Biology offers new non-stick technology
Medical device manufacturers need materials that are not only biocompatible but will help reduce adverse interactions and improve performance. Speciality chemicals supplier Vertellus has developed a technology that fits the bill
Recent developments in drug/device combination products have brought about a step-change in parts of the medical device arena. Perhaps the most notable example has been the drug-eluting stent (DES) market, which saw an explosion of growth from US$1.5bn to $5bn (b1bn to b3.4bn) over a two-year period.
In particular, phosphorylcholine (PC) coatings have played a significant part in this area, with the launch of Abbott Laboratories’ PC/dexamethasone-coated Dexamet stent and Medtronic’s PC-coated zotarolimus-eluting Endeavor DES system. The latter system has shown no cases of late stent thrombosis after two years follow-up in a trial group of around 1,300 patients. These applications illustrate the value that PC materials can bring to the medical market.
Vertellus Biomaterials, based in Hampshire, UK, is a business unit of Vertellus Specialties UK, and has been exploiting PC Technology – a proprietary platform of polymers incorporating phosphorylcholine – in healthcare and industrial applications.
Polar material
In this biomimetic range of synthetic methacrylate-based polymers, the PC group has both positive and negative charges but is overall electrically neutral. The resulting materials are very polar and have a great affinity for water. As a result, materials with the PC group are surrounded by molecular layers of water that effectively mask the substrate, providing a biological “non-stick” surface that resists protein or cell adhesion.
The flexible chemistry upon which PC polymers are based allows modification with a wide range of monomers. The resulting polymers are available as coatings, bulk materials, gels or solutions and can be customised for each application, especially medical devices and industrial antifouling products. They can offer specific properties such as:
- resistance to protein adhesion
- antifouling properties
- reduced soiling
- easy cleaning
- conditioning properties
- non-irritant properties
- improved wicking
- reduced bacterial adhesion
- reduced odour.
The PC materials demonstrate improved compatibility with soft tissue, making them particularly useful as drug depot matrices. PC coatings have also been shown to reduce the adhesion of proteinaceous drugs to glass and plastic surfaces: this could reduce loss of actives through adsorption and aggregation in primary pharmaceutical packaging applications. Vertellus has built up experience in the development and commercialisation of new drug device combinations that offer clinical benefit through the controlled release of therapeutic agents.
The clinical benefits of PC Technology are also demonstrated through three FDA-allowed label claims including: “…The coating has been shown to be resistant to staphylococcal biofilm formation and pseudomonal biofilm formation….” They also reduce blood activation and inflammatory response, cutting the risk of thrombosis.
This means the materials have particular potential in medical device applications, such as stents, guide-wires, blood circuit components, dialysis components, intra-ocular lenses, catheters and more.
PC has also been shown to reduce fouling in oral healthcare applications and to demonstrate moisturising properties in cosmetics. It has potential wider uses in latex products, textiles, building materials, anti-fouling paints and coatings for food processing equipment.
The ability to reduce bacterial adhesion and biofilm formation can offer benefits of reduced risk of infection in hospitals and reduced contamination and spoilage in food processing areas. Its ability to reduce protein adhesion also means reduced fouling and easier cleaning of food processing and pharmaceutical processing equipment. The materials have been used successfully to coat metals, plastics, rubbers, glass and ceramics, tooth enamel and other tissues.
Vertellus Specialities UK, which is part of the Health and Specialty Products Division of Vertellus Specialties Inc, has established facilities for the production of bulk tonne quantities of PC materials and has recently opened a new polymer chemistry r&d laboratory to support the bio-materials division. The company also welcomes any collaborations that would investigate new applications for PC technology.