Sunflower seed husk biochar: synthesis and toxicity risk assessment

Aim. Searching for efficient biocompatible sorbents that possess zero neurotoxicity is an actual task. Biochars are auspicious carbon materials for the adsorption of heavy metals in the environment, wastewater, and also in human organisms. Methods. Biochar from sunflower seed husk (SB) was synthesized by pyrolysis at 800 C without special functionalization. Neurotoxicity risk of SB was assessed in an animal model using presynaptic nerve terminals isolated from rat cortex (synaptosomes). Results. It was shown in radiolabelled experiments that SB did not change the synaptosomal ambient levels of the excitatory neurotransmitter L-[3H] glutamate and inhibitory neurotransmitter [3H] GABA within the concentration range 0.25–1.0 mg/ml. In the fluorimetric experiments using the dye JC-1, SB at a concentration of 1.0 mg/ml did not change the mitochondrial membrane potential of the nerve terminals. Conclusions. SB demonstrated the absence of neurotoxicity signs and high biocompatibility, and therefore, SB has the potential to be used as an adsorbent in biotechnology and medicine.