Today, single-use plastics are still widely utilized for the production of many medical and diagnostic devices despite their detrimental environmental impact. Increased use of plastics in COVID-19 test kits and personal protective equipment throughout the last two years has set the world back in its struggle against plastic waste. Indeed, according to the International Solid Waste Association (ISWA), single-use plastics may have increased as much as 300 percent since the start of the COVID-19 pandemic, and it is estimated that every single time that a COVID-19 lateral flow test is performed, 10 grams of plastics is thrown away into the environment.

Given their growing use of at-home and professional testing for COVID-19 and other pathogens, the creation of more sustainable and eco-friendly lateral flow devices is of immense importance to the future of our planet. Efforts are currently underway for the design and manufacture of innovative biobased test kits that easily decompose in nature. Read along to find out more about biodegradable test kits, proposed materials for their production, their advantages, and their limitations.

 

 

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What are the traditional materials used for the production of test kits?

The vast majority of the lateral flow test kits currently in use are made from high-density polystyrene (HIPS). High-density polystyrene (HIPS) is a non-biodegradable material derived from petrochemical products and polymerized with benzoyl peroxide. Given that benzoyl peroxide functions as the catalyst in a reactor that requires a significant amount of electricity/fuel, high-density polystyrene is associated with a large carbon footprint. Most of the polystyrene used for the production of lateral flow test cassettes ends up in landfill sites after their disposal in general waste. A smaller proportion of polystyrene is disposed of via incineration, which creates significant carbon emissions to the environment. The recycling of polystyrene is possible through mechanical, chemical, and thermal methods, these methods are not applicable to complex and contaminated forms of waste such as lateral flow test cassettes. Altogether, polystyrene can last centuries in the environment and harm various habitats, including the soil, seas, rivers, and oceans along with their inhabitants.

On the other hand, the waste bags incorporated into the test kits are often made of polyethylene. Polyethylene is another non-biodegradable material derived from petrochemical products that are currently among the most commonly produced forms of plastic worldwide. As with polystyrene, recycling polyethylene is an uncommon and costly process. The decomposition of a single plastic bag made of polyethylene may take up to 450 years. Given its slow degradation rate, the use of polyethylene presents significant environmental hazards.

Which materials are available for the production of biodegradable test kits?

Biodegradable materials available for the production of eco-friendly test kits include cellulose, starch, chitosan, and bioplastics such as polybutylene-adipate terephthalate (PBAT) and polylactic acid (PLA). In addition to their biodegradability, affordability, and sustainability, these materials can also withstand the high temperatures required for the thermoforming process, allowing the material to be easily shaped per the intended purpose of the device.

Cellulose and starch are natural plant-based polymers that offer an affordable option for the production of lateral flow test kits. Cellulose-based and starch-based materials such as cellulose acetate can easily be composted and disposed of after use without polluting the environment. Chitosan is another natural polymer derived from chitin. It is a fully biodegradable material that can safely be utilized for the production of lateral flow test kits. Finally, bioplastics refer to plastics that are derived from fully renewable and biocompatible resources, including corn starch, sugarcane, or cassava. Despite their similar properties to traditional thermoplastics such as polystyrene, bioplastics are entirely biodegradable and easily compostable materials that are suitable for the production of test kits. The use of bioplastics allows for the safe disposal of single-use assays after use.

What are the potential challenges of switching to biodegradable materials for the production of test kits?

Although affordable and convenient options of materials are available for the production of biodegradable test kits, it is worthwhile to note that biobased materials may not offer as much durability as traditional materials. Devices made of biobased materials may also not withstand the same conditions of storage and transportation as our current test kits. Therefore, it is crucial to consider the characteristics of the material in relation to the intended use of the designed device, ensure its compliance with the regulations, and consult experts or regulatory bodies if necessary.

What are some of the new projects concerning the design and manufacture of biodegradable test kits?

There are various projects and prototypes concerning biodegradable alternatives to lateral flow assays designed for the purposes of single-use testing. Utilizing bioplastics such as polybutylene-adipate terephthalate (PBAT) and polylactic acid (PLA), some companies have pioneered the production of eco-friendly COVID-19 lateral flow test kits. Other prototypes of COVID-19 lateral flow assays have turned to cellulose-based materials to replace high-density polystyrene (HIPS) and polyethylene. Alongside COVID-19 testing, biobased alternatives to other lateral flow tests designed for single-use purposes, such as drug testing, are also being developed. Efforts to design and manufacture more sustainable, affordable, and eco-friendly diagnostic devices are underway and are expected to soon become public use.