Stimuli triggering characteristic

Table 7. Summary of Diverse Stimuli Triggering Characteristic Behavior or Morphological Changes toward Oomycete (Peronomycctc) Zoospores...

Table L Diverse Stimuli Triggering Characteristic Behaviors and/or Morphological Changes of Aphanomyces cochUoides or Other Peronosporomycetes (Oomycetes) Zoospores...

Selected examples of block copolymer micelles in both aqueous and organic media will then be presented in Sects. 3 and 4. Section 4.3 emphasizes stimulus-responsive micellar systems from double-hydrophilic block copolymers. Prediction of the dimensional characteristic features of block copolymer micelles and how it varies with the composition of the copolymers will be shortly outlined in Sect. 5, with a consideration of both the theoretical and experimental approaches. Tuning of micellar morphology and triggering transitions between different morphologies will then be discussed in Sect. 6. 

If the operation of the devices considered above on their specific substrate (photon, electron, ion) is triggered by external optical, electrical or chemical stimuli, their features may be switched between two (or more) states presenting different characteristics. Such switching devices are therefore formed by two main components a trigger, the switching unit, activated by an external stimulus and a substrate, the switched species they should operate with efficiency, reversibility and resistance to fatigue. 

DeBusschere and Kovacs [28] developed a portable microfluidic platform integrated with a complementary metal-oxide semiconductor (CMOS) chip which enables control of temperature as well as the capacity to measure action potentials in cardiomyocytes. When cells were stimulated with nifedipine (a calcium channel blocker), action potential activity was interrupted. Morin et al. [29] seeded neurons in an array of chambers in a microfluidic network integrated with an array of electrodes (Fig. 5b). The electrical activity of cells triggered with an electrical stimulus was monitored for several weeks. Cells in all chambers responded asynchronously to the stimulus. This device illustrates the utility of microfluidic tools that can investigate structure, function, and organization of biological neural networks. A similar study probed the electrical characteristics of neurons as they responded to thermal stimulation [30] in a microfluidic laminar flow. Neurons were seeded on an array of electrodes (Fig. 5c) which allowed for measurements of variations in action potentials when cells were exposed to different temperatures. 

The stimulus to evoke membrane channel currents can be electrical, chemical, luminous or mechanical. An example of the mechanical stimulus is given in the stretch-activated channels, where it consists of the pressure applied to the recording pipette. The luminous stimulation that generates electrical responses on photoreceptors, is done with the appropriate optical set-up. In the case of chemical stimulation, the substances that will interact with channels can be applied in different ways. If the time-course of the response is not important, the chemical stimulation can be obtained simply by the perfusion of the experimental chamber. When the chemical stimulation has to be applied transiently pressure ejection microperfusion or iontophoresis can be used [16]. The stimulation can be driven by an electrical signal, in order to have a triggering signal to study the time behavior of the responses. In any case, an electrical stimulus is also required, not only to analyze voltage-sensitive channels, but also to monitor the electrical characteristics of the patch, as will be shown in section 4. 

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