Enhanced cellular uptake and long-term retention of chitosan-modified iron-oxide nanoparticles for MRI-based cell tracking

Abstract

Tracking cells after therapeutic transplantation is imperative for evaluation of implanted cell fate and function. In this study, ultrasmall superparamagnetic iron oxide nanoparticles (USPIO NPs) were surface functionalized with water-soluble chitosan, a cationic polysaccharide that mediates enhanced endocytic uptake, endosomal escape into the cytosol, and subsequent long-term retention of nanoparticles. NP surface and chitosan were independently fluorescently labeled. Our NPs enable NP trafficking studies and determination of fate beyond uptake by fluorescence microscopy as well as tracking of labeled cells as localized regions of hypointensity in T 2 *-weighted magnetic resonance imaging (MRI) images. Adult rat neural stem cells (NSCs) were labeled with NPs, and assessment of NSC proliferation rates and differentiation potential revealed no significant differences between labeled and unlabeled NSCs. Significantly enhanced uptake of chitosan NPs in comparison to native NPs was confirmed by transmission electron microscopy, nuclear magnetic resonance (NMR) spectroscopy and in vitro cellular MRI at 11.7 Tesla. While only negligible fractions of native NPs enter cells, chitosan NPs appear within membranous vesicles within 2 hours of exposure. Additionally, chitosanfunctionalized NPs escaped from membrane-bound vesicles within days, circumventing NP endo-lysosomal trafficking and exocytosis and hence enabling long-term tracking of labeled cells. Finally, our labeling strategy does not contain any NSC-specific reagents. To demonstrate general applicability across a variety of primary and immortalized cell types, embryonic mouse NSCs, mouse embryonic stem cells, HEK 293 kidney cells, and HeLa cervical cancer cells were additionally exposed to chitosan-USPIO NPs and exhibited similarly efficient loading as verified by NMR relaxometry. Our efficient and versatile labeling technology can support cell tracking with close to single cell resolution by MRI in vitro, for example, in complex tissue models not optically accessible by confocal or multi-photon fluorescence microscopy, and potentially in vivo, for example, in animal models of human disease or injury.

Preparation, characterization, and in vitro and in vivo investigation of chitosan-coated poly (d,l-lactide-co-glycolide) nanoparticles for intestinal delivery of exendin-4

“…36 Panyam et al 37 suggested a rapid endolysosomal escape into the cytosol by PLGA nanoparticles, due to their selective reversal of the surface charge (from anionic to cationic) in the acidic endolysosomal compartment. The similar phenomenon of endolysosomal escape was also reported for chitosanmodified iron oxide nanoparticles, 38 which probably results from the "proton-sponge" effect.…”

Non-chemotoxic induction of cancer cell death using magnetic nanowires

“…33,36 This would have to be taken into account in in vivo applications. For instance, it has been shown that iron oxide nanoparticles remain in an organism for several days 56 or even up to 6 months. 57 aMF-cells interaction Figure 5 shows MTT results when an AMF was applied to colon cancer cells using the MTT assay.…”

Chitosan Modified Poly(lactic-Co-Glycolic) Acid Nanoparticles Interaction With Normal, Precancerous Keratinocytes and Dental Pulp Cells

“…Our results were in agreement with previous studies which showed a high uptake of polymeric NPs when fortifi ed with chitosan, and that the uptake of chitosan coated NPs was much higher that that of uncoated NPs. 6,[30][31][45][46] In a study from 2015, S.Alqahtani showed a signifi cantly higher 3.5 fold cellular uptake of chitosan coated PLGAChi NPs compared to PLGA NPs in Caco-2 cells. 31 In another study, positively charged chitosan covered PLGA NPs exhibited enhanced mucoadhesion, compared to negatively charged PLGA NPs and enhanced intracellular uptake in A549 cell line human lung carcinoma cells.…”