Nanoparticle Surface Engineering with Heparosan Polysaccharide Reduces Serum Protein Adsorption and Enhances Cellular Uptake

Abstract

Nanoparticle modification with poly­(ethylene glycol) (PEG) is a widely used surface engineering strategy in nanomedicine. However, since the artificial PEG polymer may adversely impact nanomedicine safety and efficacy, alternative surface modifications are needed. Here, we explored the “self” polysaccharide heparosan (HEP) to prepare colloidally stable HEP-coated nanoparticles, including gold and silver nanoparticles and liposomes. We found that the HEP-coating reduced the nanoparticle protein corona formation as efficiently as PEG coatings upon serum incubation. Liquid chromatography–mass spectrometry revealed the protein corona profiles. Heparosan-coated nanoparticles exhibited up to 230-fold higher uptake in certain innate immune cells, but not in other tested cell types, than PEGylated nanoparticles. No noticeable cytotoxicity was observed. Serum proteins did not mediate the high cell uptake of HEP-coated nanoparticles. Our work suggests that HEP polymers may be an effective surface modification technology for nanomedicines to safely and efficiently target certain innate immune cells.

Controlling Nanoparticle Uptake in Innate Immune Cells with Heparosan Polysaccharides

“…In Figure S1, we demonstrated that HEP-coated gold nanoparticles (HEP-AuNPs) efficiently target antigen-presenting cells, such as macrophages and dendritic cells, consistent with our previous findings . This study used RAW 264.7 macrophages and DC 2.4 dendritic cells as model immune cells.…”

“…To further validate the time-dependent cellular internalization, we performed confocal laser scanning microscopy (CLSM) to monitor the nanoparticle uptake behavior in real-time in RAW 264.7 macrophages up to 7 h post-incubation (Figure C,D; Figure S4). The HEP-AuNPs were imaged label-free via nanoparticle light scattering and were mainly present surrounding the cell membrane after 1 h of incubation. , We observed strong intracellular nanoparticle signals at 4.5, 5, and 7 h time points post-incubation. To corroborate the intracellular localization, we subsequently visualized the spatial distribution of nanoparticles in RAW 264.7 macrophages at 3, 6, and 24 h (Figure E and Figure S5) and DC 2.4 dendritic cells at 3 and 24 h (Figure S6) post-incubation by transmission electron microscopy (TEM).…”

“…In the past decade, multiple nanoparticle surface engineering strategies have been used to target cells of the innate immune system. ,− However, the observed levels of nanoparticle uptake are not always appropriate for clinical use and may cause cellular or systemic toxicity. , There is a need to develop methods to control nanoparticle uptake into innate immune cells to elicit desired immune responses. ,,− This approach can minimize undesirable side effects of nanomedicines, enabling the development of new nanoparticle-based applications for immunomodulation, immunotherapy, and vaccination. ,,− …”

“…We demonstrated that heparosan (HEP) is an effective surface engineering technology to create nanoparticles that exhibit reduced protein corona formation with favorable interactions with antigen-presenting cells . This study investigated the interactions between HEP-modified nanoparticles and innate immune cells mechanistically by determining the nanoparticle cellular uptake characteristics and associated endocytosis pathways.…”

Absolute Quantification of Nanoparticle Interactions with Individual Human B Cells by Single Cell Mass Spectrometry

“…We then qualitatively assessed nanoparticle association with B cells with CLSM using a label-free light scattering approach to visualize AuNPs associated with B cells. , Due to the ability of metallic nanoparticles to scatter light, fluorophores were not required to visualize AuNPs. Interestingly, only B cells exposed to K7C-modified AuNPs had detectable intracellular CLSM light scattering signals (Figure C).…”