Interaction of electromagnetic radiation with organic molecules gives rise to different phenomena, all of them of interest for imaging and therapy application. Depending on the feature of the organic material and the energy of the impinging radiation organic can behave like contrast agent (X-ray imaging of tissues), fluorescent probes, photosensitizers of reactive oxygen species[1] and – upon photoisomerization and/or redistribution of their electron density – nanoactuators in complex light mediated biological phenomena. Photoinduced modulation of neuronal activity is of particular interest in neuroscience. In addition to the potential represented by optogenetics, research in this field is moving towards the development of nanomachines capable of altering the membrane potential of neuronal cells following light stimulation. The most direct practical application of this type of technology is the development of synthetic retinas capable of restoring photosensitivity to patients suffering from degenerative diseases affecting the photoreceptors present in the eye. I will discuss the design, synthesis and characterization of a family of photosensitive molecules capable of spontaneously localizing into the neuronal membrane. Upon photoexcitation, such derivatives give rise to a complex sequence of phenomena that have two macroscopic consequences on the structure of the neuronal membrane: a membrane depolarization and the formation of pores in the membrane itself.[2] The latter property can be exploited to increase the local permeability of the membrane, providing a much less invasive analogue to the common patch-clamp technique, i.e. the mechanical perforation of the neuronal membrane with special needles. The effects of membrane depolarization and perforation can be discriminated based on the intensity and duration of light stimulation. The same probes can also act as efficient photosensitizers for bacterial photodynamic inactivation.[3]

Attaining ion transport with artificial molecular transport systems (AMTS) is of high interest for many bioelectronic applications, as drug delivery or ion sensing.[1],[2] To drive the active transport of protons and metal ions, a potential drop is generated across an ionic membrane, which drives the ions through. While wired transport has been extensively investigated,[3],[4]contactless approaches for generating the potential drop have not been studied to the same extent so far. Asymmetric light illumination, for example, generates a potential drop that pumps the ions across the membrane, allowing for contactless, low-invasive transport. Existing AMTS are typically composed of lipid or liquid membranes.[5],[6] However, these lipid or liquid membranes come with challenges such as poor eficiency, fragilness, and compatibility issues with interacting components. To overcome these limitations , ionic, cross-linked and bio-compatible polymeric membranes have been proposed. Herein, we present the synthesis and characterization of different ionic/cross-linkable thiophene-based conjugated monomers, which are then electrochemically copolymerized, obtaining ionic cross-linked polythiophenes. We obtain homogeneous films with desirable VIS light absorption and stable electrochemical properties. With these characteristics, the obtained ionic cross-linked thiophene-based copolymers have the potential to be used as light-gated ion pump systems in biolectronic applications such as drug delivery.

In comparison with inorganic semiconductors, organic semiconducting polymers (OSCs) development and commercialization as materials for next-generation bioelectronic devices is limited by batch-to-batch variations and performance differences due to molecular weight effects. Despite OSCs presenting important advantages, such as mechanical flexibility, synthetic tunability, and solution processability, one of the critical challenges is their purity. [1], [2] Impurities left over from synthesis, such as heavy metal ions or low-molecular-weight chains, negatively impact electronic charge transport and long-term stability. When employed in bioelectronic devices, leakage of heavy metal ions left in the polymer can harm biological systems and cells. Traditional purification techniques, such as Soxhlet extraction [3] and metal scavenging [4], are often ineffective in removing chemical side products left over from synthesis, making it difficult to study the intrinsic properties of the materials. Therefore, developing complementary purification techniques to remove these side products is crucial in achieving reproducible and safe bioelectronic devices.

In my talk, I will describe how high-performance liquid chromatography (HPLC) improves the purity of polymeric n-type OSCs. HPLC fractionation allows separation based on hydrodynamic volume, making it possible to narrow the molecular-weight distribution and the selectively remove low-molecular-weight chains as well as metal residues. OSCs based on naphthalene-1,4,5,8-tetracarboxylic-diimide-bithiophene (NDI-T2) achieve improved electronic charge transport properties in organic electrochemical transistors (OECTs) and fewer batch-to-batch variations in device performance and stability.

Nowadays living cells stimulation is an emerging and hot topic. Contactless and wireless methods are extremely appealing due to a reduced alteration of the analyzed biological systems.¹ In this context, light emerges as a non-invasive, wireless solution with high spatiotemporal precision for bio-stimulation.² Material-based light transducers (conjugated molecules and macromolecules) have demonstrated efficacy at the interface with living cells and tissues, thanks to their photophysical properties, biocompatibility, and chemical versatility. ^3,4

In this presentation, I will discuss the use of phototransducers for muscular cell activation,^5–7 highlighting their photo-chemical properties.^8,9 Beyond single-cell photopacing, these materials have been employed to stimulate in vitro muscular microphysiological systems developed using classical tissue engineering techniques as well as advanced methods like electrospinning and 3D printing.^10,11 The interactions between light and these different tissue types will also be analyzed to understand and optimize photostimulation efficacy in complex biological contexts.

These systems mimic muscle tissue native properties and represent a promising platform for the development of bio-hybrid actuators, regenerative medicine tools, drug testing, and disease screening applications.

1.             Manfredi, G. et al. The physics of plasma membrane photostimulation. APL Mater. 9, 030901 (2021).

2.             Ronzitti, E. et al. Recent advances in patterned photostimulation for optogenetics. J. Opt. 19, 113001 (2017).

3.             Dai, Y. et al. Soft hydrogel semiconductors with augmented biointeractive functions. Science 386, 431–439 (2024).

4.             Vurro, V., Venturino, I. & Lanzani, G. A perspective on the use of light as a driving element for bio-hybrid actuation. Appl. Phys. Lett. 120, 080502 (2022).

5.             Lodola, F., Vurro, V., Crasto, S., Di Pasquale, E. & Lanzani, G. Optical Pacing of Human‐Induced Pluripotent Stem Cell‐Derived Cardiomyocytes Mediated by a Conjugated Polymer Interface. Adv. Healthc. Mater. 8, 1900198 (2019).

6.             Vurro, V. et al. A Polymer Blend Substrate for Skeletal Muscle Cells Alignment and Photostimulation. Adv. Photonics Res. 2, 2000103 (2021).

7.             Vurro, V. et al. Optical modulation of excitation-contraction coupling in human-induced pluripotent stem cell-derived cardiomyocytes. iScience 26, 106121 (2023).

8.             Paternò, G. M. et al. Membrane Environment Enables Ultrafast Isomerization of Amphiphilic Azobenzene. Adv. Sci. 7, 1903241 (2020).

9.             Vurro, V. et al. Molecular Design of Amphiphilic Plasma Membrane-Targeted Azobenzenes for Nongenetic Optical Stimulation. Front. Mater. 7, 631567 (2021).

10.           Vurro, V. et al. Light-triggered cardiac microphysiological model. APL Bioeng. 7, 026108 (2023).

11.           Venturino, I. et al. Skeletal muscle cells opto-stimulation by intramembrane molecular transducers. Commun. Biol. 6, 1148 (2023).

Electrolyte-gated organic field-effect transistors (EGOFETs) are emerging as powerful, ultrasensitive, label-free biosensors due to their low cost, straightforward electrical readout, and inherent signal amplification. Their operation is based on the formation of two electrical double layers (EDLs) at the organic semiconductor–electrolyte and electrolyte–gate interfaces when a gate voltage is applied. This interaction modulates charge transport along the organic semiconductor, rendering EGOFETs highly responsive to interfacial changes—a property extensively harnessed in biosensor development. A common approach for biosensor fabrication involves the biofunctionalization of the gate electrode using antibody immobilization strategies. Such methodologies have enabled the detection of biologically relevant molecules at ultra-low concentrations, positioning EGOFETs as promising candidates for next-generation point-of-care (PoC) diagnostics. In our group, we have leveraged this platform to detect alpha-synuclein, a biomarker of Parkinson’s disease, with a detection limit as low as 0.1 pM, and to monitor the aggregation kinetics of betaamyloids [1–2]. Despite their diagnostic potential, the portability of EGOFET-based assays is often hindered by the need of integrating them in microfluidic systems and performing multi-step synthetic protocols. To overcome these limitations, we present a simplified EGOFET integrated with lateral flow paper fluidics, enabling a reusable, compact, and cost-effective PoC test with rapid turnaround (~30 minutes). This platform was validated for the detection of Human Immunoglobulin G, demonstrating a broad linear range, high selectivity, reproducibility, and an impressive detection limit of 0.1 fM [3].

References

[1] S. Ricci, S. Casalini, V. Parkula, M. Selvaraj, G. D. Saygin, P. Greco, F. Biscarini, M. Mas-Torrent, Biosensors and Bioelectronics 2020, 167, 112433.

[2] S. Ruiz-Molina, C. Martinez-Domingo, S. Ricci, S. Casalini, Marta Mas-Torrent, ACS Appl. Electron. Mater. 2024, 6, 12, 8998.

[3] M. J. Ortiz-Aguayo, C. Martínez-Domingo, D. Gutiérrez, D: Kos, Adv. Mater. 2025, DOI: 10.1002/adma.202513468.

The identification of novel physiological biomarkers requires real-time human monitoring using advanced soft, flexible, and hypoallergenic materials and devices. Therefore, imperceptible and reliable daily monitoring depends on mechanically and biologically compatible interfaces to securely perform long-term advanced biosensing. I will present our latest work on developing versatile electronic biosensing interfaces for electrophysiological and sweat monitoring, employing a sustainable approach in the development of organic bioelectronic materials and devices. With the progress of additive manufacturing, traditional coating techniques together with advanced 3D printing have demonstrated new opportunities for monolithic integration of sensing devices within garments [1]. Remaining research-level progress, yet with a high capability for scale production, these devices enable continuous tracking of physiological responses triggered by environmental conditions. Developing circular-use strategies for active materials, along with enhancing the reusability of biocompatible elastomers, helps reduce the growing volume of medical-device waste—a problem intensified by the surge in commercial health gadgets and heightened cross-contamination concerns in clinical settings.

Organic Electrochemical Transistors (OECTs) have been attracting extensive research attention within the last several years. Their applications as chemical/biological sensors and in neuromorphic circuits are particularly appealing due to their high transconductance, efficient electron-ion coupling, compatibility with aqueous solutions, conformability and low voltage operation. These advantageous properties arise from the unique characteristics of the channel material, organic mixed ionic-electronic conductors (OMIECs), which support the simultaneous transport of electronic charges and ionic species. This channel layer can be processed directly using electropolymerization. Comparing to other processing techniques, electropolymerization offers several advantages. It allows for precise control over the thickness of the polymer film by adjusting the deposition parameters, such as the applied potential, quantity of change deposited and time. The morphology of the electropolymerized film can be tuned again by controlling the polymerization conditions, enabling the formation of nanostructures or porous films. Moreover, electropolymerization can be performed selectively on the individual channel, enabling direct patterning of the polymer layer without the need for complex photolithography and etching processes, which is beneficial for simplifying the fabrication process and integration of OECTs into more complex circuits. In this work, we explore the performance of OECTs incorporating several electropolymerized channel materials. We begin with devices fabricated using a conventional PEDOT channel, highlighting their application in dopamine detection.(1) We then introduce PEDOT:N3, a clickable OMIEC variant whose threshold voltage can be finely tuned through control of the electropolymerization parameters, an essential feature for the design of adaptable biosensors and neuromorphic elements. (2) Finally, we present OECTs based on P-tri-DPA for zinc ion detection, showing that this material enables low detection limits together with high specificity toward Zn²⁺ ions. (3) These results show the versatility of electropolymerization as a fabrication strategy for high-performance OECTs and underscore the value of OMIEC materials engineering in advancing next-generation bioelectronic devices.

Scalable, high-throughput platforms capable of non-invasively recording action potentials (APs) from excitable cells are increasingly essential for advancing disease modelling and accelerating drug discovery. Yet, despite decades of progress, AP measurements in vitro still rely predominantly on patch clamp, a gold-standard technique that remains invasive, low-throughput, and technically demanding. Non-invasive alternatives, such as planar MEAs, cannot capture true APs without membrane poration, thereby limiting their ability to resolve subtle disease phenotypes or pharmacological responses. In this talk, I will present our development of a next-generation electrophysiology platform based on Electrolyte-Gated Organic Transistors (EGOTs) [1-3]. This technology achieves patch-clamp-like signal fidelity from human stem cell-derived cardiomyocytes without perturbing the membrane, enabling the detection of drug-induced proarrhythmic events such as early and delayed afterdepolarizations. I will also highlight our ongoing efforts to scale up the technology from single devices to multiwell arrays for high-throughput screening. Additionally, I will discuss our current work on extending its application to other excitable cells, which opens up new opportunities for scalable, non-invasive electrophysiology.

Organic electrochemical transistors (OECTs) require electrolytes that unite high ionic conductivity and mechanical compliance with intrinsic biocompatibility and sustainability, a combination difficult to achieve by conventional aqueous liquids, ionic liquids, or synthetic hydrogels. Here we demonstrate that a natural Aloe vera gel can serve as a single-component quasi-solid electrolyte for high performance OECTs, leveraging its native minerals (Ca²⁺, K⁺, Na⁺, Mg²⁺ ions) and high-water content. Rheological tests confirm a soft, viscoelastic gel network, and electrical measurements reveal an ionic conductivity of ~6.1 mS/cm with interfacial capacitance of ~58.5 µF/cm². In OECT devices, the aloe electrolyte yields high-performance transistors: peak transconductance of ~11 mS and ON-current of ~6.5 mA, comparable to conventional phosphate buffered saline (PBS) gating. Transient analysis confirmed rapid switching kinetics, with high stability demonstrated by >96% drain current retention after 100 cycles. These results establish natural aloe vera gel as a unique, non-diffusion-limited, inherently biocompatible and biodegradable gating medium, overturning expectations of slow solid-state performance and charting a path toward truly sustainable ("green") bioelectronic systems.

The climate change and growing population call for plants with increased tolerance to biotic and abiotic stress and for plants with higher productivity. I will present our recent advancements on interfacing bioelectronic tools with model plant systems with the aim to enable new discoveries and possibilities in plant science. We recently developed conformable multielectrode arrays based on organic electronics for large-scale and high-resolution plant electrophysiology. This technology enabled us to performed precise spatiotemporal mapping of the action potential in Venus flytrap, a model system for fast electrical signalling, and to reveal key properties of the AP. Currently we are extending the application of this technology to other plant species with the aim to contribute to the mechanistic understanding of long-distance responses in plants particularly related to environmental stress. Apart from monitoring electrical signals we also used electric field to stimulate plants. We developed a bioelectronic platform, the eSoil, that stimulates the growth of plants in hydroponics culture, increasing their biomass by 50%. This work opens the pathway for enhancing plant growth in hydroponics using materials science and bioelectronics that may result in more sustainable food production.

Wearable biosensing routines use skin-contact electrodes. Traditional gel-based electrodes dry out over time, lose performance, and contribute to substantial electronic waste generation. [1] In response, we developed soft, breathable electrodes made of porous PDMS sponges coated with PEDOT:PSS (poly(3.4-ethylenedioxythiophene): poly(styrenesulfonate))— a conducting polymer forming a gel-free device that conforms naturally to the skin.[2,3] This approach makes use of both commercial and recovered PEDOT:PSS, from spent formulations, towards sustainable sensor manufacturing. Additionally, an original way of sponge structure fabrication was applied via a sugar-templating method, achieving a porous network that enhances their conformal contact and breathability.[4] The conductive coating is then applied through dip-coating and chemical crosslinking to ensure its strong adherence. Electrochemical impedance spectroscopy and long-term stability testing show that the electrodes from the recycled and commercial formulations uphold low skin–electrode impedance even after extended wear (10 hours). Simultaneous heart and brain wave recordings with both electrode types demonstrated high-fidelity signal acquisition and signal-to-noise ratios compared to gold standard Ag/AgCl electrodes. The stable performance over hours of continuous use confirms the sponge electrode’s capacity to perform in long-term, wearable monitoring. By merging comfort, performance, and recyclability, this work paves the way for the next generation of sustainable wearable sensor manufacturing.

The evolution of agricultural systems by including digital technologies into agriculture is reshaping post-harvest monitoring, enabling sustainable, non-destructive quality assessment methods. Electrochemical Impedance Spectroscopy (EIS) offers a robust method for characterizing physicochemical changes in fruits and thereby providing insight into quality evolution during ripening and rotting. Despite its potential, broader adoption of EIS is hindered by the reliance on non-biodegradable, short-term adhesive electrodes.

Here, we present an edible electrically conductive adhesive, fabricated from food-derived materials such as zein (a corn-derived protein) as adhesive matrix and activated carbon (food additive E 153) as conductive filler.^[1] The formulated acrylic-like viscous ink is compatible with ink brushing deposition technique permitting direct application on fruits. Thus, the dried adhesive on fruit constitutes novel EIS sensing electrodes which exhibit food contact safety and long-term adhesion and electrical conductivity, overcoming the current limitations for sustained EIS. We apply his food-safe approach for the reliable monitoring of the bioimpedance of table grapes, as a function of storage time, chosen as a relevant study case as they are one of the most economically significant horticultural crops worldwide. Our system enabled continuous monitoring of grapes over several days and detected significant impedance changes within the first 24 hours. These findings demonstrate the potential of our food-compatible EIS platform for fruit quality monitoring.

N-type organic electrochemical transistors (OECTs) are essential for building fully complementary, low-voltage organic circuits for bioelectronics; however, their development, particularly for selective cation recognition, lags significantly behind that of p-type materials. In this work, we present a molecularly tunable strategy for imparting ion-recognition capability to the benchmark n-type polymer poly(benzimidazobenzophenanthroline) (BBL). We report a BBL:PVB18C6 polymer blend formed via an acid-mediated in situ polymerization of vinylbenzo-18-crown-6 (VB18C6) directly in the presence of BBL in methanesulfonic acid. This synthesis route enables homogeneous incorporation of 18-crown-6 units, imparting selective affinity toward potassium ions without disrupting the electronic backbone of BBL. Quantitative X-ray photoemission spectroscopy confirms pronounced differences in sodium and potassium uptake between pristine BBL and the BBL:PVB18C6 blend, directly validating the crown-ether-driven cation recognition mechanism. When used as the OECT channel, BBL:PVB18C6 exhibits enhanced drain current and markedly higher volumetric capacitance (C*) in 0.1 M KCl, reaching 395 F cm⁻³, an increase of 76 percent compared to the C* measured in 0.1 M NaCl (225 F cm⁻³). This elevated capacitance in KCl directly reflects the preferential interaction between the crown ether units and K⁺, leading to more efficient cation uptake, volumetric charging, and transistor modulation. The resulting OECTs display strong concentration-dependent responses toward K⁺ over Na⁺, validating the cation-selective behavior. Importantly, incorporation of the crown ether does not compromise device operational stability even under repeated electrochemical cycling. By demonstrating selective K⁺ responsiveness, improved volumetric capacitance, and reliable transistor operation, this work addresses a critical materials gap and provides a foundation for cation-dependent n-type OECTs. More broadly, BBL:PVB18C6 establishes a molecular design strategy that advances the realization of complementary organic circuits for the next generation of ion-selective, bioelectronic circuitry.