Flexible sensor platforms

Weltin, A., Enderle, B., Kieninger, J., Urban, G.A., 2014. Multiparametric, flexible microsensor platform for metabohc monitoring in vivo. Sensors Journal, IEEE 14 (10), 3345-3351. 

A modular and flexible approach to polythiophene sensors based on the polymerization of a thiophene-activated ester has been reported (Bernier et al. 2002). Subsequent reaction of the pol5mierized NHS ester with a variety of diamines permits the synthesis of sensors for different analytes from a common platform. For example, reaction of the NHS polymer with an aminomethyl-modified 15-crown-5 derivative yielded a polymer that underwent color changes in the presence of alkah cations (Fig. 12.14). 

Surface-chemical patterns are often useful in sensor, diagnostic, or cell-biological applications, and there are many ways to create them. We found that one very flexible method was — by means of standard photolithography — to create a platform pattern of the right geometry based on two oxides with different adsorption chemistries (such as titania and silica), and then to use complementary adsorbates (such as PLL-g-PEG and alkylphosphates) to create the desired pattern in chemical functionality. In our paper (4.11), we describe the process, termed selective molecular assembly patterning or SMAP, and show how proteins can then be readily patterned on such a surface, and used, in turn as a template for the patterning of cells. 

The researchers of the National Centre for Sensor Research, Dublin City University (Ireland), developed chemical sensors able to measure and analyze sweat in real time on the body. They designed a microchip version of the platform to measure changes in the pH of sweat. The color change of the pH sensitive fabric was detected by placing a surface mount LED and photodiode module on either side of the chip, aligned with the pH sensitive fabric. The final device (180 pm thick) is flexible and can adapt to the body (Benito-Lopez et al., 2009). 

Homothia-, homoselena and homoazacalix[n]arenes of different sizes and substitution patterns have become available via a number of straightforward synthetic methods. These molecules complement the better known calix[/i]arenes and have additional features due to the presence of the heteroatoms and their larger conformational flexibilities, allowing them to be more than just platforms but also to act as host. It is hoped that this review could stimulate further research in this interesting class of macrocycles, for instance towards applications in molecular recognition studies and as chemical sensors. 

The robot structure is made from alumimun (Pacheco, et al., 2011). Figure 1 shows the different levels where different parts are placed. The first level has two differential driven wheels, controlled by two DC motors and an omni-directional wheel that is the third contact point with the floor. The second level contains an embedded PC computer and the third level has specific hardware and the sonar sensors. A fourth level can be used because of the flexibility of the system to place a machine vision system and/or a multimedia set up, depending on the platform application. 

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