The Study Of Halloysite Nanotubes Toxicity In Mice

Halloysite?Al₂Si₂O₅?OH?₄·nH₂O?is a natural inorganic nanoparticles with hollow tubular structure.Because of its rich production,low price and unique nanostructures,halloysite nanotubes?HNTs?have been widely used in various fields,including ceramic materials,polymer materials and sewage treatment.In recent years,the application of HNTs in cosmetic additives,drug carrier,ultrasound contrast agent,teeth fillers and bone implants became a popular research.Before the new applications,the study of the safety of HNTs is extremely urgent.Up to now,the safety of HNTs is still not systematically evaluated.In the previous works,in vitro toxicity of HNTs on cells and microorganisms has been investigated.Currently,only one in vivo study has been carried out to examine the toxicity of HNTs in Caenorhabditis elegans.However the toxicity of HNTs in mammals is still unclear.In this study,we attempted to assess toxicity of HNTS in mice after 30 days intragastric administration.HNTs were purified by the ultrasonic scission and uniform viscosity centrifugation method.The whole thesis is divided into four chapters.Chapter 1:We introduced the characteristics of the nanomaterials,the factors influent the toxicity of nanomaterials and the main way of invasion firstly.And then,we make a summary of the characteristics and applications of HNTs in many fields.Finally,we summarized the available data on HNTs toxicity,including in vitro and in vivo toxicity.Chapter 2:The purified HNTs were characterized by TEM and XRF.Then,we explored the stability of purified HNTs in the artificial gastric juice,intestinal juice,and blood and determined its hydrodynamic radius by DLS.Finally,the toxicity of HNTs was preliminarily evaluated,after oral administration of HNTs at 2000 mg/kg BW dosage for 7d;Al accumulation and fibrosis were observed in lung.The cellular edema,spotty necrosis and fatty degeneration generate were observed in liver.The kidney showed mild cellular edema and glomerular atrophy.The preliminary results indicated the HNTs were toxic to lung,liver and kidney.Chapter 3:We investigated the toxicity of HNTs in the lung at different doses?5,50,300 mg/kg BW?.The results showed that 5 mg/kg BW was a safety dose to lung with no toxicity.HNTs at high dose??50 mg mg/kg BW?induced accumulation of Al and deposition of HNTs in the lung and caused exudation of red cells,proliferation of alveolar epithelial cells and small areas of fibrosis in the pulmonary tissue.Chapter 4:We investigated the toxicity of HNTs in the liver and kidney at different doses?5,50,300 mg/kg BW?.HNTs showed nontoxic to the liver and kidney at 5 mg/kg BW dose.However,HNTs at 50,300 mg/kg BW caused tissue lesions and dysfunction in the liver and kidney.Meanwhile,we found that HNTs stimulated the growth of the mice at 5 mg/kg BW,but inhibited the growth of the mice at 50 or 300 mg/kg BW.