Label-Free Chemically and Molecularly Selective Magnetic Resonance Imaging

Abstract

Biomedical imaging, especially molecular imaging, has been a driving force in scientific discovery, technological innovation, and precision medicine in the past two decades. While substantial advances and discoveries in chemical biology have been made to develop molecular imaging probes and tracers, translating these exogenous agents to clinical application in precision medicine is a major challenge. Among the clinically accepted imaging modalities, magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) exemplify the most effective and robust biomedical imaging tools. Both MRI and MRS enable a broad range of chemical, biological and clinical applications from determining molecular structures in biochemical analysis to imaging diagnosis and characterization of many diseases and image-guided interventions. Using chemical, biological, and nuclear magnetic resonance properties of specific endogenous metabolites and native MRI contrast-enhancing biomolecules, label-free molecular and cellular imaging with MRI can be achieved in biomedical research and clinical management of patients with various diseases. This review article outlines the chemical and biological bases of several label-free chemically and molecularly selective MRI and MRS methods that have been applied in imaging biomarker discovery, preclinical investigation, and image-guided clinical management. Examples are provided to demonstrate strategies for using endogenous probes to report the molecular, metabolic, physiological, and functional events and processes in living systems, including patients. Future perspectives on label-free molecular MRI and its challenges as well as potential solutions, including the use of rational design and engineered approaches to develop chemical and biological imaging probes to facilitate or combine with label-free molecular MRI, are discussed.

225Ac-Labeled Antibody for Fibroblast Activation Protein-Targeted Alpha Therapy

“…Once tumor volumes reached 1000 mm 3 , the mice were anesthetized and euthanized using inhalation of a 5% isoflurane/oxygen gas mixture. Hematoxylin and eosin (H&E) staining was performed as in a previous study . For the toxicity study, 4T1-hFAP tumor-bearing mice were injected with saline and 11.1 kBq [ 225 Ac]­Ac-DOTA-PKU525 with DAR 3.87, respectively.…”

“…Hematoxylin and eosin (H&E) staining was performed as in a previous study. 37 For the toxicity study, 4T1-hFAP tumor-bearing mice were injected with saline and 11.1 kBq [ 225 Ac]Ac-DOTA-PKU525 with DAR 3.87, respectively. The mice were sacrificed and a complete blood count (CBC) was performed on days 7 and 19 (n = 5).…”