Overcoming Hypoxia-Induced Ferroptosis Resistance via a 19 F/1 H-MRI Traceable Core-Shell Nanostructure.

Lipid peroxides accumulation induced ferroptosis is an effective cell death pathway for cancer therapy. However, the hypoxic condition of tumor microenvironment significantly suppresses the efficacy of ferroptosis. Here, we design a novel nanoplatform to overcome hypoxia-induced ferroptosis resistance. Specifically, we synthesize a novel kind of perfluorocarbon (PFOB)@manganese oxide (MnOx) core-shell nanoparticles (PM-CS NPs). Owing to the good carrier of O2 as fuel, PM-CS NPs can induce higher level of ROS generation, lipid peroxidation and GSH depletion, as well as lower activity of GPX4, compared with MnOx NPs alone. Moreover, the supplement of O2 can relieve tumor hypoxia to break down the storage of intracellular lipid droplets and increase expression of ACSL4 (a symbol for ferroptosis sensitivity). Furthermore, upon stimulus of GSH or acidity, PM-CS NPs exhibit the "turn on" 19 F-MRI signal and activatable T1 /T2 -MRI contrast for correlating with the release of Mn. Finally, PM-CS NPs exert high cancer inhibition rate for ferroptosis based therapy via synergetic combination of O2 -mediated enhancement of key pathways of ferroptosis.

Degradable Magnetic Nanoplatform with Hydroxide Ions Triggered Photoacoustic, MR Imaging, and Photothermal Conversion for Precise Cancer Theranostic.

Theranostic agents based on inorganic nanomaterials are still suffered from the nonbiodegradable substances with long-term retention in body and unavoidable biological toxicity, as well as nonspecificity biodistribution with potential damage toward normal tissues. Here, we develop magnetic ions (FeIII, FeII, GdIII, MnII, and MnIII) coordinated nanoplatform (MICN) with framework structure and modify them with PEG (MICN-PEG). Notably, MICN-PEG demonstrates hydroxide ions (OH-) triggered the structure collapse along with responsive near-infrared photoacoustic (PA) signal, magnetic resonance imaging (MRI), and photothermal therapy (PTT) performances. Thereby, MICN-PEG is able to remain stable in tumors and exert excellent PA/MRI and PTT effects for multimodal imaging-guided cancer treatment. In contrast, MICN-PEG is gradually collapsed in normal tissues, resulting in the significant improvement of imaging accuracy and treatment specificity. MICN-PEG is gradually cleared after administration, minimizing concerns about the long-term toxicity.

Oxygen-Embedded Quinoidal Acene Based Semiconducting Chromophore Nanoprobe for Amplified Photoacoustic Imaging and Photothermal Therapy.

Photoacoustic (PA) imaging as a noninvasive biomedical imaging technology exhibits high spatial resolution and deep tissue penetration for in vivo imaging. In order to fully explore the potential of PA imaging in biomedical applications, new contrast agents with improved PA stability and efficiency are in high demand. Herein, we present a new PA agent based on an oxygen-embedded quinoidal nonacene chromophore that is self-assembled into nanoparticles (Nano(O-Nonacene)-PEG), assisted by polyethylene glycol (PEG). Notably, the photothermal conversion efficiency of Nano(O-Nonacene)-PEG is 1.5 fold that of semiconducting polymer nanoparticles (Nano(PCPDTBT)-PEG) and 2.8 fold that of Au nanorods, owing to the low quantum yield of Nano(O-Nonacene)-PEG. Thereby, Nano(O-Nonacene)-PEG possess a greatly elevated PA signal intensity, compared to Nano(PCPDTBT)-PEG and Au nanorods, which have been widely explored for PA imaging. Due to the high resistance to photo bleaching, Nano(O-Nonacene)-PEG exhibits higher PA signal stability, which may be employed for long-term PA imaging. Moreover, when magnetic Zn0.4Fe2.6O4 nanoparticles are incorporated into Nano(O-Nonacene)-PEG, not only are magnetic resonance signals generated but also the photoacoustic efficacy is greatly enhanced. Therefore, Nano(O-Nonacene)-PEG offers distinct properties: (i) the elevated photoacoustic effect allows for high-resolution photoacoustic imaging, (ii) small size (10 nm in diameter) results in efficient tumor-targeting, and (iii) the facile application of efficient photothermal therapy in vivo. The current work offers the possibility of oxygen-embedded quinoidal acene as a promising PA probe for precision phototheranostics.

Supplementation with low concentrations of melatonin improves nuclear maturation of human oocytes in vitro.

PURPOSE: Studies in bovine and porcine have indicated that melatonin (MT) could induce meiotic maturation of immature oocytes in vitro. The object of the current study was to investigate if MT could ameliorate human oocytes maturation during rescue in vitro maturation (IVM). METHODS: Two hundred seventy eight germinal vesicle (GV) oocytes and 451 (MI) metaphase I oocytes were vitrified, thawed and then matured in vitro. All the oocytes were randomly allocated into six groups in which the oocytes were cultured in medium supplemented with different concentrations of MT (0, 10(-2), 1, 10(2), 10(4), 10(6) nM) and nuclear maturation was evaluated at 6 h, 12 h, 18 h, 24 h and 48 h of culture. RESULTS: The optimal MT concentration for both GV and MI oocytes was 1 nM. At 24 h of culture, nuclear maturation rate of MI oocytes cultured in 1 nM MT medium was significantly higher than other groups (P < 0.05); Nuclear maturation rate of GV oocytes cultured in 1 nM MT medium was also significantly higher than the control group (P < 0.05). On the other hand, decreased nuclear maturation rate was observed in the high MT concentration group (10(6) nM). CONCLUSIONS: The current study demonstrated that low concentration of exogenous MT could ameliorate nuclear maturation of human oocyte during rescue IVM, while high concentration of MT presented negative effects.