Organometallic Nanoconjugates for Biomedical Imaging and Theranostics: A Molecular Engineering Perspective

Organometallic nanoconjugates represent a transformative class of nanoscale systems uniquely positioned at the interfaces of chemistry, biology, and nanomedicine. This review provides a comprehensive molecular engineering perspective on the design, synthesis, and biomedical applications of organometallic nanoconjugates for imaging and theranostics. These hybrid constructs, which integrate organometallic cores such as gold, ruthenium, platinum, and iron with biocompatible ligands and targeting moieties, offer tunable physicochemical properties, enabling precise control over biodistribution, cellular uptake, and stimuli-responsive behaviour. The advanced engineering approaches are examined, including ligand architecture, surface functionalization, and bioconjugation techniques to enhance specificity and multifunctionality. The utility of these nanoconjugates is further explored across diverse imaging modalities, such as fluorescence, photoacoustic, MRI, CT, and PET/SPECT, emphasizing their potential for multimodal diagnostics. On the therapeutic front, applications span photothermal therapy, chemotherapy, gene delivery, and immune modulation, highlighting their versatility in combating complex diseases, such as cancer and infections. A dedicated section addresses theranostic integration, in which diagnostics and therapy are unified within a single platform for real-time monitoring and personalized treatment. Finally, future directions involving smart nanoconjugates, AI-guided design, and biosensing-enabled feedback systems are discussed, underscoring the potential of organometallic nanoconjugates in next-generation precision medicine.