Early surgical resection and chemotherapy of bone cancer are commonly used in the treatment of bone tumor, but it is still highly challenging to prevent recurrence and fill the bone defect caused by the resection site. In this work, we report a rational integration of photonic-responsive two-dimensional (2D) ultrathin niobium carbide (Nb2C) MXene nanosheets (NSs) into the 3D-printed bone-mimetic scaffolds (NBGS) for osteosarcoma treatment. The integrated 2D Nb2C-MXene NSs feature specific photonic response in the second near-infrared (NIR-II) biowindow with high tissue-penetrating depth, making it highly efficient in killing bone cancer cells. Importantly, Nb-based species released by the biodegradation of Nb2C MXene can obviously promote the neogenesis and migration of blood vessels in the defect site, which can transport more oxygen, vitamins and energy around the bone defect for the reparative process, and gather more immune cells around the defect site to accelerate the degradation of NBGS. The degradation of NBGS provides sufficient space for the bone remodeling. Besides, calcium and phosphate released during the degradation of the scaffold can promote the mineralization of new bone tissue. The intrinsic multifunctionality of killing bone tumor cell and promoting angiogenesis and bone regeneration makes the engineered Nb2C MXene-integrated composite scaffolds a distinctive implanting biomaterial on the efficient treatment of bone tumor.

Instead of the traditional isocyanate curing system as the binder of solid propellant, a triazole curing system has been developed by the reaction of azide group and alkynyl group due to a predominant advantage of avoiding to the interference of humidity. In this work, the propargyl-terminated polybutadiene (PTPB) was blended with glycidyl azide polymers (GAPs) to produce new composites under the catalysis of cuprous chloride at ambient temperature. The triazole-crosslinked network structure was regulated by changing the molar ratio of azide group in GAP versus alkynyl group in PTPB, and hence various crosslinked densities together with the composition changes of GAP versus PTPB cooperatively determined the mechanical properties of the resultant composites. Furthermore, the formed triazole-crosslinked network derived from the azide group in GAP and alkynyl group in PTPB resulted in the slight increase of glass transition temperatures and a-transition temperatures, and improved the miscibility between GAP and PTPB.

(S)-2-Chloro-1-(3,4-difluorophenyl)­ethanol (1) is a vital chiral intermediate for the synthesis of Ticagreloran effective treatment for acute coronary syndromes. A ketoreductase (KRED) KR-01 in our KRED library was screened to transform 2-chloro-1-(3,4-difluorophenyl)­ethanone (2) into the chiral alcohol 1. During process optimization, the bioreduction procedure was performed at a substrate concentration of 500 g/L, giving a near 100% conversion with >99.9% ee. The product 1 was directly obtained by extraction and can be used for the synthesis of (1R,2R)-2-(3,4-difluorophenyl)­cyclo­propane­carboxylic acid ethyl ester (3) with a yield of 98% and >99.9% de, greatly simplifying the original process operation and reducing the safety risk. This process is green and environmentally sound with high productivity of biocatalysis and a space–time yield of 145.8 mmol/L/h. It has an opportunity to be very useful in industrial applications. Additional studies have indicated that KR-01 can also be used to prepare (R)-1-(3,5-bis­(trifluoromethyl)­phenyl)­ethanol (4) with a substrate concentration of 500g/L.

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