The unexpected potential responses to electrically neutral thiophenols (ArSHs) of anion-exchanger doped polymeric membranes are described. Based on the dimerization reactions of ArSHs via horseradish peroxidase (HRP)-catalyzed oxidations, a sensitive and facile potentiometric biosensing platform for HRP has been developed. Unexpected potential responses to electrically neutral thiophenols of anion-exchanger doped polymeric membranes have been observed and applied in potentiometric biosensing of horseradish peroxidase.
Objective： To observe the effect of acupoint massage in relieving pain after ureteroscopic holmium laser lithotripsy. Methods： Ninety-two patients undergone ureteroscopic holmium laser lithotripsy were enrolled and randomized into a treatment group and a control group, 46 in each group. Patients in the control group were given regular nursing care, while patients in the treatment group were intervened by acupoint massage in addition to the regular nursing care. The pain was evaluated by visual analogue scale （VAS） at 6 h, 12 h, and 24 h after operation, and compared between the two groups. Results： There was no significant difference in comparing the VAS score at 6 h after operation between the two groups （P〉0.05）. The VAS scores in the treatment group at 12 h and 24 h after operation were significantly lower than those in the control group （both P〈0.05）. Fewer patients in the treatment group used analgesics compared with those in the control group. Conclusion： Acupoint massage can effectively relieve the pain after ureteroscopic holmium laser lithotripsy, reduce the use of analgesics, and promote the recovery.
acents We highlight the unique properties of nanomaterials as solid contacts. acents We describe potentiometric sensors based on ionophore-modified nanomaterials. acents We present recent developments in nanomaterial-based potentiometric biosensors.
The determination of peroxidase activities is the basis for enzyme-labeled bioaffinity assays, peroxidase-mimicking DNAzymes- and nanoparticles-based assays, and characterization of the catalytic functions of peroxidase mimetics. Here, a facile, sensitive, and cost-effective solvent polymeric membrane-based peroxidase detection platform is described that utilizes reaction intermediates with different pK.sub.a values from those of substrates and final products. Several key but long-debated intermediates in the peroxidative oxidation of o-phenylenediamine (o-PD) have been identified and their charge states have been estimated. By using a solvent polymeric membrane functionalized by an appropriate substituted tetraphenylborate as a receptor, those cationic intermediates could be transferred into the membrane from the aqueous phase to induce a large cationic potential response. Thus, the potentiometric indication of the o-PD oxidation catalyzed by peroxidase or its mimetics can be fulfilled. Horseradish peroxidase has been detected with a detection limit at least two orders of magnitude lower than those obtained by spectrophotometric techniques and traditional membrane-based methods. As an example of peroxidase mimetics, G-quadruplex DNAzymes were probed by the intermediate-sensitive membrane and a label-free thrombin detection protocol was developed based on the catalytic activity of the thrombin-binding G-quadruplex aptamer.
Thin shell CdSe/CdS colloidal quantum dots with a small 3 nm core diameter exhibit typical blinking and a binary PL Intensity distribution. Electrochemical charging with one electron suppresses the blinking. With a larger core of 5 nm, the blinking statistics of on and off states is identical to that of a smaller core but the dots also display a grey state with a finite duration time (similar to 6 ms) on glass. However, the grey state disappears on the electron-accepting ZnO nanocrystals film. In addition, the grey state PL lifetime on glass is similar to the trion lifetime measured from electrochemically charged dots. Therefore, the grey state is assigned to the photocharged negative dots. It is concluded that a grey state is always present as the dots get negatively photocharged even though it might not be observed due to the brightness of the trion and/or the duration time of the negative charge. With thick shell CdSe/CdS dots under electrochemical control, multiple charging, up to four electrons per dot, is observed as sequential changes in the photoluminescence lifetime which can be described by the Nernst equation. The small potential increment confirms the weak electron confinement with the thick CdS shell. Finally, the mechanism of hole-trapping and surface oxidation by the hole is proposed to account for the grey state and off state in the blinking.
An all-solid-state polymeric membrane Ca super(2+)-selective electrode based on hydrophobic octadecylamine-functionalized graphene oxide has been developed. The hydrophobic composite in the ion-selective membrane not only acts as a transduction element to improve the potential stability for the all-solid-state Ca super(2+)-selective electrode, but also is used to immobilize Ca super(2+) ionophore with lipophilic side chains through hydrophobic interactions. The developed all-solid-state Ca super(2+)-selective electrode shows a stable potential response in the linear range of 3.010 super(-7)-1.010 super(-3)M with a slope of 24.7 plus or minus 0.3mV/dec, and the detection limit is (1.6 plus or minus 0.2 )10 super(-7)M (n=3). Additionally, due to the hydrophobicity and electrical conductivity of the composite, the proposed all-solid-state ion-selective electrode exhibits an improved stability with the absence of water layer between the ion-selective membrane and the underlying glassy carbon electrode. This work provides a simple, efficient and low-cost methodology for developing stable and robust all-solid-state ion-selective electrode with ionophore immobilization.
Reactive intermediates rather than stable reactants or products have been found to induce large potential responses on an appropriately formulated polymeric membrane electrode, which provides a novel methodology for ultrasensitive potentiometric biosensing based on the horseradish peroxidase-H 2 O 2 oxidation reaction. Reactive intermediates have been found to induce large potential responses on an appropriately formulated polymeric membrane electrode, which provides a novel methodology for ultrasensitive potentiometric biosensing based on the horseradish peroxidaseH 2 O 2 oxidation reaction.
Using Zn 2+ -BPMP or Cu 2+ -BPMP as a receptor and o -mercaptophenol as an indicator, potentiometric sensing of aqueous phosphate by competition assays was achieved. With attractive features of portability, low cost and resistance to interference from turbidity and color, this sensor was successfully used for phosphate detection in biological and water samples. Using Zn 2+ -BPMP or Cu 2+ -BPMP as a receptor and o -mercaptophenol as an indicator, potentiometric sensing of aqueous phosphate by competition assays was achieved.