Green Synthesis and Biomedical Applications of Nickel Oxide Nanoparticles

Nickel oxide nanoparticles (NiO NPs) have attracted considerable attention as multifunctional agents combining unique magnetic, optical and redox properties with biological activity. Green synthesis strategies employ natural extracts or biopolymers to reduce nickel precursors under mild, eco-friendly conditions, yielding spherical to polyhedral NiO NPs typically 10–60 nm in diameter. The intrinsic high surface-to-volume ratio and surface functionalities imparted by biomolecules support strong interactions with microbial membranes, enabling broad-spectrum antibacterial activity through reactive oxygen species generation and metal ion release. In oncology, ligand-decorated NiO NPs have demonstrated selective cytotoxicity against cancer cell lines via apoptosis induction, while minimising effects on normal cells. Preliminary studies also indicate potential as contrast agents, leveraging magnetic responsiveness for imaging and as carriers for targeted drug delivery. Beyond direct therapeutic effects, NiO NPs can modulate enzyme activities and act as antioxidant scavengers or photodynamic enhancers. The scalability, low cost and biocompatibility of green routes position NiO NPs as promising candidates for next-generation nanomedicines. Remaining challenges include precise control of size and surface chemistry, in‐depth toxicological profiling and translation to in vivo models.

Research from Nature Portfolio

Recent studies have demonstrated the biosynthesis of NiO NPs using marine macroalgae extract as both reducing and stabilising agent. The resulting 32 nm spherical particles bear organic capping layers that confer a high surface area (~45 m² g⁻¹) and enable magnetic recovery. These biogenic NiO NPs catalyse the one-pot synthesis of pyridopyrimidine derivatives in aqueous media with yields exceeding 90% and retain activity over multiple cycles. The finely tuned surface chemistry in this work underlines the potential for modular functionalisation in future biomedical delivery systems and sustainable chemical manufacturing.

Green Synthesis and Biomedical Applications of Nickel Oxide Nanoparticles publication trend

The graph below shows the total number of articles in green synthesis and biomedical applications of nickel oxide nanoparticles across all publications each year (not limited to Nature Index journals).

Technical terms

Green synthesis: A fabrication approach using biological extracts or polymers to reduce metal salts under mild, environmentally benign conditions without harsh chemicals.

Phytochemical reduction: A process in which plant‐derived compounds serve as both reducing and stabilising agents during nanoparticle formation.

Capping agent: A molecule that binds to nanoparticle surfaces, controlling growth, preventing aggregation and imparting functional surface groups.

Cytotoxicity assay: An in vitro test measuring the capacity of a substance to kill or inhibit the growth of cultured cells, often quantified by IC₅₀ values.

Reactive oxygen species (ROS): Highly reactive oxygen‐containing molecules generated by nanoparticles that can damage cellular components, contributing to antimicrobial or anticancer effects.

References

1. Recent Advances in the Synthesis and Stabilization of Nickel and Nickel Oxide Nanoparticles: A Green Adeptness. International Journal of Analytical Chemistry (2016).
2. Algal magnetic nickel oxide nanocatalyst in accelerated synthesis of pyridopyrimidine derivatives. Scientific Reports (2021).
3. Green-based bio-synthesis of nickel oxide nanoparticles in Arabic gum and examination of their cytotoxicity, photocatalytic and antibacterial effects. Green Chemistry Letters and Reviews (2021).
4. Phytogenic Synthesis of Nickel Oxide Nanoparticles (NiO) Using Fresh Leaves Extract of Rhamnus triquetra (Wall.) and Investigation of Its Multiple In Vitro Biological Potentials. Biomedicines (2020).
5. Green Synthesized Phytochemically (Zingiber officinale and Allium sativum) Reduced Nickel Oxide Nanoparticles Confirmed Bactericidal and Catalytic Potential. Discover Nano (2020).