Science Good. Plastics Bad. Balancing Requirements with the Environment.

14/08/19

Plastics are ubiquitous in modern life – and the world of laboratory consumables is no different. Balancing the requirements of modern science with the environmental concern about plastic waste is a key challenge in managing a life science lab. Here we look at why plastic fulfills this pivotal role in the lab – and where there are opportunities for minimizing the environmental impact of scientific research.

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As the boundaries of research have been pushed back, so the requirements for new and different lab consumables – with varying material properties – have increased in order to fulfill developing experimental requirements. Modern laboratories are expected to work to the highest standards when it comes to data accuracy, cleanliness, and reproducibility, and researchers expect the same high standards from the equipment and materials they use. When it comes to their laboratory consumables, users expect precision and accuracy (especially when working with low volumes), consistency, purity, and ruggedness in order to make their daily work as fast and consistent as possible.

In life science labs, the number of places where you find plastic consumables seems infinite. However, the main product types (by total volume) for which plastics are the materials of choice are single-use consumables for liquid handling, sample handling and cell handling. These include pipette tips for various kinds of pipetting, tubes of any kind, plates with different characteristics, or cell culture consumables.

Why plastics?

When it comes to consumables, laboratory researchers have many needs, which usually cannot be satisfied with historical materials such as glass. In the main they need to be transparent, but they also need to be lightweight, and have a high impact resistance (unlike glass). Additionally, many life science applications have highly specific needs: cell culture requires absolute sterility, and molecular biology assays require consumables that are free of DNA, DNase, RNA, RNase1, and other additives that can leach into a sample2. Therefore, they need to be manufactured from raw materials with a high virgin purity, and which can be sterilized as part of the manufacturing process. It was the need for higher standards, increased reproducibility, and the enabling properties of plastics that drove the transition from glass to plastic in laboratories3.

Common lab plastics, such as polypropylene and polystyrene, have a range of mechanical and surface properties that make them highly suitable for lab consumables. Polypropylene combines all the benefits of plastics mentioned above with the fact that it can be manufactured in a way that makes it highly water-repellent (hydrophobic). This property is important in, for example, pipette tips where it prevents most liquids from remaining on the surface, thereby improving the accuracy and reproducibility of the volume of liquid dispensed.

Conversely, any surface used for cell attachment, such as cell culture flasks and plates, needs to be optimized for cell adhesion, which means they need to be more hydrophilic4. At first glance, polystyrene seems like a strange choice for this application, because it is naturally hydrophobic. However, polystyrene cultureware undergoes a special treatment involving the introduction of hydroxyl groups to make it more hydrophilic, and it is only possible to manufacture these special surfaces when using plastic5.

Balancing laboratory necessity and environmental impact

An important and growing concern is the environmental impact of single-use plastics. In the last six decades humans have created 8.3 billion tons of plastic, and only 9% of that has been recycled. Comfortingly, laboratories only contribute a tiny percentage to this total, though it is important to look at ways to reduce plastic use in all aspects of life. From a laboratory research perspective, the essential benefits of plastic consumables are clear, and so reduction in plastic use has to be balanced with the required properties that, currently, only plastics can provide.

The natural desire for labs to reduce their environmental impact is also affected by governmental regulations. After use, most consumables are treated as either hazardous waste, clinical waste, or sharps6, and depending on local regulations, they are either incinerated or taken to landfill sites. Even in countries that have schemes for recycling plastics, lab consumables are usually not allowed to be recycled due to the regulations concerning the safe disposal of hazardous, or potentially hazardous waste.

So, what steps can be taken by the research community to reduce the overall impact of plastics? At the top of the list of alternatives are avoidance and reduction of raw material usage wherever possible. However, as described above, there are many factors that make it difficult, if not impossible, to do that for laboratory consumables. But what about plastics for packaging or storage of consumables? These components do offer potential for savings and improvements by changing the design or shape. Another possibility is improving plastic wastage through improvements in purchasing and training. On the disposal side, encouraging recycling of non-hazardous waste where possible can also reduce environmental impact.

From a manufacturer’s perspective, significant time, money and effort has been, and continues to be, devoted to researching the use of more environmentally-friendly alternatives to the commonly used single-use, oil-based plastics. These include plastics from renewable biomass, biodegradable plastics, and recycled plastics, and the key challenge when considering these new materials is to ensure that any switch does not impact quality and consistency – the fundamental requirements of the modern laboratory.

In the next series of articles, we will discuss these proposed alternative sources of materials for lab consumables, and outline the benefits, drawbacks, and current hurdles to success in a laboratory environment. So watch this space to stay up-to-date with the latest on the environmental aspects of laboratory plastics.

References

[1] https://bitesizebio.com/163/10-ways-to-work-rnase-free/

[2] https://online-shop.eppendorf.at/SP-en/eshopdownload/downloadbykey/146279_186

[3] https://handling-solutions.eppendorf.com/cell-handling/about-cells-and-culture/detailview/news/cultureware-from-glass-to-plastic/

[4] Max, J et al. The Evolution of Polystyrene as a Cell Culture Material. Tissue Engineering Part B, 2018;24(5): 359–372.

[5] Zeiger, AS et al. Why the dish makes a difference: Quantitative comparison of polystyrene culture surfaces. Acta Biomaterialia 2013;9: 7354–7361.

[6] https://ehs.princeton.edu/book/export/html/361