Chitosan Nanoparticles: Shedding Light on Immunotoxicity and Hemocompatibility

Abstract

Nanoparticles (NPs) assumed an important role in the area of drug delivery. Despite the number of studies including NPs are growing over the last years, their side effects on the immune system are often ignored or omitted. One of the most studied polymers in the nano based drug delivery system field is chitosan (Chit). In the scientific literature, although the physicochemical properties [molecular weight (MW) or deacetylation degree (DDA)] of the chitosan, endotoxin contamination and appropriate testing controls are rarely reported, they can strongly influence immunotoxicity results. The present work aimed to study the immunotoxicity of NPs produced with different DDA and MW Chit polymers and to benchmark it against the polymer itself. Chit NPs were prepared based on the ionic gelation of Chit with sodium tripolyphosphate (TPP). This method allowed the production of two different NPs: Chit 80% NPs (80% DDA) and Chit 93% NPs (93% DDA). In general, we found greater reduction in cell viability induced by Chit NPs than the respective Chit polymers when tested in vitro using human peripheral blood monocytes (PBMCs) or RAW 264.7 cell line. In addition, Chit 80% NPs were more cytotoxic for PBMCs, increased reactive oxygen species (ROS) production (above 156 µg/mL) in the RAW 264.7 cell line and interfered with the intrinsic pathway of coagulation (at 1 mg/mL) when compared to Chit 93% NPs. On the other hand, only Chit 93% NPs induced platelet aggregation (at 2 mg/mL). Although Chit NPs and Chit polymers did not stimulate the nitric oxide (NO) production in RAW 264.7 cells, they induced a decrease in lipopolysaccharide (LPS)-induced NO production at all tested concentrations. None of Chit NPs and polymers caused hemolysis, nor induced PBMCs to secrete TNF-α and IL-6 cytokines. From the obtained results we concluded that the DDA of the Chit polymer and the size of Chit NPs influence the in vitro immunotoxicity results. As the NPs are more cytotoxic than the corresponding polymers, one should be careful in the extrapolation of trends from the polymer to the NPs, and in the comparisons among delivery systems prepared with different DDA chitosans.

Albumin-Albumin/Lactosylated Core-Shell Nanoparticles: Therapy to Treat Hepatocellular Carcinoma for Controlled Delivery of Doxorubicin

“…The percent of hemolysis from all nanoparticles was below 2%, indicating the hemocompatibility of nanoparticles. Nanostructured systems are considered non-toxic if the hemolysis value is below 5%, according to the ASTME2524-08 standard [ 43 ].…”

<p>Evidence Supporting the Safety of Pegylated Diethylaminoethyl-Chitosan Polymer as a Nanovector for Gene Therapy Applications</p>

“…Thus, some CH formulations have the ability to induce NO production as part of the oxidative stress response, 59 while others have no effect. 80 It was also reported that CH possesses the ability to reduce the LPS-induced NO levels by Raw 264.7 macrophages. 80,82 This conflicting data can be explained by the preparation procedures of the CH samples and their physicochemical characteristics, such as composition, size, charge and surface reactivity.…”

“…80 It was also reported that CH possesses the ability to reduce the LPS-induced NO levels by Raw 264.7 macrophages. 80,82 This conflicting data can be explained by the preparation procedures of the CH samples and their physicochemical characteristics, such as composition, size, charge and surface reactivity. 76 Taking into consideration the general results from all assays, and the fact that DPBS outcomes are comparable to those of non-treated cells, we concluded that this particle suspension medium did not influence the data.…”

“…79 Also noteworthy is the literature data showing the capacity of CH to produce ROS and consequently oxidative stress. Jesus et al 80 found that ROS production in Raw 264.7 macrophage cells was associated with the %DDA of their CH polymer. Thus an 80% DDA in CH nanoparticles and polymer were able to induce ROS in a concentration-dependent manner, while a 93% DDA did not.…”

Systematic Modification and Evaluation of Enzyme-Loaded Chitosan Nanoparticles

“…The optimized mild and self-controlled system allowed the encapsulation of hPAH in CS nanoparticles, maintaining the enzyme’s functional and biophysical properties. However, CS has been reported as potentially immunogenic and it has also been generally described as a haemostatic material that by a complex series of events, such as protein adsorption, platelet and leukocyte adhesion and activation of coagulation pathway, may potentially result in thrombogenicity [ 12 ]. In line with these observations, depending on its DD, molecular mass (MM) and protonation, CS has been applied as an adjuvant in the development of vaccines and as a haemostatic and complement activating material.…”