Bioinorganic Chemistry of Trace Elements: Biological Functions and Toxicological Implications (a review)

Bioinorganic chemistry illuminates the remarkable thermodynamic and kinetic precision with which chemical evolution has harnessed the periodic table. Over geological timescales, biological systems have adapted to the physical properties of inorganic ions—tuning coordination geometries, oxidation potentials, and Lewis acidities—to drive fundamental life processes. Essential trace elements serve as irreplaceable catalytic engines, redox shuttles, and structural anchors that empower metabolic networks far beyond the scope of organic functional groups alone. Yet, this essentiality exists on a strict chemical knife-edge. The very intrinsic properties that endow trace transition metals with catalytic utility—such as flexible coordination environments and facile electron transfer—render them potent cellular toxins when uncoordinated, unregulated, or present in excess. Unshielded redox-active metals trigger destructive Fenton chemistry, generating hydroxyl radicals that compromise membrane fluidity, protein stability, and genomic integrity. Concurrently, non-essential heavy metals exploit these same coordination principles, infiltrating cellular pathways through high-affinity thiophilic interactions, isomorphous substitution (mis-metallation), and the disruption of structural metalloprotein folds. Deciphering the delicate interplay between trace element coordination chemistry, homeostatic transport, and molecular toxicity pathways is essential for modern biomedical science. Advancing our mechanistic insight into these bioinorganic systems underpins the development of high-selectivity clinical chelation agents, targeted metallodrug therapies, and robust risk-assessment frameworks in environmental toxicology. 

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