M1 Phase Research Articles

New (FeCoCrNi)-(B,Si) high-entropy metallic glasses, study of the crystallization processes by X-ray diffraction and Mössbauer spectroscopy.

The role of B and Si in the formation of (FeCoCrNi)100-x-yBxSiy high-entropy metallic glasses is studied. It is found that a content of B between 10 and 20 at% and of Si between 5 and 15 at% is able to produce a completely amorphous structure. The microstructural evolution of two of this high-entropy metallic glass compositions, (FeCoCrNi)80B20 and (FeCoCrNi)80B10Si10, have been studied by X-ray diffraction and Transmission Mössbauer Spectroscopy. In both compositions, the first crystallization process corresponds to the formation of metastable, M3B, and stable, M2(B,Si), borides where M stands for metallic atoms. In the Si containing sample a BCC phase also appears. At the second crystallization stage the metastable and the BCC phases disappear and stable M2B or M2(B,Si) phases begin to grow simultaneously with an FCC structure that presents a distribution of possible environs. The fully crystallized structure consists of boride and silicide phases and a paramagnetic FCC phase. The presence of Si promotes the crystallization of a BCC phase and the refinement of the microstructure leading to smaller and more uniform grains.

On the Promoting Effects of Te and Nb in the Activity and Selectivity of M1 MoV-Oxides for Ethane Oxidative Dehydrogenation

The pathways of ethane oxidative dehydrogenation and total combustion have been elucidated for M1 phase type Mo–V oxide catalysts with different metal composition. The ethane oxidation mechanism is not affected by the presence of Te or Nb. Conversely, the selectivity is strongly affected by stoichiometry of M1 catalysts. This is attributed to the facile oxidation of ethene to COx upon formation of unselective VOx species in the absence of Te and Nb.

Structural phase control and thermochromic modulation of VO2 thin films by post thermal annealing

Monoclinic M1 to rutile structural phase transition (SPT) in thermochromic VO2 is accompanied by the insulator to metal transition and transition from an infrared (IR) transparent to IR opaque phase. Fine control over the phase stabilization and the functional properties without additional doping can offer the ability to tailor VO2 thin films for their respective applications. In this work, post deposition thermal annealing was used to control the phase stabilization and the modulation in thermochromic performance of polycrystalline VO2 thin films. Monoclinic M1 to rutile SPT in VO2 thin films was tracked by in-situ temperature dependent synchrotron X-ray diffraction measurements and an increase in the SPT temperature was observed with increasing annealing temperature. Intermediate monoclinic M2 phase emerges near the SPT temperature at higher annealing temperature. Temperature dependent X-ray absorption spectroscopy (XAS) measurements revealed the higher electron correlation effect among the V 3d|| states across the phase transition in VO2 thin film having the intermediate phase. Spectral weight of V 3d|| states was found to increase with the annealing temperature. Lower annealing temperature drives the IR switching temperature towards room temperature while the higher annealing temperature improves the IR switching performance of VO2 thin films.

New Multicomponent MoVSbNbCeOx/SiO2 Catalyst with Enhanced Catalytic Activity for Oxidative Dehydrogenation of Ethane to Ethylene

AbstractIn our study, we have obtained a multicomponent MoVSbNbCeOx/SiO2 catalyst with high catalytic activity for oxidative dehydrogenation of ethane (ODE) to ethylene. To date, multicomponent MoVTe(Sb)NbOx catalysts, which have been intensively studied during the last years, were found as very promising for the ODE to produce ethylene. It was generally agreed that the MoVTeNbOx catalyst was more efficient than MoVSbNbOx. The major drawback of using Te‐containing catalysts is the presence of environmentally harmful, toxic tellurium, and its volatility during the catalyst preparation and catalytic reaction conditions. In our work, the Mo1V0.24Sb0.23Nb0.08Ce0.01Ox/50 wt. % SiO2 catalyst was prepared via the spray‐dry method of aqueous solutions of the starting components, followed by heat‐treatment in He at 350 and 600 °C. For comparative purpose, one of the best Te‐containing catalysts Mo1V0.3Te0.23Nb0.12Ox was also tested in this reaction under the similar reaction conditions. A comparison of the catalytic properties of Sb− and Te− containing catalysts at the reaction temperature of 400–450 °C illustrates for both catalysts relatively high catalytic properties for ODE. The yield of ethylene of ca. 74 % was obtained for these catalysts, which exceeds the best yield reported in literature for Sb‐containing catalysts. The two main phases – M1 and M2 were revealed by XRD in the Sb‐containing catalyst. Intergrowth between the crystals of M1 and M2 phases with the formation of the interphase boundary in the highly active and selective Sb‐containing catalyst can be proposed from HRTEM results. The nature of the active state in this catalyst is discussed.

Quantitative functional imaging of VO2 metal-insulator transition through intermediate M2 phase

VO2 exhibits metal-insulator transition (MIT) accompanied by structural phase transformation between rutile R phase and monoclinic M1 phase, and an intermediate monoclinic phase M2 may also emerge, stabilized by strain. The evolution of microstructures and properties across phase transition is not only critical for understanding the nature of MIT, but also important for numerous device applications, yet they are quite challenging to characterize. Utilizing advanced atomic force microscopy (AFM) techniques in combination with polarized light microscopy, X-ray diffraction, and Raman spectroscopy, we map the microstructure evolution of VO2 when it is heated from room temperature M1 phase to high temperature R phase through intermediate M2 phase, and acquire functional imaging of VO2 spanning these three phases as well. These result in quantitative mapping of electric conduction and Young's modulus of VO2 in one-to-one correspondence to its domain patterns, especially those with austenite-martensite interface between M2 and R phases. Young's modulus of M1, M2, and R phase of VO2 are determined to be 95 GPa, 65-117 GPa, and 98-100 GPa respectively, and significant anisotropy is observed in M2 phase. Rigorous continuum analysis has also been carried out to analyze the complicated domain pattern, validating our experimental observations that match theoretical expectation well.

Comparison of structural and catalytic properties of monometallic Mo and V oxides and M1 phase mixed oxides for oxidative dehydrogenation

Mo and V containing oxides are among the most important oxidative dehydrogenation catalysts. The effects of differences in structure and compostion among SiO2 supported VOx, unsupported V2O5 and MoO3 and M1 phase MoV mixed oxide catalysts on catalytic properties are probed using their reactivity and dehydrogenation selectivity in oxidative conversion of ethane (C2H6) and cyclohexane (C6H12). The C2H6 and C6H12 activation rates are nearly insensitive to VOx loading on SiO2 at low loadings that predominantly form monovanadate species, but decrease at high loadings due to the formation of V2O5 nanoparticles with low V dispersion. The C–H activation enthalpies are lower at high loadings and in unsupported V2O5, suggesting that intrinsic reactivity of V2O5 nanoparticles is higher than monovanadates. The C2H6/C6H12 rate ratios are below 0.01 on all VOx/SiO2 catalysts, consistent with weaker C–H bonds in C6H12, but are higher on V2O5 nanoparticles than on low loading VOx/SiO2 samples. MoO3 samples exhibit lower rates and higher activation energies than VOx/SiO2 and V2O5 samples, and similar C2H6/C6H12 rate ratios as V2O5. M1 phase MoVTeNb and MoV mixed oxides contain one-dimensional micropores of size similar to C2H6 but much smaller than C6H12; preparation methods significantly affect their elemental composition, accessible micropore volumes and surface areas. Post-synthesis treatment of MoVTeNbO with H2O2 improves M1 phase purity, and increases in C2H6 and C6H12 activation rates are consistent with increase in their intrapore and external surface areas. The C2H6 and C6H12 activation rates in MoVO without Te and Nb are higher than values predicted from MoVTeNbO and their surface micropores and external surface areas, because higher V content in MoVO increases their reactivity by slightly decreasing activation energies. The C2H6/C6H12 rate ratios in these samples are much higher than VOx/SiO2, V2O5, and MoO3 and roughly correlate with internal/external surface ratios, which is consistent with C2H6 and C6H12 activation occurring inside and outside the pores, respectively. The M1 phase samples exhibit much higher selectivity than VOx/SiO2, V2O5, and MoO3, but among the M1 phase samples the selectivity is slightly lower in MoVO than in MoVTeNbO. Local structure and composition affect reactivity in M1 phase oxides and oxides without heptagonal micropores, but C2H6/C6H12 rate ratios and C2H4 selectivities are much higher in the M1 phase, which confirms for a broad range of oxides previously proposed roles of micropores in activating C2H6 selectively.

Hexagonal Mo/V/W mixed oxide as a catalyst for the partial oxidation of methacrolein to methacrylic acid

This work evaluates for the first time the catalytic performance of a hexagonal Mo/V/W mixed oxide, the so-called h-phase, in the partial oxidation of methacrolein to methacrylic acid. Three catalysts with different phase compositions were compared. One catalyst predominantly contained h-phase, a further consisted of the well-known M1 phase, and a third catalyst was composed of both, h-phase and M1, in similar amounts. The selectivity of the h-phase catalyst is comparable to that of M1.

Repolarization of glioblastoma macrophage cells using non-agonistic Dectin-1 ligand encapsulating TLR-9 agonist: plausible role in regenerative medicine against brain tumor

Aim of the study Glioblastoma multiforme (GBM) is the most severe forms of brain cancer, eventually becoming the leading cause of brain cancer-related death worldwide. Owing to the bleak surgical interventions and resistance to the different treatment regime, GBM is a parlous disease demanding newer therapeutical perspective for its treatment. Toll-like receptors (TLRs) are well-known members of pathogen recognition receptors (PRRs) and have been extensively explored for their therapeutic and prophylactic potential in an array of disease including cancer. Recent trends in drug delivery research has shown shift towards delivering short DNA sequences (CpG DNA) to endosomal TLR9 within immune cells (macrophages, dendritic cells, etc.) for the activation of desired inflammatory response using non-agonistic β-glucan particles; a well-known ligand for Dectin-1 receptors. Our study is therefore focused to explore the role of nano-encapsulated CpG ODN as critical players in polarizing M2 scavenging to much desired pro-inflammatory type. Materials and methods The nanoparticles entrapping CpG ODN 1826 were prepared by using a fungal polymer Schizophyllan (SPG). The constructed nanoparticles were characterized and assessed for their efficacy on rat glioblastoma cells (C6). Results The constructed Schizophyllan (SPG) nanoparticles entrapping CpG ODN 1826 (95.3%) were of 25.49 nm in diameter and thus capable of crossing blood–brain barrier. The rat glioblastoma (C6) cells evaluated for intracellular oxidative burst and cytokine levels pre- and post-incubation with nanoparticles exhibited marked elevation in the expression of intracellular ROS and IFN-γ as well as IL-1β post treatment. Conclusion The findings indicate towards potentiality of repolarizing the M2 macrophages to much desired M1 phase by inducing higgh levels of oxidative burst and inflammatory cytokines. Consequently, the apoptosis was induced in glioblastoma cells establishing the suitablity of CpG ODN carrying nanoformulations as emerging therapeutic intervention for GBM.

Inhibition of Cell Cycle and Induction of Apoptosis y Ethanol Leaves Extract of Chrysanthemum cinerariifolium (Trev.) In T47D Breast Cancer Cells

Chrysanthemum cinerariifolium (C.cinerariifolium) is a plant of the Asteraceae family, which has been applied by the community as an ornamental plant and traditional medicine. In this study, the effect of C. cinerariifolium leaves extract on inhibition of cell cycle and induction of apoptosis in T47D breast cancer cells was tested and compared to the standard chemotherapy agent. The citotoxic activity of C. cinerariifolium leaves extract against T47D cancer cells and Vero normal cells was tested by MTT method. Profile of apoptosis and cell cycle were observed by flow cytometry method. Based on chemical compounds profil which is tested used TLC showed that C.cinerariifolium leaves extracts contained flavonoid and terpenoid chemical compounds. The result of cytotoxic test showed that leaves extract of C. cinerariifolium was able to inhibit the growth of T47D cancer cell at IC50 418.8μg/mL. Doxorubicin, extracted from Streptomyces peucetius used as treatment in several cancers including breast cancer. Doxorubicin could inhibit the growth of T47D cancer cells in 115.1μg/mL. The results of cell cycle analysis showed that the C. cinerariifolium leaves extract inhibited cell cycle in G0-G1 and S phase, whereas doxorubicin was able to inhibit cell cycle in G0-G1 phase but experienced cell accumulation in G2-M phase. The percentage of apoptosis in cycle was showed in M1 (sub G1) and M5 (multinuclear) phase which treatment of C. cinerariifolium leaves extract was higher than doxorubicin. Therefore, C. cinerariifolium leaves extract has potential activity as anticancer agent causes inhibition of cell cycle and induction apoptosis.

Electron correlations and memory effects in ultrafast electron and hole dynamics in VO2

By applying an approach based on time-dependent density functional theory and dynamical mean-field theory (TDDFT+DMFT) we examine the role of electron correlations in the ultrafast breakdown of the insulating M1 phase in bulk VO2. We consider the case of a spatially homogeneous ultrafast (femtosecond) laser pulse perturbation and present the dynamics of the melting of the insulating state, in particular the time-dependence of the excited charge density. The time-dependence of the chemical potential of the excited electron and hole subsystems shows that even for such short times the dynamics of the system is significantly affected by memory effects—the time-resolved electron–electron interactions. The results pave the way for obtaining a microscopic understanding of the ultrafast dynamics of strongly-correlated materials.

Probing phase transition in VO2 with the novel observation of low-frequency collective spin excitation

VO2 is well known for its first order, reversible, metal-to-insulator transition (MIT) along with a simultaneous structural phase transition (SPT) from a high-temperature metallic rutile tetragonal (R) to an insulating low-temperature monoclinic (M1) phase via two other insulating metastable phases of monoclinic M2 and triclinic T. At the same time, VO2 gains tremendous attention because of the half-a-century-old controversy over its origin, whether electron-electron correlation or electron-phonon coupling trigger the phase transition. In this regard, V1-xMgxO2 samples were grown in stable phases of VO2 (M1, M2, and T) by controlled doping of Mg. We have observed a new collective mode in the low-frequency Raman spectra of all three insulating M1, M2 and T phases. We identify this mode with the breather (singlet spin excitation) mode about a spin-Pierls dimerized one dimensional spin ½ Heisenberg chain. The measured frequencies of these collective modes are phenomenologically consistent with the superexchange coupling strength between V spin ½ moments in all three phases. The significant deviation of Stokes to anti-Stokes intensity ratio of this low-frequency Raman mode from the usual thermal factor exp(hʋ/KBT) for phonons, and the orthogonal dependency of the phonon and spinon vibration in the polarized Raman study confirm its origin as spin excitations. The shift in the frequency of spin-wave and simultaneous increase in the transition temperature in the absence of any structural change confirms that SPT does not prompt MIT in VO2. On the other hand, the presence of spin-wave confirms the perturbation due to spin-Peierls dimerization leading to SPT. Thus, the observation of spin-excitations resulting from 1-D Heisenberg spin-½ chain can finally resolve the years-long debate in VO2 and can be extended to oxide-based multiferroics, which are useful for various potential device applications.

Apoptotic with Double-Staining Test, P53, and Cyclooxygenase-2 to Proliferation Colon Cancer Cell (WiDr) of Dolichol in Three Mangrove Leaves

BACKGROUND: Mangroves secondary metabolites are mostly consisting of sterols, ubiquinones, isoprenoids, and polyisoprenoids. Polyisoprenoid is divided into two types, namely, polyprenol and dolichol, which has been reported to have biological and pharmacological activities.
 AIM: This research was aimed to analyze apoptosis 48 h with double staining and immunocytochemistry (ICC) 48 h of P53 and cyclooxygenase-2 (COX-2) gene expression from chemical constituents of dolichol in three mangrove leaves of Ceriops tagal, Nypa fruticans, and Rhizophora mucronata.
 METHODS: Apoptosis with the double-staining method was employed to analyze the genes expression in growth and development of cancer cells, P53, and COX-2 with ICC and flow cytometry method. The data were statistically analyzed using one-way ANOVA parametric statistical analysis followed by Duncan’s test.
 RESULTS: The result revealed that the increased apoptosis of samples C. tagal was 70% fluorescence orange, while N. fruticans and R. mucronata were 35% and 30% fluorescence orange, respectively. However, it was compared with the positive control; it produced orange fluorescent as much as 75%, suggesting that C. tagal have a position similar to 5-FU. Predominance dolichol in N. fruticans and C. tagal leaves led the expression gene of p53 to have 1.57% M1 phase, indicating the domination in G0-G1 phase (70–80%). Inhibit the expression for 48 h in p53 and COX-2 showing that n-hexane extract of C. tagal had the most percentage (80.733 ± 0.11%) to upregulate the p53 and less percentage (20.16 ± 1.19%) to downregulate the COX-2, indicating positive extract belong to N. fruticans and R. mucronata leaves.
 CONCLUSION: The present study confirmed the pharmacological properties of dolichol from three mangrove leaves as an anticancer of tumor suppressor genes and significantly proliferated of cancer cell growth from mangrove leaves.

Seasonal variation of the principal tidal constituents in the Bohai Sea

Abstract. The seasonal variation of tides plays a significant role in water level changes in coastal regions. In this study, seasonal variations of four principal tidal constituents, M2, S2, K1, and O1, in the Bohai Sea, China, were studied by applying an enhanced harmonic analysis method to two time series: 1-year sea level observations at a mooring station (named E2) located in the western Bohai Sea and 17-year sea level observations at Dalian. At E2, the M2 amplitude and phase lag have annual frequencies, with large values in summer and small values in winter, while the frequencies of S2 and K1 amplitudes are also nearly annual. In contrast, the O1 amplitude increases constantly from winter to autumn. The maxima of phase lags appear twice in 1 year for S2, K1, and O1, taking place near winter and summer. The seasonal variation trends estimated by the enhanced harmonic analysis at Dalian are different from those at E2, except for the M2 phase lag. The M2 and S2 amplitudes show semi-annual and annual cycles, respectively, which are relatively significant at Dalian. The results of numerical experiments indicate that the seasonality of vertical eddy viscosity induces seasonal variations of the principal tidal constituents at E2. However, the tested mechanisms, including seasonally varying stratification, vertical eddy viscosity, and mean sea level, do not adequately explain the observed seasonal variations of tidal constituents at Dalian.

Modelling the enthalpy change and transition temperature dependence of the metal-insulator transition in pure and doped vanadium dioxide.

We compare various calculation methods to determine the electronic structures and energy differences of the phases of VO2. We show that density functional methods in the form of GGA+U are able to describe the enthalpy difference (latent heat) between the rutile and M1 phases of VO2, and the effect of doping on the transition temperature and on the band gap of the M1 phase. An enthalpy difference of ΔE0 = -44.2 meV per formula unit, similar to the experimental value, is obtained if the randomly oriented spins of the paramagnetic rutile phase are treated by a non-collinear spin density functional calculation. The predicted change in the transition temperature of VO2 for Ge, Si or Mg doping is calculated and is in good agreement with the experiment data.

Oxidative dehydrogenation of ethane over M1 MoVNbTeO catalysts modified by the addition of Nd, Mn, Ga or Ge

Modification by Nd, Mn, Ga, and Ge substantially affect both physicochemical and catalytic properties of MoVNbTeO oxides in the oxidative dehydrogenation of ethane (ODE). The introduction of modifying additives changes the content of the M1 phase, surface acidity, and surface composition. It does not have an influence on the state of Mo, V, Nb, and Te on catalyst surface, but it induces surface enrichment (Ga, Mn) or depletion (Ge, Nd) by the modifying element. All of these additives have positive effects on catalytic properties at the M/Mo (M = modifying element) ratio of 0.0075 ÷ 0.025. They exhibit an increase of activity and prevent ethylene over-oxidation. The relationship between the rate constant of total ethane transformation and the M1 content confirms that this phase is active in ODE. The correlation between ethylene selectivity and the relative number of intermediate acid sites is revealed, indicating the role of surface acidity on ethylene over-oxidation.

Enhanced energy density in Mn-doped (1-x)AgNbO3-xCaTiO3 lead-free antiferroelectric ceramics

Ceramics of 0.2 wt% Mn-doped (1-x)AgNbO3-xCaTiO3 (x = 0.00–0.04) were prepared in flowing oxygen with the solid state method. The microstructure, antiferroelectricity and energy storage performance were investigated to explore the potential for use in energy storage capacitors. Incorporation of CaTiO3 in AgNbO3 effectively inhibits the grain growth and gives rise to high dielectric breakdown strength. The temperature-dependent dielectric property and Raman spectroscopy measurements demonstrate the enhanced stability of antiferroelectricity by CaTiO3 addition through adjusting the M1–M2 phase transition. As a result of both improved antiferroelectricity and dielectric breakdown strength, a high recoverable energy density of 3.7 J/cm3 was achieved in the 2 mol% CaTiO3-modified AgNbO3 ceramic, which represents one of the highest recoverable energy density in recently studied lead-free ceramics. Furthermore, the energy storage performance displays an excellent thermal stability with a low variation (3%) over a wide temperature range (20–120 °C). These results indicate that modifying AgNbO3 simultaneously on the A- and B-sites in the ABO3 perovskite structure may lead to the discovery of new antiferroelectric materials with a high energy density.

Negative differential resistance behavior in a single-crystalline vanadium dioxide nanobeam without epitaxial interfacial strain

We investigate the current-dependent negative differential resistance (NDR) behavior in a single-crystalline vanadium dioxide (VO2) nanobeam without epitaxial interfaces. VO2 nanobeams are grown out of the basal r plane of sapphire and then mechanically transferred onto an oxidized silicon substrate using a stamping transfer technique. Interestingly, compared to a previous report on an epitaxially grown VO2 nanobeam with a strong adhesion strain at interfaces, the transferred VO2 nanobeam without epitaxial interfaces exhibits distinctly different NDR phenomena. We observe three different NDR behaviors along with the appearance of an intermediate M2 phase in the current–voltage (I–V) characteristics of the transferred VO2 nanobeam device obtained using the current-sweeping mode. This result is well supported by temperature-dependent Raman spectra and corresponding optical microscope images showing the appearance of an intermediate M2 phase and the spatial distribution of insulating and metallic domains along the length of the transferred nanobeam without epitaxial interfaces, which is likely attributed to different surface stresses, including interfacial stress.

Prograde polyphase regional metamorphism of pelitic rocks, NW of Jamshedpur, eastern India: constraints from textural relationship, pseudosection modelling and geothermobarometry

AbstractThe study area belongs to the Singhbhum metamorphic belt of Jharkhand, situated in the eastern part of India. The spatial distribution of the index minerals in the pelitic schists of the area shows Barrovian type of metamorphism. Three isograds, viz. garnet, staurolite and sillimanite, have been delineated and the textural study of the schists has revealed a time relation between crystallization and deformation. Series of folds with shifting values of plunges in the supracrustal rocks having axial-planar schistosity to the folds have been widely cited. Development of these folds could be attributed to the second phase of deformation. In total, two phases of deformation, D1 and D2, in association with two phases of metamorphism, M1 and M2, have been lined up in the study area. Chemographic plots of reactant and product assemblages corresponding to various metamorphic reactions suggest that the pattern of metamorphic zones mapped in space is in coherence with the temporal-sequential change during prograde metamorphism. The prograde P–T evolution of the study area has been obtained using conventional geothermobarometry, internally consistent winTWQ program and Perple_X software in the MnNCKFMASHTO model system. Our observations suggest that the progressive metamorphism in the area is not related to granitic intrusion or migmatization but that it was possibly the ascending plume that resulted in the M1 phase of metamorphism followed by D1 deformation. The second and prime metamorphic phase, M2, with its possible heat source generated by crustal overloading, was preceded by D1 and it lasted until late- to post-D2 deformation.

Preconditioning of canine adipose tissue-derived mesenchymal stem cells with deferoxamine potentiates anti-inflammatory effects by directing/reprogramming M2 macrophage polarization

Preconditioning with hypoxia or hypoxia-mimetic agents has been tried with mesenchymal stem cells (MSCs) to improve the secretion of anti-inflammatory factors. These preconditioning procedures upregulate hypoxia inducible factor (HIF) 1-alpha leading to the transcription of HIF-dependent tissue protective and anti-inflammatory genes. Due to the limited number of studies exploring the activity of deferoxamine (DFO)—a hypoxia-mimetic agent—in MSCs, we aimed to determine whether DFO can enhance the secretion of anti-inflammatory substances in canine adipose tissue-derived (cAT)-MSCs. Furthermore, we investigated whether this activity of DFO could affect macrophage polarization and activate anti-inflammatory reactions. cAT-MSCs preconditioned with DFO exhibited enhanced secretion of anti-inflammatory factors such as prostaglandin E2 and tumor necrosis factor-α-stimulated gene-6. To evaluate the interaction between DFO preconditioned cAT-MSCs and macrophages, RAW 264.7 cells were co-cultured with cAT-MSCs using the Transwell system, and changes in the expression of factors related to macrophage polarization were analyzed using the quantitative real-time PCR and western blot assays. When RAW 264.7 cells were co-cultured with DFO preconditioned cAT-MSCs, the expression of M1 and M2 markers decreased and increased, respectively, compared to co-culturing with non-preconditioned cAT-MSCs. Thus, cAT-MSCs preconditioned with DFO can more effectively direct and reprogram macrophage polarization into the M2 phase, an anti-inflammatory state.

Decellularized brain matrix enhances macrophage polarization and functional improvements in rat spinal cord injury

Spinal cord injury (SCI) is a devastating lesion lacking effective treatment options currently available in clinics. The inflammatory process exacerbates the extent of the lesion through a secondary injury mechanism, where proinflammatory classically activated macrophages (M1) are prevalent at the lesion site. However, the polarized alternatively activated anti-inflammatory macrophages (M2) are known to play an important role in wound healing and regeneration following SCI. Herein, we introduce porcine brain decellularized extracellular matrix (dECM) to modulate the macrophages in the injured spinal cord. The hydrogels with collagen and dECM at various dECM concentrations (1, 5, and 8 mg/ml) were used to cultivate primary macrophages and neurons. The dECM hydrogels were shown to promote the polarization of macrophages toward M2 phase and the neurite outgrowth of cortical and hippocampal neurons. When the dECM hydrogels were applied to rat SCI models, the proportion of M1 and M2 macrophages in the injured spinal cord was substantially altered. When received dECM concetration of 5 mg/ml, the expression of molecules associated with M2 (CD206, arginase1, and IL-10) was significantly increased. Consistently, the population of total macrophages and cavity area were substantially reduced in the dECM-treated groups. As a result, the locomotor functions of injured spinal cord, as assessed by BBB and ladder scoring, were significantly improved. Collectively, the porcine brain dECM with optimal concentration promotes functional recovery in SCI models through the activation of M2 macrophages, suggesting the promising use of the engineered hydrogels in the treatment of acute SCI. Statement of significanceSpinal cord injury (SCI) is a devastating lesion, lacking effective treatment options currently available in clinics. Here we delineated that the treatment of injured spinal cord with porcine brain decellularized matrix-based hydrogels for the first time, and could modulate the macrophage polarization and the ultimate functional recovery. When appropriate formulations were applied to a contused spinal cord model in rats, the decellularized matrix hydrogels shifted the macrophages to polarize to pro-regenerative M2 phenotype, decreased the size of lesion cavity, and finally promoted the locomotor functions until 8 weeks following the injury. We consider this work can significantly augment the matrix(biomaterial)-based therapeutic options, as an alternative to drug or cell-free approaches, for the treatment of acute injury of spinal cord.