Novel route for rapid biosynthesis of copper nanoparticles using aqueous extract of Calotropis procera L. latex and their cytotoxicity on tumor cells

This paper accounts for novel, low-cost, eco-friendly route for rapid biosynthesis of copper nanoparticles. Cysteine proteases present in the latex of Calotropis procera L. were used to fabricate copper nanoparticles from copper acetate. Copper nanoparticles were initially characterized by transmission electron microscopy (TEM) and X-ray diffraction technique (XRD). Transmission electron microscopy (TEM) was used to estimate the size and shape of nanoparticles. The average size of copper nanoparticles was found to be 15 ± 1.7 nm. Energy dispersive analysis of X-rays (EDAX) showed distinct peaks of copper. Fourier transform infrared spectroscopy (FTIR) was performed to confirm capping behavior of the latex proteins that contributed to long term stability of copper nanoparticles (6 months) in aqueous medium. Copper nanoparticles synthesized by above method were monodisperse type. Cytotoxicity studies of latex stabilized copper nanoparticles were carried out on HeLa, A549 and BHK21 cell lines by MTT dye conversion assay. HeLa, A549 and BHK21 cells showed excellent viability even at 120 μM concentration of copper nanoparticles. This shows that copper nanoparticles synthesized by above method hold excellent biocompatibility.

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► One step route was designed to obtain monodisperse copper nanoparticles with average diameter of 15 ± 1.7 nm by using 0.5% aqueous extract prepared from latex of Calotropis procera L.
► To the best of our knowledge this is the first report for biosynthesis of monodisperse copper nanoparticles showing stability over a long period of time in aqueous medium.
► Synthesizing copper nanoparticles by above method would be a challenging alternative to the present chemical methods.
► Biogenic copper nanoparticles were non-cytotoxic against HeLa, A549 and BHK-21 cancer cell lines.