Metal-coordinated chitosan nanocarriers: A promising platform for high efficiency drug loading and stimuli-responsive release.

The incorporation of metal-coordination chemistry into chitosan (CS)-based nanocarriers has expanded possibilities in the domain of intelligent drug delivery systems. CS serves as an optimal foundation for developing multifunctional carriers that enable targeted and stimuli-responsive drug release. This study emphasizes current progress in the design and use of metal-coordinated CS nanocarriers, concentrating on their coordination processes, drug loading techniques and controlled release characteristics. Special emphasis is placed on systems that include transition metals like Zn2+, Fe3+ and Cu2+, which improve structural integrity, facilitate environmentally induced release and sometimes provide further therapeutic benefits. Case studies illustrate the effectiveness of zinc-based CS nanocarriers integrated with mesoporous silica and biotin surface modification in tumor-targeted administration, pH-responsive release and selective cytotoxicity. Notwithstanding encouraging preclinical results, obstacles such as coordination bond stability, physiological interference, long-term safety and regulatory ambiguity continue to pose significant impediments to clinical translation. Proposed future paths include the advancement of theranostic platforms, multi-metallic systems and artificial intelligence (AI)-driven design tools. Metal-coordinated CS nanocarriers are a versatile and effective approach for precision nanomedicine with considerable promise in cancer, infectious disorders and regenerative medicine.