Musca domestica (Diptera: Muscidae) as a biological model for the assessment of magnetite nanoparticles toxicity.

The use of nanoparticles (NPs) is rapidly expanding; there is a critical need for efficient assays to first determine the potential toxicity of NPs before their use in human applications. Magnetite nanoparticles (FeO NPs) have tremendous applications which include cell separation, arsenic removal from water and DNA separation. Spherically shaped FeO NPs with sizes ranging from 23 to 30 nm were used in this study. The housefly, Musca domestica is the most common fly species. It is present worldwide and considered to be an important medical insect which can carry and transmit over 100 human pathogens and zoonotic agents. It has been used in this study to assess FeONPs toxicity and give us an overview of their impact. The larvicidal activity of FeONPs was tested against the third instar larvae of M. domestica. We investigated the effects of six varying concentrations (15, 30, 45, 60, 75 and 90 μg/mL) used under laboratory conditions in two differential application assays: contact and feeding. The LC value for FeO NPs was 60 and 75 μg/mL by feeding and contact, respectively. To investigate the toxicity effects of FeO NPs on houseflies, morphological and histoarchitectural changes in larvae, pupae and adult flies were analyzed. NP exposure caused morphological abnormalities of larvae and pupae as well as larval pupal intermediates, and deformed adult with crumpled wings. Also, some adults couldn't emerge and remained in their puparia. The histological examinations showed that FeO NPs caused severe tissue damage especially in the cuticle and the digestive system. Thus, besides affecting the organ of first contact (digestive system), remote organs such as the integument are also targeted by FeO NPs suggesting a systemic impact on fly development and physiology.