Advantages and limitations of nanostructures for biomedical applications.

This review examines recent progress in developing nanoscale drug delivery systems for biomedical applications. Key nanocarriers, including inorganic nanoparticles, dendrimers, protein nanoparticles, polymeric micelles, liposomes, carbon nanotubes (CNTs), quantum dots (QDs), and biopolymeric nanoparticles, were summarized. Compared with free drugs, the tunable physicochemical properties of these materials allow for the encapsulation of therapeutics and improved pharmacokinetics. However, limitations such as toxicity, poor biodegradability, lack of controlled release, and low encapsulation efficiency remain. Inorganic nanoparticles exhibit issues with accumulation and toxicity. Dendrimers require complex syntheses and demonstrations of long-term safety. Protein nanoparticles suffer from low drug loading and stability. Polymeric micelles have stability and tumor penetration limitations. Liposomes exhibit low encapsulation efficiency and rapid clearance. Carbon nanotubes demonstrate toxicity and poor aqueous solubility. Quantum dots contain heavy metals, leading to toxicity. Biopolymeric nanoparticles have low stability and control over release kinetics. Strategies such as surface engineering with polymers and ligands aim to enhance nanoparticle targeting and biocompatibility. The combination of nanostructures in hybrid systems aims to synergize benefits while mitigating individual limitations. Stimulus-responsive and multifunctional nanoparticles enable triggered release and imaging capabilities. Overall, continued research into novel bioinspired designs, smart responsiveness and hybrid approaches is critical to fully realize the clinical potential of engineered nanomedicines for advanced drug delivery applications.