Materials
Now, some countries are exploring how to take PFAS restrictions further. That includes the EU and UK, with the EU currently considering a blanket ban. What does this mean for device makers? The possibility of an outright ban raises a complex challenge: finding replacement materials that can perform to the required standard without harming patients or the environment.
Seeking PFAS substitutes Fluoropolymers have properties that are very hard to replicate, says Professor Ian Cousins of Stockholm University. “I would say it’s nearly impossible to get exactly the same properties [in a replacement material].” Yet there may be alternatives out there. To find them, Cousins and his colleagues at the Department of Environmental Science have developed an online database based on a “functional substitution” approach, which considers the functions PFAS perform and the different ways these could be provided without them. The results, published in the journal Environmental Science & Technology, cover 325 PFAS applications across 18 use categories, including medical products, and identify 530 PFAS-free alternatives overall. The substitution approach asks you to think critically about the function you need the replacement material to have, Cousins explains. You then work backwards from there. He gives an example: when finding an alternative to bisphenol A, an endocrine disruptor, in cashier receipts, you could think about what the end product needs to achieve (conveniently providing specific information). Then, you would consider the various ways to solve that problem. For instance, replacing the chemical itself, using a different paper that doesn’t allow for ink transfer, or using electronic receipts instead. You could apply the same logic to medical devices. In some applications, the substitute might not need to have all of the properties of the fluoropolymer to do what you want it to. “You can find a material or chemical which can replace it, and can give good enough performance and function,” Cousins says. However, he acknowledges that in some cases, suitable alternatives may not yet be available. In practice, this process involves extensive research and testing (particularly when performance and safety requirements are strict). But many labs and companies worldwide are already working on it. PFAS-free hydrophilic coatings are now available, for example. These might be used to create low-friction surfaces for catheters or other devices. Studies show that hydrogels based on polymers such as PEG or chitosan may offer similar properties to PFAS-treated surfaces. Alternative materials to PFAS include the polymer PEEK and polyamides (PA), which are mechanically strong and chemically resistant.
The life-cycle problem It’s also important to consider the life-cycle impact of
www.medicaldevice-developments.com
any potential PFAS alternative. Fluoropolymers may be safe to use, but they can release harmful emissions during manufacture and disposal.
For Cousins, the engineering challenge (finding replacement materials that could do the job) is potentially solvable. “I don’t see it as a problem to find an alternative that works. The question is really: is it really better, in terms of environmental impact, from a life-cycle perspective?”
Here, you want to make sure that a replacement material isn’t just creating new issues. “When you make the monomers [for PFAS] and then during the actual polymerisation process… you release a lot of PFAS,” Cousins says. A well-known example is the release of perfluorooctanoic acid (PFOA), which is harmful to health, when producing the PFAS material PTFE (aka Teflon). However, thanks to regulatory changes (PFOA is heavily restricted in the UK and EU), emissions have improved significantly. Your replacement material might not release PFOA, but if it gives off a different harmful gas, then you’re dealing with another version of the same problem. “You have to think from a whole life-cycle perspective,” Cousins says. “From the extraction of the raw materials all the way to the end of life when it’s disposed of.” Whether a PFAS-free alternative can be disposed of safely is another thing for manufacturers to bear in mind. PFAS-containing devices must be incinerated at high temperatures: it’s the only way to destroy the PFAS and prevent it from re-entering the environment. “But it’s often not done like that,” Cousins adds. “I think the end of life isn’t always optimised.” Plus, there’s the challenge of product development. Under a blanket ban, device makers would also need to identify where PFAS is being used in their processes, says Vishal Thakker, head of the UK Approved Body for Medical Devices and IVDs at the British Standards Institution (BSI). “It can be used in any stage. [For example,] it’s used as an additive when you’re doing extrusion moulding.”
For more complex devices, this can be quite tricky – you may need to trace materials back through the supply chain. Device makers should then make any necessary adjustments (potentially making design, material, or process changes) to these steps, too. There’s an argument that because fluoropolymers are used in many life-saving devices, like cardiac implants, banning their use could be dangerous for patients. Yet this perspective risks overlooking the impact of the device over its lifetime. “I think it’s an emotional argument,” says Cousins. “You have to have a cool head and look at the technical side.”
Getting ready for change With PFAS restrictions on the horizon, device makers must prepare to meet new regulatory requirements. Yet currently, it’s not completely clear what they can expect. According to BSI guidance, EU PFAS restrictions are expected to come into force no earlier
63
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102
