Discussion
Despite the recent reports highlighting the potential toxic effects of photovoltaic devices (cite Patel, 2015; Hailegnaw, 2015; Spross, 2014; and Benmessaoud, 2015), industrial production of perovskites-based photovoltaic devices is on going with a project of commercialization in 2018. We showed in this paper the effects of perovskites on the Caenorhabditis elegans. Although nematodes are invertebrate small animals, they represent the gold standard in toxicology with their intact and metabolically active digestive, reproductive, endocrine, sensory and neuromuscular systems. Unfortunately, mammalian models will continue to be used to predict safe human exposure levels because no combination of current alternative assays can replicate the complexity of interacting metabolism, homeostasis and signaling mechanisms that are present in mammals (Tice et al.,2013). However, given the high percentage of commercially available chemicals for which there is little or no toxicity data available (Dix et al., 2007; Judson et al., 2009), toxicity screenings that can at least flag for further studies those chemicals with the most potential for harm are urgently needed. As an intermediate between in vitro and mammalian testing, combining various C. elegans assays on a single experiment using our microfluidic device contributes significantly to the field of toxicology.
The in vivo experimentation presented in this paper strengthens the in vitro outcomes presented previously (CITE benmessaoud etal 2016), and validates the toxic profile of perovskites, which will potentially constitute the next generation of solar panels that will cover our buildings. The eco-toxic effects observed in our study demonstrate the hazards on small model organisms ( nematode), and are translated in a decrease of viability, a retard in growth and development, as well as in an altered fertility. These effects may be due by an induced mitochondrial stress, as predicted by the RNA-seq data (TO BE PUBLISHED). We believe a homolog of the transcription factor p53 in C. elegans (CEP-1 )(Hoffman et al., 2014; Schumacher et al., 2001) may be at the origin of the mitochondrial stress, which, together with DNA damage, could be responsible of the adverse effects of perovskites observed on the whole organisms. Mitochondrial stress and DNA damage may target the hormone ecdysone, which directs progression through larval stages. (Ahn et al., 2014; Posgai et al., 2011) Additionally, strong correlation of mitochondrial or DNA damage and cell cycle or apoptosis have been made to evidence developmental impacts and even a shortened life span.(Stergiou et al., 2004) These publications may hold an explanation of our results, and encourage our research to assess mitochondrial correlation of mitochondrial or DNA damage and cell cycle or apoptosis have been made to evidence developmental impacts and even a shortened life span.199 These publications may hold an explanation of our results, and encourage our research to assess mitochondrial imbalance as well as metal traces in C. elegans. Considering the genome conservation between humans and C. elegans, (Bier et al., 2005) and the analysis of the genome expression profile obtained from human cells using RNA-seq (TO BE PUBLISHED), the data presented in this paper could predict the potential hazards of the photovoltaic perovskites on humans. As an outlook of this in vivo study, our protocols must obviously be improved for a more accurate and predictable outcome. There is room for debate regarding dose, time lapse and pathway of exposure to perovskites. These tests should be performed on other small organisms such as Drosophila melanogaster or Danio rerio, and can be even pursued to verify whether generations n2 and n3 still suffer the exposure of their grand-parents, and determine when the observed toxic effects stop inter-generation transmission. For C. elegans, because of a lack of space after one week (Figure?), worms should be transferred into petri dishes and evaluation of toxicity should be continued without adding extra perovskites.