Nanocelluloses: hazard characteristics and possible risks (literature review)

Abstract

Nanocelluloses (NCs) have broad application prospects in medicine as implants, cell scaffolds and dressings, in the production of composite materials and coatings, electronics, food and pharmaceutical products. The main types of NCs include nanofibrous (NFC), nanocrystalline (NCC) cellulose isolated from natural, predominantly plant materials, and bacterial nanocellulose (BNC) obtained by microbial synthesis. The production process of NC can include many factors potent of affecting their toxicological characteristics, such as residual amounts of chemicals and enzyme preparations used in the isolation and modification of NC, contamination of NC from natural sources with mycotoxins, heavy metals, pesticides, and dioxins. In the case of NCs of microbial origin, the question of the safety of the respective producer strains remains open, most of which are genetically modified. Special attention deserves the ability of NC to exhibit toxicity to living organisms, different from their chemical counterpart in its traditional form. Expanding the range of products containing NC in close contact with human, primarily food products, packaging materials, pharmacological preparations and medical materials, requires a thorough assessment of the possible risks associated with the impact of NC on the human body. 
 The purpose of the research is to review the literature over 2010 to 2021 on the potential risks associated with the toxic effects of NC on living organisms through various exposure routes.
 Information is provided on toxicity in in vitro systems, in particular, the ability to induce oxidative stress and inflammation. There are presented results of studies on inhalation and oral toxicity in vivo, data on carcinogenicity, immune cell response to NC and its ability to induce immunological tolerance. Based on the results of a comparative analysis of the studies, various NC types were found to have little effect on cell viability d and acute toxicity in vivo, however, the conflicting results of studies of the pro-inflammatory and immunological effects of different NCs indicate the need for further long-term studies to establish the maximum inactive doses of NC, primarily, with their inhalation and oral intake.