A key challenge for sensor miniaturization is to create electrodes with smaller footprints, while maintaining or increasing sensitivity. In this work, the electroactive surface of gold electrodes was enhanced 30‐fold by wrinkling followed by chronoamperometric (CA) pulsing. Electron microscopy showed increased surface roughness in response to an increased number of CA pulses. The nanoroughened electrodes also showed excellent fouling resistance when submerged in solutions containing bovine serum albumin. The nanoroughened electrodes were used for electrochemical detection of Cu2+ in tap water and of glucose in human blood plasma. In the latter case, the nanoroughened electrodes allowed highly sensitive enzyme‐free sensing of glucose, with responses comparable to those of two commercial enzyme‐based sensors. We anticipate that this methodology to fabricate nanostructured electrodes can accelerate the development of simple, cost‐effective, and high sensitivity electrochemical platforms.

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The ability to provide high sensitivity with small footprints makes miniaturized electrodes key components of biosensing, wearable electronics and lab-ona-chip devices. Recently, thin film deposition onto polystyrene films, followed by thermal shrinking has been used to produce microstructured electrodes (MSEs) with high electroactive surface area (ESA). Nevertheless, the high cost associated with film deposition through evaporation used in microfabrication and the variability in performance of screen-printed electrodes (SPEs) remain key barriers that limit their widespread deployment. Here, a simple and inexpensive method is developed for the solution-based patterning of high-quality metallic films on polystyrene substrates for MSE fabrication. The ESA of electrodes produced through this method is 2 × and 12 × larger than that of microstructured and planar electrodes produced through sputtering, respectively, and their cost is only 20% of sputtered ones. This methodology allows the fabrication of on-chip microstructured electrochemical cells (SMECs) with excellent analytical performance (3% RSD inter-day reproducibility and 0.3% RSD repeatability), superior to that of commercially available SPEs. In addition, the ESA of SMECs is significantly higher than that of SPEs, and they show excellent response toward dopamine detection. We anticipate that this solution-based fabrication approach will expedite the development of miniaturized sensing platforms for point-ofcare applications.

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Among the various forms of cancer, non-small cell lung cancer is the most frequently diagnosed and the leading cause of deaths. CIMAvax-EGF has been introduced as a first-of-its-kind EGF immune-depleting therapy and shows promise for improvement of the survival rate and quality of life of patients with NSCLC. As part of the continued development of this vaccine, it is of paramount importance to attain long-term treatment. In this work, we have used hydroxyapatite nanoparticles (a biocompatible and biodegradable material) with an average size of 60 ± 10 nm to induce an anti-EGF immune response. Three candidates referred to as HANp–rhEGF–rP64k, HANp-MC, and HANp-IP were obtained through covalent interactions between proteins and nanoparticles. The total anti-EGF IgG titers induced by the three nanoparticulate systems in mice were between 1:5000 and 1:10,000 during all periods of study (4 immunization doses and 3 extractions, 104 days). No differences in the IgG2/IgG1 ratio were observed in comparison to CIMAvax-EGF, with both being consistent with a Th2 polarization pattern. Histological evaluation of muscle tissues showed that the new nanoparticulate systems do not affect the injection sites in mice. Finally, a study of immune response induction with CIMAvax-EGF and maintenance with HANp–rhEGF–rP64k demonstrated that it is possible to maintain the immune response over the course of treatment (91 days). These results introduce these new hydroxyapatite nanoparticulate systems as effective candidates for the long-term treatment of lung and other cancers of epithelial origin.