Catalysis under magnetic control: magnetic nanoparticles as next-generation bioorthogonal reactors

Chemical reactions within living systems are made possible by bioorthogonal catalysis without interfering with regular biological processes. However, under physiological conditions, many transition-metal catalysts become toxic or unstable. By enhancing stability, safeguarding the catalyst, and enabling regulated, magnetically controlled activation and directed delivery to particular locations, magnetic nanoparticles (MNPs) overcome these difficulties. Reliable reactions like palladium-mediated decaging and in situ prodrug activation are supported by their adjustable cores and versatile organic or inorganic coatings. Systems based on Fe-Pd nanowires, silica-confined catalytic shells, magnetothermia-responsive nanoreactors, SPAAC-clickable surfaces, and cascade magnetic sensors show that MNPs may carry out effective and selective catalysis in challenging biological settings. All things considered, MNP platforms offer a viable approach for secure, focused, and manageable bioorthogonal reactions that are beneficial for medical and diagnostic uses. In addition, recent developments in bioorthogonal catalysis activated by external stimuli such as light, ultrasound, and other physical fields are briefly discussed. The present review aims to comprehensively discuss the current state of magnetic nanoreactors for bioorthogonal catalysis, addressing key challenges in biological integration and projecting future directions for clinical and diagnostic translation.