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The biological response to nanometre-sized polymer particles
Aiqin Liu1, Laura Richards1, Catherine L Bladen1
1Institute of Medical and Biological Engineering, University of Leeds, Leeds LS2 9JT, UK.
Acta Biomaterialia
|May 26, 2015
Summary
Nanometre-sized wear particles from joint replacements do not trigger an inflammatory response. However, micrometre-sized particles and larger nanometre-sized particles significantly increase osteolytic cytokine release, indicating size is critical for biological activity.
Area of Science:
- Biomaterials Science
- Immunology
- Orthopedic Surgery
Background:
- Nanometre-sized ultra-high molecular weight polyethylene (UHMWPE) particles from joint replacements are increasingly identified.
- Micrometre-sized UHMWPE particles (0.1-1.0μm) are known to provoke inflammatory responses linked to aseptic loosening.
- The biological activity of nanometre-sized particles remains largely unstudied.
Purpose of the Study:
- To investigate the biological response of nanometre-sized and micrometre-sized UHMWPE particles.
- To compare the osteolytic cytokine release induced by various particle sizes and types.
- To determine the threshold size for particle-induced inflammatory activation.
Main Methods:
- Primary human peripheral blood mononuclear cells (PBMNCs) were exposed to clinically-relevant UHMWPE wear particles (nano- and micro-sized).
- Model nanometre-sized polyethylene particles (Ceridust 3615®) and polystyrene particles (FluoSpheres, 20nm-1.0μm) were used for comparison.
- Osteolytic cytokine release (TNF-α, IL-1β, IL-6, IL-8) was measured after 12 and 24 hours.
Main Results:
- Nanometre-sized UHMWPE, Ceridust 3615®, and 20nm FluoSpheres did not significantly increase cytokine release.
- Micrometre-sized UHMWPE particles (0.1-1.0μm) and larger FluoSpheres (60nm, 200nm, 1.0μm) significantly elevated osteolytic cytokine release.
- Particles below approximately 50nm appeared to fail in activating PBMNCs.
Conclusions:
- Particle size is a critical factor in the biological response of PBMNCs.
- Particles below a certain size threshold (circa 50nm) do not elicit a significant osteolytic cytokine response.
- Particle size, composition, and morphology critically influence cytokine release from stimulated macrophages.
