In vivo leucocyte interactions on Pellethane surfaces

Area of Science:

• Biomaterials Science
• Immunology
• Polymer Science

Background:

• Understanding leukocyte-biomaterial interactions is crucial for developing biocompatible medical implants.
• Pellethane, a polyurethane elastomer, is used in various medical devices, but its interaction with immune cells requires further characterization.

Purpose of the Study:

• To investigate the in vivo leukocyte interactions with Pellethane materials of varying hardness.
• To quantitatively and qualitatively assess cellular events at the leukocyte-biomaterial interface over a 21-day implantation period.

Main Methods:

• Utilized a cage implant system for in vivo studies.
• Employed scanning electron microscopy (SEM) for qualitative surface evaluation.
• Performed quantitative assays including intracellular enzyme activity, cell density, and foreign body giant cell (FBGC) formation.
• Conducted contact angle analysis to determine surface properties.

Main Results:

• Increased Pellethane hardness correlated with enhanced leukocyte activation, indicated by higher intracellular enzyme activity and cell density.
• SEM revealed macrophage adherence, spreading, and fusion into FBGCs on Pellethane surfaces.
• Foreign body giant cells exhibited increased fusion ability, membrane spreading, cytoplasmic vacuoles, and prolonged enzymatic activity compared to macrophages.
• Pellethane surfaces were characterized as hydrophobic with low hysteresis, and surface tension increased with hardness.

Conclusions:

• Pellethane hardness significantly influences in vivo leukocyte response, promoting greater cellular activation and FBGC formation with increasing hardness.
• Surface properties, including hydrophobicity and surface tension, are affected by Pellethane hardness and may contribute to observed cellular interactions.
• These findings provide insights into the biocompatibility of Pellethane and inform the design of polyurethane-based medical devices.