Surface Engineered Carboxymethylchitosan/Poly(amidoamine) Dendrimer Nanoparticles for Intracellular Targeting

Abstract

Novel highly branched biodegradable macromolecular systems have been developed by grafting carboxymethylchitosan (CMCht) onto low generation poly(amidoamine) (PAMAM) dendrimers. Such structures organize into sphere‐like nanoparticles that are proposed to be used as carriers to deliver bioactive molecules aimed at controlling the behavior of stem cells, namely their proliferation and differentiation. The nanoparticles did not exhibit significant cytotoxicity in the range of concentrations below 1 mg mL−1, and fluorescent probe labeled nanoparticles were found to be internalized with highly efficiency by both human osteoblast‐like cells and rat bone marrow stromal cells, under fluorescence‐activated cell sorting and fluorescence microscopy analyses. Dexamethasone (Dex) has been incorporated into CMCht/PAMAM dendrimer nanoparticles and release rates were determined by high performance liquid chromatography. Moreover, the biochemical data demonstrates that the Dex‐loaded CMCht/PAMAM dendrimer nanoparticles promote the osteogenic differentiation of rat bone marrow stromal cells, in vitro. The nanoparticles exhibit interesting physicochemical and biological properties and have great potential to be used in fundamental cell biology studies as well as in a variety of biomedical applications, including tissue engineering and regenerative medicine.

The uptake, retention and clearance of drug-loaded dendrimer nanoparticles in astrocytes – electrophysiological quantification

“…Although not strongly statistically significant (P = 0.103, ANOVA), a visible increase in the rate of endosome formation occurs after the exposure of astrocytes to NPs. In contrast to previous studies where the internalization of the CMCht/ PAMAM dendrimer NPs was detected only after 12 h of incubation, reaching the maximum intracellular load 24 h after exposure, 13 this study revealed changes in vesicle trafficking immediately upon exposure of astrocytes to NPs. These results suggest that the presence of NPs per se may stimulate endocytosis.…”

“…56 CMCht-grafted PAMAM dendrimers have been suggested to follow unspecified endocytotic routes. 13 However, studies involving inhibitors of endocytosis have shown that inhibitors are not selective, influencing more than a single pathway. 57 Therefore, complementary methods are crucial to better understand the mechanisms of cellular NP trafficking.…”

“…CMCht/PAMAM dendrimer NPs have many attractive features that render them promising nanocarrier candidates to be used in biomedical applications, namely in CNS disorders. [12][13][14][15] CMCht/PAMAM dendrimer NPs have already been tested in neuroinflammation models. In vitro and in vivo experiments have shown that CMCht/PAMAM dendrimer NPs are biocompatible in primary nerve cell cultures and cause no toxicity in rat models after intravenous or local administration, 14,15 however the mechanisms underlying the interaction of these NPs with cells remain unclear.…”

“…7 Although it has recently become evident that the physical and chemical properties of dendrimers have a considerable effect on the interaction with cells, particularly cell internalization and trafficking mechanisms, [8][9][10] there are still only a few reports addressing the interplay between dendrimers and cell membranes and intracellular trafficking. 11 Experiments on poly(amidoamine) (PAMAM) dendrimers with carboxymethylchitosan (CMCht), incorporating the therapeutic lipophilic drug, methylprednisolone (MP), [12][13][14] revealed their potential for use as nanocarriers in the central nervous system (CNS) for conditions targeting injured neural tissue. 15,16 However, how these NPs interact with neuroglia, homeostatically supporting neuronal networks and contributing to the maintenance of the blood-brain barrier, has not yet been addressed.…”

Chitosan derivatives obtained by chemical modifications for biomedical and environmental applications

“…Very recently novel water-soluble nanoparticles that consist of a PAMAM dendrimer core with grafted carboxymethyl chitosan chains were successfully synthesized [120]. The non-cytotoxicity and successful internalization of these dendrimer nanoparticles by two different types of cells, i.e., cell lines and primary cultures, was demonstrated in this work.…”