Aastha Mahanta, associate consultant, polymers & specialty chemicals, ChemBizR, discusses the role of bioplastics in the medical industry.
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Bioplastic molecule
In recent years, the production and utilisation of bioplastics have seen significant growth, driven by increased demand for sustainable materials, particularly in developed economies. According to European Bioplastics, the global production capacity of bioplastics was 2.18 million tons in 2023 and is projected to reach approximately 7.43 million tons by 2028. This growth has been largely driven by bio-based biodegradable polymers, with polyhydroxyalkanoates (PHA) and polylactic acid (PLA) leading the charge. Over the past five years, production capacity for PHA has grown by a factor of six (~ 10 KT), while PLA production has doubled (~ 60 KT).
Bioplastics in the medical industry
Bioplastics have long been integral to the medical sector, offering distinct advantages due to their biocompatibility, specific properties, and functionalities. Medical applications of bioplastics range from surgical sutures to scaffolds for tissue engineering, with materials like PLA and starch-based composites playing key roles. For instance, bio-based polyether block amide (PEBAX) is widely used in catheters. PLA is increasingly used in wound management, including surgical sutures, dental wound healing, and postoperative adhesion prevention. It is particularly dominant in medical devices, accounting for 40% of all biodegradable biopolymers. Rigid and strong, it is increasingly used in single-use medical devices such as syringes and catheters due to its biocompatibility and biodegradability.
Beyond PLA, other bioplastics like polycaprolactone (PCL), polyhydroxyalkanoates (PHA), and poly(lactic-co-glycolic acid) (PLGA) are also making their mark in medical applications. PCL is used in tissue engineering and drug delivery due to its slow degradation rate and compatibility with biological tissues. PHA, produced by bacterial fermentation, is used in resorbable surgical implants, with poly-3-hydroxybutyrate (PHB) being ideal for osteosynthesis plates because of its controlled biodegradability. PLGA, approved by the FDA and European Medicines Agency, is frequently used in conjunction with materials like ceramics to enhance bone reformation and tissue regeneration. Bio-based polyamide 11 (PA 11), derived from vegetable oils, is another notable bioplastic used in medical applications. PA 11 is known for its great mechanical properties and is ideal for surgical instruments. Bioplastics are also gaining traction in the packaging of medical devices, offering a more sustainable alternative to traditional materials.
Bioplastics: Production and sustainability
Bioplastics are produced using renewable resources, which reduces greenhouse gas emissions because they are derived from plants such as corn, sugar beet, or soya, as opposed to traditional plastics. They can be disposed of using various methods, such as composting and anaerobic digestion, improving medical waste management. Moreover, they can reduce carbon dioxide emissions by at least 30% and carbon footprints by 42%, while using 65% less energy than traditional plastics. Incorporating bioplastics in the medical sector offers a sustainable replacement for conventional plastics, thus significantly reducing environmental impact and promoting a greener future. The production of bioplastics is not a challenge worldwide, but their incorporation into medical devices and implants is still being researched and awaits regulatory and commercial acceptance.
It is interesting to note that not all bioplastics are highly biodegradable, which makes their usage in industry applications challenging. For instance, the biodegradation of PLA is not as clean as it appears because it needs temperatures above 50–60°C. Also, depending on the environment, the degradation of PLA happens at a different pace, making the process of degradation long and not superbly effective.
When it comes to medical applications, a blend of different biobased polymers holds more prominence and showcases better potential. One such example is a lignin-PHB copolymer, where the brittleness of PHB is countered by lignins, providing great mechanical strength and antioxidant properties.
The use of bioplastics in the medical field necessitates a thorough understanding of the blends that work best for internal or external usage in the human body. Some of the available bioplastics have yet to meet the performance requirements, necessitating additional R&D efforts by the stakeholders.
Market innovation and happenings
The required and acceptable performance in the medical sector can stop the widespread adoption of bioplastics. For instance, not every bioplastic on the market is made to withstand high temperatures. However, companies such as Total Corbion have developed high-heat PLA resins that can withstand temperatures of more than 100℃.
NatureWorks, an international bioplastics manufacturer, announced in 2022 that they are building a plant in Thailand to increase their production capacity by 50%. Recently, they got funding from Krungthai Bank of around $350 million to speed up the innovation and production of bioplastics. With an annual capacity of 75,000 tons of Ingeo biopolymer, this fully integrated PLA complex is anticipated to be operational by 2025. This range is a low-carbon alternative because it is made from ethically sourced, renewable bio-based feedstock.
Asia is capitalising on this opportunity to position itself as a potential hub for bioplastic production. Thailand's Board of Investment (BOI) is supporting the industrial efforts to position the country as a major centre for producing biodegradable plastics, contributing to environmental preservation. The biodegradable plastics industry has seen over $1.1 billion in investments in the last 5 years. Similar advancements are happening in NORAM and Europe, both in terms of production and consumption.
The market is currently searching for sustainable sources and the best production technology to create the bioplastics of the future.
Lysozyme, an enzyme found in egg whites, is recognised for its ability to impede bacterial growth. Researchers at the University of Georgia are thus exploring the use of egg whites to create antibacterial bioplastics. The researchers intended to utilise these bioplastics in various medical applications, such as wound dressings, sutures, catheter tubes, and drug delivery devices.
SymbioTex, a company known for innovating materials to create bioplastics for the medical industry, is exploring the use of seaweed as a material for manufacturing medical equipment and devices. Currently, the company is in the research and testing phase, investigating the potential of seaweed-based plastic as an alternative to traditional plastics. Algae-based bioplastics offer exciting possibilities for producing medical devices and implants that decompose naturally.
The medical sector continues to see promising developments in bioplastics, particularly with the integration of advanced technologies like nanotechnology and 3D printing. These innovations are enabling the creation of custom implants and surgical tools, as well as addressing challenges such as polymeric stent recoil and clot-induced thrombosis. Notably, French researchers have combined chromium-platinum stents with PLA coatings to elute anti-restenosis drugs, while a Dutch team has developed a biodegradable stent prototype for neurovascular surgery. Additionally, intelligent shape-memory bioplastics are being studied for use in stents and devices for aneurysm occlusion and clot removal.
Limitations and industrial Impact
Despite their many benefits, bioplastics face challenges in medical applications, particularly regarding their mechanical properties. While biodegradable polymers like PCL, PLA, and PLGA are valued for their bioresorbable and biocompatible characteristics, they often fall short in mechanical strength, limiting their use in bone regeneration or replacement, as well as some tissue engineering applications. Moreover, many bioplastics have lower resistance to high temperatures and the harsh chemicals commonly used in medical settings, making it difficult for them to replace traditional metal instruments.
To address these limitations, ongoing research is focused on blending bioplastics with other materials to enhance their properties. For example, the copolymerisation of PLA with other materials has resulted in more flexible blends, improving their suitability for medical use. Additionally, PLGA is being explored for its enhanced biocompatibility when combined with ceramics or biologically active glass, particularly in applications such as bone reformation.
While bioplastics hold promise as a sustainable alternative to traditional plastics in the medical industry, researchers are examining their efficiency and safety for use in medical devices and equipment. They are also being considered for packaging products used in the medical industry. However, biodegradable plastics break down faster than regular plastics, so there might be challenges in product storage, leading to shelf-life issues. Also, price parity is a major concern because bioplastics are still a premium category product, making them a tricky choice for packaging.
In another context, studies show that bioplastics are still harmful as they contain a high number of chemicals, ranging anywhere from 1,000-20,000 chemicals. Because of this, bioplastics raise concerns about their long-term viability. Concerns regarding bioplastics and their use, particularly in the medical sector, have been raised by the possibility that these chemicals, when used in various end applications, could result in varying degrees of toxicity.
Conclusion
Currently, medical bioplastics are more expensive than petroleum-based plastics. PLA can be 30-50% more costly than comparable materials. This is because of the higher cost of raw materials and biotechnology-based production processes. While these factors present challenges, bioplastics hold significant potential as a viable and eco-friendly alternative, driven by increasing industry interest. The adoption in the healthcare sector is though notably slow, typically taking 5-10 years due to rigorous testing and validation requirements. However, their production volumes remain low, limiting their availability and widespread adoption. Any new bioplastic should meet stringent sterility, safety, and performance standards, including the ability to withstand autoclaving, resist punctures, and avoid triggering immune responses.
Despite these challenges, the growing interest and continued development in bioplastics signal a promising future. The regulatory front plays a crucial role in accelerating the adoption of bioplastics. For instance, the European Green Deal offers a framework to promote a circular bioeconomy, supporting the transition toward sustainable materials. Policies such as carbon taxes can help narrow down the cost differences between bioplastics and petroleum-based plastic products, ultimately increasing their commercial acceptance at scale.