Enhancement of in-plane magnetic anisotropy in (111)-oriented Co0.8Fe2.2O4 thin film by deposition of PZT top layer

The CoFe₂O₄ and Co_0.8Fe_2.2O₄ single layer (CFO) as well as PZT/CoFe₂O₄ and PZT/Co_0.8Fe_2.2O₄ bilayer thin films were grown using the pulsed laser deposition technique on Pt(111)/Si substrates at 600 °C. All films had a perfect (111)-orientation and the degree of orientation of CFO films was improved by the deposition of a PZT top layer. Precision X-ray diffraction analysis (avoiding the shift of peaks due to sample misalignment) revealed that the CFO films on Pt(111)/Si substrate were under an out-of-plane contraction and the deposition of a PZT top layer led to the increase in the out-of-plane contraction. The (111)-oriented CFO single layer films had a strong in-plane magnetic anisotropy as a result of orientation as well as the stress-induced magnetic anisotropy. The magnetic properties of CFO film were altered by the deposition of a PZT top layer leading to the enhancement of in-plane magnetic anisotropy. The enhanced in-plane magnetic anisotropy was more detectable in PZT/Co_0.8Fe_2.2O₄ rather than PZT/CoFe₂O₄ bilayer film, which could be expected from its higher magnetocrystalline as well as magnetostriction constants.     

Profiling and semiquantitative analysis of the cell surface proteome in human mesenchymal stem cells

Mulitpotent mesenchymal stem cells (MSCs) derived from human bone marrow are promising candidates for the development of cell therapeutic strategies. MSC surface protein profiles provide novel biological knowledge concerning the proliferation and differentiation of these cells, including the potential for identifying therapeutic targets. Basic fibroblast growth factor (bFGF) affects cell surface proteins, which are associated with increased growth rate, differentiation potential, as well as morphological changes of MSCs in vitro. Cell surface proteins were isolated using a biotinylation-mediated method and identified using a combination of one-dimensional sodium dodecyl sulfate–polyacrylamide gel electrophoresis and mass spectrometry. The resulting gel lines were cut into 20 bands and digested with trypsin. Each tryptic fragment was analyzed by liquid chromatography–electrospray ionization tandem mass spectrometry. Proteins were identified using the Mascot search program and the International Protein Index human database. Noble MSC surface proteins (n?=?1,001) were identified from cells cultured either with (n?=?857) or without (n?=?667) bFGF-containing medium in three independent experiments. The proteins were classified using FatiGO to elucidate their function. We also confirmed the proteomics results using Western blotting and immunofluorescence microscopic analysis. The nature of the proteins identified makes it clear that MSCs express a wide variety of signaling molecules, including those related to cell differentiation. Among the latter proteins, four Ras-related Rab proteins, laminin-R, and three 14-3-3 proteins that were fractionated from MSCs cultured on bFGF-containing medium are implicated in bFGF-induced signal transduction of MSCs. Consequently, these finding provide insight into the understanding of the surface proteome of human MSCs.

Activated Platelet‐Derived Vesicles for Efficient Hemostatic Activity

In this study, activated platelet‐derived vesicles (Act‐VEs) are developed as a novel hemostatic biomaterial. Spherical Act‐VEs (114.40 ± 11.69 nm in size) with surface charges of ?24.73 ± 1.32 mV are successfully prepared from thrombin‐activated murine platelets with high surface expression of active glycoprotein IIb/IIIa (GP IIb/IIIa, also known as αIIbβ3) and P‐selectin. Although nanosized vesicles from resting platelets (VEs) and Act‐VEs showed similar sizes and surface charges, Act‐VEs formed much larger aggregates in the presence of thrombin and CaCl₂, compared to VEs. After incubation with fibrinogen, Act‐VEs formed much denser fibrin networks compared to platelets or VEs, probably due to active αIIbβ3 on the surfaces of the Act‐VEs. After intravenous injection of the Act‐VEs, tail bleeding time and the blood loss are greatly reduced by Act‐VEs in vivo. In addition, Act‐VEs showed approximately sevenfold lower release of pro‐inflammatory interleukin‐1β (IL‐1β) during incubation for 4 days, compared to platelets. Taken together, the formulated Act‐VEs can serve as a promising hemostatic biomaterial for the efficient formation of fibrin clots without releasing pro‐inflammatory cytokine.     

Unlocking the pH‐Responsive Degradability of Fumaramic Acid Derivatives Using Photoisomerization

Fumaramic acid derivatives can be converted into their cis isomer maleamic acid derivatives under UV illumination, and these maleamic acid derivatives show pH‐responsive degradability at acidic pH only after the preceding photoisomerization. The rate of the tandem photoisomerization–degradation of fumaramic acid derivatives can be finely controlled by changing the substituents on the double bond. Photoisomerization‐based unlocking of the pH‐responsive degradability of fumaramic acid derivatives has strong potential for the development of multisignal‐responsive smart materials in biomedical applications.