Review of Advanced Nanosensors in Nanomedicine: Bridging Biosensing Innovations With Therapeutic Applications

ABSTRACT Nanosensors represent a cornerstone of modern nanomedicine, enabling ultrasensitive, real‐time biosensing that bridges diagnostics and therapeutics towards personalised and proactive healthcare. This comprehensive review systematically examines the core principles of advanced nanosensors, including their classification by transduction mechanisms – electrochemical, optical (with emphasis on surface‐enhanced Raman spectroscopy for single‐molecule‐level detection), piezoelectric, and thermometric – and by biorecognition elements (enzymes, antibodies, aptamers, whole cells, and synthetic receptors). We highlight their transformative applications in early disease detection (e.g., cancer biomarkers, neurodegenerative aggregates, and infectious agents); continuous physiological monitoring (glucose, cardiac troponins, and inflammatory markers); enhanced in vivo imaging (magnetic resonance imaging/PET/fluorescence contrast agents); and intelligent stimuli‐responsive theranostic platforms that integrate targeted drug delivery with real‐time efficacy feedback. Recent breakthroughs (2023–2026) incorporate wearable and implantable devices, AI‐driven data analytics, multimodal sensing strategies, and closed‐loop systems for precision oncology, neurological disorders, and metabolic diseases. Despite remarkable progress, critical challenges persist, including long‐term biocompatibility, shape‐ and size‐dependent nanotoxicity (particularly for gold and silver nanoparticles in suspension for in vivo use), manufacturing scalability, and stringent regulatory pathways. By critically addressing these gaps and outlining promising future directions – such as biodegradable nanomaterials, AI‐optimised designs, and large‐scale clinical validation – this review positions nanosensors as indispensable tools for revolutionising precision medicine, improving global health equity, and enabling predictive, patient‐centric care.