Cardiovascular disease is one of the major contributors to global disease burden. Atherosclerosis is an inflammatory process that involves the accumulation of lipids and fibrous elements in the large arteries, forming an atherosclerotic plaque. Rupture of unstable plaques leads to thrombosis that triggers life-threatening complications such as myocardial infarction. Current diagnostic methods are invasive as they require insertion of a catheter into the coronary artery. Molecular imaging techniques, such as magnetic resonance imaging, have been developed to image atherosclerotic plaques and thrombosis due to its high spatial resolution and safety. The sensitivity of magnetic resonance imaging can be improved with contrast agents, such as iron oxide nanoparticles. This review presents the most recent advances in atherosclerosis, thrombosis, and myocardial infarction molecular imaging using iron oxide-based nanoparticles. While some studies have shown their effectiveness, many are yet to undertake comprehensive testing of biocompatibility. There are still potential hazards to address and complications to diagnosis, therefore strategies for overcoming these challenges are required.

Cardiovascular disease (CVD) is the leading cause of death worldwide. CVD includes a group of disorders of the heart and blood vessels such as myocardial infarction, ischemic heart, ischemic injury, injured arteries, thrombosis and atherosclerosis. Amongst these, atherosclerosis is the dominant cause of CVD and is an inflammatory disease of the blood vessel wall. Diagnosis and treatment of CVD remain the main challenge due to the complexity of their pathophysiology. To overcome the limitations of current treatment and diagnostic techniques, theranostic nanomaterials have emerged. The term "theranostic nanomaterials" refers to a multifunctional agent with both therapeutic and diagnostic abilities. Theranostic nanoparticles can provide imaging contrast for a diversity of techniques such as magnetic resonance imaging (MRI), positron emission tomography (PET) and computed tomography (CT). In addition, they can treat CVD using photothermal ablation and/or medication by the drugs in nanoparticles. This review discusses the latest advances in theranostic nanomaterials for the diagnosis and treatment of CVDs according to the order of disease development. MRI, CT, near-infrared spectroscopy (NIR), and fluorescence are the most widely used strategies on theranostics for CVDs detection. Different treatment methods for CVDs based on theranostic nanoparticles have also been discussed. Moreover, current problems of theranostic nanoparticles for CVDs detection and treatment and future research directions are proposed.

We have for the first time reported 120 nm silver/iron oxide hybrid nanopopcorns with surface plasmon resonance tuned at near-infrared (NIR) range for imaging and therapeutic applications. The nano-popcorns displayed excellent photothermal thrombolytic effect and anticancer activity in a concentration-dependent manner upon NIR laser irradiation, benefiting the photothermal treatment of thrombosis and cancer. At low concentrations, the nano-popcorns exhibited relatively good reactive oxygen species (ROS) scavenging capability. Notably, the nano-popcorns exerted excellent magnetic resonance imaging (MRI) T 2 -signal after being sequestered within cells or binding on the surface of the thrombus, becoming a promising imaging agent for cell labeling and thrombus detection. Cytotoxicity, biodistribution studies, and histology analysis demonstrated no significant toxicity caused by the nano-popcorns. There was no longterm retention of the nano-popcorns in the mouse organs at the dose treated. These results give insight into the potential of using these nano-popcorns for diagnosis and treatment of diseases related to ROS, cancer, and thrombosis.