Coordination‐Responsive Longitudinal Relaxation Tuning as a Versatile MRI Sensing Protocol for Malignancy Targets

Abstract

Biomarkers (e.g., acidity, H2O2, hypoxia, and specific molecules) as one primary component of tumor microenvironments are closely associated with occurrence, invasion, and metastasis of malignancy, thus can act as biological targets. However, their monitoring remains a challenging task. Herein, a coordination‐dependent longitudinal relaxation tuning (CLRT) that occurs between a Mn2+ “donor” and a Mn2+ “acceptor” is established to enable biological target sensing. Relying on the differences of coordination ability and spatial structure between donors and acceptors, the biological targets as Mn2+ acceptor can take Mn2+ away from the donors (i.e., modified ligands) in nanoscale probes, which consequently varies T1‐weighted (T1W) magnetic resonance imaging (MRI) signal. The coordination ability and spatial structure of the modified Mn2+ “donor” and the pore diameter of donor carrier are demonstrated to determine the feasibility, specificity, and generality of CLRT. With CLRT, this MRI‐based ruler is demonstrated for the successful specific detection of biological targets (i.e., hyaluronic acid and glutathione) of malignancy, and its potential in quantitative measurement of hyaluronic acid is further demonstrated. CLRT can serve as a novel and general sensing principle to augment the exploration of a wide range of biological systems.

Recent Development on Controlled Synthesis of Mn‐Based Nanostructures for Bioimaging and Cancer Therapy

“…[8][9][10] Manganese(II) and its derivatives, with good biodegradability, biocompatibility, low toxicity, high spin number, and long electron relaxation time have been well-used as a promising alternative to MRI CAs. [11][12][13][14][15][16] In addition, the Mn-based CAs are gradually diversified, such as inorganic metal salt, metal oxide, small molecules organic chelate, and macromolecules, all of which have promising applications in clinical settings with good biocompatibility. In particular, Mn-based nanoparticles could simulate the catalytic function and activity of some biological enzymes upon the tumor microenvironment (TME), which was well known as weak acidity, overexpression of H 2 O 2 , low catalase activity, hypoxia, and glutathione (GSH) overexpression.…”

Targeted Therapy against Metastatic Melanoma Based on Self‐Assembled Metal‐Phenolic Nanocomplexes Comprised of Green Tea Catechin

“…Targeted drug delivery systems that can directly deliver drugs to a specific site with minimal systemic exposure provide significant advantages over current treatments; however, the bioavailability of therapeutic molecules delivered through drug carriers targeted to metastatic melanoma remains low. This is mainly due to the rapid proliferation and bloodstream/lymphatic migration of metastatic melanoma.…”

Reactive oxygen species scavenging and inflammation mitigation enabled by biomimetic prussian blue analogues boycott atherosclerosis

“…2 e), suggesting PMPB NC also scavenged singlet oxygen that is another type of ROS. Furthermore, the H 2 O 2 scavenging ability of PMPB NC was also explored since H 2 O 2 is also a type of ROS [ 39 ]. Although H 2 O 2 damage ability to artery vessels is weaker than free radicals, the much more H 2 O 2 than free radicals in inflammation determines that artery vessel tissues are undoubtedly subjected to severe H 2 O 2 -induced damages [ 30 ].…”