Metformin is a widely used first-line antidiabetic drug that has been shown to protect against a variety of specific diseases in addition to diabetes, including cardiovascular disorders, polycystic ovary syndrome and cancer. However, the precise mechanisms underlying the diverse therapeutic effects of metformin remain elusive. Here, we report that transforming growth factor-β1 (TGF-β1), which is involved in the pathogenesis of numerous diseases, is a novel target of metformin. Using a surface plasmon resonance-based assay, we identified the direct binding of metformin to TGF-β1 and found that metformin inhibits [¹²⁵I]-TGF-β1 binding to its receptor. Furthermore, based on molecular docking and molecular dynamics simulations, metformin was predicted to interact with TGF-β1 at its receptor-binding domain. Single-molecule force spectroscopy revealed that metformin reduces the binding probability but not the binding force of TGF-β1 to its type II receptor. Consequently, metformin suppresses type II TGF-β1 receptor dimerization upon exposure to TGF-β1, which is essential for downstream signal transduction. Thus, our results indicate that metformin is a novel TGF-β suppressor with therapeutic potential for numerous diseases in which TGF-β1 hyperfunction is indicated.

To improve CO ₂ separation performance, porous carbon nanosheets (PCNs) were used as a filler into a Pebax MH 1657 (Pebax) matrix, fabricating mixed matrix membranes (MMMs). The PCNs exhibited a preferential horizontal orientation within the Pebax matrix because of the extremely large 2D plane and nanoscale thickness of the matrix. Therefore, the micropores of the PCNs provided fast CO ₂ transport pathways, which led to increased CO ₂ permeability. The reduced pore size of the PCNs was a consequence of the overlapping of PCNs and the polymer chains penetrating into the pores of the PCNs. The reduction in the pore size of the PCNs improved the CO ₂ /gas selectivity. As a result, the CO ₂ permeability and CO ₂ /CH ₄ selectivity of the Pebax membrane with 10 wt% PCNs-loading (Pebax–PCNs-10) were 520 barrer and 51, respectively, for CO ₂ /CH ₄ mixed-gas. The CO ₂ permeability and CO ₂ /N ₂ selectivity of the Pebax–PCNs-10 membrane were 614 barrer and 61, respectively, for CO ₂ /N ₂ mixed-gas.

The CO₂ permeability and CO₂/CH₄ selectivity of SPEEK/amino acid salt membranes surpassed the 2008 Robeson upper bound limit.