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 (Fe3O4 NPs) have tremendous applications which include cell separation, arsenic removal from water and DNA separation. Spherically shaped Fe3O4 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 Fe3O4NPs toxicity and give us an overview of their impact. The larvicidal activity of Fe3O4NPs 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 LC50 value for Fe3O4 NPs was 60 and 75 μg/mL by feeding and contact, respectively. To investigate the toxicity effects of Fe3O4 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 Fe3O4 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 Fe3O4 NPs suggesting a systemic impact on fly development and physiology.