engleski

Stability of PVP AgNPs in media of interest for polyelectrolyte multilayer build-up

Rapid advances in the nanomaterials synthesis and characterization have enabled their safe integration into orthopaedic implants. Coating implants with metal/metal oxide nanoparticles can be considered an efficient approach to develop bioactive antimicrobial coatings that, in principle, do not promote bacterial resistance.1 To date, various coating methods have been used, of which polyelectrolyte multilayers (PE MLs) have attracted particular attention due to the possibility of coating substrates of different size, composition, and topology. In order to obtain stable and effective PE MLs/AgNPs coatings, extensive preliminary studies of the nanoparticles’ stability in various media of interest for the assembly of PE MLs are required. The aim of this study was to find the most suitable and stable options for incorporating AgNPs into poly-L-lysine (PLL) and poly-L-glutamic acid (PGA) ML. Polyvinylpyrrolidone stabilized silver nanoparticles (PVP AgNPs) were synthesized by reduction of silver nitrate2 and characterized by UV-Vis spectrometry and transmission electron microscopy (TEM). The stability of PVP AgNPs was investigated in ultrapure water, HEPES/NaCl buffer with or without PLL or PGA by dynamic (DLS) and electrophoretic light scattering (ELS) during 24 hours. The structure of the PLL/PGA multilayer containing PVP AgNPs was visualized by atomic force microscopy (AFM). The PVP AgNPs had a bimodal size distribution with hydrodynamic diameters of 15.65 nm and 40.95 nm Stability studies showed that the optimal way to incorporate the NPs into the multilayer would be to adsorb a layer of NPs from a HEPES/NaCl suspension. The AFM micrographs showed that deposition of (PLL-PGA)2 (PLL-PVPAgNP) (PLL-PGA)2 ML leads to the formation of dispersed granular structures that become denser after 10 deposited bilayers i.e. [(PLL-PGA)2 (PLL-PVPAgNP) (PLL- PGA)2]2 ML, indicating successful incorporation of AgNPs. The obtained results indicate a versatile method to prepare PE MLs containing various metal/metal oxide nanoparticles of interest for biomedical applications.

antimicrobial coatings ; stability ; polyelectrolyte multilayers ; nanoparticles

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