Soft and Flexible Bioelectronic Micro-Systems for Electronically Controlled Drug Delivery

The concept of targeted and controlled drug delivery, which directs treatment to precise anatomical sites, offers benefits such as fewer side effects, reduced toxicity, optimized dosages, and quicker responses. However, challenges remain to engineer dependable systems and materials that can modulate host tissue interactions and overcome biological barriers. To stay aligned with advancements in healthcare and precision medicine, novel approaches and materials are imperative to improve effectiveness, biocompatibility, and tissue compliance. Electronically controlled drug delivery (ECDD) has recently emerged as a promising approach to calibrated drug delivery with spatial and temporal precision. This article covers recent breakthroughs in soft, flexible, and adaptable bioelectronic micro-systems designed for ECDD. It overviews the most widely reported operational modes, materials engineering strategies, electronic interfaces, and characterization techniques associated with ECDD systems. Further, it delves into the pivotal applications of ECDD in wearable, ingestible, and implantable medical devices. Finally, the discourse extends to future prospects and challenges for ECDD.

Making time and space for calcium control of neuron activity

Calcium directly controls or indirectly regulates numerous functions that are critical for neuronal network activity. Intracellular calcium concentration is tightly regulated by numerous molecular mechanisms because spatial domains and temporal dynamics (not just peak amplitude) are critical for calcium control of synaptic plasticity and ion channel activation, which in turn determine neuron spiking activity. The computational models investigating calcium control are valuable because experiments achieving high spatial and temporal resolution simultaneously are technically unfeasible. Simulations of calcium nanodomains reveal that specific calcium sources can couple to specific calcium targets, providing a mechanism to determine the direction of synaptic plasticity. Cooperativity of calcium domains opposes specificity, suggesting that the dendritic branch might be the preferred computational unit of the neuron.

Nano-scale solution of the Poisson-Nernst-Planck (PNP) equations in a fraction of two neighboring cells reveals the magnitude of intercellular electrochemical waves

The basic building blocks of the electrophysiology of cardiomyocytes are ion channels integrated in the cell membranes. Close to the ion channels there are very strong electrical and chemical gradients. However, these gradients extend for only a few nano-meters and are therefore commonly ignored in mathematical models. The full complexity of the dynamics is modelled by the Poisson-Nernst-Planck (PNP) equations but these equations must be solved using temporal and spatial scales of nano-seconds and nano-meters. Here we report solutions of the PNP equations in a fraction of two abuttal cells separated by a tiny extracellular space. We show that when only the potassium channels of the two cells are open, a stationary solution is reached with the well-known Debye layer close to the membranes. When the sodium channels of one of the cells are opened, a very strong and brief electrochemical wave emanates from the channels. If the extracellular space is sufficiently small and the number of sodium channels is sufficiently high, the wave extends all the way over to the neighboring cell and may therefore explain cardiac conduction even at very low levels of gap junctional coupling.

Electrosorption of phenolic compounds from olive mill wastewater: Mass transport consideration under a transient regime through an alginate-activated carbon fixed-bed electrode

Olive mill wastewater (OMWW) is an environmentally critical effluent, specifically due to its high content of phenolic compounds (PCs), which are hazardous due to their antimicrobial activities in water. However, their properties have good health effects at suitable doses. For the first time, the electrosorption of PCs from actual OMWW has been proposed for their possible recovery as value-added compounds, while decontaminating OMWW. A bio-sourced alginate-activated carbon (AC) fixed-bed electrode was prepared based on the reuse of olive pomace solid waste as powdered AC. At the optimal AC content (1% w/v), the internal ohmic drop voltage was lower (2.26 V) and the mass transport coefficient was higher (9.7 10^-5 m s^-1) along with the diffusivity (7.3 10^-9 m² s^-1), which led to enhanced electrosorption rates. Afterward, an optimal electrode potential was obtained (-1.1 V vs. Ag/AgCl), while higher voltages led to faradaic reactions. Moreover, the adsorption capacity was lower (123 mg g^-1) than that of electrosorption (170 mg g^-1) and was even higher (307 mg g^-1) with actual effluents. This was probably due to the influence of electromigration, which was confirmed by new models that could predict the electrosorption kinetics well considering mass transport and acid dissociation constants.