Before a reusable medical device obtains market approval and enters real-world clinical settings, it must go through rigorous testing and development to ensure it is safe for use. Verification and validation processes help identify potential safety or functionality issues before a manufacturer submits their device for approval. This is a critical part of guaranteeing new medical device designs meet industry standards and offer effective and dependable solutions for healthcare professionals.
One critical part of device testing is biocompatibility, which determines the safety of the materials used in reusable medical devices. Learn more about biocompatibility and what it means in medical device testing—including what kinds of tests help validate the safety of device materials—with this overview.
What Is Biocompatibility?
Biocompatibility refers to the risk—or lack thereof—of certain materials coming into contact with the body. If a medical device consists of materials that aren’t biocompatible, it leads to harmful reactions and puts patients’ safety at risk. Biocompatible materials don’t cause any adverse reactions, making them safe to use on patients.
Because biocompatibility is all about how materials interact, medical manufacturers must look at each device on a case-by-case level. They must review how the materials of each device interact with a specific part of the body.
For example, a pressure cuff must be able to touch skin without causing irritation. There are many materials that can do that, making it easier to find biocompatible solutions. A scalpel, on the other hand, must be able to enter the body and interact with blood, internal tissues, and other more sensitive areas without creating a harmful reaction. This means biocompatible material options are more limited than they would be for a device intended for external use only.
These different levels of risk call for precise, comprehensive testing. Only through thorough biocompatibility analysis can manufacturers ensure their reusable medical devices are safe for patients in a real-world healthcare setting.
Consequences of Not Testing for Biocompatibility
There is no overstating the importance of biocompatibility in medical device testing. It serves to protect patients, healthcare professionals, and the device itself.
One of the biggest risks of using materials that aren’t biocompatible is the harm it can cause patients. Adverse reactions of non-biocompatible materials can lead to problems ranging from minor irritation to life-threatening complications. These reactions include:
- Skin irritation
- Inflammation
- Cell disruption
- Blood clots
- Narrowing of blood vessels
- Generation of cytotoxic compounds
It is important to note that even biocompatible materials can cause adverse reactions in patients. However, these effects are minor and relatively safe—such as temporary inflammation or other natural immune responses—making them acceptable for use according to industry standards.
Another consequence of non-biocompatible materials is the risk to device safety. Problems such as corrosion, complications in sterility, cleaning, and other reprocessing procedures, or other device damage are more likely to result from non-biocompatible materials.
Biocompatibility Testing
Testing for biocompatibility is a core part of designing and approving medical devices. Through comprehensive testing and analysis, developers choose the right materials to support patient safety as well as device functionality and longevity.
There are several different types of tests medical device manufacturers can use, each looking at different factors of biocompatibility. The most common biocompatibility tests include cytotoxicity, sensitization, irritation, hemocompatibility, genotoxicity, and systemic toxicity.
Cytotoxicity
Cytotoxicity testing is a highly sensitive, in vitro form of biocompatibility testing. It uses cultures of mammalian tissue cells and introduces them to any cytotoxic material present on or in the medical device. Testers then study and evaluate cell growth, reproduction, and any morphological effects that occur.
One of the reasons cytotoxicity testing is so sensitive is that it removes cells from the body’s natural defense against cytotoxins. If cells can resist the harmful effects of cytotoxins in this environment, manufacturers can guarantee a stricter, more dependable level of biocompatibility for their device in a real-world setting.
Sensitization
Sensitization testing aims to prove whether repeated exposure to a device causes an adverse reaction. Certain materials, such as adhesives or biodegradable polymers, can cause allergic reactions or other complications that only arise after repeat exposure. Biocompatibility sensitization testing determines whether a device will cause this type of reaction by using animal models and monitoring their immune systems during repetitive exposure to the device extraction. The test also monitors rest periods between exposure to study antibody production.
Biocompatibility sensitization testing is the most time-consuming biocompatibility test. It should take place later on in the validation process after the device has passed cytotoxicity tests.
Irritation
Irritation testing, like sensitization testing, looks for adverse reactions to extracts of the device. Unlike sensitization testing, though, it specifically focuses on immediate reactions such as skin redness or swelling. This form of biocompatibility testing helps determine if toxic materials are leaching from plastics or other materials at a high enough level to cause harm to patients.
Hemocompatibility
Hemocompatibility is a type of biocompatibility test specific to higher-risk devices that are intended to have direct or indirect contact with circulating blood. Blood hemolysis tests involve exposing mammalian red blood cells to the medical device or device extract. Scientists incubate these test samples for a specific amount of time, giving hemolysis the chance to occur.
After this test period, scientists use centrifugation to detect the presence of hemoglobin, which can’t be removed by centrifuging the cells. If little to no hemoglobin is detected, the device passes the test.
Genotoxicity
Genotoxicity testing aims to determine whether device materials can cause gene mutations, changes in chromosome structure, or other DNA or gene changes. There are several types of genotoxicity testing discussed in the ISO 10993 standard. This form of testing can use mammalian cells, non-mammalian cells, bacteria, yeasts, fungi, or whole animals to study the effects of the device materials on DNA and genes.
Systemic Toxicity
Systemic toxicity refers to the generalized adverse effects of non-biocompatible materials. These effects stem from the absorption, distribution, and metabolism of leachates from the device materials, which allows those materials to harm parts of the body they never come into direct contact with. As a result, systemic toxicity presents a risk for organs and organ systems that never interact with a medical device. There are several systemic toxicity test options discussed in the ISO 10993 standard.
Biocompatibility Testing With Highpower Validation
The team at Highpower Labs has years of experience studying and validating the safety of reusable medical devices. Our comprehensive list of biocompatibility tests adheres to methods outlined by ISO 10993, ANSI/AAMI/ISO TIR15499, and other regulatory guidelines. When you work with Highpower, you work with an expert team that knows the ins and outs of device testing. Learn more about our medical device testing lab and see how we can help you bring your reusable medical device to market when you talk to our team today.