The information available online regarding ‘characterising existing medical devices’ is vast, however, most of the information that’s instantly accessible on characterisation falls into just two main categories: Chemical characterisation or Material characterisation.
Chemical characterisation is used to assess the safety or biocompatibility of a medical device, usually though in vivo tests. This test looks at whether device components or extracts from the device have the capacity to cause irritation, damage or toxicity through leaching in a biological system.
Material characterisation refers to identifying all the component materials of a device. For example, this can include plasticizers, colourants, metals or ceramics. Mechanical or performance tests are usually used to determine how the material make up of components function in use. This identifies any compositional changes due to fatigue, processing or in some cases accelerated aging.
Both methods are fundamental to accurately carrying out a successful medical device characterisation project but shouldn’t be set apart. They both offer a fantastic insight into the characteristics, performance and life cycle of a device. However, there is more to medical device characterisation than just these two methods. At HD we don’t focus on one area of the device during a characterisation project, instead we look at the device in its entirety, evaluating all aspects: chemical, material, design, fit, form & function.
The first step in device characterisation is simply to understand the device and how it works! Walk through the user steps from the IFU (Instructions for Use) and become accustom to how the device operates, understanding the functionality and identifying the critical features. It is important to identify the physical features of the device and how the individual components interact with each other, looking for snap fits, running fits, clips, threads, living hinges etc. stripping down the device into its individual components, then building it back up again is always a great way to help understand the function and the anatomy of the device.
Once there is an understanding of how the device physically functions, then the chemical / material characterisation section of the project can be kicked off. Correctly identifying the specific polymers or other materials used in the device is extremely important when trying to replicate the characteristics of the clips and fits etc. Having this material knowledge is a huge time saver and a key part of a characterisation project!
Next step, Measurement of components…keep checking back for the next installment!