Hydrazone Molecular Switches with Paramagnetic Center as F Magnetic Resonance Imaging Relaxation Enhancement Agents for pH Imaging.

The design and synthesis of hydrazone-based switches with a CF reporting group for F pH imaging using relaxation rate changes were described. A paramagnetic center was introduced into the hydrazone molecular switch scaffold by substitution of an ethyl functional group with a paramagnetic complex. The mechanism of activation relies on a gradual increase in and magnetic resonance imaging (MRI) relaxation times as pH decreases due to / isomerization, which results in a change in the distance between fluorine atoms and the paramagnetic center.

Tuning the pH of Activation of Fluorinated Hydrazone-Based Switches─A Pathway to Versatile F Magnetic Resonance Imaging Contrast Agents.

Molecular switches have become an area of great interest in recent years. They are explored as high-density data storage and organic diodes in molecular electronics as well as chemosensors due to their ability to undergo a transition between well-defined structures under the action of external stimuli. One of the types of such switches is hydrazones.

Design Principles of Responsive Relaxometric F Contrast Agents: Evaluation from the Point of View of Relaxation Theory and Experimental Data.

F magnetic resonance imaging (MRI) is a promising tool in medical diagnostics. An important class of F MRI contrast agents is based on paramagnetic resonance enhancement. This effect allows an improvement in sensitivity by increasing the number of scans per unit of time or facilitates the development of responsive contrast agents that are based on changes in relaxation rates as a detection principle.

Ratiometric pH-Responsive F Magnetic Resonance Imaging Contrast Agents Based on Hydrazone Switches.

Hydrazone-based molecular switches serve as efficient ratiometric pH-sensitive agents that can be tracked with F NMR/MRI and H NMR. Structural changes induced between pH 3 and 4 lead to signal appearance and disappearance at H and F NMR spectra allowing ratiometric pH measurements. The most pronounced are resonances of the CF group shifted by 1.

F MRI Probes for Multimodal Imaging.

Magnetic resonance imaging (MRI) is one of the most powerful imaging tools today, capable of displaying superior soft-tissue contrast. This review discusses developments in the field of F MRI multimodal probes in combination with optical fluorescence imaging (OFI), H MRI, chemical exchange saturation transfer (CEST) MRI, ultrasonography (USG), X-ray computed tomography (CT), single photon emission tomography (SPECT), positron emission tomography (PET), and photoacoustic imaging (PAI). In each case, multimodal F MRI probes compensate for the deficiency of individual techniques and offer improved sensitivity or accuracy of detection over unimodal counterparts.