Smart Stimuli-responsive Nanocarriers in Nanotechnology-based Cancer Diagnosis and Treatment

Drug resistance, systemic toxicity, and poor selectivity limit existing therapy for cancer, which continues to be one of the most urgent global health issues. Intelligent, stimuli-responsive nanocarriers that enable site-specific drug delivery, enhance bioavailability, and reduce adverse effects have been made possible by advances in nanotechnology. The foundations of nanomedicine are covered in this chapter, along with FDA-approved nanodrugs that have helped in clinical translation. Therapeutics can be delivered in a controlled, sustained, and co-delivered manner thanks to smart nanocarriers like liposomes, micelles, dendrimers, and carbon-based systems that are designed to react to both internal (pH, redox gradients, enzyme activity, hypoxia) and external (temperature, light, magnetic fields, ultrasound) stimuli. Stability, targeting, and imaging capabilities are enhanced by functional biomaterials, including biocompatible polymers (PEG, PLGA, chitosan) and inorganic components (gold, iron oxide, silica). Their theragnostic uses are emphasized, especially when combined with fluorescence, MRI, and PET imaging for real-time monitoring. Along with release mechanisms like the Enhanced Permeability and Retention effect, the chapter also examines the co-delivery of genes and medications. Stability in biological fluids, tumour heterogeneity, immunogenicity, and regulatory hurdles remain issues despite advancements. In precision oncology, new approaches such as biomimetic engineering, AI-assisted carrier design, and tailored nanomedicine present encouraging avenues for safer, patient-specific cancer treatment.