<p>Nanotechnology, based on the utilization of nanoparticles, has revolutionized drug delivery techniques, offering groundbreaking methods for managing and diagnosing intricate ailments over the past four decades. This article aims to underscore how the use of these particles has been used to treat previously incurable diseases such as cancer, Alzheimer’s, and Parkinson’s disease. Recently, the integration of diagnostic imaging and targeted therapy using theranostic nanoparticles has improved cancer treatment precision. Moreover, exosome-based drug delivery has demonstrated high <i>in vivo</i> biocompatibility and antigen-carrying ability during vaccine development. The unique properties of these tiny particles enable their transport to specific locations inaccessible to large drug molecules. The development of these nanodrugs by either encapsulation or adsorption of drugs on particles has allowed the loading of both hydrophilic and hydrophobic drugs. Innovative engineering approaches have enabled the engineering of shear-sensitive nanoparticles for site-targeted drug release, which eliminates the requirement for frequent doses, which is common in conventional drug delivery. Factors such as size, shape as well as surface modification are considered during the top-down and bottom-up approaches for engineering nanoparticle-based systems. However, issues related to scaling up manufacturing, long-term safety, and regulatory approval for these techniques must be resolved. The use of these drug delivery systems offers many therapeutic advantages. This article examines the application of these systems across various medical domains including cancer treatment, infectious diseases, cardiovascular disorders, central nervous system ailments, and ophthalmic conditions. This fusion of nanotechnology with drug delivery has the potential to elevate healthcare standards in the future by introducing innovative frameworks for revolutionizing therapeutic practices.</p> Graphical Abstract <p></p>