Innovative green synthesis of zinc-doped lignin nanoparticles from almond shell wastes: Examining photocatalytic, antibacterial, and cytotoxicity

In this study, zinc-doped lignin nanoparticles (Zn-doped lignin NPs) were synthesized from almond shell waste. The incorporation of Zn²⁺ into lignin NPs aimed to improve their physical, chemical, and biological properties. XRD patterns confirmed the amorphous nature of the doped nanoparticles. TEM and FESEM imaging revealed spherical NPs with an average diameter of 15.17 nm. The cytotoxicity of Zn-doped lignin NPs was assessed on the breast cancer MDA-MB-231 cell line, revealing significant toxicity with an IC 50 value of approximately 364 μg/mL after 48 h. Additionally, agar diffusion tests showed that Zn-doped lignin NPs exhibited stronger antibacterial activity than pure lignin NPs against Acinetobacter baumannii ( ATCC 19606 and clinical strains ) and Staphylococcus aureus ( ATCC 25923 and clinical strains ) . Moreover, the photocatalytic effects demonstrated the high efficiency of Zn-doped lignin NPs in degrading organic dyes such as Rhodamine B (91%, RhB) and methylene blue (88%, MB) under UV light.