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Sandwich-structured strain sensor based on high L/D ratio NiNWs and Ecoflex with high sensitivity and stretchability.

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The mesh-type USB piezoelectric ultrasonic transducer (USB-PUT) used in household humidifiers and inhalation therapy devices is very cheap, small, and energy saving. It holds great promise for sonochemistry. However, the microtapered apertures in the center of the stainless steel substrate of mesh-type USB-PUT can lead to rapid atomization of solution, leakage of solutions containing surfactants and organic solvent through the apertures, and high background emission. Herein, we design a new type of USB-PUT by replacing the meshed stainless steel substrate with an apertureless stainless steel substrate. We have found that this apertureless USB-PUT can not only induce intense sonochemiluminescence (SCL) but can also enable sensitive luminol SCL detection of hydrogen peroxide which is practically impossible using mesh-type PUT because of the strong background SCL emission. By using this apertureless device to induce SCL and using smart phone as a detector, a visual hydrogen peroxide SCL detection method with a linear range of 0.5−50 μM and a detection limit of 0.32 μM is established. Moreover, the device can achieve the detection of glucose oxidase (GOD) activity and glucose by enzymatic conversion of glucose to hydrogen peroxide. The linear range of GOD detection is 1−200U/L with a detection limit of 0.86 U/L. The linear range of glucose detection is 0.5−70 μM with a detection limit of 0.43 μM. The cheap (a few dollars) and user-friendly apertureless USB-PUT is promising for sonochemistry applications and chemical education.

Potentiometric sensors based on ion-selective membrane electrodes have continued to get great attention from the scientific community. These sensors have been employed in several applications including medicine, forensic analysis, environmental assessment, industry, agriculture, and pharmaceutical drug analysis. Indeed these sensors possess several advantages for example simple design, fabrication, and manipulation, rapid response time, good selectivity, applicability to colored and turbid solutions, and possible interfacing with automated and computerized systems. On the other hand, therapeutic drug monitoring and detection of pharmaceutical drugs in their pharmaceutical formulations and biological matrices are highly significant from a medical point of view especially for drugs with a narrow therapeutic index such as anticancer drugs which can cause fatal side effects for patients. Interestingly, potentiometric sensors have been broadly employed as one of the most important electrochemical approaches for pharmaceutical drug analysis. Moreover, the breakthroughs in potentiometric sensors based on ion-selective electrodes (ISEs) make them superior to the other reported methods for pharmaceutical drug analysis in terms of many performance parameters such as sensitivity, selectivity, low detection limit, and low cost. In this review, we try to offer a summary prologue to the applicability and merits of the potentiometric sensors that have been employed for pharmaceutical drug analysis emphasizing their application for the assay of pharmaceutical drugs in their dosage forms and the in-vivo assay of pharmaceutical drugs in different biological samples such as milk, water, plasma, and urine.