With the rapid development of nanotechnology, much has been anticipated with copper oxide nanoparticles (CuO NP) due to their extensive industrial and commercial application. However, it has raised concern over the environmental safety and human health effects. In this study, CuO nanoparticles were synthesized using the green method with floral extract of Calotropis gigantea and characterized by standard physiochemical techniques like DLS, Zeta potential determination, UV- Visible Spectroscopy, XRD, FTIR, FESEM, and TEM. Mechanistic cytotoxicity studies were performed using experimental and computational assays including morphological analysis, hatching, and viability rate analysis along with ROS and apoptosis analysis. Physiochemical characterization of CuO NP determined the size and zeta potential of synthesized nanoparticles to be 30 ± 09 nm to 40 ± 2 nm and −38 mV ± 12 mV respectively. Cytotoxicity evaluation with Zebrafish revealed malfunctioned organ development with differential viability and hatching rate at 48 hpf and 72 hpf with LC50 of 175 ± 10 mg/l. Computational analysis depicted the influential role of CuO nanoparticles on zebrafish embryo’s he1a, sod1 and p53 functional expression through hydrophobic and hydrogen bond interaction with amino acid residues. Study demonstrated valuable information of cytotoxic impact which can be influential in further studies of their eco-toxicological effects.

This study investigates the in vivo cytotoxicity of ZnO nanoparticles synthesized at industrial scale with embryonic Zebrafish. Industrial synthesis of ZnO nanoparticles was mimicked at lab scale by high energy ball milling technique by milling bulk ZnO particles for 15 h. Synthesized 7 h and 10 h ZnO nanoparticles showed significant alteration of size, zeta potential and optical properties in comparison to Bulk ZnO. Mortality and hatching rate in Zebrafish embryos were influenced by these alterations. Size and charge dependent effect of ZnO nanoparticles exposure on physiology and development of Zebrafish embryos were evident by malfunctioned organ development and abnormal heartbeat rate. Similar dependency on quenching of ROS due to influential hydrogen bond interaction with glycine residue of Sod1 oxidative stress protein and increased apoptosis were observed in cells. The study revealed the mechanism of cytotoxicity in exposed embryonic Zebrafish as an effect of accumulation and internalization inside cells instigating to generation of hypoxic condition and interference with the normal adaptive stress regulation signaling pathways leading towards enhanced apoptosis. The study revealed hidden size and charge dependent in vivo cytotoxicity mechanism of ZnO nanoparticles in Zebrafish embryos insight of the environmental and clinical importance of attention on industrially synthesized ZnO nanoparticles.

Synthesized nano ZnO exhibit size-dependent antibacterial action as consequences of interactions with cell membrane proteins via hydrogen bond interaction with amino acid residues followed by internalization, membrane depolarization and induction of reactive oxygen species generation.

The toxicological impact of TiO nanoparticles on the environment and human health has been extensively studied in the last few decades, but the mechanistic details were unknown. In this study, we evaluated the impact of industrially prepared TiO nanoparticles on the biological system using zebrafish embryo as an model. The industrial synthesis of TiO nanoparticles was mimicked on the lab scale using the high energy ball milling (HEBM) method by milling bulk TiO particles for 5 h, 10 h, and 15 h in an ambient environment. The physiochemical properties were characterized by standard methods like field emission scanning electron microscopy (FESEM), dynamic light scattering (DLS), X-ray diffraction (XRD) and UV-Visible spectroscopy. cytotoxicity was assessed on zebrafish embryos by the evaluation of their mortality rate and hatching rate. Experimental and computational analysis of reactive oxygen species (ROS) induction, apoptosis, and neutral lipid alteration was done to study the effects on the cellular level of zebrafish larvae. The analysis depicted the change in size and surface charge of TiO nanoparticles with respect to the increase in milling time. investigations revealed the significant role of ROS quenching and altered neutral lipid accumulation functionalised by the molecular interaction of respective metabolic proteins in the cytotoxicity of TiO nanoparticles with zebrafish embryos. The results reveal the hidden effect of industrially synthesized TiO nanoparticle exposure on the alteration of lipid accumulation and ROS in developing zebrafish embryos. Moreover, the assessment provided a detailed mechanistic analysis of cytotoxicity at the molecular level.