In this paper, we further investigate the properties of off-stoichiometry thiol-ene polymers (OSTE) aiming its application in microchip electrophoresis for bioanalytical applications. The proportion of 1.3:1 (allyl:thiol) and 1:2.5 (allyl:thiol) presented the best results in terms of sealing. Raman imaging mapping of the polymers surfaces revealed an outstanding homogeneity. Water contact angle were measured as 68° ± 6° and 71° ± 5° for 1.3:1 allyl and 1:2.5 thiol, respectively. Substrates prepared with OSTE demonstrated to be less prone to sorption of nonpolar compounds. The electroosmotic flow measured for this OSTE composition was 3.8 ± 0.3·10 cm s V, 1.5 times higher than the one found for polydimethylsiloxane microchips under the same conditions. As a proof-of-concept for the applicability of OSTE microchips in bioanalysis the immobilization of α-amylase on the polymer surface and the implementation of a Saccharomyces cerevisiae cell counter using contactless conductivity detection are demonstrated.

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Dielectrophoresis (DEP) is the electrokinetic movement of non-charged particles when they are subjected to a non-uniform electric field. This is a growing area of research, which can be used for trapping, concentrating and separating different particles. Some work has been reported with the intention of trapping metal particles to optimize the surface enhanced Raman spectroscopy (SERS) effect. In this paper, we use DEP with insulating structures (iDEP) to generate a non-uniform electric field for trapping gold nanoparticles (AuNP). The system was coupled to a Raman spectrometer for the detection of Crystal Violet by utilizing the SERS effect.

Alternative techniques for applying agricultural products, such as pressurized endotherapy, have shown promise in pest and disease control in coconut palms (Cocos nucifera Linn.).

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