Biosensor platforms consisting of layer by layer films combining materials with different functionalities have been developed and used to obtain improved catechol biosensors. Tyrosinase (Tyr) or laccase (Lac) were deposited onto LbL films formed by layers of a cationic linker (chitosan, CHI) alternating with layers of anionic electrocatalytic materials (sulfonated copper phthalocyanine, CuPcS or gold nanoparticles, AuNP). Films with different layer structures were successfully formed. Characterization of surface roughness and porosity was carried out using AFM. Electrochemical responses towards catechol showed that the LbL composites efficiently improved the electron transfer path between Tyr or Lac and the electrode surface, producing an increase in the intensity over the response in the absence of the LbL platform. LbL structures with higher roughness and pore size facilitated the diffusion of catechol, resulting in lower LODs. The [(CHI)-(AuNP)-(CHI)-(CuPcS)]2-Tyr showed an LOD of 8.55∙10−4 μM, which was one order of magnitude lower than the 9.55·10−3 µM obtained with [(CHI)-(CuPcS)-(CHI)-(AuNP)]2-Tyr, and two orders of magnitude lower than the obtained with other nanostructured platforms. It can be concluded that the combination of adequate materials with complementary activity and the control of the structure of the platform is an excellent strategy to obtain biosensors with improved performances.

Future AI applications require performance, reliability, and privacy that the existing, cloud-dependant system architectures cannot provide. In this article, we study orchestration in the device-edge-cloud continuum, and focus on AI for edge, that is, the AI methods used in resource orchestration. We claim that to support the constantly growing requirements of intelligent applications in the device-edge-cloud computing continuum, resource orchestration needs to embrace edge AI and emphasize local autonomy and intelligence. To justify the claim, we provide a general definition for continuum orchestration, and look at how current and emerging orchestration paradigms are suitable for the computing continuum. We describe certain major emerging research themes that may affect future orchestration, and provide an early vision of an orchestration paradigm that embraces those research themes. Finally, we survey current key edge AI methods and look at how they may contribute into fulfilling the vision of future continuum orchestration.

An enzymatic electrochemical biosensor for catechol detection based on silver nanowires (AgNWs), has been developed. The employment of AgNWs was essential to improve the electron transfer in comparison with that offered by an ITO substrate. AgNWs’ electrocatalytic properties and high affinity with biomolecules make them desirable for constructing biosensors. Combining nanomaterials with enzymes reduces insulating effects, due to the high-efficient electrical activity from the active site of the enzyme to the electrode. Moreover, the employment of these proteins increases the specificity of the sensor. Among the variety of processes available to synthesize AgNWs [1,2], polyol process has been selected, because of the simplicity and reliability it offers. The employed method consisted in a silver precursor (AgNO3) reduction in presence of Ethylene glycol as a solvent and polyvynilpyrrolidone, which is a surfactant that facilitates the AgNWs dispersion. The developed biosensor results from the immobilization of tyrosinase (TYR) on the top of the AgNWs deposited by spin coating in a different concentration ratio. FTIR, UV-vis, DRX and AFM have confirmed the proposed structure and cyclic voltammetry has shown the amplification caused by the combination of the nanomaterial and the enzyme in the film denoting their excellent performance, sensitivity and reproducibility. Moreover it has been demonstrated that the concentration of AgNWs employed in the development of the biosensors is crucial in terms of reproducibility, in addition to being excellent electronic mediators. Figure 1. Voltametric response of ITO-Tyr (red) and ITO-AgNWs-TYR (black) onto ITO surface to 10-4M catechol in phosphate buffer 10-2M. [1] Xu, L. et al. Anal. Methods 7, 5649-5653 (2015), [2] Kumar-Krishnan, S. et al. RSC Adv. 6, 20102–20108 (2016) Acknowledgments: Financial support by MINECO and FEDER (RTI2018-097990-B-100 and BES-2016-077825) and the Junta de Castilla y León-FEDER (VA-275P18) is gratefully acknowledged. Figure 1