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Comment by codybontecou | Hacker News Reader

Can microplastics never get small enough to interact with T cells?

Once microplastics fall apart futher, to nano-plastic, it will start to get absorbed by T cells because they want to destroy any invaders. Once absorbed, T-Cell start to produce H2O2 to destroy anything they absorbed. Unfortunately, plastics are mostly chemically neutral and so, it cannot be destroyed like that. T-Cells produce more H2O2, eventually it leaks outside and start inflamation of surrunding tissue. There is research about it.

Link to that research, please. It would add meaningfully to this discussion.

AKA nanoplastic-induced oxidative stress, but it's actually macrophages (and neutrophils), not T-cells.

The reason this is problem is because cells can never destroy nano-plastic so they keep self destroying forever (chronic inflammation).

I still have my doubts about actual scale of this, especially how we still haven't solved pm2.5 pollution or even asbestos and heavy metals. And then there's PFAS, VOCs, Phthalates and Bisphenols. There's insane amounts of benzene in gas stations and traffic jam, yet no one really gives a fuck (until there's like a ppm in a sunscreen lol).

You are most likely to inhale it due to plastic abundance in environment, just like thousands of other things. It doesn't even have ICD yet. Ingested microplastic unlikely to breakdown while it travels thru your body.

p.s. my partner de-plastified a lot of my life (thru a lot of opposition of me) to the point where a lot of plastic objects feel gross now.

> macrophages

Right, and when it comes to "what happens when the macrophage can't destroy what it engulfed", we can probably learn a lot from parallel work studying tattoos, where the ink-particles are similarly "attacked".

Plus it's a lot easier to create studies or even just observe the cells in question.

So microplastics are indeed harmless!

(/s)

Too bad common discourse is too distracted to consider nanoplastics…

By the time the public tires of microplastics debates, they’ll be in no mood to relitigate nanoplastics

There’s a transition point where things stop being micro plastics, then nano plastics, and become specific chemicals.

Those molecules may be toxic but the interactions are distinct from microplastics or nano plastics.

Unknown to me, but something useful to know is that there is something smaller than microplastics called nanoplastics. The distinguishing factor is that nanoplastics are particles smaller than 1 micron, while microplastics are particles between 1 micron and around 5 millimeters. As your other respondent notes, at some point you're talking about single molecules. As plastics is an entire category and not a single thing, there's no one size where that happens, but some polymers have chains that are as little as 0.01 (1/100th of a) micron in size.

As far as I am aware, we have yet to have effective, replicable research on what if any biointeractions exist with nanoplastic particles, including single polymer chains.

> 5 millimeters

TIL thermoplastic pellets are “microplastics” :)

I don't make the definition

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