Poly-lactic acid (PLA) is a biodegradable, bio-based thermoplasticderived primarily from renewable resources such as corn starch or sugarcane. It's widely used in packaging, biomedical devices, textiles, and increasingly in 3D printing, owing to its ease of processing, compostability, and relatively low environmental impact.

While it is generally considered non-toxic in its bulk form, its degradation products, such as lactic acid and related oligomers, and micro/nanoplastics, may pose risks to aquatic ecosystems. This study investigates the potential effects of PLA microplastics (MPs) on Schmidtea mediterranea, a freshwater planaria, recognized for itsregenerative capability and sensitivity to environmental stressors, positioning it as promising bioindicator in toxicological research. Exposure experiments were designed to evaluate the effects of PLA MPs through the alimentary route, while comparative analyses withMPs derived from the conventional plastic polyethylene terephthalate (PET), were also performed.

Environmentally relevant PLA and PET MPs were produced throughmechanical fragmentation of bigger particles, enabling the generation of MPs with realistic chemical and morphologicalcharacteristics. Through size fractionation the desired size distributions of both models were selected, and a detailed physicochemical analysis was performed revealing their characteristics. Alimentary exposure experiments to the planaria indicate that the MPs were effectively introduced in the digestive system of the planaria, with the PLA MPs not to exert significant toxic effects, likely due to the organisms’ ability to efficiently eliminate the ingested particles (Bernardeschi, NanoBio&Med2025 December 02-04, 2025).