Some 3D printing materials may cause skin irritation, Czech study finds
Experts from Charles University tested commonly used 3D printing materials and found that some of them can negatively affect human cells when used over a long period, potentially causing eczema or itching. The results of the Czech research have appeared in the prestigious scientific journal Nature Scientific Reports.
3D printing materials are widely used today in a growing range of everyday products, prompting Czech researchers to investigate how some of them may affect human cells with prolonged use.
Jiří Dejmek from Charles University’s Faculty of Medicine in Plzeň says that originally, the primary objective of the study was to find a material for 3D printing that was certifiably safe.
“We needed a material that we could be 100 percent sure that it does not harm cells in the research we were conducting. We needed a special aid that we wanted to print from 3D material, and had a problem finding information that would guarantee which material was certifiably safe. ” he adds.
The Biomedicine Centre’s laboratory shelves are full of different types of 3D printing materials of various colours, textures and properties. These diverse qualities are achieved through additives. These additives, however, need not always be 100 percent safe when they come into contact with living cells. So far, nobody had investigated this, as the materials are primarily technical products intended for manufacturing atypical components.
Researcher Jiří Dejmek says that ascertaining what additives are present is generally problematic because it is a trade secret. However, some of the findings are cause for concern and will require further study.
“One of the materials that we consider problematic is flex. We found that after seven days of direct contact with the skin, it significantly damages very resilient cells and, in sensitive people, it can cause itching or eczema. For instance if they wear a bracelet printed from this material for a longer period of time,” he explains.
The research team tested 16 types of the most common 3D printing materials. Iveta Paurová explains the process:
“We printed identical samples and placed roughly ten-millimetre cubes next to laboratory cells in an incubator. After a week of cultivation, we take them out. We remove the old medium, remove the test material and add fluorescent dye to the cells sitting at the bottom of the plate. Healthy cells gradually change colour from purple to pink,” she says.
Those that do not change colour point to a problem. The changes can be clearly seen under a special microscope, as Jiří Dejmek demonstrates:
“Here you can see that part of the sample remains purple. This means that the cell is not metabolising. Its digestion has stopped working. It is very likely damaged in some way because it was exposed to toxic material. Under a microscope we can see that the cells that were affected by the flex material have swollen nuclei. They definitely look different from healthy cells,” he says.
If, for example, a bracelet is printed from flex, long-term wear could therefore cause a rash or itching on the skin.
Not all the materials studied were found to be problematic. Dejmek says that materials such as PLA, which is polylactic acid, and most ABS and ASA materials showed no negative effects on human skin cells.
The team will now analyse flexible flex materials for 3D printing in greater detail.
