Covalent organic frameworks (COFs) with redox-active units are a class of ideal materials for electrochemical-energy-storage devices. A novel two-dimensional (2D) PDC–MA–COF with redox-active triazine units was prepared via aldehyde–amine condensation reaction by using 1,4-piperazinedicarboxaldehyde (PDC) and melamine (MA) as structural units, which possessed high specific surface area (S BET = 748.2 m2 g–1), narrow pore width (1.9 nm), large pore volume (1.21 cm3 g–1), and high nitrogen content (47.87%), for pseudocapacitance application. The interlayer C–H···N hydrogen bonding can “lock” the relative distance between two adjacent layers to avoid an interlayer slip, which is more conducive to maintaining the ordered pore structure of the COF and improving a fast charge transfer between the electrode interface and triazine units. The PDC–MA–COF exhibited an excellent electrochemical performance with the highest specific capacitance of 335 F g–1 along with 19.71% accessibility of the redox-active triazine units in a three-electrode system and 94 F g–1 in a two-electrode system at 1.0 A g–1 current density. Asymmetric supercapacitor of PDC–MA–COF//AC assembled using PDC–MA–COF and activated carbon (AC) as positive and negative electrode materials, respectively, exhibited a high energy density of 29.2 W h kg–1 with a power density of 750 W kg–1. At the same time, it also showed an excellent cyclic stability and could retain 88% of the initial capacitance after 20 000 charge–discharge cycles, which was better than those of the most of the analogous materials reported previously. This study provided a new strategy for designing redox-active COFs for pseudocapacitive storage.

Stem cells contribute to physiological processes such as postischemic neovascularization and vascular re-endothelialization, which help regenerate myocardial defects or repair vascular injury. However, therapeutic efficacy of stem cell transplantation is often limited by inefficient homing of systemically administered cells, which results in a low number of cells accumulating at sites of pathology. In this study, anti-CD34 antibody-coated magnetic nanoparticles (Fe3O4@PEG-CD34) are shown to have high affinity to stem cells. The results of hemolysis rate and activated partial thromboplastin time (APTT) tests indicate that such nanoparticle may be used safely in the blood system. In vitro studies showed that a nanoparticle concentration of 100 μg/mL gives rise to a significant increase in cell retention using an applicable permanent magnet, exerting minimal negative effect on cell viability and migration. Subsequent in vivo studies indicate that nanopartical can specifically bind stem cells with good magnetic response. Anti-CD34 antibody coated magnetic nanoparticle may be used to help deliver stem cells to a lesion site in the body for better treatment.

A nanocomposite of HKUST‐1 (MOF) and electroreduction graphene oxide (ERGO) is prepared and applied as an electrochemical sensor for the simultaneous determination of paracetamol and dopamine by means of one‐step electrodeposition. The MOF/ERGO composite displays excellent electrochemical catalytic activities towards the paracetamol and dopamine, which is attributed to the synergistic effect of big surface area, porosity and high electrocataytic activity of the MOF and good conductivity of ERGO. The modified electrode could be applied to determine simultaneously paracetamol and dopamine in biochemical samples with wide linear ranges (0.2 μM to 160 μM for paracetamol and 0.2 μM to 300 μM for dopamine) and low detection limits (0.016 μM for paracetamol and 0.013 μM for dopamine). Meanwhile, the proposed sensor still displays high sensitivity, good selectivity and excellent stability.

The rapid protein adsorption on a material surface causes blood coagulation, platelet activation, and complement system activation, which poses a risk for failure of cardiovascular devices. In this study, a chemically hydroxylated titanium surface was aminosilanized and covalently grafted with poly(ethylene glycol). The reaction conditions on the grafted quantity were studied by the respective amine and carboxyl densities. The blood compatibility of the PEGylated surfaces with different poly(ethylene glycol) densities and chain lengths was evaluated; the PEGylated surfaces with higher grafted density and longer chain length had less fibrinogen adsorption, less fibrinogen γ-chain exposed, less adherent platelets, and lower activation of the adherent platelets. In addition to the influence on blood, the longer chain PEGylated surfaces resisted, not only smooth muscle cell attachment and proliferation, but also macrophage attachment and death. This method is a good candidate for improving cardiovascular implant surfaces.

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