DESPITE mounting evidence that we eat, drink and breathe microplastics, it still isn鈥檛 clear whether these tiny particles get absorbed into our organs, tissues and cells and affect our health. In 2021, we will finally discover whether microplastic particles make it into our blood 鈥� the gateway to our organs and tissues 鈥� and, crucially, if they can infiltrate our cells.
鈥淲e鈥檙e very, very close,鈥� says Juliette Legler at Utrecht University in the Netherlands. Legler is involved in two of four new research projects being funded by the European Commission that are investigating the impact of microplastics on human health. 鈥淚 expect breakthroughs in the coming year for sure,鈥� she says.
Before we can understand how microplastics might affect health, we have to detect them in the first place. Most studies of microplastics have focused on particles in the micrometre range because these are easiest to find in experiments, says Legler. 鈥淏ut it鈥檚 very clear that the smaller the plastic particle is, the easier it is to be taken into the cell and the greater the chance that there may be an adverse effect.鈥�
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In particular, nano-sized particles may be able to cross the blood-brain barrier, one of the body鈥檚 key defences, says Dick Vethaak at Deltares, a research institute inDelft, the Netherlands.
鈥淲e learned from decades of air pollution exposure that particle size can be one of the contributing factors to understanding the toxicity of air pollution, and I think 鈥� you know, this is my opinion and I don鈥檛 have any evidence backing this up 鈥� but I think size is also going to bean important consideration for the microplastic particles as well,鈥� says DouglasWalker at the Icahn School ofMedicine at Mount Sinai, New York.
Legler, Vethaak and Walker believe that advances in analytical chemistry and microscopy will give us the ability to detect these much tinier plastic particles in humans. In August last year, researchers at Arizona State University developed a method to detect and quantify both microplastic and nanoplastic fragments inhuman tissues and organs. With new techniques like this, we can expect to see a flurry of results in the coming months.
鈥淚n 2021, we will finally find out whether microplastic particles make it into our blood and infiltrate our cells鈥�
鈥淭here are a number of groups on the brink of publishing some very good data, very, very high-quality data,鈥� says Legler. Her research group has spent the past year or so looking at microplastics in the placenta and investigating whether there are potential risks to a fetus in the uterus. It still isn鈥檛 known whether microplastic particles can cross the placenta in humans.
鈥淲e鈥檒l be looking in the laboratory with human placenta, measuring human placenta samples,鈥� says Legler. 鈥淲e have seen in animal studies that microplastics dosed directly to pregnant mice or rats will be taken up by the fetus.鈥�
Her team is also discovering hints that microplastic particles may be capable of penetrating human placental cells grown in a dish in the laboratory. The next step will be to investigate how any exposure to microplastics affects the developing fetus.
Just the mechanical stress of having microplastic particles inside cells could be enough to cause damage, she says. But there are also concerns that microplastics could carry harmful microbes, such as viruses and bacteria, into our cells. 鈥淚t鈥檚 a very broad and complex area and I think we鈥檒l be learning a lot more over the next few years,鈥� says Walker.
