Influence of Poly(ethylene glycol) Molecular Architecture on Particle Assembly and Ex Vivo Particle–Immune Cell Interactions in Human Blood

Abstract

Poly­(ethylene glycol) (PEG) is widely used in particle assembly to impart biocompatibility and stealth-like properties in vivo for diverse biomedical applications. Previous studies have examined the effect of PEG molecular weight and PEG coating density on the biological fate of various particles; however, there are few studies that detail the fundamental role of PEG molecular architecture in particle engineering and bio–nano interactions. Herein, we engineered PEG particles using a mesoporous silica (MS) templating method and investigated how the PEG building block architecture impacted the physicochemical properties (e.g., surface chemistry and mechanical characteristics) of the PEG particles and subsequently modulated particle–immune cell interactions in human blood. Varying the PEG architecture from 3-arm to 4-arm, 6-arm, and 8-arm generated PEG particles with a denser, stiffer structure, with increasing elastic modulus from 1.5 to 14.9 kPa, inducing an increasing level of immune cell association (from 15% for 3-arm to 45% for 8-arm) with monocytes. In contrast, the precursor PEG particles with the template intact (MS@PEG) were stiffer and generally displayed higher levels of immune cell association but showed the opposite trend―immune cell association decreased with increasing PEG arm numbers. Proteomics analysis demonstrated that the biomolecular corona that formed on the PEG particles minimally influenced particle–immune cell interactions, whereas the MS@PEG particle–cell interactions correlated with the composition of the corona that was abundant in histidine-rich glycoproteins. Our work highlights the role of PEG architecture in the design of stealth PEG-based particles, thus providing a link between the synthetic nature of particles and their biological behavior in blood.

Anti-PEG Antibodies Boosted in Humans by SARS-CoV-2 Lipid Nanoparticle mRNA Vaccine

“…The human blood assay was conducted based on a modified previously developed method. 16 The fresh human blood was collected from a healthy volunteer (donor 16) into sodium heparin vacuettes (Greiner Bio-One). The blood was centrifuged (900 g , 15 min, no brake), followed by removing plasma in the top layer.…”

“…6 To determine the potential of anti-PEG antibodies induced by SARS-CoV-2 LNP mRNA vaccination to promote immune-mediated clearance of nanomaterials containing PEG, we used a previously developed ex vivo human blood assay to assess the impact of plasma on particle−immune cell association (Experimental design shown in Scheme 1). 16 The assay incubates nanoparticles for 1 hr with fresh primary human blood cells containing monocytes, granulocytes, and B cells in the presence of plasma before and after vaccination and measures nanoparticle and immune cell association by flow cytometry (details in Methods, gating strategy shown in Figure S5). We studied three PEGylated nanoparticles, including 100 nm PEGylated mesoporous silica (PEG-MS) nanoparticles, PEGylated doxorubicin-encapsulated liposomes that contain the same lipid composition and drug/lipid ratio as clinically used liposomal doxorubicin agent (Doxil) for anti-cancer chemotherapy, 17 and PEGylated LNPs that were formulated with the same molar composition of lipids used in the US Food and Drug Administration-approved Onpattro (Patisiran) LNP formulation for treating transthyretin-mediated amyloidosis (characterization in Figure 4, Table S4).…”

Tumor Microenvironment-Responsive Shell/Core Composite Nanoparticles for Enhanced Stability and Antitumor Efficiency Based on a pH-Triggered Charge-Reversal Mechanism

“…Coating the surface of nanoscale drug delivery systems (NDDS) with polyethylene glycol (PEG)—namely, PEGylation—has been extensively applied to inhibit protein adsorption and prevent rapid elimination [ 1 ]. The PEGylation strategy thus improves pharmacokinetics of NDDS with prolonged circulation, an enhanced permeability and retention (EPR) effect, and reduced premature drug leakage, while also decreasing collateral damage to normal healthy tissues [ 2 , 3 ]. However, PEGylation hinders the internalization of tumors, resulting in limited tumor accumulation, which is referred to as the “PEG dilemma” [ 4 ].…”

Structure–function relationships in polymeric multilayer capsules designed for cancer drug delivery

“…However, in the case of interaction of immune cells (peripheral blood mononuclear cells) with polystyrene latex beads and their subsequent co-culturing with cancer cells (the HT-29 human colorectal adenocarcinoma or RKO human colon carcinoma cell line), the amounts of three proinflammatory cytokines, TNF-α, IL-1β, and IL-6, decrease, while those of the anti-inflammatory IL-10 and IL-1ra remain unchanged 144 . The presence of PEG molecules on the capsule surface may prevent the capsule uptake by phagocytic cells 145,146 . However, the presence of targeting molecules on top of the PEG coating may enhance the capsule interaction with phagocytic cells, although association with monocytes and granulocytes is not changed significantly after functionalization of PEG-110 capsules with bsAbs.…”