Essential aspects of biocompatibility testing of medical devices

What is biocompatibility testing?

Medical devices, such as pacemakers, insulin pumps and surgical instruments are used every day in a variety of medical applications. Medical device manufacturers are crucial in this situation since they are responsible for making sure their products are secure for patients.

Biocompatibility testing is a key aspect of this assurance of safety. Biocompatibility, in the context of medical devices, refers to the ability of a device or material to interact safely with the human body. This rigorous evaluation process is critical to preventing side effects, increasing product efficacy and achieving compliance with regulatory standards.

Why are biocompatibility tests important?

Body fluids can react with materials used in medical devices, e.g. when blood comes into contact with the surface of the device, it can cause dangerous clotting due to material incompatibility. Similarly, metal components in contact with body fluids can corrode and release ions, causing adverse reactions or even tissue damage over time.

Biocompatibility testing is a key control point for detecting potential risks at an early stage in the development and production of medical devices so that the final products are safe and effective.

ISO guidelines for biocompatibility testing

Biological assessment falls within the strict regulatory framework that governs the medical industry. These guidelines describe the necessary testing protocols that vary depending on the nature of the product, its intended use and the duration of contact with the human body.

The ISO 10933 standard of the ISO international organization is the starting point for biocompatibility testing of medical devices and the primary reference point for major global regulatory bodies in Europe, Asia and the United States. The ISO 10993 standard provides a detailed framework for assessing the biosafety of medical devices and covers a wide range of potential interactions with the human body.

Types of biocompatibility testing

Biocompatibility testing should answer a number of questions about the material components used in the finished medical device. If it is not possible to test the entire final product, a representative sample of the medical product is prepared according to the recommendations of ISO 10993. The choice of tests depends on the medical product and its purpose:

• Cytotoxicity: Does it affect cell health, growth and proliferation?
• Sensitization: Does it cause an allergic reaction?
• Irritation: Does it irritate or damage the skin or subcutaneous tissue?
• Long-term effects: Does prolonged exposure affect surrounding tissues and organs?
• Hemocompatibility: Does it cause blood clotting or other side effects?

General workflow of biocompatibility testing

The biocompatibility testing process usually begins with material characterization, where the physical and chemical properties of the materials used in the medical device are documented and analyzed. Depending on the intended use of the product, the duration of contact and the assessed risks, the following series of tests may include cytotoxicity, sensitization, irritation, systemic toxicity or others.

Samples are then prepared, often in the form of extracts, to simulate conditions in living tissues. These samples are tested using standardized protocols, either in controlled laboratory settings (in vitro) or, for certain assessments, using animal models (in vivo).

Risk-based approach to testing

Regulatory bodies, such as the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA), require medical device manufacturers to perform risk assessments as part of their regulatory submissions. This analysis is performed early in development to identify potential hazards associated with the materials of the medical device and its interaction with the human body. Early availability of this data helps inform decisions about design, materials, and testing protocols.

A thorough analysis also streamlines the workflow and reduces the cost of biocompatibility testing. If the material has a well-documented history of safe use, some tests may not be necessary. This allows manufacturers to prioritize and ensure that biocompatibility testing is focused on the most relevant and potentially risky aspects of the device.

The role of laboratory equipment in biocompatibility testing

The choice of fundamental laboratory elements directly affects the accuracy, reliability and repeatability of test results. To ensure product quality and safety, it is best to choose well-known brands, establish rigorous maintenance and calibration procedures and train personnel in the proper use of instruments.

Current analytical methods in biocompatibility testing rely heavily on mass spectrometry to measure extractables and leachables. For best results, it is essential to use ultrapure water and reliable plastic consumables when preparing eluents and calibration standards.

Read: 10 facts about laboratory water systems

Connectivity and compliance support are also essential; regulated laboratories need complete records of protocols and results for traceability and audit readiness. Connected tools also have the benefit of automated reminders for regular maintenance and feature upgrades, ensuring top performance.

Solutions for biocompatibility testing

Sartorius basic laboratory instruments are well known for their performance, usability and connectivity that medical device manufacturers need. Cubis® II analytical balances and Picus® 2 electronic pipettes easily integrate with existing workflows, in addition to offering dedicated applications to manage workflows, devices, operators and routine maintenance.

For HPLC and other elemental analyses, a reliable source of high-quality water such as an Arium® ultrapure water system can prevent up to 80% of data artifacts. Minisart® syringe filters with industry-leading Sartorius membranes also enable robust removal of particulates from samples and help prevent clogging in chromatographic analysis.

Explore laboratory equipment for biocompatibility testing

The article was downloaded and translated from the official Sartorius website.