Cell-Membrane-Inspired Silicone Interfaces that Mitigate Proinflammatory Macrophage Activation and Bacterial Adhesion

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Medical Device Engineering

Background:

• Biofouling on silicone implants leads to severe complications including fibrotic encapsulation, infection, and device failure.
• Developing effective antifouling and antibacterial surfaces is crucial for improving the long-term performance and biocompatibility of medical implants.

Purpose of the Study:

• To engineer antifouling and antibacterial silicone surfaces by covalently grafting a cell-membrane-inspired zwitterionic gel layer.
• To investigate the influence of substrate stiffness on cell adhesion and inflammatory response.
• To assess the efficacy of the modified surfaces in preventing macrophage and bacterial attachment.

Main Methods:

• Surface modification of poly(dimethylsiloxane) (PDMS) with 2-methacryloyl phosphorylcholine (MPC) using surface-initiated atom-transfer radical polymerization (SI-ATRP).
• Culturing human-blood-derived macrophages and Escherichia coli on PDMS and MPC gel surfaces with varying stiffness (0.5-50 kPa).
• Contact angle measurements to confirm surface hydrophilicity and cytokine secretion assays to evaluate inflammatory response.

Main Results:

• MPC gel surfaces exhibited superhydrophilicity and resistance to biofouling, preventing stable cell adhesion.
• MPC-modified PDMS surfaces showed a significant decrease in contact angle from 110° to 20°.
• Macrophage and bacterial attachment were reduced by over 70% on MPC-grafted surfaces compared to unmodified PDMS.
• MPC gels demonstrated a lower potential for triggering pro-inflammatory macrophage activation.

Conclusions:

• Covalent grafting of MPC zwitterionic gel layers creates effective antifouling and antibacterial silicone surfaces.
• These modified surfaces significantly improve the biocompatibility of silicone implants by reducing inflammatory responses and microbial adhesion.
• The developed technology offers a promising strategy for enhancing the long-term success and safety of various medical implants.