Advancements in metal and metal oxide nanoparticles for targeted cancer therapy and imaging: Mechanisms, applications, and safety concerns

Conventional cancer treatments, including chemotherapy, radiation, and surgery, can produce significant adverse effects, hence limiting their therapeutic efficacy and compliance among patients. Conversely, nano- technology has arisen as a viable alternative, offering innovative prospects for therapeutic and diagnostic uses in cancer treatment. Metal-based nanoparticles (MNPs), due to their unique physical, chemical, and physicochemical characteristics, have demonstrated considerable potential in tackling numerous issues in cancer therapy. This review highlights that among the diverse array of MNPs examined, silver (Ag), iron (Fe), and gold (Au) nanoparticles have been thoroughly investigated by researchers globally for their distinctive properties in imaging and therapy. Moreover, the research emphasises that the functionalisation of magnetic nanoparticles and altering their surface characteristics can markedly improve their efficacy by augmenting tumor targeting and bioavailability via processes like the increased permeability and retention (EPR) effect. This review investigates the molecular processes by which MNPs impede cancer proliferation, encompassing their functions in inducing apoptosis, altering cellular signalling pathways, and producing reactive oxygen species (ROS) that result in cancer cell mortality. The review also analyses the influence of synthesis methods-chemical, green, or biosynthesis on the characteristics of MNPs. Significant instances of metallic and metal oxide nanoparticles, including iron (Fe), gold (Au), zinc (Zn), silver (Ag), copper (Cu), cerium (Ce), titanium (Ti), barium (Ba), nickel (Ni), magnesium (Mg), bismuth (Bi), and calcium (Ca), are examined, highlighting their functions in imaging and therapeutic applications.