Microcalorimetric and microscopic studies of the effect of chitosan quaternary ammonium salt on mitochondria

Chitosan quaternary ammonium salt (HACC) has been regarded as an effective biomedical carrier with good application because of its good water-solubility, high cationic potential and strong cell adhesion. Mitochondria are important organelle involved in ATP production and are the center of energy metabolism. In this work, we firstly investigated the effect of HACC on the thermogenic curve of isolated mitochondria! metabolism by microcalorimetry. The results showed that different concentration of HACC had great influence on the mitochondrial energy metabolism. Specifically, low level of HACC stimulated the metabolic activity of mitochondria and the inhibition was found with high concentration of HACC. Then, the effect of HACC on mitochondrial respiratory chain was studied, which was consistent with the results of microcalorimetry. Finally, the alteration of mitochondrial structure induced by HACC was observed and it showed that the membrane of mitochondria was dramatically damaged. These new findings can help us deeply understand the influence and action mechanism of HACC in the metabolic process and provide theoretical and practical foundation for the biosafety of HACC as a medical carrier. (C) 2018 Published by Elsevier B.V.