Harrick Plasma → Applications → Materials → Polymers →
Silicone elastomers are widely used in medical devices and soft robotic systems because of their flexibility, chemical stability, and ease of fabrication. Examples include breast implants, urinary catheters, neural shunts, pacemaker leads, tubing, soft robots, and microfluidic devices.
However, unmodified silicone surfaces are typically hydrophobic and bioinert, which can limit coating adhesion, promote biofouling, or contribute to adverse host responses such as fibrosis and thrombosis.
Ambient temperature RF plasma treatment using Harrick Plasma Cleaners provides a robust, solvent‑free route to chemically activate silicone surfaces and enable stable functional coatings. Plasma introduces polar functional groups, enhances wettability, and enables covalent bonding of hydrogels, small molecules, dendrimers, and nanocomposites.
This Application Note summarizes plasma‑enabled surface engineering across three major categories of silicone medical devices. Below you will find a Summary Table of plasma parameters and outcomes.
Silicone Breast Implants
Plasma treatment plays a critical enabling role in preparing silicone breast implants for advanced anti‑fibrotic surface coatings. In published studies, smooth silicone implants were exposed to air plasma for one minute per side using a Harrick Expanded Plasma Cleaner, operated at 700–800 mTorr, to oxidize the surface and introduce reactive functional groups. This activation step allowed immediate covalent bonding of the small‑molecule coating Met‑Z2‑Y12, which was confirmed through mass spectrometry and nuclear magnetic resonance. Plasma‑enabled coatings produced significant reductions in capsule thickness, especially under challenging conditions such as delayed radiotherapy, demonstrating that plasma treatment is essential for achieving stable, biologically active surface modifications on silicone breast implants.
Silicone Breast IMplant Articles
Karinja, S. J., Bernstein, J. L., Mukherjee, S., Jin, J., Lin, A., Abadeer, A., Kaymakcalan, O., Veiseh, O., & Spector, J. A. (2023). An antifibrotic breast implant surface coating significantly reduces periprosthetic capsule formation. Plastic & Reconstructive Surgery, 152(4), 775–785. https://doi.org/10.1097/prs.0000000000010323
Yevick, H. G., Duclos, G., Bonnet, I., & Silberzan, P. (2015). Architecture and migration of an epithelium on a cylindrical wire. Proceedings of the National Academy of Sciences, 112(19), 5944–5949. https://doi.org/10.1073/pnas.1418857112
Silicone Urinary Catheters & Urological Devices
Plasma activates silicone urinary catheters and other urological devices, creating reactive surface groups that enable stable bonding of advanced antimicrobial, antifouling, and low‑friction coatings. Oxygen plasma irradiation has been shown to generate surface radicals that covalently immobilize multifunctional fucoidan‑MoS₂ nanomicelles on silicone catheters, producing durable antibacterial, anti‑inflammatory, and anti‑adhesive performance under physiologic conditions. In other studies, oxygen plasma applied for 45 seconds at 30 W enabled strong grafting of tough hydrogel laminates to silicone tubing and catheter surfaces, yielding highly lubricious, impermeable coatings that resist delamination even under severe deformation. Air plasma treatment has also allowed uniform formation of ultrathin hydrogel “skins” on both the inner and outer surfaces of silicone Foley catheters, producing tissue‑like softness, exceptional antifouling behavior, and long‑term mechanical stability. Collectively, these plasma‑enabled modifications significantly enhance silicone catheter biocompatibility and performance across diverse urological applications.
Key Outcomes
• Reduced bacterial adhesion
• Lowered inflammatory response
• Improved hemocompatibility
Silicone Urinary Catheter & Urological Device Articles
Yu, Y., Yuk, H., Parada, G. A., Wu, Y., Liu, X., Nabzdyk, C. S., Youcef‐Toumi, K., Zang, J., & Zhao, X. (2018). Multifunctional “Hydrogel Skins” on Diverse Polymers with Arbitrary Shapes. Advanced Materials, 31(7), e1807101. https://doi.org/10.1002/adma.201807101
Zhu, Z., Yu, F., Chen, H., Wang, J., Lopez, A. I., Chen, Q., Li, S., Long, Y., Darouiche, R. O., Hull, R. A., Zhang, L., & Cai, C. (2017). Coating of silicone with mannoside-PAMAM dendrimers to enhance formation of non-pathogenic Escherichia coli biofilms against colonization of uropathogens. Acta Biomaterialia, 64, 200–210. https://doi.org/10.1016/j.actbio.2017.10.008
Neural & Hydrocephalus‑Related Silicone Devices
Plasma modification has also proven valuable for silicone components used in neural and hydrocephalus‑related devices, where unwanted cell overgrowth can compromise function. In these applications, silicone surfaces are exposed to a 5‑minute oxygen plasma treatment using systems such as the Harrick Basic Plasma Cleaner, creating an oxidized, more reactive interface. This activated surface readily supports the formation of hydrophobic self‑assembled monolayers, including fluorinated and alkyl silanes, which maintain stable contact angles over extended periods in saline. These plasma‑enabled coatings significantly limit the attachment and proliferation of astrocytes and choroid plexus epithelial cells—two cell types closely associated with shunt obstruction—highlighting plasma treatment as a practical strategy to improve the longevity and reliability of silicone‑based neurological implants.
Neural & Hydrocephalus Related Silicone Devices
Patel, K. R., Tang, H., Grever, W. E., Ng, K. Y. S., Xiang, J., Keep, R. F., Cao, T., & McAllister, J. P. (2005). Evaluation of polymer and self-assembled monolayer-coated silicone surfaces to reduce neural cell growth. Biomaterials, 27(8), 1519–1526. https://doi.org/10.1016/j.biomaterials.2005.08.009
Conclusion
Across breast implants, urinary catheters, and neural/hydrocephalus devices, plasma treatment reliably transforms silicone’s inert surface into a chemically reactive platform for durable, functional biomedical coatings. Harrick Plasma Cleaners provide the activation step that enables covalent bonding, antifouling hydrogels, beneficial biofilms, anti‑fibrotic molecules, and reduced cellular adhesion, extending the performance and biocompatibility of silicone‑based devices.
| Device Type | Plasma Parameters | Surface Chemistry Enabled | Key Outcomes |
| Breast implants | Air plasma 60s each side, 30 W, 700–800 mTorr, Harrick Expanded Plasma Cleaner | Covalent attachment of Met‑Z2‑Y12 small molecule after plasma oxidation | Significant reduction in capsule thickness; densified collagen alignment; altered macrophage infiltration |
| Urinary catheters (Fu–MoS₂ nanocoating) | Plasma irradiation used to activate silicone catheters for immobilization of nanomicelles (oxygen plasma used to generate radicals) | Covalent grafting of Fu–MoS₂ nanomicelles to plasma‑activated silicone | Reduced bacterial adhesion, inflammation, coagulation, and tissue adhesion |
| Tubing / catheters (Hydrogel laminates) | 45s O₂ plasma, 30 W, 350 mTorr, Harrick Expanded Plasma Cleaner | Benzophenone‑enabled UV‑grafted tough hydrogel laminate onto silicone | Strong hydrogel–elastomer bonding, low friction, impermeable to small molecules, withstands stretching and deformation |
| Foley catheters (Hydrogel skins) | 3‑minute atmospheric plasma using Harrick Expanded Plasma Cleaner | Formation of interpenetrating hydrogel skins (5–25 µm) on inner/outer surfaces | Tissue‑soft surfaces (~30 kPa), antifouling, highly lubricious, mechanically robust |
| Catheter biofilm strategy (Mannoside–dendrimer coating) | 45s CO₂ plasma, 6.8 W, Harrick Basic Plasma Cleaner | Covalent immobilization of PAMAM–PPh‑Man dendrimers | Dense fim⁺ E. coli biofilms; >3‑log reduction of uropathogen colonization over 11 days; biofilm withstands >0.5 Pa shear |
| Anti‑fibrotic catheter coatings | Multiple cycles of 30W air plasma, 600–700 mTorr, Harrick Expanded Plasma Cleaner | Covalent bonding of Met‑Z1‑A3 / Met‑B2‑A17 anti‑fibrotic small molecules | Reduced capsule thickness around silicone catheters in vivo |
| Neural / hydrocephalus silicone devices | 300s oxygen plasma treatment, Harrick Basic Plasma Cleaner | Deposition of hydrophobic SAMs (OTS / FAS) on activated silicone | Reduced astrocyte and choroid plexus cell adhesion; improved resistance to fouling; stable contact angles for 30 days |