Synthesis and characterization of tellurium nanoparticles with antimicrobial and anticancer properties made by green synthesis with orange extract

Bacterial infections are a major concern for the current healthcare system. Evolving strains and mutating populations of antibiotic-resistant bacteria are currently responsible for 2 million infections and 23,000 deaths in the United States alone and rising. Novel solutions and treatments currently include the use of nanotechnology and metallic nanoparticles. Traditionally, chemical and physical approaches are utilized for the synthesis of nanoparticles. However, drawbacks include expensive procedures and the use of chemicals that are potentially harmful to the environment, due to toxic by-products and the use of harsh conditions. Therefore, there is a growing need for nanoparticles produced by green and eco-friendly methods. Here, orange juices were used as the unique reducing and capping agents for the biosynthesis of needle-shaped tellurium nanoparticles with a uniform size distribution (12.1±6.4 nm width and 101.3±23.7 nm length). The green synthesized tellurium nanoparticles exhibited great antibacterial activity against both Gram negative and Gram positive bacteria, ranging in concentrations from 5 to 50 µg/mL. Nanoparticles were also tested for their biocompatibility with human dermal fibroblasts (HDF) cells, and showed no significant cytotoxic effect for concentrations up to 50 µg/mL Afterwards, tellurium nanoparticles were cultured with melanoma cancer cells, showing cytotoxic effect and inhibiting the normal growth of cells within the same range of concentration. Therefore, tellurium nanoparticles synthesized using a green-synthesis approach with orange juice were developed as both antibacterial and anticancer agents, with no significant cytotoxic effect against healthy human cells, using a completely green-synthesis approach, overcoming the main problems of traditional nanoparticle synthesis.