Bioplastics are nothing new to the medical sector. In fact, it’s one of the sectors where bioplastics have been in use for a very long time because they offer significant benefits in terms of specific properties and functionalities. They also provide opportunities to make applications and processes more sustainable – a field of innovation that is only slowly tapped into in the medical sector.
Sustainable feedstock is key for bio-based plastics
Bioplastics are produced from renewable resources, mainly from crops like corn, sugar beet, or castor plants. But lignocellulosic feedstock, like wood, is also used, and other options, like organic waste or algae as feedstocks are being explored, too. The use of agri-based feedstock to produce bioplastics is still subject of a rather emotional debate. Yet, the global agricultural area currently used to cultivate crops for bioplastics amounts to not more than 0.02%. To guarantee sustainable sourcing of feedstock, dedicated certification schemes are in place that specifically focus on environmental and socioeconomic aspects along the entire biomass value chain. Life cycle assessment (LCA) can be another tool that is used to assess the environmental sustainability of bioplastics, ensuring that potential impacts on the environment from feedstock sourcing to end-of-life options are minimised. Compared to fossil-based plastics, the use of bio-based plastics helps to reduce the dependency on non-renewable resources and reduce the emission of greenhouse gases., and to increase resource efficiency through a closed resource cycle and use cascades. Additionally, bioplastics offer established and new end-of-life options.
The choice of material and right end-of-life option
Biocompatible materials have gained lots of interest for medical applications. For example, surgical sutures made of polylactic acid (PLA)1 are already well-established, starch-based materials are used in scaffolds for tissue engineering2. When choosing the right bioplastic material to be used for a certain medical application, looking at available end-of-life routes is crucial. It is an aspect that is often overlooked, but that is an essential factor in making the medical sector more sustainable. While the standard ISO 10993 provides test methods for the biological evaluation of medical devices, biocompatibility needs to be distinguished from biodegradability. Speaking about or claiming biodegradation of plastics (outside of the human body) requires a clear designation of time frame, environment, and purpose. Since most of the medical applications are single-use plastic products and the waste is being collected properly, biodegradation in industrial composting or anaerobic digestion facilities (requirements for this so-called organic recycling are laid down in EN 13432 and EN 14995) could be a potential end-of-life route for some of products. There have been successful approaches with on-site anaerobic digestion systems in hospitals for the organic recycling of bedpans and urine bottles made of PHAs3. However, industrial compostable plastics are most beneficial in applications that help to increase the collection of biowaste.
Yet, most of the waste from hospitals and medical applications will have to be incinerated due to contamination, i.e. recycling in whatsoever form is not an option. Here bioplastics can be advantageous due to their bio-based content. Materials like for example bio-based PP (applicable for ventilator breathing circuits), bio-based TPEs, or PLA are produced using crops (or waste products thereof) including their biogenic carbon, which is set free as carbon dioxide to the atmosphere once the material is incinerated or composted. That way, the carbon cycle stays closed, and the overall greenhouse gas emissions are not increased.
The independence of non-renewable resources, the uptake of biogenic carbon, a potential for closed-looped systems, combined with innovative properties that meet the demand of the medical sector, are strong arguments for a long-term change to sustainable bioplastics.
1) Madhavan N.K., Nair N.R., John R.P. An overview of the recent developments in polylactide (PLA) research. Bioresource Technol. 2010;101, pp. 8493–8501.
2) Riza Roslan et al. Tissue Engineering Scaffold Based on Starch: A review. International Conference on Electrical, Electronics, and Optimization Techniques (ICEEOT; Conference Paper). 2016
3) Karen Laird, Reinventing Waste – Bacteria and Biopolymers key players in innovative hospital waste management system, Bioplastics Magazine 01/2014, p.30
This article was first published in Anaesthesia News 2022; Issue 415; 6-7.