Scientists give new lease of life to e-waste plastics
Upcycling method reduces environmental footprint of plastic waste stream


Date:
December 13, 2021
Source:
Nanyang Technological University
Summary:
Plastics found in electronic waste (e-waste) are rarely recycled
due to their complex composition and hazardous additives, but
scientists have now developed a new use for them -- by repurposing
them as an alternative to the plastics used in laboratory cell
culture containers, such as petri dishes.



FULL STORY ========================================================================== Plastics found in electronic waste (e-waste) are rarely recycled due
to their complex composition and hazardous additives, but scientists at
Nanyang Technological University, Singapore (NTU Singapore) have developed
a new use for them -- by repurposing them as an alternative to the
plastics used in laboratory cell culture containers, such as petri dishes.


==========================================================================
The team at NTU Singapore-CEA Alliance for Research in Circular Economy (SCARCE) repurposed the e-waste plastics, subjecting them only to sterilisation, before being trialled in lab experiments.

The team found that over 95 per cent of the human stem cells seeded on
plastics scavenged from discarded computer components remained healthy
after a week, a result comparable to cells grown on conventional cell
culture plates.

These findings, described in a study published online in the scientific
journal Science of the Total Environment, indicate a potential new
sustainable use for e-waste plastics, which account for about 20 per
cent of the 50 million tonnes [1] of e-waste produced worldwide each year.

Repurposing them for cell culture in the lab would not only allow
maximum value to be recovered from e-waste plastics, but also help to
reduce the amount of plastic waste generated from biomedical research,
said the NTU research team. A study in 2015 estimated that 5.5 million
tonnes of lab-related plastic waste [2], including cell culture dishes,
is generated globally in a year.

These new findings build on a 2020 study led by the same NTU team,
which investigated the effect of e-waste plastics on six different human
cell types and found healthy cell growth despite the hazardous elements
to be found in e- waste plastics. These findings inspired the research
team to upcycle e-waste plastic scraps and trial them in advanced cell
culture applications.



========================================================================== Assistant Professor Dalton Tay of the NTU School of Materials Science
and Engineering and School of Biological Sciences, who led this interdisciplinary study, said: "E-waste plastics contain hazardous
components which may get released into the environment if not disposed
of properly. Interestingly, we found through our studies that certain
e-waste plastics could successfully maintain cell growth, making them
potential alternatives to the cell culture plastics used in labs today." "Repurposing them for immediate use rather than recycling them enables
the immediate extension of the lifespan of e-waste plastics and minimises environmental pollution. Our approach is in line with the zero-waste
hierarchy framework, which prioritises the reuse option through materials science and engineering innovation." Providing an independent point of
view, Professor Seeram Ramakrishna, Board Member of the Plastics Recycling Association of Singapore and Chairman of the Plastics Recycling Centre of Excellence, said: "With plastic a critical component in our manufacturing
and logistical processes, we are in urgent need of sustainable solutions
to plastic waste to mitigate its impact on the environment and social
costs. Innovative solutions, such as the idea developed by Asst Prof
Tay and his team to repurpose e-waste plastic, could serve to address
the ubiquitous plastic waste problem in Singapore and around the world,
and move us towards plastics circularity." The NTU scientists' research
that turns waste into treasure is in line with the NTU 2025 vision and the University's Sustainability Manifesto, which aspire to develop sustainable solutions to address some of humanity's pressing grand challenges.

E-waste plastics encourage healthy cell growth For this study, the NTU
team used plastic scavenged from e-waste collected by a local waste
recycling facility. Three kinds of e-waste plastic were chosen for their
varied surface features -- the keyboard pushbuttons and diffuser sheet
obtained from LCDs have a relatively flat and smooth surface, while the
prism sheet, also found in LCDs, has highly aligned ridges.



==========================================================================
To test the viability of using e-waste plastics for cell cultures, the
NTU team seeded stem cells onto 1.1cm-wide circular discs of sterilised
e-waste plastics.

A week later, the scientists found that more than 95 per cent of live
and healthy stem cells seeded on the e-plastics remained -- a result
comparable to the experimental control of stem cells grown on commercially available cell culture plates made of polystyrene.

The stem cells grown on the e-waste plastics also retained their ability
to differentiate -- a process in which stem cells become specialised
cells with a more specific function, such as blood cells, brain cells,
heart muscle cells or bone cells.

E-waste plastic surface features affect stem cell growth Stem cells
can undergo differentiation under the right conditions in the body or
a lab. One way to facilitate this process in the lab is the addition of
a medium that 'nudges' the stem cells in a certain direction.

To investigate the effect of e-waste plastic on the stem cells' differentiation, the NTU team added two types of medium in equal amounts
to the cells cultured on e-waste plastic and on polystyrene cell culture plates. One type coaxes the stem cells to develop into fat cells and
the other nudges the stem cells to become bone cells.

At the end of two weeks, a higher proportion of stem cells cultured on
e-waste plastics successfully went through differentiation compared to
those on the conventional polystyrene cell culture plate.

The scientists also found that the stem cells cultured on keyboard
plastic and diffuser sheet were more likely to develop into bone cells,
while stem cells cultured on the prism sheet, with its ridges, were more
likely to develop into fat cells.

Asst Prof Tay said: "In tissue engineering, we use advanced techniques
to engineer surfaces and study how they can influence stem cell differentiation.

Now, we have shown that e-waste plastics are a ready source of such microstructures that allow us to further study how stem cell development
can be directed -- the 'holy grail' of regenerative medicine and more
recently, lab- grown meat. There are important biomaterials and scaffold
design rules and lessons we can learn from these e-waste plastic scraps."
Going forward, the NTU team aims to further develop resource-effective remanufacturing processes to upcycle e-waste plastics that would support
other high-value biotechnological applications.

This would help to promote sustainable practices in research and
innovative waste-to-resource solutions for the industry, say the
scientists.

The research is supported by Singapore's National Research Foundation
and the National Environment Agency, under the Closing the Waste Loop
Funding Initiative.

[1] Electronic devices 'need to use recycled plastic' BBC, 15 Oct 2019
[2]'Labs should cut plastic waste too', Nature, 23 Dec 2015

========================================================================== Story Source: Materials provided by
Nanyang_Technological_University. Note: Content may be edited for style
and length.


========================================================================== Journal References:
1. Pujiang Shi, Chiew Kei Tan, Zhuoran Wu, Jean-Christophe P. Gabriel,
Madhavi Srinivasan, Jong-Min Lee, Chor Yong Tay. Direct reuse of
electronic plastic scraps from computer monitor and keyboard to
direct stem cell growth and differentiation. Science of The Total
Environment, 2021; 151085 DOI: 10.1016/j.scitotenv.2021.151085
2. Pujiang Shi, Yan Wan, Agne`s Grandjean, Jong-Min Lee, Chor Yong Tay.

Clarifying the in-situ cytotoxic potential of electronic waste
plastics.

Chemosphere, 2021; 269: 128719 DOI:
10.1016/j.chemosphere.2020.128719 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/12/211213121826.htm

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