Bone tissue scaffolds based on bioactive polymer–hydroxyapatite composites have caused infections that seriously limit their extended application. In this study, we proposed a practical ion substitution method to syn...Bone tissue scaffolds based on bioactive polymer–hydroxyapatite composites have caused infections that seriously limit their extended application. In this study, we proposed a practical ion substitution method to synthesize in situ silver phosphate on the surface of a two-level, threedimensional chitosan/nano-hydroxyapatite scaffold. A release test of silver ions in a phosphate buffered saline(PBS) solution was performed to demonstrate that silver ions were released continuously from the silver phosphate during the initial 6 days of the study. The antibacterial property and cytocompatibility of the scaffolds treated with different concentrations of silver nitrate solution were assessed by in vitro assays with Escherichia coli and MC3T3-E1, respectively. The ability of the silver-containing scaffolds to induce bacteriostasis was confirmed by the inhibition zone(15 mm) and high bactericidal rate([99 %). Cell proliferation, morphology and the alkaline phosphatase activity of MC3T3-E1 cultured on the scaffold with low silver phosphate contents were comparable with those cultured on control samples.展开更多
Lead-halide perovskite single crystal(SC)heterojunctions have attracted significant attention for X-raydetection owing to their unique combination of high sensitivity,resolution,stability and low detection limit.Howev...Lead-halide perovskite single crystal(SC)heterojunctions have attracted significant attention for X-raydetection owing to their unique combination of high sensitivity,resolution,stability and low detection limit.However,the toxicity of lead in those perovskite heterojunctions limitstheir practical applications.Herein,we report the constructionof the first all-inorganic lead-free Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunctions with an area of 20×20 mm^(2)via a facile liquidphase epitaxial method through temperature-lowering crystallization.The epitaxial crystallization of the three-dimensional(3D)Cs_(2)AgBiBr_(6)SC film on a 2D Cs_(3)Bi_(2)Br_(9)SCsubstrate requires a large driving force for transitioning fromthe Volmer–Weber mode to the layer-by-layer growth modeunder a rapid cooling rate.The Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunction detector achieves a high sensitivity of1390μC Gy_(air)^(−1)cm^(−2)for 100 keV hard X-ray detection atroom temperature,which is enhanced to 2075μC Gy_(air)^(−1)cm^(−2)at 75℃,demonstrating impressive high-temperature stability.Moreover,the detector achieves a detection limit of37.48 nG_(yair)s^(−1)and excellent stability for 90 days without anyencapsulation.This work demonstrates the feasibility of usingthe epitaxial mechanism of perovskite formation on a highsurface-energy substrate for the controllable construction of a3D/2D heterojunction that significantly enhances X-ray detection performance.展开更多
基金supported by the National Natural Science Foundation of China(51372142,51321091)the Fundamental Research Funds of Shandong University(2014QY003-09)
文摘Bone tissue scaffolds based on bioactive polymer–hydroxyapatite composites have caused infections that seriously limit their extended application. In this study, we proposed a practical ion substitution method to synthesize in situ silver phosphate on the surface of a two-level, threedimensional chitosan/nano-hydroxyapatite scaffold. A release test of silver ions in a phosphate buffered saline(PBS) solution was performed to demonstrate that silver ions were released continuously from the silver phosphate during the initial 6 days of the study. The antibacterial property and cytocompatibility of the scaffolds treated with different concentrations of silver nitrate solution were assessed by in vitro assays with Escherichia coli and MC3T3-E1, respectively. The ability of the silver-containing scaffolds to induce bacteriostasis was confirmed by the inhibition zone(15 mm) and high bactericidal rate([99 %). Cell proliferation, morphology and the alkaline phosphatase activity of MC3T3-E1 cultured on the scaffold with low silver phosphate contents were comparable with those cultured on control samples.
基金financially supported by the National Natural Science Foundation of China(62274103 and 51972194)the National Key Research and Development Program of China(2022YFB3204101)the 111 Project 2.0(BP2018013)。
文摘Lead-halide perovskite single crystal(SC)heterojunctions have attracted significant attention for X-raydetection owing to their unique combination of high sensitivity,resolution,stability and low detection limit.However,the toxicity of lead in those perovskite heterojunctions limitstheir practical applications.Herein,we report the constructionof the first all-inorganic lead-free Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunctions with an area of 20×20 mm^(2)via a facile liquidphase epitaxial method through temperature-lowering crystallization.The epitaxial crystallization of the three-dimensional(3D)Cs_(2)AgBiBr_(6)SC film on a 2D Cs_(3)Bi_(2)Br_(9)SCsubstrate requires a large driving force for transitioning fromthe Volmer–Weber mode to the layer-by-layer growth modeunder a rapid cooling rate.The Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunction detector achieves a high sensitivity of1390μC Gy_(air)^(−1)cm^(−2)for 100 keV hard X-ray detection atroom temperature,which is enhanced to 2075μC Gy_(air)^(−1)cm^(−2)at 75℃,demonstrating impressive high-temperature stability.Moreover,the detector achieves a detection limit of37.48 nG_(yair)s^(−1)and excellent stability for 90 days without anyencapsulation.This work demonstrates the feasibility of usingthe epitaxial mechanism of perovskite formation on a highsurface-energy substrate for the controllable construction of a3D/2D heterojunction that significantly enhances X-ray detection performance.
