Sustainable Plastics - January/February 2023 - 15

bioplastics
Alternatives in
antimicrobial additives
Antimicrobials in plastics can provide protection against many different types of
microorganisms such as algae, bacteria and fungi. Researchers at Valencia, Spainbased
plastics technology centre Aimplas explored the potential of natural-based
solutions that go beyond the use of metal compounds.
By Andrea Morandini, Lodovico Agostinis, Aimplas Chemical Technology Team
T
he COVID-19 pandemic
has highlighted
just how easily
pathogens can be
transmitted from surfaces and
has made it necessary to use
chemical agents for continuous,
thorough disinfection.
Besides the use of many different
products, this practise
also depends on operator performance
and quality. The need
to develop surfaces capable of
killing or repelling pathogens is
therefore a key part of infection
control, especially for plastics.
In terms of promoting products
that can form part of the
circular economy, one approach
involves using carbon-based
nanomaterials and
bio-based antimicrobial products,
whereas considerable
interest has also been shown
in different application sectors
in the shift away from common
additives such as metal ions
and oxides of silver, copper
and titanium, which are under
scrutiny due to their possible
toxicity and disposal issues.
Carbon-based nanomaterials
are known for having several
properties, including electrical
conductivity, mechanical
strength and thermal conductivity.
Recently, however, they
have been found to possess
strong bactericidal properties.
Their antibacterial mechanism
is complex and depends on factors
such as composition and
surface concentration, but they
appear to be able to act on cell
membranes and destroy them
and/or cause oxidative stress,
as in the case of silver-based
nanomaterials. Because these
materials can act on contact
without releasing substances,
they are suitable for medical
applications such as prostheses
and implants in constant conElectron
microscope image
of a virus infection.
Can alternative
antimicrobials play
a role in the fight
against AMR?
used biopolymers
for food coating and
packaging and has
tact with the body.
Natural antibacterial agents
derived from extracts of animals,
plants and microorganisms
are generally considered
safe, healthy and environmentally
friendly. Natural antimicrobial
peptides such as nisin,
natamycin, leucocin, enterocin
and pediocin are recognized
biopreservatives that are used
to inhibit and kill pathogens
and bacteria that can cause
food spoilage. Because they are
composed of proteins, they are
sensitive to high temperatures,
making them difficult to use
in thermoplastic compounds.
However, they can be encapsulated
in porous inorganic or heterostructure
(inorganic/organic
hybrid) matrices to make them
more resistant to high-temperature
processes.
Chitosan is one of the most
intensively researched and
excellent antimicrobial properties.
It is the most abundant
polysaccharide in the world and
is also biodegradable and biocompatible.
Chitosan is becoming
increasingly important as an
antimicrobial additive in plastic
applications and its derivatives
are widely used as natural alternatives
to antibacterial and
antioxidant agents, especially in
food-contact applications.
Antimicrobial compounds
have applications in a wide
range of technology industries,
such as protection of crops from
pest infestations in agriculture
and the search for solutions in
health care.
In the agricultural sector,
there is great interest in developing
bio-based antimicrobial
technologies and finding new
applications for them, given
that inappropriate application
and storage of their synthetic
counterparts often lead to
contamination of plant tissues,
as well as contamination of the
air, water and soil. Moreover,
the presence of pesticides can
increase the development of
tolerance, resistance and persistence
of the microbiomes
of these environments and
even their ability to degrade
these pesticides. It has been
observed that it is difficult for
bio-based materials to develop
antimicrobial resistance
(AMR), so their activity is assured
over time.
AMR is and will be a very
important issue for hospitals
and the health care sector, as
indicated by the WHO when it
included AMR as one of the 10
global public health threats that
humanity will have to face in the
coming decades. Developing
new antimicrobial materials that
do not allow bacteria and other
microbes to generate resistance
is a key area for future development
in the medical sector.
January/February 2023
15

Sustainable Plastics - January/February 2023

Table of Contents for the Digital Edition of Sustainable Plastics - January/February 2023

Contents
Sustainable Plastics - January/February 2023 - Cover1
Sustainable Plastics - January/February 2023 - Cover2
Sustainable Plastics - January/February 2023 - Contents
Sustainable Plastics - January/February 2023 - 4
Sustainable Plastics - January/February 2023 - 5
Sustainable Plastics - January/February 2023 - 6
Sustainable Plastics - January/February 2023 - 7
Sustainable Plastics - January/February 2023 - 8
Sustainable Plastics - January/February 2023 - 9
Sustainable Plastics - January/February 2023 - 10
Sustainable Plastics - January/February 2023 - 11
Sustainable Plastics - January/February 2023 - 12
Sustainable Plastics - January/February 2023 - 13
Sustainable Plastics - January/February 2023 - 14
Sustainable Plastics - January/February 2023 - 15
Sustainable Plastics - January/February 2023 - 16
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Sustainable Plastics - January/February 2023 - 18
Sustainable Plastics - January/February 2023 - 19
Sustainable Plastics - January/February 2023 - 20
Sustainable Plastics - January/February 2023 - 21
Sustainable Plastics - January/February 2023 - 22
Sustainable Plastics - January/February 2023 - 23
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Sustainable Plastics - January/February 2023 - 25
Sustainable Plastics - January/February 2023 - 26
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Sustainable Plastics - January/February 2023 - 28
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Sustainable Plastics - January/February 2023 - 32
Sustainable Plastics - January/February 2023 - 33
Sustainable Plastics - January/February 2023 - 34
Sustainable Plastics - January/February 2023 - Cover3
Sustainable Plastics - January/February 2023 - Cover4
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