New types of fluorescence DNA-based silver nanoclusters（DNAn-Ag NCs, n = 1, 2, 3c, 4c, 5c） were synthesized by C3T-rich nucleotides as templates. It is found that the assembly of DNAn-Ag NCs with nucleotides containing GAG sequences produce silver clusters with an enhanced red emission. Results indicate that GAG is the good enhancer of DNAn-Ag NCs constructed by C3T-rich nucleotides. The fluorescence titration reveals that enhanced red emission is sensitive to Fe（Ⅲ/Ⅱ） ions with the formation of non-emission nanoclusters. Thus, the GAG-containing nucleotide can be an enhancer for the emission of silver clusters with C3T-rich nucleotide and a mediator of the iron-cluster interplay.
We previously identified a novel synthesized metal compound, LMnAc （[L2Mn2（Ac）（H20）e]（Ac） （L=bis（2-pyridylmethyl） amino-2-propionic acid））. This compound exhibited significant inhibition on cancer cell proliferation and was more selective against cancer cells than was the popular chemotherapeutic reagent cisplatin. In this study, we further investigated the underlying molecular mechanisms of LMnAc-induced cancer cell death. We found that LMnAc achieved its selectivity against cancer cells through the transferrin-transferrin receptor system, which is highly expressed in tumor cells. LMnAc triggered cancer cells to commit autophagy and apoptosis, which was mediated by the mitochondrial pathway. Moreover, LMnAc disrupted mitochondrial function, resulting in mitochondrial membrane potential collapse and ATP reduction. In addition, LMnAc induced intracellular Ca^2＋ overload and reactive oxygen species generation. Interestingly, its anticancer effect was significantly reduced following pretreatment with the antioxidant N-acetyl cysteine, indicating that reactive oxygen species triggered cell death. Altogether, our data suggest that LMnAc appears to be a selectively promising anticancer drug candidate.
LI XiangZHAO KaiDiGUO WenJieLIU XuLIU JiaGAO JingCHEN QiuYunBAI YiDong
To develop a new type of non-oxidant electron acceptors for water oxidation, 3-（methyl）phenyl-（3,5- dimethyl-1H-pyrrol-2-yl）methanone modified silica（SiO2@py） was synthesized and used as host to Co4O4 cubane forming nanoparticles（SiO2@pyCo4）. In the presence of Ru（bpy）3^2＋ and under the irradiation of white LED（light emitting diode） light（10 W）, SiO2@pyCo4 can catalyze water oxidation without extra electron acceptor（e.g., Na2S2O8） Moreover, the turnover frequency（TOF） value of SiO2@pyCo4 is larger than that of Co4O4 cubane under the same conditions, and the longer lasting time of SiO2@pyCo4 indicates that SiO2@py can enhance the stability of Co4O4 in water. Our results provide an economic route to develop dioxygen evolution systems based on the assembly of organic electron acceptor modified silica with active cobalt complexes.
