Flexible multilevel nonvolatile biocompatible memristor with high durability.

Current protein or glucose based biomemristors have low resistance-switching performance and require complex structural designs, significantly hindering the development of implantable memristor devices. It is imperative to discover novel candidate materials for biomemristor with high durability and excellent biosafety for implantable health monitoring. Herein, we initially demonstrate the resistance switching characteristics of a nonvolatile memristor in a configuration of Pt/AlOOH/ITO consisting of biocompatible AlOOH nanosheets sandwiched between a Indium Tin Oxides (ITO) electrode and a platinum (Pt) counter-electrode. The hydrothermally synthesized AlOOH nanosheets have excellent biocompatibility as confirmed through the Cell Counting Kit-8 (CCK-8) tests. Four discrete resistance levels are achieved in this assembled device in responsible to different compliance currents (ICC) for the set process, where the emerging multilevel states show high durability over 103 cycles, outperforming the protein-based biomemristors under similar conditions. The excellent performance of the Pt/AlOOH/ITO memristor is attributed to the significant role of hydrogen proton with pipe effect, as confirmed by both experimental results and density functional theory (DFT) analyses. The present results indicate the nonvolatile memristors with great potential as the next generation implantable multilevel resistive memories for long-term human health monitoring.

Dramatic improvement in the mechanical properties of polydopamine/polyacrylamide hydrogel mediated human amniotic membrane.

Human amniotic membrane (hAM) is a promising material for tissue engineering due to several benefits, including desirable biocompatibility, stem cell source, antibacterial activity, etc. However, because of its low elasticity, the clinical application of hAM is severely restricted. To solve this issue, we employed polydopamine/polyacrylamide (PDA/PAM) hydrogels to toughen hAM. The test results indicated that the PDA/PAM hydrogel can enhance the toughness of hAM dramatically due to the formation of abundant chemical bonds and the strong mechanical properties of the hydrogel itself. Compared to pure hAM, the break elongation and tensile strength of PDA/PAM-toughened hAM rose by 154.15 and 492.31%, respectively. And most importantly, the fracture toughness was almost 15 times higher than untreated hAM. In addition, the cytotoxicity of the PDA/PAM-coated hAM was not detected due to the superior biocompatibility of the chemicals used in the study. Treating hAM with adhesive hydrogels to increase its mechanical characteristics will further promote the application of hAM as a tissue engineering material.

Nanoscale pulverization effect in double-layered MOF-derived hierarchical G/Co@C composites for boosting electromagnetic wave dissipation.

Metal-organic frameworks (MOFs) have drawn a lot of interest as prospective starting points for highly effective electromagnetic wave (EMW) absorbers. However, the inevitable shrinkage and probable densification that occur during pyrolysis significantly reduce the microwave-loss capacity. A dual-layer MOF, ZIF-8@ZIF-67, is created and effectively decorated on graphene sheets as a solution to this problem. The shrinkage and densification were then suppressed by the subsequent pulverization effect between the two MOFs. Due to suitable compositions and specialized microstructures, G/Co@C exhibits excellent impedance matching and dissipates EMW by combining magnetic and dielectric loss. The maximum reflection loss of G/Co@C-7/paraffin is -55.0 dB at 5.8 GHz with just 7% filler. Therefore, the preparation of high-efficiency MOF-derived microwave absorbers by the pulverization effect is demonstrated to be an efficient strategy.