The Cytotoxicity of Biodegradable Microplastics and Nanoplastics: Current Status and Research Prospects

The growth in the production and use of biodegradable plastics, positioned as an environmentally friendly alternative to traditional polymers, has led to an increase in their distribution in the environment. However, in conditions other than industrial composting facilities, biodegradable polymers can persist for a long time, fragment, and form biodegradable micro- and nanoplastics (BioMNP) with potential toxicity. Unlike traditional microplastics, the impact of BioMNP on human health has been poorly studied. This review summarises the available data on the cytotoxicity of BioMNP, including mechanisms of interaction with human cells, routes of entry into the body, induction of inflammation, oxidative stress, and cellular dysfunction. Particular attention is paid to the interaction of microplastics with cells of various body systems, including the digestive, respiratory, immune, and urogenital systems, as well as with the skin. The identified knowledge gaps highlight the need for further research to assess the risks associated with the impact of BioMNP on humans and to develop safer forms of biopolymers. Among biodegradable plastics, PLA-based particles tend to exhibit stronger cytotoxic effects. Nanoplastics generally induce more severe cellular responses than microplastics. Organs such as the liver and lungs appear particularly vulnerable.