Tragacanth gum biopolymer as reducing and stabilizing agent in biosonosynthesis of urchin-like ZnO nanorod arrays: A low cytotoxic photocatalyst with antibacterial and antifungal properties

•Application of Tragacanth gum biopolymer as reducing and stabilizing agent.•Green sonochemical synthesis of ZnO nanorods by using Tragacanth gum.•Low cytotoxic ZnO photocatalyst with degradation efficiency of 92.2%.•Safe ZnO nanorods as antibacterial and antifungal agent.•Reduced cytotoxicity of ZnO nanorods due to presence of Tragacanth. Tragacanth, a natural gum, has been used for centuries as emulsifier, thickener, stabilizer and binder in various fields such as food, medical and cosmetic industries. In this study, Tragacanth gum was used as a clean and natural reducing and stabilizing agent for preparation of urchin-like ZnO nanorod arrays at low-temperature using ultrasonic irradiation. The morphology and structure of urchin-like ZnO nanorod arrays was investigated by XRD, FESEM images, EDX, UV–vis and FT-IR spectroscopy. The hexagonal zinc oxide nanorods were synthesized with the average diameter of 55–80nm and length of 240nm. The peak appeared in 447cm−1 in FTIR spectra and the peak around 362.3nm in UV–vis spectra of ZnO nanorods confirmed the successful synthesis of ZnO nanorods. The urchin-like ZnO nanorod arrays indicated a good photocatalytic activity through degradation of methylene blue with 92.2% efficiency and rate constant of 0.0027min−1 at 120min. Finally, the synthesized urchin-like ZnO nanorod arrays indicated 100% antibacterial activity against S. aureus and E. coli and 93% antifungal activity against C. albicans with a low cytotoxicity.