The material at the heart of the study, published in the journal Angiogenesis, is a polymer built from 2-methacryloyloxyethyl phosphorylcholine, abbreviated MPC, whose side chains carry the same phosphorylcholine head group that decorates the outer leaflet of every human cell membrane. Phosphorylcholine-based polymers have a long and distinguished history in biomedical engineering precisely because of this biomimicry. They are zwitterionic, meaning they carry paired positive and negative charges that produce a strongly hydrated surface, which resists protein adsorption, platelet adhesion, and thrombus formation. That property has made MPC polymers the coating of choice for cardiovascular stents, contact lenses, and other blood-contacting medical devices. What the Montreal team, led by co-senior authors May Griffith and Bruno Larrivée, has done is to flip the script on this famously inert material: instead of exploiting phosphorylcholine chemistry to keep cells at arm’s length, they deploy nanoparticles of the polymer as an active biological stimulus that vessel cells willingly devour.

The nanoparticles themselves are formed from polyMPC, the polymerized form of the methacrylated monomer, and were engineered to fall below a critical size threshold of roughly 150 nanometers in diameter. That figure is not arbitrary. Work on size-dependent cellular uptake stretching back to classic studies of clathrin- and caveolae-mediated endocytosis has shown that particles in this range are internalized by cells far more efficiently than larger counterparts, which tend to remain at the surface or enter through less productive pathways. When the researchers exposed human umbilical vein endothelial cells, the workhorse HUVEC model of vascular biology, to these sub-150-nanometer particles, the cells readily swallowed them. Once inside, the nanoparticles did something remarkable: rather than sitting inertly in endosomes, they triggered a cascade of signaling events that pushed the endothelial cells into an actively angiogenic state.

Tracing that cascade led the team to protein kinase C, or PKC, a family of enzymes that sits at a major signaling crossroads in many cell types. Upon internalization of the polyMPC nanoparticles, PKC was recruited to the plasma membrane, the canonical step that converts the kinase from an inactive cytosolic form into its active, membrane-bound state. PKC activation in endothelial cells is tightly linked to the stimulation of endothelial nitric oxide synthase, which produces nitric oxide, a master regulator of vessel dilation, endothelial migration, and new vessel sprouting. The finding that a synthetic zwitterionic polymer can engage this pathway offers a mechanistic explanation for how a material long considered biologically quiet can, in nanoparticle form, become a potent pro-angiogenic agent. It also suggests that the cell membrane itself, or the membrane trafficking machinery that processes the internalized particles, may be the unexpected trigger that converts a physical delivery event into a biochemical signal.

The downstream consequences of this activation were mapped with RNA sequencing, an unbiased technique that captures the full transcriptional response of treated cells. The profiles of HUVECs exposed to polyMPC nanoparticles showed upregulation of pro-angiogenic growth factors, including VEGF and fibroblast growth factor 2 (FGF2), two of the most important drivers of blood vessel growth in both development and repair. In other words, the nanoparticles did not act as growth factors themselves; they acted upstream, flipping genetic switches inside endothelial cells so that the cells became factories for their own angiogenic signals. Functional assays confirmed the transcriptional story: treated endothelial cells proliferated more vigorously and mounted characteristic angiogenic responses in culture, forming the tube-like networks that are the in vitro hallmark of vessel-forming behavior.

Crucially, the pro-angiogenic effect was not confined to a single cell type. The researchers found that polyMPC nanoparticles also promoted the expansion of endothelial progenitor cells derived from human cord blood and bone marrow. These progenitors are the circulating seed cells that the body uses to repair and rebuild vasculature, and their mobilization and expansion are central goals of cell-based approaches to ischemic disease. A material that can simultaneously stimulate mature endothelial cells and support the growth of progenitor populations could therefore act on both arms of vascular regeneration, the local sprouting of new vessels from existing ones and the recruitment of the cellular precursors that seed new vascular networks.

To test whether the effect would survive the far messier environment of living tissue, the team implanted polyMPC nanoparticles inside Matrigel plugs under the skin of mice, a standard in vivo assay in which a basement-membrane extract serves as a neutral scaffold. Blood vessels from the surrounding host tissue grow into the plug only if something inside it attracts them, so the degree of vascularization provides a direct readout of pro-angiogenic activity. The polyMPC-laden plugs produced a significant angiogenic response, drawing in host vessels at levels that confirmed the cell culture results translated to a living organism. Equally important was a observation about persistence: the delivered nanoparticles could be retained in tissue for extended periods, which means a single implantation could provide a sustained stimulus rather than the brief pulse of activity that plagues injected protein therapeutics. Because the nanoparticles work by inducing the tissue’s own production of VEGF, FGF2, and other growth factors, the therapeutic signal is continuously renewed at the site where it is needed, in the correct proportions and in the natural context of the tissue microenvironment.

The clinical problem the researchers are aiming at is enormous. Ischemic vascular pathologies, including peripheral artery disease, critical limb ischemia, and myocardial infarction, affect hundreds of millions of people worldwide and are a leading cause of amputation and heart failure. Existing attempts at therapeutic angiogenesis have ranged from gene therapy delivering VEGF or hepatocyte growth factor genes to infusions of autologous stem cells, with mixed and often underwhelming results in controlled trials. Recombinant protein approaches face pharmacological hurdles: free growth factors have short half-lives, risk ectopic vessel growth and leaky, malformed vasculature, and are costly to produce in pharmaceutical grade. The polyMPC strategy sidesteps several of these objections at once. The particles are made from a polymer with an established safety record in approved medical devices, they are relatively inexpensive to synthesize compared with recombinant proteins or viral vectors, and their mechanism recruits the body’s own regulated programs of vessel growth rather than flooding tissue with a single supraphysiological factor.

There are also broader implications for the field of biomaterials science. Phosphorylcholine polymers have been celebrated for four decades as the archetypal non-fouling, non-activating surface chemistry, and their zwitterionic cousins are now being engineered into next-generation lipid nanoparticles for drug and RNA delivery, where their ability to modulate interactions with lipid rafts and membrane trafficking pathways is increasingly recognized. The Montreal study adds a new chapter to that story by showing that the same membrane-mimetic chemistry, presented in the right physical form and size range, can be an active participant in cell signaling rather than a passive bystander. The boundary between a biomaterial that hides from biology and one that directs biology may be thinner than the field has assumed, and size, presentation, and cell type all appear to determine which side of that boundary a given formulation occupies.

The work remains at the preclinical stage, and the path from subcutaneous Matrigel plugs in mice to treating a diabetic patient’s ischemic foot is long and demanding, requiring tests of dose, delivery route, long-term biocompatibility, and efficacy in models of true tissue ischemia. The authors have filed a provisional patent application through their hospital research centre, a signal that they see a translational pathway for the technology. Even at this early stage, the concept is striking: a cheap, stable, biocompatible polymer particle that quietly enters blood vessel cells, wakes up their internal growth programs, and leaves the tissue to heal itself with vessels built from its own blueprint. If that concept survives the gauntlet of preclinical and clinical testing, phosphorylcholine, one of the most familiar molecules in biomaterials science, may find its most consequential role not in coating devices, but in regrowing the vasculature that failing tissues so desperately need.

Subject of Research: Polymer nanoparticles that stimulate angiogenesis in ischemic tissue

Article Title: Angiogenesis-promoting properties of phosphorylcholine mimetic nanoparticles

Article References: Moradi, M., Poudel, B. K., Hooker, E., Aghajanzadeh-Kiyaseh, M., Rusu, D., Griffith, M., & Larrivée, B. (2026). Angiogenesis-promoting properties of phosphorylcholine mimetic nanoparticles. Angiogenesis, 29(4), Article 71. https://doi.org/10.1007/s10456-026-10094-0

Image Credits: AI Generated

DOI: 10.1007/s10456-026-10094-0

Keywords: angiogenesis, nanoparticles, polyMPC, phosphorylcholine, therapeutic angiogenesis, endothelial cells, protein kinase C, VEGF, FGF2, endothelial progenitor cells, RNA sequencing, ischemic disease