Mycobacterium tuberculosis Heat-Shock Protein 16.3 Induces Macrophage M2 Polarization Through CCRL2/CX3CR1.

Mycobacterium tuberculosis, the pathogen of tuberculosis (TB), can survive in host macrophages and induce macrophages to M2 phenotype might result in latent MTB infection. During the latent phase, the expression of MTB heat-shock protein 16.3 (Hsp16.3) is markedly increased among most of bacterial proteins, but the role of Hsp16.3 in macrophage M2 polarization is not clear. In this work, we found that macrophages incubated with 100 ng/ml MTB Hsp16.3 increased the production of Arg-1, IL-10, TGF-beta, and CD206. These results showed that MTB Hsp16.3 may induce macrophage M2 phenotype. And the interaction of Hsp16.3 with macrophages was found to depend on chemokine receptors CCRL2 and CX3CR1. Additionally, we used overexpression and silencing techniques to further verify the effect of CCRL2 and CX3CR1 on MTB Hsp16.3-induced M2 polarization macrophages. Furthermore, we explored the downstream signaling molecules of CCRL2 and CX3CR1 and we found MTB Hsp16.3 altered the signal transduction of the AKT/ERK/p38-MAPK. Taken together, this study provides evidence that MTB Hsp16.3 promotes macrophages to M2 phenotype and explores its underlying mechanism.

Band Alignment Boosts Charge-Carrier Collection in Sn-based Perovskite over Pb Counterparts.

The diverse elemental compositions endow metal halide perovskites with tailorable electronic structures and broad optoelectronic applications. For Sn-based perovskites, their bandedge positions, which govern interfacial charge-carrier transport, are less well studied than their Pb counterparts. In this work, the valence band maximum (VBM) of CsSnBr3 was experimentally and theoretically determined to be -5.2 eV, to which Au forms a good contact. The conduction band minimum (CBM) of CsSnBr3 at -3.4 eV is matched by 1,3,5-tris(4-phenylquinolin-2-yl)benzene (TQB), an organic electron transport material and a ligand to Sn(II). Thanks to proper band alignment, the device structure Al/TQB/CsSnBr3/Au constitutes a photodetector responsive to the entire visible spectrum without a bias voltage and outperforms Pb-based devices under similar conditions. Our results highlight the advantage of combined experimental and theoretical tools in understanding intrinsic material properties and guiding device fabrication.

All-Inorganic Perovskite CsSnBr3 as a Thermally Stable, Free-Carrier Semiconductor.

Hybrid organic-inorganic perovskites, especially methylammonium lead triiodide (MAPbI3 ), are intensely studied for their optoelectronic properties. The organic MA+ cation is held responsible for the superior performance of MAPbI3 but also its instability toward moisture and heat. To explore compositions beyond MAPbI3 , we performed experiments and calculations on two isomorphous perovskites CsSnBr3 and MASnBr3 . CsSnBr3 is slightly smaller than MASnBr3 in cell dimension, but outperforms MASnBr3 in band gap energy, charge-carrier reduced effective mass, and optical dielectric constant all by ≈19 %. These merits accumulate to drastically cut the exciton binding energy from 33 meV for MASnBr3 to 19.6 meV for CsSnBr3 , making CsSnBr3 a black, free-carrier semiconductor. CsSnBr3 also exhibits distinctly higher stability toward moisture and heat than its organic counterparts. These advantages suggest ecofriendly applications for CsSnBr3 , such as tandem solar cells and direct X-ray detectors.