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MnO2 Nanosheet-mediated Ratiometric Fluorescence Biosensor for MicroRNA Detection and Imaging in Living Cells
摘要： MicroRNA (miRNA) plays significant roles in cell proliferation, differentiation and apoptosis, and has been considered to be valuable biomarker for cancer. Accurate and sensitive detection of miRNA is crucially significant for cancer diagnosis and treatment. Here, a MnO2 nanosheet-mediated ratiometric fluorescence biosensor was designed for miRNA detection and imaging in living cells. It contained MnO2 nanosheets acting as DNA carrier, and fluorescent donor (FAM)-labeled hairpin H1 (recognition probe) and fluorescent acceptor (TAMRA)-labeled hairpin H2 (amplification probe). When the biosensor entered cell by endocytosis, MnO2 nanosheets were degraded to Mn2+ via intracellular glutathione (GSH) and the adsorbed hairpins H1 and H2 were released. The intracellular target miRNA-21 hybridized with the recognition unit of H1 to initiate catalyzed hairpin assembly (CHA) and a large amount of H1-H2 duplexes were produced. This brought fluorescent donor FAM and fluorescent acceptor TAMRA into close proximity to produce fluorescence resonance energy transfer (FRET), inducing a ratiometric fluorescent response (donor signal decreased and acceptor signal enhanced) for miRNA-21 detection. Furthermore, this method could be applied to differentiate the expression levels of miRNA-21 in HeLa, HepG-2 and L02 cells. These results indicated that the proposed method possessed great potential in the early diagnosis of miRNA-related diseases.
关键词： MicroRNA detection,MnO2 nanosheets,Ratiometric,Cell imaging
更新于2025-11-21 11:24:58
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MSOT/CT/MR imaging Guided and hypoxia Maneuvered Oxygen self-sufficiency radiotherapy based on One-pot MnO2-mSiO2 @ Au nanoparticle
摘要： Radiotherapy (RT) is one of the most widely applied treatments for cancer therapy in the clinic. Herein, we constructed an innovative multifunctional nanotheranostic MnO2-mSiO2@Au-HA nanoparticles (MAHNPs) based on one-pot MnO2-mSiO2 nanohybrids (MNHs) and gold nanoparticles (AuNPs) for multispectral optoacoustic tomography (MSOT)/ computed tomography (CT) and magnetic resonance (MR) imaging guided hypoxia-maneuvered radiotherapy. The MNHs were prepared by a facile one-pot approach which avoided the leakage of MnO2 nanoparticles as well as increased the efficiency on preparation. The Mn2+ ions could trigger the breakdown of endogenous H2O2 to generate O2 to convert the hypoxic tumor micro-environment (TME), thus enhancing radiotherapy by self-sufficiency oxygen. In addition, hyaluronic acid (HA) was employed to modify the surface of MnO2-mSiO2@Au nanoparticles to improve biocompatibility and cellular uptake. The well-designed nanoparticles could perform remarkable photothermal therapy (PTT) and hypoxia-maneuvered radiotherapy (RT) simultaneously as well as MSOT/CT/MR imaging. In vivo studies showed that MAHNPs achieved almost entirely suppression of tumor growth without observable recurrence, which raised new possibilities for clinical nanotheranostics with multimodal diagnostic and therapeutic coalescent design.
关键词： photothermal therapy (PTT),gold nanoparticles,nanotheranostics,MSOT/CT/MR imaging,hypoxia-maneuvered radiotherapy,MnO2-mSiO2 nanohybrids
更新于2025-11-19 16:56:35
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Robust Janus fibrous membrane switchable infrared radiation properties for potential building thermal management application
摘要： Buildings heating and cooling consumes a large part of global energy, contributing to aggravating the global warming and energy crisis. It is strongly desired but still lacking in realizing heating and cooling functions within the same material without intensive energy input. Herein, a Janus thermal management membrane with trilayer structure has been prepared by using the ZnO nanorods array-coated cellulose (ZnO-NRs@cellulose), ultralong MnO2 nanowires (UL-MnO2-NWs) and silver nanowires (Ag-NWs) as building blocks. The ZnO-NRs@cellulose fiber layer with rough surface was fabricated by a hydrothermal progress based on the controlled growth of ZnO nanorods on cellulose surfaces. Subsequently, the hydrothermally synthesized UL-MnO2-NWs and Ag-NWs were filtered onto the ZnO-NRs@cellulose layer in turn, forming laminated Janus membrane. The Janus membrane exhibited asymmetric radiation properties on each side: the ZnO-NRs@cellulose side of the Janus membrane shows high solar radiation reflectivity and high infrared emissivity to minimize heat input from sun and enhance the heat dissipation in hot environment, while Ag-NWs side of that exhibits relatively high solar radiation absorption rate and low infrared emissivity for enhancing heat input from sun and reducing the heat radiation loss in cold environment. The introduction of UL-MnO2-NWs and Ag-NWs into the laminated Janus membrane endows the membrane with high tensile stress of 61.4 MPa. Moreover, the strong compatible entanglement among three layers of the Janus membrane causes the satisfactory interface stability. Due to the special asymmetric radiation performance, excellent interfacial compatibility, and high mechanical stability, such Janus membrane might be potential useful in building energy saving, personal thermal management and other facilities.
关键词： solar radiation,infrared radiation,laminated structure,MnO2 nanowire,Ag nanowire,Janus membrane
更新于2025-11-19 16:56:35
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Free-label dual-signal responsive optical sensor by combining resonance Rayleigh scattering and colorimetry for sensitive detection of glutathione based on ultrathin MnO2 nanoflakes
摘要： Glutathione (GSH) plays a critical role in the living system and its abnormalities are closely associated with numerous clinical diseases. Thus, monitoring and detecting the content of GSH in the living system is still of great importance. Herein, a novel dual-signal responsive optical sensor is developed by using resonance Rayleigh scattering (RRS) and colorimetry for sensitive detection of GSH. In this sensor, MnO2 nanoflakes are used as both GSH recognizer and signal transducer of RRS and colorimetry. The solution of MnO2 nanoflakes shows strong RRS and absorption signals because MnO2 nanoflakes possess a large surface area and high molar extinction coefficient. However, MnO2 can be reduced to Mn2+ and MnO2 nanoflakes can be etched to small nanoparticles by GSH, causing both the RRS and absorption signals to decrease. Based on the change of RRS signal and absorbance of MnO2 nanoflakes, a novel dual-signal responsive optical sensor is successfully constructed to detect the content of GSH. The as-developed optical sensor toward GSH presents a favorable sensitivity with a detection limit of 0.033 and 0.67 μM for RRS and colorimetry, respectively. Furthermore, the as-developed approach is straightforward, quickly responsive, free-label, and cost-effective. More significantly, this method combines the advantages of RRS and colorimetry for the detection of GSH. Beyond this, the proposed RRS method has also been successfully utilized to detect the content of GSH in glutathione injection samples.
关键词： Glutathione,Resonance Rayleigh scattering,MnO2 nanoflakes,Colorimetry,Dual-signal
更新于2025-11-14 17:04:02
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Switchable Photoacoustic Imaging of Glutathione Using MnO2 Nanotubes for Cancer Diagnosis
摘要： Glutathione is overexpressed in tumor cells and regulates cancer growth, metastasis and drug resistance. Therefore, detecting glutathione levels may greatly facilitate cancer diagnosis and treatment response monitoring. Photoacoustic (PA) imaging is a noninvasive modality for high-sensitivity, high-resolution, deep-tissue optical imaging. Switchable PA probes that offer signal on/off responses to tumor targets would further improve the detection sensitivity and signal-to-noise ratio of PA imaging. Here we explore the use of MnO2 nanotubes as a switchable and biodegradable PA probe for dynamic imaging of glutathione in cancer. Glutathione reduces black MnO2 nanotubes into colorless Mn2+ ions, leading to decreased and “signal off” PA amplitude. In phantoms, we observed a linear response of reduced PA signals of MnO2 nanotubes to increased glutathione concentrations. Using melanoma as the disease model, we demonstrated that MnO2 nanotubes-based PA imaging of glutathione successfully distinguished B16F10 melanoma cells from BEAS-2b normal cells and discriminated B16F10 tumors from healthy skin tissues. Our results showed that MnO2 nanotubes are a potent switchable and biodegradable PA probe for glutathione imaging in cancer diagnosis.
关键词： photoacoustic imaging,nanotubes,cancer,glutathione,melanoma,switchable contrast reagent,MnO2
更新于2025-09-23 15:21:21
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Reduced graphene oxide supported MnO2 nanorods as recyclable and efficient adsorptive photocatalysts for pollutants removal
摘要： The emerging concept of two dimensional (2D) hybrid materials with large surface area and good interfacial contacts is highly desirable for diverse catalytic applications. Herein, we have designed and developed novel 1D-2D nanocomposite by loading manganese dioxide (MnO2) nanorods over reduced graphene oxide (RGO) nanosheets by facile hydrothermal synthesis method to exploit the large surface area, close contact of 1D-2D components with abundant reaction sites. The as prepared MnO2-RGO nanocomposite has been characterized in detail using state-of-art techniques and has been successfully utilized efficient adsorptive photocatalysts for the removal of a colored dye (neutral red) and a colorless pollutant (ciprofloxacin) from water. In addition, the stability and recyclability of this catalyst has also been demonstrated. This work is expected to pave way for the development of many new 1D-2D binary nanocomposite catalysts for environmental remediation applications.
关键词： Reduced graphene oxide,MnO2 nanorods,Photocatalysis,Pollutants removal,Ciprofloxacin,Neutral red
更新于2025-09-23 15:21:21
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Characterizing Molecular Adsorption on Biodegradable MnO <sub/>2</sub> Nanoscaffolds
摘要： Biodegradable MnO2 nanoscaffolds have recently been designed for advanced stem cell therapy. These nanomaterials strongly bind extracellular matrix proteins and effectively deliver therapeutic molecules, which significantly enhance stem cell survival and neuronal differentiation both in vitro and in vivo. In this work, we combine molecular dynamics simulations, density functional theory calculations and UV-Vis spectroscopy experiments to examine the selectivity and efficiency of a MnO2 nanosheet in adsorbing neurogenic drugs. To uncover the fundamental principles governing the drug loading process, we have systematically examined a series of model aromatic and alkyl compounds with characteristic functional groups and demonstrated that molecular adsorption on the MnO2 nanosheet results from an interplay of dispersion, electrostatic and charge transfer interactions. We have then proposed a metric that efficiently predicts the qualitative adsorption affinity of a guest molecule on the MnO2 nanosheet based on its structural and chemical features, which will facilitate the experimental screening of proper adsorbates for efficient molecular delivery and aid the development of MnO2-based nanoscaffolds for biomedical applications.
关键词： adsorption affinity,molecular dynamics simulations,density functional theory,MnO2 nanoscaffolds,neurogenic drugs,UV-Vis spectroscopy
更新于2025-09-23 15:21:21
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The synergistic effects study between metal oxides and graphene on far-infrared emission performance
摘要： Materials with high far-infrared (FIR) emissivity are quiet promising in modern medical care field, owing to its accelerating effects to blood circulation and metabolism. In this work, we synthesized two serials composites: MnO2/graphene nanoplate (GNPs) and Fe2O3/GNPs via in situ hydrothermal process. Positive synergistic effects on FIR emission were shown between either MnO2 or Fe2O3 and GNPs. In particular, MnO2/GNPs (2%) showed a super high FIR emissivity of 0.981 compared with pristine MnO2 (0.940) and GNPs (0.878) in the wavelength of 8–14 μm. The FIR emissivity of Fe2O3/GNPs (1%) was up to 0.953 that was much higher than those of pristine Fe2O3 (0.877) and GNPs as well. Benefiting from the characteristics of graphene such as large specific surface, lightweight and thin-layer, MnO2 and Fe2O3 nanocrystals grew on graphene surface and formed different morphologies. A coralloid-like morphology was formed to MnO2/GNPs (2%), suggesting a highly porous surface that meant more unstable atoms or molecules were exposed. The morphologies of metal oxide/GNPs were thought to relate with the good synergistic effects between GNPs and metal oxides. Therefore, this work provides that metal oxides/graphene composites have promising application for high FIR emission materials.
关键词： MnO2,Graphene,Far-infrared emission,Fe2O3
更新于2025-09-23 15:21:01
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[IEEE 2018 IEEE SENSORS - New Delhi, India (2018.10.28-2018.10.31)] 2018 IEEE SENSORS - Hierarchical MnO<inf>2</inf> Nanoflowers Based Efficient Room Temperature Alcohol Sensor
摘要： In the present work, hierarchical 3-D MnO2 nanoflowers (consisting of 2D nanosheets) were synthesized employing hydrothermal technique and subsequently alcohol sensing performance of the MnO2 NFs was investigated. The morphological (FESEM, Transmission Electron Microscopy), and surface compositional (X-ray Photoelectron Spectroscopy) characterizations were carried out. Lattice fringe of TEM image confirmed that constituents of 3-D nanoflower to be birnessite (i.e. δ-MnO2) 2-D nanosheets. In addition, core level XPS spectra validated the presence of mixed valence state of Mn (i.e. Mn3+ and Mn4+states) in the MnO2 NFs. Further, Electrochemical Impedance Spectroscopy measurement (Mott Schottky analysis) revealed that the n-type conductivity of MnO2 NFs based sensing layer. It is clearly observed from the transient response characteristics that the device offered promising room temperature sensing performance towards alcohols (i.e. methanol, ethanol and 2-propanol). However, the device offered better sensing performance towards methanol than that of ethanol and 2-propanol. The response time and recovery time of the sensor also found to be moderately fast at room temperature. Interestingly, the device resistance was increased in presence of reducing vapor (although MnO2 NFs is a n-type material).
关键词： Birnessite (i.e. δ-MnO2),Room temperature Alcohol sensor,Anomalous gas sensing performance,Hierarchical 3-D MnO2 nanoflowers
更新于2025-09-19 17:15:36
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DNA-MnO2 Nanosheets as Washing- and Label-Free Platform for Array-Based Differentiation of Cell Types
摘要： Accurate and facile differentiation of cell types is critical for accurate diagnosis and therapy of diseases. However, it remains challenging due to low specificity, requirement of sophisticated instruments, and tedious operation steps. Herein, a simple, washing- and label-free chemical tongue was constructed for differentiation of cell types. In the array-based sensing platform, DNA-ligand ensembles adsorbed on the surface of MnO2 nanosheets were used as sensing probes. Instead of aptamers from cell-SELEX, the randomly designed DNA strands were used, offering versatile interactions with cells. The property that MnO2 nanosheets can be degraded by intracellular glutathione makes the platform avoid the washing step. Eight types of cell lines were distinguished from each other after the data were treated with principal component analysis (PCA). In addition, a 95% of identification accuracy for the randomly selected unknown samples was achieved. The strategy shows an excellent performance not only in distinguishing cell lines but also in the identification of unknown cell samples.
关键词： label-free,pattern recognition,cell types,DNA-MnO2 nanosheets,washing-free
更新于2025-09-19 17:15:36