Polymeric Metal Contrast Agents for T₁-Weighted Magnetic Resonance Imaging of the Brain

Abstract

Imaging plays an integral role in diagnostics and treatment monitoring for conditions affecting the brain; enhanced brain imaging capabilities will improve upon both while increasing the general understanding of how the brain works. T 1 -weighted magnetic resonance imaging is the preferred modality for brain imaging. Commercially available contrast agents, which are often required to render readable brain images, have considerable toxicity concerns. In recent years, much progress has been made in developing new contrast agents based on the magnetic features of gadolinium, iron, or magnesium. Nanotechnological approaches for these systems allow for the protected integration of potentially harmful metals with added benefits like reduced dosage and improved transport. Polymeric enhancement of each design further improves biocompatibility while allowing for specific brain targeting. This review outlines research on polymeric nanomedicine designs for T 1 -weighted contrast agents that have been evaluated for performance in the brain.

Surface Bio‐engineered Polymeric Nanoparticles

“…Successfully grafting biofunctional molecules onto nanoparticles modulates their surface characteristics and achieves desired biological activity such as biosensing, [34][35][36] bioimaging, [37,38] and targeted therapy [39,40] (Figure 1). For instance, nanoparticle structures specifically modified with ions, fluorophores, or antibodies can behave as nanoprobes for surface chemical fluctuations such as pH as well as sensors for reactive oxygen species (ROS) and biologically threatening agents.…”

Iron gallic acid biomimetic nanoparticles for targeted magnetic resonance imaging

“…Exogenous contrast agents are typically employed to enhance imaging sensitivity [ 2 ]. Among these, T 1 -weighted contrast agents are favored in clinical practice for their ability to produce brighter signals from surrounding tissues [ 3 ]. In comparison, T 2 -weighted contrast agents yield dark signals that are indistinguishable from naturally dark areas.…”

Alpha‐Synuclein Oligomers Driven T1–T2 Switchable Nanoprobes for Early and Accurate Diagnosis of Parkinson's Disease

“…[ 16 ] Although gadolinium‐based chelates are routinely used as T1 contrast agents to exert bright contrast by accelerating longitudinal (T1) relaxation of water protons, there is a lack of α‐syn oligomers targeting. [ 17 ] The α‐syn oligomers‐targeted iron oxide nanoparticles based T2 contrast agents have been developed, which exhibit hypointensity in the regions of α‐syn oligomers. However, these nanoparticles also show decreased MRI signals in other lesions in the brain, such as neuroinflammation‐relevant areas, [ 18 ] yielding false‐positive results due to robust magnetic nanoparticles uptake by microglia.…”