Poly-l-lysine modified MOF nanoparticles with pH/ROS sensitive CIP release and CUR triggered photodynamic therapy against drug-resistant bacterial infection.

The challenge of drug resistance in bacteria caused by the over use of biotics is increasing during the therapy process, which has attracted great attentions of the clinicians and scientists around the world. Recently, photodynamic therapy (PDT) triggered by photosensitizer (PS) has become a promising treatment method because of its high efficacy, easy operation, and low side effect. Herein, the poly-l-lysine (PLL) modified metal-organic framework (MOF) nanoparticles, ZIF/PLL-CIP/CUR, were synthesized to allow both reactive oxygen species (ROS) responsive drug release and photodynamic effect for synergistic therapy against drug resistant bacterial infections. The PLL was modified on the shell of the zeolite imidazole framework (ZIF) by the ROS-responsive thioketal linker for controllable CIP release. CUR were encapsulated in ZIF as the photosensitizer for blue light mediated photodynamic effect to produce singlet oxygen (1O2) and superoxide anion radical (O2-) for efficient inhibition towards methicillin-resistant Staphylococcus aureus (MRSA). The charge conversion from negative charge (-4.6 mV) to positive charge (2.6 mV) was observed at pH 7.4 and pH 5.5, and 70.9 % CIP was found released at pH 5.5 in the presence of H2O2, which suggests the good biosafety at physiological pH and ROS-responsive drug release of the as-prepared nanoparticle in the bacterial microenvironment. The as-prepared nanoparticles could effectively kill MRSA and disrupt bacterial biofilm by combination of chemo- and photodynamic therapy. In mice model, the as-prepared nanoparticles exhibited excellent biosafety and synergistic effect with 98.81 % healing rate in treatment of MRSA infection, which is considered as a promising candidate in combating drug resistant bacterial infection.

Synthesis of Wafer-Scale Monolayer Pyrenyl Graphdiyne on Ultrathin Hexagonal Boron Nitride for Multibit Optoelectronic Memory.

Graphdiyne is a new two-dimensional carbon allotrope with many attractive properties and has been widely used in various applications. However, the synthesis of large-area, high-quality, and ultrathin (especially monolayer) graphdiyne and its analogues remains a challenge, hindering its application in optoelectronic devices. Here, a wafer-scale monolayer pyrenyl graphdiyne (Pyr-GDY) film is obtained on hexagonal boron nitride (hBN) via a van der Waals epitaxial strategy, and top-floating-gated multibit nonvolatile optoelectronic memory based on Pyr-GDY/hBN/graphene is constructed, using Pyr-GDY as a photoresponsive top-floating gate. Benefiting from the excellent charge trapping capability and strong absorption of the graphdiyne film, as well as the top-floating-gated structure and the ultrathin hBN film used in the device, the optoelectronic memory exhibits high storage performance and robust reliability. A huge difference in the current between the programmed and erased states (>26 µA µm-1 at Vds = 0.1 V) and a prolonged retention time (>105 s) enable the device to achieve multibit storage, for which eight and nine distinct storage levels (3-bit) are obtained by applying periodic gate voltages and optical pulses in the programming and erasing processes, respectively. This work provides an important step toward realizing versatile graphdiyne-based optoelectronic devices in the future.

Microwave-assisted multicomponent reactions: rapid and regioselective formation of new extended angular fused aza-heterocycles.

A new multicomponent domino reaction for rapid and regioselective synthesis of highly functionalized benzo[h]naphtho[2,3-a]acridine-15,16(5H,14H)-diones has been established. The reaction can be conducted by using readily available and inexpensive substrates under microwave irradiation. The procedures are facile, avoiding timeconsuming and costly syntheses, tedious work-up and purifications of precursors as well as protection/deprotection of functional groups. This method is much more efficient due to short reaction times and easy work up. The resulting naphthoacridines have been readily converted into benzoquinoxaline-fused benzoquinoline analogues by treating with benzene-1,2-diamine under microwave irradiation. The structural assignment has been ambiguously confirmed by X-ray analysis. A new mechanism has been proposed for this new multicomponent domino process.

N-Cyclo-hexyl-3-(4-hydr-oxy-6-oxo-1,6-dihydro-pyrimidin-5-yl)-3-p-tolyl-propanamide.

In the mol-ecule of the title compound, C(20)H(25)N(3)O(3), the aromatic rings are oriented at a dihedral angle of 88.36 (3)°. The cyclo-hexane ring adopts a chair conformation. In the crystal structure, inter-molecular N-H⋯O and O-H⋯N hydrogen bonds link the mol-ecules. C-H⋯π inter-actions are also present.

N-Cyclo-pentyl-3-(4-hydr-oxy-6-oxo-1,6-dihydro-pyrimidin-5-yl)-3-p-tolyl-propanamide.

In the mol-ecule of the title compound, C(19)H(23)N(3)O(3), the six-membered rings are oriented at a dihedral angle of 73.06 (3)°. The cyclo-pentyl ring adopts an envelope conformation. In the crystal structure, inter-molecular N-H⋯O and O-H⋯N hydrogen bonds link the mol-ecules. In the tolyl ring, the H atoms and all but one of the C atoms are disordered over two positions and were refined with occupancies of 0.51 (3) and 0.49 (3).