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  1. Article ; Online: Manganese Oxide Nanoparticle Synthesis by Thermal Decomposition of Manganese(II) Acetylacetonate.

    Martinez de la Torre, Celia / Bennewitz, Margaret F

    Journal of visualized experiments : JoVE

    2020  , Issue 160

    Abstract: For biomedical applications, metal oxide nanoparticles such as iron oxide and manganese oxide (MnO), have been used as biosensors and contrast agents in magnetic resonance imaging (MRI). While iron oxide nanoparticles provide constant negative contrast ... ...

    Abstract For biomedical applications, metal oxide nanoparticles such as iron oxide and manganese oxide (MnO), have been used as biosensors and contrast agents in magnetic resonance imaging (MRI). While iron oxide nanoparticles provide constant negative contrast on MRI over typical experimental timeframes, MnO generates switchable positive contrast on MRI through dissolution of MnO to Mn
    MeSH term(s) Glass/chemistry ; Hydrophobic and Hydrophilic Interactions ; Hydroxybutyrates/chemistry ; Manganese/chemistry ; Manganese Compounds/chemistry ; Metal Nanoparticles/chemistry ; Metal Nanoparticles/ultrastructure ; Nitrogen/chemistry ; Oxides/chemistry ; Particle Size ; Pentanones/chemistry ; Spectroscopy, Fourier Transform Infrared ; Surface Properties ; Temperature ; Water/chemistry ; X-Ray Diffraction
    Chemical Substances Hydroxybutyrates ; Manganese Compounds ; Oxides ; Pentanones ; Water (059QF0KO0R) ; acetyl acetonate (17272-66-1) ; Manganese (42Z2K6ZL8P) ; manganese oxide (64J2OA7MH3) ; Nitrogen (N762921K75)
    Language English
    Publishing date 2020-06-18
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Video-Audio Media
    ZDB-ID 2259946-0
    ISSN 1940-087X ; 1940-087X
    ISSN (online) 1940-087X
    ISSN 1940-087X
    DOI 10.3791/61572
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Caveat Emptor: Commercialized Manganese Oxide Nanoparticles Exhibit Unintended Properties.

    Martinez de la Torre, Celia / Freshwater, Kasey A / Looney-Sanders, Mara A / Wang, Qiang / Bennewitz, Margaret F

    ACS omega

    2023  Volume 8, Issue 21, Page(s) 18799–18810

    Abstract: Nano-encapsulated manganese oxide (NEMO) particles are noteworthy contrast agents for magnetic resonance imaging (MRI) due to their bright, pH-switchable signal ("OFF" to "ON" at low pH), high metal loading, and targeting capability for increased ... ...

    Abstract Nano-encapsulated manganese oxide (NEMO) particles are noteworthy contrast agents for magnetic resonance imaging (MRI) due to their bright, pH-switchable signal ("OFF" to "ON" at low pH), high metal loading, and targeting capability for increased specificity. For the first time, we performed a head-to-head comparison of NEMO particles from In-house and commercialized sources (US Nano vs Nanoshel) to assess their potential as bright T
    Language English
    Publishing date 2023-05-18
    Publishing country United States
    Document type Journal Article
    ISSN 2470-1343
    ISSN (online) 2470-1343
    DOI 10.1021/acsomega.3c00892
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Manganese oxide nanoparticle synthesis by thermal decomposition of manganese(ii) acetylacetonate

    Martinez de la Torre, Celia / Bennewitz, Margaret F

    Journal of visualized experiments. 2020 June 18, , no. 160

    2020  

    Abstract: For biomedical applications, metal oxide nanoparticles such as iron oxide and manganese oxide (MnO), have been used as biosensors and contrast agents in magnetic resonance imaging (MRI). While iron oxide nanoparticles provide constant negative contrast ... ...

    Abstract For biomedical applications, metal oxide nanoparticles such as iron oxide and manganese oxide (MnO), have been used as biosensors and contrast agents in magnetic resonance imaging (MRI). While iron oxide nanoparticles provide constant negative contrast on MRI over typical experimental timeframes, MnO generates switchable positive contrast on MRI through dissolution of MnO to Mn2+ at low pH within cell endosomes to ‘turn ON’ MRI contrast. This protocol describes a one-pot synthesis of MnO nanoparticles formed by thermal decomposition of manganese(II) acetylacetonate in oleylamine and dibenzyl ether. Although running the synthesis of MnO nanoparticles is simple, the initial experimental setup can be difficult to reproduce if detailed instructions are not provided. Thus, the glassware and tubing assembly is first thoroughly described to allow other investigators to easily reproduce the setup. The synthesis method incorporates a temperature controller to achieve automated and precise manipulation of the desired temperature profile, which will impact resulting nanoparticle size and chemistry. The thermal decomposition protocol can be readily adapted to generate other metal oxide nanoparticles (e.g., iron oxide) and to include alternative organic solvents and stabilizers (e.g., oleic acid). In addition, the ratio of organic solvent to stabilizer can be changed to further impact nanoparticle properties, which is shown herein. Synthesized MnO nanoparticles are characterized for morphology, size, bulk composition, and surface composition through transmission electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy, respectively. The MnO nanoparticles synthesized by this method will be hydrophobic and must be further manipulated through ligand exchange, polymeric encapsulation, or lipid capping to incorporate hydrophilic groups for interaction with biological fluids and tissues.
    Keywords Fourier transform infrared spectroscopy ; X-ray diffraction ; automation ; biosensors ; encapsulation ; endosomes ; hydrophilicity ; hydrophobicity ; iron oxides ; ligands ; magnetism ; manganese ; manganese monoxide ; oleic acid ; pH ; polymers ; solvents ; stabilizers ; synthesis ; temperature profiles ; thermal degradation ; transmission electron microscopy
    Language English
    Dates of publication 2020-0618
    Size p. e61572.
    Publishing place Journal of Visualized Experiments
    Document type Article
    Note NAL-AP-2-clean
    ZDB-ID 2259946-0
    ISSN 1940-087X
    ISSN 1940-087X
    DOI 10.3791/61572
    Database NAL-Catalogue (AGRICOLA)

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  4. Article ; Online: PEGylation of Metal Oxide Nanoparticles Modulates Neutrophil Extracellular Trap Formation.

    Snoderly, Hunter T / Freshwater, Kasey A / Martinez de la Torre, Celia / Panchal, Dhruvi M / Vito, Jenna N / Bennewitz, Margaret F

    Biosensors

    2022  Volume 12, Issue 2

    Abstract: Novel metal oxide nanoparticle (NP) contrast agents may offer safety and functionality advantages over conventional gadolinium-based contrast agents (GBCAs) for cancer diagnosis by magnetic resonance imaging. However, little is known about the behavior ... ...

    Abstract Novel metal oxide nanoparticle (NP) contrast agents may offer safety and functionality advantages over conventional gadolinium-based contrast agents (GBCAs) for cancer diagnosis by magnetic resonance imaging. However, little is known about the behavior of metal oxide NPs, or of their effect, upon coming into contact with the innate immune system. As neutrophils are the body's first line of defense, we sought to understand how manganese oxide and iron oxide NPs impact leukocyte functionality. Specifically, we evaluated whether contrast agents caused neutrophils to release web-like fibers of DNA known as neutrophil extracellular traps (NETs), which are known to enhance metastasis and thrombosis in cancer patients. Murine neutrophils were treated with GBCA, bare manganese oxide or iron oxide NPs, or poly(lactic-co-glycolic acid) (PLGA)-coated metal oxide NPs with different incorporated levels of poly(ethylene glycol) (PEG). Manganese oxide NPs elicited the highest NETosis rates and had enhanced neutrophil uptake properties compared to iron oxide NPs. Interestingly, NPs with low levels of PEGylation produced more NETs than those with higher PEGylation. Despite generating a low rate of NETosis, GBCA altered neutrophil cytokine expression more than NP treatments. This study is the first to investigate whether manganese oxide NPs and GBCAs modulate NETosis and reveals that contrast agents may have unintended off-target effects which warrant further investigation.
    MeSH term(s) Animals ; Contrast Media ; Extracellular Traps ; Humans ; Metal Nanoparticles ; Mice ; Nanoparticles ; Neutrophils/metabolism ; Oxides
    Chemical Substances Contrast Media ; Oxides
    Language English
    Publishing date 2022-02-16
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2662125-3
    ISSN 2079-6374 ; 2079-6374
    ISSN (online) 2079-6374
    ISSN 2079-6374
    DOI 10.3390/bios12020123
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Tuning the size and composition of manganese oxide nanoparticles through varying temperature ramp and aging time.

    Martinez de la Torre, Celia / Grossman, Jasmine H / Bobko, Andrey A / Bennewitz, Margaret F

    PloS one

    2020  Volume 15, Issue 9, Page(s) e0239034

    Abstract: Manganese oxide (MnO) nanoparticles (NPs) can serve as robust pH-sensitive contrast agents for magnetic resonance imaging (MRI) due to Mn2+ release at low pH, which generates a ~30 fold change in T1 relaxivity. Strategies to control NP size, composition, ...

    Abstract Manganese oxide (MnO) nanoparticles (NPs) can serve as robust pH-sensitive contrast agents for magnetic resonance imaging (MRI) due to Mn2+ release at low pH, which generates a ~30 fold change in T1 relaxivity. Strategies to control NP size, composition, and Mn2+ dissolution rates are essential to improve diagnostic performance of pH-responsive MnO NPs. We are the first to demonstrate that MnO NP size and composition can be tuned by the temperature ramping rate and aging time used during thermal decomposition of manganese(II) acetylacetonate. Two different temperature ramping rates (10°C/min and 20°C/min) were applied to reach 300°C and NPs were aged at that temperature for 5, 15, or 30 min. A faster ramping rate and shorter aging time produced the smallest NPs of ~23 nm. Shorter aging times created a mixture of MnO and Mn3O4 NPs, whereas longer aging times formed MnO. Our results indicate that a 20°C/min ramp rate with an aging time of 30 min was the ideal temperature condition to form the smallest pure MnO NPs of ~32 nm. However, Mn2+ dissolution rates at low pH were unaffected by synthesis conditions. Although Mn2+ production was high at pH 5 mimicking endosomes inside cells, minimal Mn2+ was released at pH 6.5 and 7.4, which mimic the tumor extracellular space and blood, respectively. To further elucidate the effects of NP composition and size on Mn2+ release and MRI contrast, the ideal MnO NP formulation (~32 nm) was compared with smaller MnO and Mn3O4 NPs. Small MnO NPs produced the highest amount of Mn2+ at acidic pH with maximum T1 MRI signal; Mn3O4 NPs generated the lowest MRI signal. MnO NPs encapsulated within poly(lactide-co-glycolide) (PLGA) retained significantly higher Mn2+ release and MRI signal compared to PLGA Mn3O4 NPs. Therefore, MnO instead of Mn3O4 should be targeted intracellularly to maximize MRI contrast.
    MeSH term(s) Contrast Media/chemistry ; Magnetic Resonance Imaging/methods ; Manganese Compounds/chemistry ; Metal Nanoparticles/chemistry ; Nanoparticles/chemistry ; Oxides/chemistry ; Temperature ; Time Factors
    Chemical Substances Contrast Media ; Manganese Compounds ; Oxides ; manganese oxide (64J2OA7MH3)
    Language English
    Publishing date 2020-09-18
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 2267670-3
    ISSN 1932-6203 ; 1932-6203
    ISSN (online) 1932-6203
    ISSN 1932-6203
    DOI 10.1371/journal.pone.0239034
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: Early life high fructose exposure disrupts microglia function and impedes neurodevelopment.

    Wang, Zhaoquan / Lipshutz, Allie / Liu, Zong-Lin / Trzeciak, Alissa J / Miranda, Isabella C / Martínez de la Torre, Celia / Schild, Tanya / Lazarov, Tomi / Rojas, Waleska Saitz / Saavedra, Pedro H V / Romero-Pichardo, Jesús E / Baako, Ann / Geissmann, Frederic / Faraco, Giuseppe / Gan, Li / Etchegaray, Jon Iker / Lucas, Christopher D / Parkhurst, Christopher N / Zeng, Melody Y /
    Keshari, Kayvan R / Perry, Justin S A

    bioRxiv : the preprint server for biology

    2023  

    Abstract: Despite the success of fructose as a low-cost food additive, recent epidemiological evidence suggests that high fructose consumption by pregnant mothers or during adolescence is associated with disrupted ... ...

    Abstract Despite the success of fructose as a low-cost food additive, recent epidemiological evidence suggests that high fructose consumption by pregnant mothers or during adolescence is associated with disrupted neurodevelopment
    Language English
    Publishing date 2023-08-15
    Publishing country United States
    Document type Preprint
    DOI 10.1101/2023.08.14.553242
    Database MEDical Literature Analysis and Retrieval System OnLINE

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