Abstract:Herein, a new magnetic resonance imaging (MRI) agent based on molecular nanoparticles of iron(III)-tannic complexes (Fe-TA NPs) is reported. The paramagnetic and molecularlike Fe-TA NPs were successfully synthesized at room temperature within a few minutes without the use of any toxic agents or expensive equipment. The coordination states of the Fe-TA NPs were pH-dependent. The r relaxivity values of the bis-dominated and tris-dominated structures of the Fe-TA NPs were determined to be 6.31 and 5.24 mMs, respe… Show more
“…Under this condition, Fe–TA complexes undergo an iron-mediated self-assembly process to form nanosized Fe–TA complexes. It should be noted that PBS buffer (pH 7.4) was chosen as the reaction medium because this condition was suitable to form predominantly Tris-coordinated Fe–TA NPs (having a more stable structure) 28 , 35 . Figure 1 ( a ) Schematic illustration of the preparation of Fe–TA NPs, ( b ) the TEM image of Fe–TA NPs, ( c ) typical characteristics of Fe–TA NPs.…”
Section: Resultsmentioning
confidence: 99%
“…This result is in consistent with the measured log P value of −1.0249, indicating good water solubility 41 . Previously, it has been demonstrated that molecular nanoparticles of Fe–TA complexes exhibit paramagnetism and enhance MRI signal intensity in T 1 -weighted imaging 28 . Similarly, the obtained Fe–TA NPs were also found to induce signal enhancement in T 1 -weighted images, with r 1 values of 3.08 mM −1 s −1 (in 4% acrylamide gel phantom), indicating that it can be used for increasing the sensitivity of MRI.…”
Section: Resultsmentioning
confidence: 99%
“…The enhancement in the signal intensity observed in the Fe–TA NP treated cells may be due to their higher accumulation within the cells. Moreover, the accumulation of the Fe–TA NPs in acidic compartments such as MVB, amphisomes, and autolysosomes is critical for enhancing the MRI signal because of the pH-dependent relaxivity of Fe–TA NPs 28 . Specifically, the dominated coordination states of the Fe–TA NPs are changed from the lower r 1 state of Tris-dominated Fe–TA NPs to the higher r 1 state of Bis-dominated Fe–TA NPs in such acidic compartments.…”
Section: Resultsmentioning
confidence: 99%
“…It is considered as a polydentate ligand that can bind to various metal ions, especially ferric ion, to form high stable metal complexes 27 . Additionally, unlike a small polyphenol, interaction of ferric ions and tannic acid has shown unique properties such as iron-mediated self-assembly of Fe–TA complexes, resulting in molecular nanoparticles of Fe–TA complexes 28 . The large Fe–TA complexes are critical for enhancing the MRI signal because large paramagnetic molecular nanoparticles have good capability of enhancing the rate of water–proton exchange by slowing down the rotational diffusion 29 .…”
Herein, a new molecular nanoparticle based on iron(III)-tannic complexes (Fe–TA NPs) is presented. The Fe–TA NPs were simply obtained by mixing the precursors in a buffered solution at room temperature, and they exhibited good physicochemical properties with capability of inducing autophagy in both hepatocellular carcinoma cells (HepG2.2.15) and normal rat hepatocytes (AML12). The Fe–TA NPs were found to induce HepG2.2.15 cell death via autophagic cell death but have no effect on cell viability in AML12 cells. This is possibly due to the much higher uptake of the Fe–TA NPs by the HepG2.2.15 cells via the receptor-mediated endocytosis pathway. As a consequence, enhancement of the T1 MRI contrast was clearly observed in the HepG2.2.15 cells. The results demonstrate that the Fe–TA NPs could provide a new strategy combining diagnostic and therapeutic functions for hepatocellular carcinoma. Additionally, because of their autophagy-inducing properties, they can be applied as autophagy enhancers for prevention and treatment of other diseases.
“…Under this condition, Fe–TA complexes undergo an iron-mediated self-assembly process to form nanosized Fe–TA complexes. It should be noted that PBS buffer (pH 7.4) was chosen as the reaction medium because this condition was suitable to form predominantly Tris-coordinated Fe–TA NPs (having a more stable structure) 28 , 35 . Figure 1 ( a ) Schematic illustration of the preparation of Fe–TA NPs, ( b ) the TEM image of Fe–TA NPs, ( c ) typical characteristics of Fe–TA NPs.…”
Section: Resultsmentioning
confidence: 99%
“…This result is in consistent with the measured log P value of −1.0249, indicating good water solubility 41 . Previously, it has been demonstrated that molecular nanoparticles of Fe–TA complexes exhibit paramagnetism and enhance MRI signal intensity in T 1 -weighted imaging 28 . Similarly, the obtained Fe–TA NPs were also found to induce signal enhancement in T 1 -weighted images, with r 1 values of 3.08 mM −1 s −1 (in 4% acrylamide gel phantom), indicating that it can be used for increasing the sensitivity of MRI.…”
Section: Resultsmentioning
confidence: 99%
“…The enhancement in the signal intensity observed in the Fe–TA NP treated cells may be due to their higher accumulation within the cells. Moreover, the accumulation of the Fe–TA NPs in acidic compartments such as MVB, amphisomes, and autolysosomes is critical for enhancing the MRI signal because of the pH-dependent relaxivity of Fe–TA NPs 28 . Specifically, the dominated coordination states of the Fe–TA NPs are changed from the lower r 1 state of Tris-dominated Fe–TA NPs to the higher r 1 state of Bis-dominated Fe–TA NPs in such acidic compartments.…”
Section: Resultsmentioning
confidence: 99%
“…It is considered as a polydentate ligand that can bind to various metal ions, especially ferric ion, to form high stable metal complexes 27 . Additionally, unlike a small polyphenol, interaction of ferric ions and tannic acid has shown unique properties such as iron-mediated self-assembly of Fe–TA complexes, resulting in molecular nanoparticles of Fe–TA complexes 28 . The large Fe–TA complexes are critical for enhancing the MRI signal because large paramagnetic molecular nanoparticles have good capability of enhancing the rate of water–proton exchange by slowing down the rotational diffusion 29 .…”
Herein, a new molecular nanoparticle based on iron(III)-tannic complexes (Fe–TA NPs) is presented. The Fe–TA NPs were simply obtained by mixing the precursors in a buffered solution at room temperature, and they exhibited good physicochemical properties with capability of inducing autophagy in both hepatocellular carcinoma cells (HepG2.2.15) and normal rat hepatocytes (AML12). The Fe–TA NPs were found to induce HepG2.2.15 cell death via autophagic cell death but have no effect on cell viability in AML12 cells. This is possibly due to the much higher uptake of the Fe–TA NPs by the HepG2.2.15 cells via the receptor-mediated endocytosis pathway. As a consequence, enhancement of the T1 MRI contrast was clearly observed in the HepG2.2.15 cells. The results demonstrate that the Fe–TA NPs could provide a new strategy combining diagnostic and therapeutic functions for hepatocellular carcinoma. Additionally, because of their autophagy-inducing properties, they can be applied as autophagy enhancers for prevention and treatment of other diseases.
“…As a result, assembling structure of FTs can be changed or are degradable in the response to specific milieu. For example, an acidic environment is able to change the coordination state of FTs from Tris-dominant to be Bis-dominant structures [22]; reactive oxygen species like H2O2 are able to cleave Fe-O bonds of FTs. In addition, due to the existence of catechol group and metal-ligand bonding in FTs [23], covalent and coordinate interaction between FTs and biomolecules can occur in living subjects [15].…”
Myocardial infarction results in a massive loss of cardiomyocytes (CMs). Unfortunately, current therapies are unsuccessful in replacing lost CMs, and thus, there is an urgent need for innovative approaches. Here, a nanosystem based on spermine‐acetalated dextran (AcDXSp) and encapsulating two drug compounds able to stimulate in vitro CMs proliferation is developed. The nanosystem is coated by deposition of a film constituted by tannic acid (TA) and Fe3+ ions. The coating with TA increases the retention of the nanocarrier in cell co‐cultures of CMs and fibroblasts stimulated with transforming growth factor (TGF)‐β, due to the high affinity of TA for components of the cardiac extracellular matrix. The system exhibits biocompatibility toward primary CMs and induces their proliferation, as indicated by the two‐fold increase of CMs in the active cell cycle. At the same time, the presence of TA synergistically helps contrasting fibrosis by reducing profibrotic genes expression, such as collagen 1 and osteopontin, by approximately 80% compared to the control. Overall, the developed nanosystem demonstrates the capability to stimulate CMs proliferation and reduce fibrosis, showing potential benefits for future in vivo applications.
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