Precision nanoscale engineering of chitosan nanoparticles via ionic gelation, eco-friendly synthesis, and ligand functionalization for improved targeted drug delivery in colon cancer treatment

Colon cancer is one of the leading cancers worldwide, with standard treatments hindered by inadequate targeting and toxicities that limit dosage. Nanotechnology offers a revolutionary framework for targeted drug delivery, utilizing nanoscale effects to improve treatment accuracy. This examination focuses on chitosan nanoparticles (CNPs) as innovative nanocarriers, leveraging their unique nanoscale features like sizes between 50-300 nm, elevated surface-to-volume ratios, and positive zeta potentials (+20 to +50 mV) to facilitate mucoadhesive interactions and improved passage through biological barriers. We emphasize novel synthesis methods, such as ionic gelation utilizing tripolyphosphate for creating particles under 100 nm and eco-friendly techniques with plant extracts for sustainable scalability, enabling accurate regulation of polydispersity indices (<0.2) and drug encapsulation efficiencies (>80%). Functionalization of surfaces with ligands (such as folate or hyaluronic acid) promotes receptor-mediated endocytosis, leveraging quantum confinement-like effects in surface charge distribution to enhance cellular uptake in colon cancer receptors that are overexpressed. Preclinical findings demonstrate stimulus-responsive actions, including pH-activated disassembly in the acidic tumour milieu (pH 5.5-6.5) or enzyme-facilitated release by colonic glycosidases, resulting in prolonged drug payloads (like 5-fluorouracil or curcumin) with 2-5 times greater bioavailability and minimized off-target impacts. Incorporating magnetic or fluorescent elements allows for multifunctional theranostics that merge nanoscale imaging with therapeutic applications. Despite challenges in mass production and in vivo stability, continuous progress in nanoscale enhancements is set to close preclinical gaps, establishing CNPs as a fundamental element for future colon cancer treatments through quantum-inspired precision and biocompatibility.