One of the most common claims about plastics is that they are chemically inert under most conditions, such as when exposed to water. This long-held belief has also challenged the idea that micro- and nanoplastics (MNPs) are dangerous to organisms such as us animals. A previously unknown mechanism between common plastics, studied by (Naixin Qian) et al. and published in Nature serves to generate highly reactive hydroxyl radicals when exposed to water.
Hydroxyl radicals (HO•) are the neutral form of the hydroxide ion (OH–). It is a free radical that tends to have an extremely short lifespan due to its reactivity, much like the singular oxygen molecule that is released at the plastic-water interface. The energy provided for this reactivity comes from the electrostatic effect, itself highly correlated with many plastics, with all six types of microplastics used in the experiment exhibiting varying levels of free radicals, particularly for the more hydrophobic types.
This high reactivity of free radicals is a well-known problem in cell biology, with evolution having developed many tools over the years to capture these radicals as well as to repair the (DNA) damage they can cause. The effect of these microplastics and the free radicals they generate was also studied.
It should be noted here that the electrostatic effect itself already serves to attract charged biomolecules, before the impact of free radicals is taken into account. Using mouse red blood cells and exposing them to polystyrene (PS) microplastics, lethal damage was observed to the red blood cells.
This indicates that there are at least three possible ways in which MNPs can be harmful to organisms. This also provides another clue as to how this may affect the aging of plastics, among other implications.
Currently, there is still an ongoing debate about whether MNPs are actually harmful and how prevalent they are, for example in our bodies. Detecting them reliably, for example in biological tissues, remains a challenge, to which this new study could also help, because one of our biggest blind spots is that we lack solid knowledge of how MNPs can behave inside an organism.
Gn Health
