Raman scattering amplification. The study demonstrates that agglomerates of this type are formed due to the adsorption of albendazole on the surface of nanoparticles in a narrow pH range corresponding to its isoelectric point. SERS analysis revealed that, in acidic media, the C-N bond of albendazole carbamate group is oriented close to the surface of silver. At elevated pH, reorientation of the molecule in the adsorption complex occurs, reducing the dispersion between the surface of silver and C-S bound/carbonyl group. In acidic media, the stability of ABZ-AgNP bond decreases, resulting in the release of albendazole. The difference between binding affinity of ABZ to nanoparticles differs by 3–5 times at physiological levels of pH and under acidic conditions. This property of a pH-depended adsorption of biologically active compounds by nanoparticles could be harnessed for target drug delivery systems

Speaker

Khrushchev А.Yu
Federal State Budgetary Institution «The Russian State Center for Animal Feed and Drug Standardization and Quality»
Russia

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