Suspended electrode was firstly used to study the mechanically activated pyrite .It is found that the dissolved oxygen in the solution has much influence on the suspended pyrite electrode by comparing the open circuit...Suspended electrode was firstly used to study the mechanically activated pyrite .It is found that the dissolved oxygen in the solution has much influence on the suspended pyrite electrode by comparing the open circuit potential of suspended electrodes at different atmosphere conditions. From the measurements of anodic quasi stable polarization of the suspended electrode, the transfer coefficients of anodic reaction process of activated pyrite and unactivated pyrite β are equal to 0.136 and 0.202 respectively in 1?mol·L -1 KCl deoxygenation electrolyte system at 25?℃.展开更多
Nanomaterials have been used increasingly in a wide variety of applications, and some of them have shown toxic effects on experimental animals and cells. In this study, a previously established photoelectrochemical DN...Nanomaterials have been used increasingly in a wide variety of applications, and some of them have shown toxic effects on experimental animals and cells. In this study, a previously established photoelectrochemical DNA sensor was employed to rapidly detect DNA damage induced by polystyrene nanosphere （PSNS） suspensions. In the sensor, a double-stranded DNA film was assembled on a semiconductor electrode, and a DNA intercalator, Ru（bpy）2（dppz）2＋ （bpy = 2,2＇-bipyridine, dppz = dipyrido[3,2-a：2＇,3＇-c]phenazine） was used as the photoelectrochemical signal indicator. After the DNA-modified electrode was exposed to 2.0 mg/mL PSNS suspension, photocurrent of DNA-bound Ru（bpy）2（dppz）2＋ decreased by about 20%. The decrease is attributed to the chemical damage of DNA and consequently less binding of Ru（bpy）2（dppz）2＋ molecules to the electrode. Gel electrophoresis of DNA samples incubated with PSNS suspension confirmed DNA damage after the chemical exposure. However, in both photoelectrochemical and gel electrophoresis experiments, extensively washed PSNS did not induce any DNA damage, and the supernatant of PSNS suspension exhibited comparable DNA damage as the unwashed PSNS suspension. Furthermore, UV-visible absorption spectrum of the supematant displayed a pattern very similar to that of styrene oxide （SO）, a compound which has been shown to induce DNA damage by forming covalent DNA adducts. It is therefore suggested that styrene oxide and other residual chemicals in the PSNS may be responsible for the observed DNA damage. The results highlight the importance of full characterization of nanomaterials before their toxicity study, and demonstrate the utility of photoelectrochemical DNA sensors in the rapid assessment of DNA damage induced by chemicals and nanomaterials.展开更多
文摘Suspended electrode was firstly used to study the mechanically activated pyrite .It is found that the dissolved oxygen in the solution has much influence on the suspended pyrite electrode by comparing the open circuit potential of suspended electrodes at different atmosphere conditions. From the measurements of anodic quasi stable polarization of the suspended electrode, the transfer coefficients of anodic reaction process of activated pyrite and unactivated pyrite β are equal to 0.136 and 0.202 respectively in 1?mol·L -1 KCl deoxygenation electrolyte system at 25?℃.
基金supported by the National Basic Research Program of China (2011CB936001)the National Natural Science Foundation of China (20825519, 20890112 & 20921063)Beijing Municipal Education Committee (KZ201110005006)
文摘Nanomaterials have been used increasingly in a wide variety of applications, and some of them have shown toxic effects on experimental animals and cells. In this study, a previously established photoelectrochemical DNA sensor was employed to rapidly detect DNA damage induced by polystyrene nanosphere （PSNS） suspensions. In the sensor, a double-stranded DNA film was assembled on a semiconductor electrode, and a DNA intercalator, Ru（bpy）2（dppz）2＋ （bpy = 2,2＇-bipyridine, dppz = dipyrido[3,2-a：2＇,3＇-c]phenazine） was used as the photoelectrochemical signal indicator. After the DNA-modified electrode was exposed to 2.0 mg/mL PSNS suspension, photocurrent of DNA-bound Ru（bpy）2（dppz）2＋ decreased by about 20%. The decrease is attributed to the chemical damage of DNA and consequently less binding of Ru（bpy）2（dppz）2＋ molecules to the electrode. Gel electrophoresis of DNA samples incubated with PSNS suspension confirmed DNA damage after the chemical exposure. However, in both photoelectrochemical and gel electrophoresis experiments, extensively washed PSNS did not induce any DNA damage, and the supernatant of PSNS suspension exhibited comparable DNA damage as the unwashed PSNS suspension. Furthermore, UV-visible absorption spectrum of the supematant displayed a pattern very similar to that of styrene oxide （SO）, a compound which has been shown to induce DNA damage by forming covalent DNA adducts. It is therefore suggested that styrene oxide and other residual chemicals in the PSNS may be responsible for the observed DNA damage. The results highlight the importance of full characterization of nanomaterials before their toxicity study, and demonstrate the utility of photoelectrochemical DNA sensors in the rapid assessment of DNA damage induced by chemicals and nanomaterials.
