Synthesis and in vitro and in vivo evaluation of manganese(III) porphyrin–dextran as a novel MRI contrast agent

Mn-porphyrin Conjugated Au Nanoshells Encapsulating Doxorubicin for Potential Magnetic Resonance Imaging and Light Triggered Synergistic Therapy of Cancer

“…Compared with other paramagnetic metal ions, manganese is less toxic and has relatively high electronic spins and fast water exchange rate 35. As T 1 contrast agents, Mn and its derivatives have been demonstrated to be potential molecular MRI probes in cancer imaging due to their excellent stability, high longitudinal relaxivity and tumorous “preferential uptake” property 35, 36. Nevertheless, nearly all paramagnetic metal complexes have short half-lives in vivo, leading to limited imaging time and poor imaging outcomes 37.…”

Covalent attachment of Mn-porphyrin onto doxorubicin-loaded poly(lactic acid) nanoparticles for potential magnetic resonance imaging and pH-sensitive drug delivery

“…The higher r 1 relaxivity of Mn(III)TPPS3-NH 2 is mainly attributed to the attractive force between water-soluble porphyrins and the surrounding water molecules. Thus, the rigid porphyrin structure can potentially modulate the internuclear distance between the paramagnetic metal center and the hydrogen atoms in the surrounding water molecules [18,19]. More excitingly, after conjugating Mn(III)TPPS3NH 2 to the surface of DOX NPs, the r 1 relaxivity of conjugated Mn(III)TPPS3NH 2 was increased to as high as 27.8 mM ÀÀ1 s ÀÀ1 .…”

“…Mn(III)TPPS3NH 2 was synthesized partially according to a procedure previously described [18,19] and the synthetic route is shown in Fig. S.1.…”

“…It is less toxic than other paramagnetic metal ions and has relatively high electronic spins and a fast water exchange rate [17]. Mn-porphyrins have been investigated as new potential molecular MRI probes [18,19]. Mn-porphyrins show high stability compared to other metalloporphyrins, usually having much higher longitudinal relaxivities [20].…”

MRI with Gadolinium‐Based Nanoparticles

“…In this case, Mn 3+ is used advantageously over Gd 3+ because of the higher stabilities of the complexes formed, Gd 3+ being released from porphyrins in solution [187]. As a nanoparticle component, Mn 3+ porphyrins have been coupled to dextran to obtain macromolecular structures exhibiting tumor cell membrane affinity with relaxivities 50-75% higher than Gd 3+ -dTpA [188]. Another possibility could be the use of the high-spin d 5 Fe 3+ .…”