Applied Nanoscience 

Abstract

The biocompatibility of NPs to blood cells is a key issue when these NPs are planned for intravenous application because of potential contact with blood cells and proteins. In this work, γ-Fe₂O₃ NPs (~ 9 nm) and their poly(N,N-dimethylacrylamide) (PDMA) and SiO₂-coated derivatives (γ-Fe₂O₃@PDMA and γ-Fe₂O₃@SiO₂, respectively) were investigated. It was detected that both PDMA and SiO₂ coatings decreased NPs’ aggregation in the buffer solutions, as well as in cell culture medium. Neither neat γ-Fe₂O₃ NPs nor their coated derivatives possessed hemolytic activity toward red blood cells. There was no significant loss of body weight observed after the intravenous injection to laboratory mice. The immune response to the injected NPs was assessed by the ELISA measuring. No antibodies of the IgM class were detected, which suggests lack of acute inflammation. On the 35th day of the experiment, there was a rise in the content of the anti-OVA IgG noticed in all three types of the NPs; however, this rise was lower compared to that induced by the positive control. The injected NPs were found to be spread and settled in the pouch cavity, and none of the tested NPs caused vascular damage or distinct signs of inflammation. Summarizing, γ-Fe₂O₃ NPs coated with the PDMA or SiO₂ manifested good compatibility with blood cells in in vitro and in vivo investigations.

Keywords Maghemite · Nanoparticles · Poly(N,N-dimethylacrylamide) · Silica · Hemolytic action · Immune response

UDC 577.615.324-027.2.615.076

   Creation of novel remedies efficient in supporting wound healing remains an actual task in pharmacology. Hydrogels showed high efficiency in wound healing and tissue regeneration due to viscosity, elasticity and fluidity that provide them with functional characteristics similar to that in extracellular matrix. The aim of the study was to create chitosan-based hydrogels functionalized with different components (chondroitin-6-sulfate, hyaluronic acid, N-stearoylethanolamine) and to estimate their biocompatibility and biodegradability in vitro. For the first time, a lipid substance N-stearoylethanolamine (NSE) known as suppressor of pro-inflammatory cytokines expression was used as hydrogel component (1.95 mg/g). FTIR analysis confirmed the complexation of chitosan molecule with hyaluronate, chondroitin-6-sulfate, NSE. MTT-test and Trypan blue exclusion test were used to study hydrogels cytotoxicity towards human cells of different tissue origin. Biodegradability of hydrogels was evaluated using direct hydrogel contact with cells and cellindependent degradation. It was shown that chondroitin-6-sulfate (<2 mg/ml), hyaluronic acid (<2 mg/ml) and NSE (26 μg/ml) did not demonstrate significant toxic effects towards pseudonormal human cells of the MCF10A, HaCat, HEK293 lines and mouse cells of the Balb/3T3 line. The studied hydrogels were stable in saline solution, while in a complete culture medium containing 10% fetal bovine blood serum they underwent degradation in >24 h. The identified biodegradability of the chitosan-based hydrogels is important for the release of noncovalently immobilized NSE into biological medium. Further studies on laboratory animals with experimental wounds are expected to explore the potential of created hydrogels as anti-inflammatory
and wound-healing agents.
K e y w o r d s: chitosan hydrogels, chondroitin-6-sulfate, hyaluronic acid, N-stearoylethanolamine, FTIR analysis, human pseudonormal cells, toxicity, biodegradability