Gabriele Tullii

Endothelial‐derived nitric oxide (·NO) is a key signaling molecule in the vascular system, exerting concentration‐dependent control over critical cellular functions such as angiogenesis, vascular tone, and endothelial barrier integrity. Tools for achieving reversible, spatiotemporally resolved modulation of intracellular ·NO, without pharmacological or genetic manipulation, are currently lacking. Here, we present a light‐activated, nanoparticle (NP)‐based strategy enabling bidirectional control of endogenous ·NO in endothelial cells. Composite NPs, based on poly(3‐hexylthiophene), P3HT, and poly(3,4‐ethylene‐dioxythiophene):poly(styrenesulfonate), PEDOT:PSS polymers, are efficiently internalized in human (HUVEC) and murine (H5V) endothelial cells. In dark, NP uptake induces a ROS‐dependent, intracellular ·NO increase (+50% and +100% in HUVEC and H5V, respectively, vs. controls), a metabolic shift toward glycolysis and upregulation of both endothelial nitric oxide synthase (eNOS, +50%) and induced nitric oxide synthase (iNOS, +40%). NP photostimulation reverses this response, decreasing ·NO below basal levels, up to −40% in HUVEC and H5V, via ROS‐mediated scavenging and iNOS downregulation (−40%), partially restoring oxidative phosphorylation metabolism. Importantly, the photoexcitation protocol is compatible with perspective in vivo use, in terms of source type (LEDs) and power density (6 mW/cm ² ). Our approach represents an innovative strategy for bidirectional endothelial ·NO modulation, providing new opportunities in the emerging field of photo‐redox medicine.

Organic bioelectronic transistors emerged as powerful tools for probing cellular electrophysiology, offering biocompatibility, mechanical softness, and operational stability in biological environments. Despite these advantages, device benchmarking focused so far exclusively on electrical figures of merit, leaving interfacial processes that contribute to signal recording fidelity largely unexplored. Poly[2‐(3,3′‐bis(2‐(2‐(2‐methoxyethoxy)ethoxy)ethoxy)‐[2,2’‐bithiophen]‐5‐yl)thieno[3,2‐b]thiophene] (p(g2T‐TT)) is a model glycolated organic mixed ionic‐electronic conductor, whose high transconductance and optimal volumetric field‐effect behavior in physiological environment have been widely documented in Organic Electrochemical Transistor (OECT) configurations. Thus, p(g2T‐TT)‐based OECT was assessed as a promising candidate for recording action potentials (APs) from human induced pluripotent stem cell‐derived cardiomyocytes (hiPSC‐CMs). Surprisingly, although AP signal transduction was observed, the recorded AP waveforms failed to reproduce the expected morphology, especially when compared to signals recorded via poly(3‐hexylthiophene‐2,5‐diyl) (P3HT)‐based Electrolyte‐Gated Field‐Effect Transistors (EGOFETs). Immunofluorescence imaging revealed improved adhesion on P3HT with respect to p(g2T‐TT), suggesting weaker cell‐device coupling as the underlying limitation. Our results show that not all polymers combining biocompatibility and high electrical performance can transduce AP signals with high‐fidelity. Instead, interfacial properties govern bioelectronic transduction and provide a foundation for the rational design of polymers and platforms enabling reliable in vitro cellular electrophysiology, with potential translation to in vivo applications.

Microporous surfaces are widely explored for their potential in applications such as sensing, catalysis, and photonics. However, achieving well-defined and reproducible porous architectures often requires complex or highly optimized fabrication techniques. In this work, we present a straightforward, ultrafast and scalable method for producing functional microporous films by combining spin-coated breath figures of cellulose acetate butyrate with polydopamine-assisted metallization. By systematically investigating the parameters influencing the breath figure process, we demonstrate precise control over the porosity and three-dimensional structure of the resulting films. The incorporation of polydopamine enables the subsequent formation of metal nanoparticles, imparting plasmonic and catalytic functionalities to the surfaces. This versatile platform offers new opportunities for the development of multifunctional materials tailored for advanced sensing and environmental applications.

Semiconducting polymers (SPs), widely used in organic optoelectronics, are gaining interest in bioelectronics owing to their intrinsic optical properties, conductivity, biocompatibility, flexibility, and chemical tunability. Among them, poly(3-hexylthiophene) (P3HT) has attracted great attention as a versatile SP, being both optically active and conductive, for the fabrication of smart materials (e.g., films and nanoparticles), allowing the modulation of their performance and final biomedical applications. This review article provides an overview of the design of different kinds of P3HT-based materials, from chemical properties to structural engineering, to be used as key opto-electronic components in the development of opto-transducers for the modulation of cell fate, as well as biosensors such as organic electrochemical transistors (OECTs) and organic field effect transistors (OEFTs). Finally, their foremost applications in the biomedical field ranging from tissue engineering to biosensing will be discussed, including the future perspectives of P3HT derivatives towards cutting-edge applications for bioelectronics, in which optoceutics plays a key role.

Organic semiconducting nanoparticles (NPs) have been attracting increasing attention for their diverse applications in biotechnology, especially as photoactive materials for spatially controlled optical modulation of living-cell functions. Different approaches to optimize their efficacy and reliability have been recently attempted, including control of photophysical/-chemical properties, ad hoc tailoring of materials synthesis, and functionalization with biological moieties. Another promising strategy is offered by the realization of composite light-sensitive NPs, with a supramolecular architecture. This work reports on the fabrication and characterization of polymer NPs based on poly(3-hexylthiophene-2,5-diyl) (P3HT) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as prototypical examples of fully biocompatible, semiconducting and conducting materials, respectively. This peculiar NP architecture, with conducting islets distributed within the semiconducting phase, translates into optimization of charge dissociation and electron-transfer efficiency, as well as photocurrent generation increase by about an order of magnitude. As an example of relevant physiological interest, effective optical modulation of angiogenesis, driven by NPs, is demonstrated in primary human endothelial cells. The reported strategy is of general validity and broadens the tools available for spatiotemporally controlled, optical modulation of living-cell functions via engineering of the NP architecture and processes at the interface with living cells.

Carbon dots (CDs) are promising candidates as oxygen photosensitizers, in cancer therapeutic applications due to their high quantum yield, superior chemical and photostability, low cytotoxicity and ease of chemical functionalization/tuning. Nitrogen doping can further improve oxygen photosensitization performance. Besides photodynamic therapy, however, the possibility to finely and remotely regulate the intracellular redox balance by using physical stimuli has been attracting more and more interest not only for nanotheranostic application, but also as a novel, fully biocompatible therapeutic tool. Here, we report on the synthesis of nitrogen-doped CDs by solvothermal methods starting from abundant, bioderived, low-cost precursors, and we characterize their interface with in vitro cultures of human embryonic kidney (HEK-293) cells, a widely accepted model of non-tumoral cells. While not affecting cell proliferation, synthesized CDs efficiently modulate, under visible light and physiological eustress conditions, intracellular calcium ion dynamics and reactive oxygen species concentration, resulting in a 4-fold increase. The reported results may broaden the application of CDs beyond photodynamic therapy, unveiling new opportunities in the field of redox medicine assisted by carbon-based nanomaterials and optical stimulation.

The integration of nanotechnology with photoredox medicine has led to the emergence of biocompatible semiconducting polymer nanoparticles (SPNs) for the optical modulation of intracellular reactive oxygen species (ROS). However, the need for efficient photoactive materials capable of finely controlling the intracellular redox status with high spatial resolution at a nontoxic light density is still largely unmet. Herein, highly photoelectrochemically efficient photoactive polymer beads are developed. The photoactive material/electrolyte interfacial area is maximized by designing porous semiconducting polymer nanoparticles (PSPNs). PSPNs are synthesized by selective hydrolysis of the polyester segments of nanoparticles made of poly(3-hexylthiophene)-graft-poly(lactic acid) (P3HT-g-PLA). The photocurrent of PSPNs is 4.5-fold higher than that of nonporous P3HT-g-PLA-SPNs, and PSPNs efficiently reduce oxygen in an aqueous environment. PSPNs are internalized within endothelial cells and optically trigger ROS generation with a >1.3-fold concentration increase with regard to nonporous P3HT-SPNs, at a light density as low as a few milliwatts per square centimeter, fully compatible with in vivo, chronic applications.

Angiogenesis is a fundamental process in biology, given the pivotal role played by blood vessels in providing oxygen and nutrients to tissues, thus ensuring cell survival. Moreover, it is critical in many life-threatening pathologies, like cancer and cardiovascular diseases. In this context, conventional treatments of pathological angiogenesis suffer from several limitations, including low bioavailability, limited spatial and temporal resolution, lack of specificity and possible side effects. Recently, innovative strategies have been explored to overcome these drawbacks based on the use of exogenous nano-sized materials and the treatment of the endothelial tissue with optical or electrical stimuli. Here, conjugated polymer-based nanoparticles are proposed as exogenous photo-actuators, thus combining the advantages offered by nanotechnology with those typical of optical stimulation. Light excitation can achieve high spatial and temporal resolution, while permitting minimal invasiveness. Interestingly, the possibility to either enhance (≈+30%) or reduce (up to −65%) the angiogenic capability of model endothelial cells is demonstrated, by employing different polymer beads, depending on the material type and the presence/absence of the light stimulus. In vitro results reported here represent a valuable proof of principle of the reliability and efficacy of the proposed approach and should be considered as a promising step towards a paradigm shift in therapeutic angiogenesis.