Engineering Nanomaterials for Raman Bioimaging and Theranostics: Advances, Challenges, and Future Directions.

Raman imaging is rapidly advancing as a transformative platform for noninvasive, label-free molecular analysis across biomedical applications. Recent innovations in nanomaterials and photonics have enabled this technique to offer unprecedented spatial and chemical resolution. Advanced strategies such as cryogenic Raman microscopy, machine learning-enhanced hyperspectral analysis, and multimodal systems that integrate Raman spectroscopy with magnetic resonance imaging and photothermal therapy are now being developed to push the boundaries of imaging resolution and real-time analysis. This review focuses on integrating advanced Raman modalities with engineered nanostructures, particularly iron oxide-based hybrid nanoparticles, to achieve real-time, high-sensitivity imaging and targeted therapeutic delivery. Key challenges are critically addressed, including signal reproducibility, photodamage, and clinical translation. Finally, a conceptual framework is proposed linking material design, intelligent sensing, and adaptive therapeutics, positioning Raman imaging as a central component in next-generation theranostic platforms for precision healthcare.