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The periodate (PI)-based advanced oxidation process is valued for environmental remediation, but current activation methods involve high costs, secondary contamination risks, and limited applicability due to external energy inputs (e.g., UV), catalyst incorporation (e.g., Fe2+), or environmental modifications (e.g., freezing). In this work, novel bioelectric activation of PI using the electrons generated by electroactive bacteria was developed and investigated for rapid removal of carbamazepine (CBZ), achieving 100%, 100%, and 76% removal efficiency for 4.22 µM of CBZ in 20 minutes at pH 2, 120 minutes at pH 6.4, and HRT of 30 minutes at pH 8.5, respectively, with a 1mM PI dose and without an input voltage. It was deduced that electrons derived from bacteria could directly activate PI using Ti mesh electrodes and generate •IO3 via single electron transfer under strongly acidic conditions (e.g., pH 2). Nevertheless, under weak alkaline conditions (e.g., pH 8.5), biogenic electrons indirectly activated PI by generating OH− via 4e− reduction at the Ti mesh cathode, resulting in the formation of •O2− and 1O2. In addition to the metal cathode, a carbon-based cathode finely modulates the 2e− reduction, yielding H2O2 and activating PI to mainly form •OH. Moreover, primarily non-toxic IO3− was produced during treatment, while no detectable reactive iodine species (HOI, I2, and I3−) were observed. Furthermore, the bioelectric activation of PI demonstrated its capability to remove various micropollutants present in secondary-treated municipal wastewater, showcasing its broad-spectrum degradation ability. This study introduces a novel, cost-effective, and environmentally friendly PI activation technique with promising applicability for micropollutant elimination in water treatment.

Here, a novel fabrication method for making free-standing 3D hierarchical porous carbon aerogels from molecularly engineered biomass-derived hydrogels is presented. In-situ formed flower-like CaCO3 molecularly embedded within the hydrogel network regulated the pore structure during in-situ mineralization assisted one-step activation graphitization (iMAG), while the intrinsic structural integrity of the carbon aerogels was maintained. The homogenously distributed minerals simultaneously acted as a hard-template, activating agent and graphitization catalyst. The decomposition of the homogenously distributed CaCO3 during iMAG followed by etching of residual CaO through a mild acid washing endowed a robust carbon aerogel with high porosity and excellent electrochemical performance. At 0.5 mA cm-2, the gravimetric capacitance increased from 0.01 F g-1 without mineralization to 322 F g-1 with iMAG, which exceeds values reported for any other free-standing or powder-based biomass-derived carbon electrodes. An outstanding cycling stability of ~104% after 1000 cycles in 1M HClO4 was demonstrated. The assembled symmetric supercapacitor device delivered a high specific capacitance of 376 F g-1 and a high energy density of 26 W h kg−1 at a power density of 4000 W kg−1, with excellent cycling performance (98.5% retention after 2000 cycles). In combination with the proposed 3D printed mold assisted solution casting (3DMASC), iMAG allows for the generation of free-standing carbon aerogel architectures with arbitrary shapes. Furthermore, the novel method introduces flexibility in constructing free-standing carbon aerogels from any ionically cross-linkable biopolymer while maintaining the ability to tailor design, dimensions and pore size distribution for specific energy storage applications.

Allergy is one of the world's most common chronic conditions. The state of the art method for allergy testing is the skin prick test (SPT) where different allergens are introduced into the skin of the tested person. This method is at best semi- quantitative, a relatively low number of tests can be performed and patients might experience unpleasant reactions. This invention is a novel allergy test providing fast, accurate and quantitative monitoring of allergic reactions in the skin. As a novelty, microneedle-based electrochemical sensor arrays are used to introduce allergens in the skin and perform electrochemical detection of biomarkers released from activated mast cells in the interstitial fluid.

Cardiovascular disease morbidity has increased worldwide. Organs-on-chips and human pluripotent stem cell (hPSC) technologies aid to overcome some of the limitations in cardiac in vitro models. Here, a bi-compartmental, monolithic heart-on-chip device that facilitates porous membrane integration in a single fabrication step is presented. Moreover, the device includes open-top compartments that allow facile co-culture of hPSC-derived cardiomyocytes and human adult cardiac fibroblast into geometrically defined cardiac microtissues. The device can be reversibly closed with a glass seal or a lid with fully customized 3D-printed pyrolytic carbon electrodes allowing electrical stimulation of cardiac microtissues. A subjacent microfluidic channel allowed localized and dynamic drug administration to the cardiac microtissues, as demonstrated by a chronotropic response to isoprenaline. Moreover, the microfluidic channel can also be populated with human induced pluripotent stem-derived endothelial cells allowing co-culture of heterotypic cardiac cells in one device. Overall, this study demonstrates a novel heart-on-chip model that systematically integrates an open-top device with a 3D printed carbon electrode for electrical pacing and culture of cardiac tissues while enabling active perfusion and dynamic drug dosing. Advances in the engineering of human heart-on-chip models represent an important step towards making organ-on-a-chip technology a routine aspect of preclinical cardiac drug development.

The design of commercial supercapacitors has remained largely unchanged since the 1970s, comprising powdered electrodes housed in rigid metal cylinders or pouches. To power the next generation of integrated technologies, an evolution in supercapacitor materials and design is needed to create multifunctional materials that allow energy storage while imparting additional material properties (e.g., flexibility and strength). Conductive free-standing electrodes produced from fibers or 3D printed materials offer this opportunity as their intrinsic mechanical properties can be transferred to the supercapacitor. Additionally, their conductive nature allows for the removal of binders, conductive agents, and current collectors from the supercapacitor devices, lowering their economic and environmental cost. In this Perspective, we summarize the recent progress on free-standing supercapacitors from new methods to create free-standing electrodes to novel applications for these devices, together with a detailed discussion and analysis on their electrochemical performance and physicochemical and mechanical properties. Furthermore, the potential directions and prospects of future research in developing free-standing supercapacitors are proposed.

In this article, a novel approach for selective passivation of three-dimensional pyrolytic carbon microelectrodes via a facile electrochemical polymerization of a non-conductive polymer (polydopamine, PDA) onto the surface of carbon electrodes, followed by a selective laser ablation is elaborated. The 3D carbon electrodes consisting of 284 micropillars on a circular 2D carbon base layer were fabricated by pyrolysis of lithographically patterned negative photoresist SU-8. As a second step, dopamine was electropolymerized onto the electrode by cyclic voltammetry (CV) to provide an insulating layer at its surface. The CV parameters, such as the scan rate and the number of cycles, were investigated and optimized to achieve a reliable and uniform non-conductive coating on the surface of the 3D pyrolytic carbon electrode. Finally, the polydopamine was selectively removed only from the tips of the pillars, by using localized laser ablation. The selectively passivated electrodes were characterized by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy methods. Due to the surface being composed of highly biocompatible materials, such as pyrolytic carbon and polydopamine, these 3D electrodes are particularly suited for biological application, such as electrochemical monitoring of cells or retinal implants, where highly localized electrical stimulation of nerve cells is beneficial.

The development of permeable three dimensional (3D) macroporous carbon architectures loaded with active pseudocapacitive nanomaterials offers hybrid supercapacitor materials with higher energy density, shortened diffusion length for ions and higher charge/discharge rate capability, and thereby is highly relevant for electrochemical energy storage (EES). Herein, structurally complex and tailorable 3D pyrolytic carbon/Mn3O4 hybrid supercapacitor electrode materials are synthesized through self-assembly of MnO2 nanoflakes and nanoflowers onto the surface of stereolithography (SLA) 3D printed architectures via a facile wet chemical deposition route, followed by a single thermal treatment. The thermal annealing of the MnO2 nanostructures concurrent with carbonization of the polymer precursor leads to formation of a 3D hybrid supercapacitor electrode material with unique structural integrity and uniformity. The microstructural and chemical characterization of the hybrid electrode reveals the predominant formation of crystalline hausmannite-Mn3O4 after the pyrolysis/annealing process, which is a favourable pseudocapacitive material for EES. With the combination of the 3D free-standing carbon architecture with self-assembled binder-free Mn3O4 nanostructures, electrochemical capacitive charge storage with very good rate capability, gravimetric and areal capacitances (186 Fg-1 and 968 mFcm-2, respectively) and long lifespan (˃92% after 5000 cycles) is demonstrated. It is worth noting that the gravimetric capacitance value is obtained by considering the full mass of the electrode including the carbon current collector. When only the mass of the pseudocapacitive nanomaterial is considered, a capacitance value of 457 Fg-1 is achieved, which is comparable to state-of-the-art Mn3O4-based supercapacitor electrode materials.