过氧化钙(CaO_(2))类芬顿反应对痕量有机污染物具有高效的处理效果.本研究建立了新型的Co^(2+)/CaO_(2)/草酸体系,利用草酸缓解Co^(2+)沉淀的形成及加速Co^(3+)转化为Co^(2+)从而增强Co^(2+)对CaO_(2)的活化效率.以磺胺二甲嘧啶(Sulfadi...过氧化钙(CaO_(2))类芬顿反应对痕量有机污染物具有高效的处理效果.本研究建立了新型的Co^(2+)/CaO_(2)/草酸体系,利用草酸缓解Co^(2+)沉淀的形成及加速Co^(3+)转化为Co^(2+)从而增强Co^(2+)对CaO_(2)的活化效率.以磺胺二甲嘧啶(Sulfadimethoxine,SMT)为目标污染物,研究了Co^(2+)浓度、CaO_(2)浓度、草酸浓度、溶液初始pH值和水体中常见离子等因素对Co^(2+)/CaO_(2)/草酸体系活性的影响.结果表明:在Co^(2+)/CaO_(2)/草酸体系中,最佳投加量比例为Co^(2+)∶CaO_(2)∶草酸=2∶1∶1时,反应10 min SMT的降解率可以达到70%,降解速率常数k比Co^(2+)/CaO_(2)体系提升了5.26倍;随着溶液初始pH升高,SMT的降解率呈下降趋势;对SMT降解起作用的活性物质有羟基自由基、超氧阴离子和单线态氧,其中,羟基自由基和超氧阴离子对SMT的降解起主要作用,贡献率分别为37.6%和59.3%;以pH为研究对象,对SMT降解速率常数与4种活性物质浓度之间进行数值分析,发现pH值与活性物质浓度呈负相关关系,超氧阴离子浓度与过氧化氢浓度呈显著正相关关系(p<0.01);硫酸根离子和氯离子对SMT降解的影响较小,碳酸根离子对SMT的降解起到明显的抑制作用.采用超高效液相色谱-质谱联用技术分析了SMT的降解产物,提出了硝基化反应、开环反应和脱硫反应3条主要降解路径,并阐述了Co^(2+)/CaO_(2)/草酸体系的作用机制,可为该类芬顿体系将来应用于处理实际抗生素污染水体提供理论支撑.展开更多
Drug transportation is impeded by various barriers in the hypoxic solid tumor,resulting in compromised anticancer efficacy.Herein,a solid lipid monostearin(MS)-coated CaO_(2)/MnO_(2) nanocarrier was designed to optimi...Drug transportation is impeded by various barriers in the hypoxic solid tumor,resulting in compromised anticancer efficacy.Herein,a solid lipid monostearin(MS)-coated CaO_(2)/MnO_(2) nanocarrier was designed to optimize doxorubicin(DOX)transportation comprehensively for chemotherapy enhancement.The MS shell of nanoparticles could be destroyed selectively by highly-expressed lipase within cancer cells,exposing water-sensitive cores to release DOX and produce O_(2).After the cancer cell death,the core-exposed nanoparticles could be further liberated and continue to react with water in the tumor extracellular matrix(ECM)and thoroughly release O_(2) and DOX,which exhibited cytotoxicity to neighboring cells.Small DOX molecules could readily diffuse through ECM,in which the collagen deposition was decreased by O_(2)-mediated hypoxia-inducible factor-1 inhibition,leading to synergistically improved drug penetration.Concurrently,DOX-efflux-associated P-glycoprotein was also inhibited by O_(2),prolonging drug retention in cancer cells.Overall,the DOX transporting processes from nanoparticles to deep tumor cells including drug release,penetration,and retention were optimized comprehensively,which significantly boosted antitumor benefits.展开更多
文摘过氧化钙(CaO_(2))类芬顿反应对痕量有机污染物具有高效的处理效果.本研究建立了新型的Co^(2+)/CaO_(2)/草酸体系,利用草酸缓解Co^(2+)沉淀的形成及加速Co^(3+)转化为Co^(2+)从而增强Co^(2+)对CaO_(2)的活化效率.以磺胺二甲嘧啶(Sulfadimethoxine,SMT)为目标污染物,研究了Co^(2+)浓度、CaO_(2)浓度、草酸浓度、溶液初始pH值和水体中常见离子等因素对Co^(2+)/CaO_(2)/草酸体系活性的影响.结果表明:在Co^(2+)/CaO_(2)/草酸体系中,最佳投加量比例为Co^(2+)∶CaO_(2)∶草酸=2∶1∶1时,反应10 min SMT的降解率可以达到70%,降解速率常数k比Co^(2+)/CaO_(2)体系提升了5.26倍;随着溶液初始pH升高,SMT的降解率呈下降趋势;对SMT降解起作用的活性物质有羟基自由基、超氧阴离子和单线态氧,其中,羟基自由基和超氧阴离子对SMT的降解起主要作用,贡献率分别为37.6%和59.3%;以pH为研究对象,对SMT降解速率常数与4种活性物质浓度之间进行数值分析,发现pH值与活性物质浓度呈负相关关系,超氧阴离子浓度与过氧化氢浓度呈显著正相关关系(p<0.01);硫酸根离子和氯离子对SMT降解的影响较小,碳酸根离子对SMT的降解起到明显的抑制作用.采用超高效液相色谱-质谱联用技术分析了SMT的降解产物,提出了硝基化反应、开环反应和脱硫反应3条主要降解路径,并阐述了Co^(2+)/CaO_(2)/草酸体系的作用机制,可为该类芬顿体系将来应用于处理实际抗生素污染水体提供理论支撑.
基金supported by National Natural Science Foundation of China(Nos.81973257,81801738,and 81703446)。
文摘Drug transportation is impeded by various barriers in the hypoxic solid tumor,resulting in compromised anticancer efficacy.Herein,a solid lipid monostearin(MS)-coated CaO_(2)/MnO_(2) nanocarrier was designed to optimize doxorubicin(DOX)transportation comprehensively for chemotherapy enhancement.The MS shell of nanoparticles could be destroyed selectively by highly-expressed lipase within cancer cells,exposing water-sensitive cores to release DOX and produce O_(2).After the cancer cell death,the core-exposed nanoparticles could be further liberated and continue to react with water in the tumor extracellular matrix(ECM)and thoroughly release O_(2) and DOX,which exhibited cytotoxicity to neighboring cells.Small DOX molecules could readily diffuse through ECM,in which the collagen deposition was decreased by O_(2)-mediated hypoxia-inducible factor-1 inhibition,leading to synergistically improved drug penetration.Concurrently,DOX-efflux-associated P-glycoprotein was also inhibited by O_(2),prolonging drug retention in cancer cells.Overall,the DOX transporting processes from nanoparticles to deep tumor cells including drug release,penetration,and retention were optimized comprehensively,which significantly boosted antitumor benefits.
