Since the 1970s, a great deal of attention has been paid to the development of semiconductor-based biosensors because of the numerous advantages they offer, including high sensitivity, faster response time, miniaturization, and low-cost manufacturing for quick biospecific analysis with reusable features. Commercial biosensors have become highly desirable in the fields of medicine, food, and environmental monitoring as well as military applications, whereas increasing concerns about food safety and health issues have resulted in the introduction of novel legislative standards for these sensors. Numerous devices have been developed for monitoring biological processes such as nucleic acid hybridization, protein–protein interaction, antigen–antibody bonds, and substrate–enzyme reactions, just to name a few. Since the 1980s, scientific interest moved to the development of semiconductor-based devices, which also include integrated front-end electronics, such as the extended-gate field-effect transistor (EGFET) biosensor, one of the first miniaturized chemical sensors. This work is intended to be a review of the state of the art focused on the development of biosensors and chemosensors based on extended-gate field-effect transistor within the field of bioanalytical applications, which will highlight the most recent research reported in the literature. Moreover, a comparison among the diverse EGFET devices will be presented, giving particular attention to the materials and technologies.
Objectives-Sclerotherapy is a therapeutic method used in the treatment of varicose veins and works by occluding damaged blood vessels with a chemical solution.Foam sclerotherapy is an attractive treatment because the results are more effective than those obtained by using liquid sclerosants. However, serious neurologic complications, which are likely related to air embolism, have been reported after treatment with foams generated by the handmade method (Tessari technique) most often used clinically. We present an alternative ultrasonic technique for preparation of sclerosing foams to treat varicose veins.Methods-Three methods of foam generation were compared: ultrasound, mechanical agitation, and Tessari techniques.Results-Optical microscopic analyses showed that low-frequency ultrasound can generate foams with smaller bubble distributions compared to those produced by handmade and mechanical agitation methods: 98% of the bubble population was less than 55 6 10 lm for sonicated foams (mean 6 SD, 19 6 1.8 lm; maximum bubble size, <138.3 6 32.5 lm), 196.7 6 38.2 lm for mechanically agitated foams (mean, 37.1 6 10.6 lm; maximum bubble size, <350 6 70.9 lm), and 211.7 6 20.8 lm for handmade foams (mean, 30.8 6 3.8 lm; maximum bubble size, <445 6 32.8 lm).Conclusions-Low-frequency ultrasonic foam generation yields smaller bubbles and more uniform size distributions than other investigated methods. These properties may reduce serious adverse events reported for sclerotherapy of varicose veins, increasing the safety of foam treatment.
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