Complex challenges need straightforward solutions

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Arjun Luthra, commercial director, BioInteractions, explains how high-performance multi-phase materials are a straightforward solution to enhancing biocompatible performance.

Biocompatibility: A complex challenge

Biomaterials are routinely used in surgical therapies for short-term and long-term applications. These materials constantly encounter major impediments such as, inflammation, infection, and thrombosis. These complex challenges lead to poorly performing devices as well as increased risks for patients. 

The difficulties are caused by biological events occurring where the biomaterial surfaces interact with the body’s components. Revolutionary biomaterials actively confront the complex nature of these biological events to improve medical device performance and enhance therapies available to patients.  

Biomaterials and blood

Biomaterials used in medical devices are likely to interact with blood first, this interaction is in itself highly complex. When blood interacts with foreign surfaces it triggers a complex series of events. These include protein adsorption, platelet activation and adhesion, coagulation, and thrombosis. The plasma proteins adsorb onto the surface which leads to activation of the blood and subsequent biological responses such as thrombus formation. Thrombus formation is a major problem in the development of long-term, blood contacting devices. A specific example being catheter thrombosis which can be seen in various forms. These forms of thrombosis account for up to 40% of catheter failures, which interrupts strict dialysis schedules, reduces flow rates of catheters, and results in the use of costly measures. Temporary treatments can be used; however, viable long-term options are required.

Biological processes are inherently complex and are governed by a variety of factors, known as surface properties. The surface properties include chemistry, topography, elasticity, surface free energy and charge. These various properties will moderate protein as well as cell interactions and are involved in governing the host response. 

Biomaterials and proteins

Biomaterials interact with blood and its hundreds of proteins, through a wide range of biological functions which are present in significantly different concentrations. Thrombosis is a critical obstacle faced by devices and is impacted by the activity of fibrinogen, fibronectin, vitronectin and von Willebrand factors (vWF).

Proteins promote platelet adhesion to a varying degree, and this is dependent on the substrate and the flow conditions. Fibrinogen is a major contributing factor to the process of biomaterial-induced thrombosis. It mediates platelet adhesion, links platelet aggregates together and stabilizes the thrombus as a fibrin polymer in low stress conditions. The vWF circulates in plasma and mediates platelet tethering, translocation, and adhesion to injured endothelium in high stress conditions. Immobilization and shear induce a conformational change in vWF which enhances binding and results in platelet adhesion.

Proteins themselves, are one of several different factors known to influence the composition, adsorption, structure, and function of proteins. These surface properties include surface free energy and wettability, surface topography and roughness as well as the surface chemistry and functional groups. Protein adsorption which leads to thrombus formation, is an energy-driven process which involves the traits of both proteins and substrates involved. Correlations have been reported between the amount of protein adsorbed on polymeric materials and total surface energy of the substrate. Furthermore, surface wettability is a crucial factor in determining the adsorption of proteins on a surface. This is another contributing factor to determining the adhesion of proteins on a surface. Hydrophobic surfaces tend to adsorb larger amounts of proteins compared to hydrophilic surfaces. This is due to the hydrophilic surface being strongly bound with water molecules which are difficult for proteins to displace. 

There are a wide variety of complex factors which play an important role in the biocompatibility of a surface. The interactions mentioned above are only a few of the many complications seen when biomaterials are used within the human body.

The challenges and the biological responses are influenced by critical factors such as surface chemistry, surface energy and surface topography. The biological events which occur on a surface are a complex result of interactions between the surface and the proteins and cells which are present at the device-body interface. These complex challenges require a straightforward, multi-phase material which considers all these varying factors in one technology. Multi-phase materials provide a high-performance surface which prevent biological responses, enhance device performance, reduce complications to the user (surgeon) and improve patient well-being, in one straightforward solution.  

Multi-phase coatings: A straightforward, high-performance solution

BioInteractions innovates high-performance, multi-phase biocompatible coatings which actively confront the varying and complex biocompatible challenges of medical device surfaces. Our 30 years of research and development, has resulted in a range of proprietary polymer coatings which targets and prevents complex biocompatible challenges. Our coatings enhance medical device performance, improve the usability for the user (surgeon), and reduce patients’ risks and complications throughout the therapy. 

Astute Active Antithrombogenic Coating prevents thrombosis formation using a high-performance, multi-phased solution. The coating technology uses an active antithrombogenic agent combined with additional passive elements to provide a highly effective, non-leaching antithrombogenic coating. The active component actively stops blood activation and prevents a thrombus from forming downstream in a patient. The passive elements electrostatically and physically prevent the various proteins in blood from interacting and adsorbing onto the device surface.

This multi-phased solution mimics the endothelial layer to improve biocompatibility in long-term applications. The coating ensures a high-performance and high-quality surface. The Astute Antithrombogenic Coating provides a highly biocompatible surface that actively stops thrombus formation whilst protecting the surface and improving laminar flow.

BioInteractions innovates and manufactures all our coating technology in house, as well as provides customer focused services. We combined our innovative, multi-phase technology with our expertise to help our partners through the development process and provide a high quality, all-in-one coating experience.

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