Iron oxide nanoparticles for inflammatory bowel disease: Recent advances in diagnosis and targeted drug therapy

Gastrointestinal tract (GI) is the second largest and essential organ in the body responsible for the absorption of nutrients and removal of wastes from the body. The proper functioning of GI is pivotal for healthy lifestyle as it regulates various metabolic processes directly or indirectly. The compromised intestinal permeability and other metabolic disorders are the major factors contributing to inflammatory bowel disease (IBD). The ulcerative colitis (UC) and Crohn's disease (CD) are the types of IBD characterized by chronic inflammation in the GI tract and carries a higher risk to develop colon cancer. Early diagnosis of IBD using pro-inflammatory cytokines as biomarkers is often challenging. Iron oxide nanoparticles (IONPs) are gaining increasing attention as they offer early and reliable confirmation of the type of IBD. Moreover, IONPs that are either encapsulated to conjugated or even engineered, can render site specific drug delivery and thus reduce high-dose induced toxic effects at the non-target sites. In this focused review, we review emphasize the diagnostic, therapeutic, theranostic applications of IONPs for IBD. In addition, current research involving studies on IONPs in experimental IBD models and clinical trials are also reviewed. The IONPs proven to have higher biodistribution in the cell compared to other conventional drug delivery systems. The surveyed literature conclusively establishes the magnificent properties, and broad-spectrum applicability of IONPs, which can be promptly used for both diagnosis and therapy including image guided drug delivery to the colon region.