(H-304) Biomimetic Glycopolymer Nanoparticles for Modulating Protein Corona and Immune Interactions for Cancer Drug Delivery

Introduction:: Nanoparticles (NPs) hold tremendous potential as drug delivery systems for cancer therapy; however, their in vivo performance is primarily governed by the formation of a protein corona, which subsequently affects their interactions with the immune system.¹ Traditional PEGylated (Polyethylene glycol) NPs, the current gold standard for creating protein avoidant NP formulations, exhibit drawbacks such as allergic reactions and cold supply chain requirements, as demonstrated by the widespread studies on COVID-19 mRNA vaccines.^2,3 Recently, glycopolymers have emerged as promising biomimetic drug delivery systems. We have shown that NPs synthesized from the glycopolymer poly(methacrylamidoglucopyranose) (PMAG) that incorporate stimuli-responsive blocks such as poly[2(diisopropylamino)ethyl methacrylate] (PDPA) and Poly(propylene sulfide) (PPS) can be used for applications such as active targeting of macrophages and co-delivery of antigen and lipophilic adjuvants.^4,5 While numerous studies have investigated the protein corona of PEGylated NPs, protein coronas for glycopolymers remain significantly underexplored. This study aims to investigate the potential of glycopolymer-based poly[2(diisopropylamino)ethyl methacrylate-b-poly(methacrylamidoglucopyranose) (PDPA-b-PMAG) nanoparticles for modulating protein corona and immuno interactions. We hypothesize PDPA-b-PMAG NPs will reduce protein adsorption and non-specific immune cell interaction compared to PEGylated NPs.


Materials and Methods:: Diblock copolymers PDPA-b-PMAG and PDPA-b-PEGMA (poly[2(diisopropylamino)ethyl methacrylate-b-poly(ethylene glycol) methacrylate) were synthesized by Reversible Addition Fragmentation chain Transfer (RAFT) polymerization and characterized using Nuclear Magnetic Resonance Spectroscopy (NMR). PDPA-b-PMAG, PDPA-b-PEGMA and PLGA (poly(lactic-co-glycolic acid)) NPs were synthesized using a combination of dialysis/nanoprecipitation. The size and surface charge of the nanoparticles were characterized using dynamic light scattering (DLS) and zeta potential measurements. Protein adsorption in human serum was assessed using the bicinchoninic acid (BCA) assay at different NP concentrations, followed by Sodium Dodecyl-Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) and Liquid Chromatography-Mass Spectrometry (LC-MS) to characterize protein identities. Cell viability experiments were conducted on MDA-MB-231 breast cancer cells using the ATP CellTiter-Glo assay to evaluate biocompatibility.


Results, Conclusions, and Discussions:: Results

PDPA-b-PMAG and PDPA-b-PEGMA NPs were monodispersed and smaller than 100 nm, with near-neutral surface charge at physiological pH. PDPA-b-PMAG demonstrated reduced protein adsorption compared to PDPA-b-PEGMA and PLGA, as evidenced by BCA assay results and SDS-PAGE. LC-MS analysis further confirmed the distinct protein corona compositions of the different NP formulations. Both PDPA-b-PMAG and PDPA-b-PEGMA NPs exhibited biocompatibility at high concentrations. These findings indicate that PDPA-b-PMAG NPs hold promise as an alternative surface engineering approach for modulating protein corona and immune- interactions in cancer drug delivery.

Discussion


This preliminary study reveals the potential of PDPA-b-PMAG nanoparticles as a biomimetic material for controlling protein corona dynamics and nano-immuno interactions, circumventing limitations of conventional PEGylation. The reduced protein adsorption and biocompatibility of PDPA-b-PMAG nanoparticles suggest their suitability for immunoengineering applications, addressing concerns such as PEG allergies and cold supply chain demands since PMAG enables the lyophilization and resuspension of glycoNPs.⁴ Interestingly, PDPA-b-PMAG showed lower percentages of many immunogenic proteins like IgG kappa, IgG heavy constant alpha 1 and Alpha-2-HS-glycoprotein compared to PDPA-b-PEGMA and PLGA. This reduced immunogenic protein adsorption is beneficial for drug delivery as it can potentially decrease nanoparticle clearance by the mononuclear phagocyte system (MPS). Also, The PDPA-b-PMAG formulation shows a higher percentage of Alpha-1-acid glycoprotein 1 compared to the PDPA-b-PEGMA and PLGA. Alpha-1-acid glycoprotein 1 is known to bind to several receptors on tumor cells, and higher adsorption of this protein might be exploited to target tumor cells more effectively.⁶

Conclusions


These findings indicate that PDPA-b-PMAG NPs hold promise as an alternative surface engineering approach for modulating protein corona and immune interactions in cancer drug delivery. In future studies, we aim to further establish structure-property relationships on the impact of material properties and protein corona dynamics on nano-immuno interactions, thus leading the way for building predictive computational models for protein corona dynamics and NP-immune cell interactions.


Acknowledgements (Optional): :

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