Nanomaterials have unusual properties not found in the bulk materials, which can be exploited in numerous applications such as biosensing, electronics, scaffolds for tissue engineering, diagnostics and drug delivery. However, research in the past few years has turned up a range of potential health hazards, which has given birth to the new discipline of nanotoxicology. Bacterial cellulose (BC) is a promising material for biomedical applications, namely due its biocompatibility. Although BC has been shown not to be cytotoxic or genotoxic, the properties of isolated BC nanofibres (NFs) on cells and tissues has never been analysed. Considering the toxicity associated to other fibre-shaped nanoparticles, it seems crucial to evaluate the toxicity associated to the BC-NFs. In this work, nanofibres were produced from bacterial cellulose by a combination of acid and ultrasonic treatment. The genotoxicity of nanofibres from bacterial cellulose was analysed in vitro, using techniques previously demonstrated to detect the genotoxicity of fibrous nanoparticles. The results from single cell gel electrophoresis (also known as comet assay) and the Salmonella reversion assays showed that NFs are not genotoxicity under the conditions tested. A proliferation assay using fibroblasts and CHO cells reveals a slight reduction in the proliferation rate, although no modification in the cell morphology is observed.

Fucan is a term used to denominate a family of sulfated polysaccharides rich in L-fucose. They are extracted mainly from brown seaweeds and echinoderms. The brown seaweed Spatoglossum schröederi (Dictyotaceae) synthesizes three heterofucans named A, B and C. Our research group purified a non-anticoagulant heterofucan (fucan A) which displays antithrombotic activity in vivo. However, its in vitro toxicity has yet to be determined. This work presents the evaluation of the potential cytotoxicity, mutagenicity and genotoxicity of this fucan. After 48 h incubation fucan A cytotoxicity was determinate using MTT assay. Tumor-cell (HeLa, PC3, PANC, HL60) proliferation was inhibited 2.0-43.7%; at 0.05-1 mg ml⁻¹ of the heterofucan, the 3T3 non-tumor cell line proliferation was also inhibited (3.3-22.0%). On the other hand, the CHO tumorigenic and RAW non-tumor cell lines proliferation were not affected by this molecule (0.05-1 mg ml⁻¹). We observed no mutagenic activity in Salmonella reversion assay when bacterial strains TA97a, TA98, TA100 and TA102 (with and without S9) were used.Comet assay showed that fucan A had no genotoxic effect (from 20 to 1000 mg ml⁻¹) on CHO cells. In conclusion, this study indicates that the S. schröederi fucan A was not found to be genotoxic or mutagenic compound; thus it could be used in new antithrombotic drug development.

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