The assembly of supramolecular structures within living systems is an innovative approach for introducing artificial constructs and developing bio-materials capable of influencing and/or regulating the biological responses of living organisms. By integrating chemical, photophysical, morphological, and structural characterizations, we show that the cell-driven assembly of DTTO into fibers results in the formation of a 'biological assisted' polymorphic form, hence the term bio-polymorph. Indeed, X-ray diffraction revealed that cell-grown DTTO fibers present a unique molecular packing leading to specific morphological, optical, and electrical properties. Monitoring the process of fibers formation in cells with time-resolved photoluminescence, we established that cellular machinery is necessary for fibers production and postulated a non-classical nucleation mechanism for their growth. These biomaterials may have different applications for the stimulation and sensing of living cells, but more crucially, the study of their genesis and properties broadens our understanding of life beyond the native components of cells.[GL1]

[GL1]Questa frase è bella, ma va oltre il contributo che stiamo dando, mi pare. Lascio a te decidere, ma noi la toglieremmo.

Signaling in physiological environments relies on physicochemical cues and biomolecular that are all processed by the cellular machinery to execute a specific response. In this presentation, designer functional peptides will be discussed as synthetically engineered materials that could enable the transduction of light to cellular cues for controlling the behavior and anisotropy of excitable cells such as cardiomyocytes. First, the structural tunability of the assembly behavior of peptides bearing optoelectronic π-conjugated units in aqueous solutions and on surfaces to generate nano- and micropatterns are discussed. While the supramolecular assemblies of these peptides can have dynamic structures in physiologically relevant solutions, on surfaces that have anisotropic topography, the resulting self-assembled optoelectronic peptides can be directed to form 1-D nanostructures with ordered molecular interactions between π-units. Additionally, fabrication approaches that allow for the generation of micropatterns of π-conjugated peptides that are stable under electrolytic cell culture media will be shown. The distinct capability of these patterned π-conjugated peptides to align cardiomyocytes interfaced with these materials will also be discussed. This property provides the potential opportunity for directional stimulation of excitable cells with spatiotemporal control, especially when the stimulation is initiated using light. Finally, material design insights that allow for enhanced photoconduction by these designer peptides will also be presented. Overall, we envision these functional peptides as transducer biomaterials that can offer a new paradigm for having systematically controlled cell-material interactions towards tissue engineering and in vitro modeling applications for excitable cells.

The employment of organic semiconductors (OSCs) promises to widen the realm of electronics to countless new applications, thanks to the advantageous properties of organics. Effectively, the field of organic electronics has been forging ahead from its initial proof-of-concept devices towards increasingly diverse materials and applications.

State-of-the-art high performance OSCs are derived from petrochemicals. Nevertheless, this class of materials can also be based on renewable, natural resources. Indeed, nature offers an extraordinary variety of systems that exhibit diverse opto-electronic functionalities. For instance, colours can vary in plants depending on the specific function, weather conditions and health/life cycle stage. Molecules responsible for this property are often dyes and pigments that show π-electron delocalization within their molecular structure and hence, that are potentially prone to showing optimal charge carrier transport properties and frontier energy levels compatible for charge injection.

Effectively, different natural molecules have been reported to display semiconducting properties and few of them have been used as active layers for electronic devices, e.g., organic thin film transistors (OTFTs). For instance, carotenoids are an interesting class of molecules, owing to their widespread availability in a large range of plants, algae, bacteria and fungi. They are hence compatible with a circular economy model, unravelling novel sustainable scenarios in organic electronics, besides being edible, thus contributing to the growth of the rising field of edible electronics. In this work we will show how a fine microstructural tuning of these materials can lead to the fabrication of efficient OTFTs with reasonable stability. Such results indicate that options for sustainable, edible semiconductors are available and can be exploited towards the integration into logic circuits.

The use of light to control the activity of different cell-types has recently come at the forefront of the scientific community thanks to a series of key-enabling features (i.e. spatial/temporal selectivity, and lower invasiveness). Optogenetics is probably the prime example of this approach and since its initial development in neuroscience has been extended to other fields. However, the need of viral gene transfer, required to induce light-sensitivity in the target organism, strongly impairs the clinical translation of optogenetics-based systems. To overcome this issue, non-genetic (geneless) optostimulation is a growing and multidisciplinary field of research at the border among physics, material science and biology that aims to achieve light sensitivity with photoactive actuators. I will present promising photoactuators for cardiac applications, focusing in particular on excitation-contraction coupling modulation. Future clinical perspectives in contexts where the possibility of obtaining precise control of cardiac cell activity could offer new insights (e.g. resynchronization and arrhythmia termination) will also be discussed.

Nature has evolved in a hierarchical manner to achieve outstanding material properties and complex organismal behaviours. Hierarchy is a ubiquitous organizing and functional principle of natural systems, which are controlled in size, shape and pattern. The properties of skeletal muscles mainly rely on their hierarchical structure, composed of fibrous actuators organized in different levels of aggregation (from cm down to nm). This strong hierarchical organization gives muscles their remarkable time-dependent viscoelastic properties, and their efficient hierarchical actuating organization at different levels, from the single sarcomere to the muscle fascicle. 

Muscles are an optimized mechanism over a million years of evolution, and have inspired artificial actuators [1]. Despite that, current actuation technologies are not able to recapitulate the features of natural skeletal muscles. The possibility to grow fully functional living muscles in vitro and use them to power soft machines has the potential to revolutionize robotics, in the long term.

Biohybrid actuation is born as a new and extremely promising actuation method, which combines a live entity, like muscle cells, with an artificial substrate to produce a mechanical movement generated by the contraction of muscle cells. Attractive advantages feature this kind of biological actuator as performance invariance with scalability (from nm to mm), high transduction efficiency, and high power-to-weight ratio. Biohybrid actuators have the potential to deliver remarkable performance with life-like movements at the macroscale to artificial devices. Biohybrid actuators usually rely on a bottom-up approach and include systems based on cardiomyocytes, insect self-contractile tissues, and engineered skeletal muscle tissues (from both mammals and insects), which can convert chemical energy from the environment into mechanical energy. Skeletal muscle cells are the muscle cell types that have generated the most interest because they may be regulated to contract in response to specific stimuli, such as chemical, electrical, or optical signals, following suitable optogenetic changes [2]. There are several examples of bio-hybrid actuators and robots in literature, as the bio-bots can walk or swim [3]. Despite that, the use of a bio-hybrid actuator to actuate a medical device as a catheter has never been explored, so far.

Catheterization is one of the most promising approaches for the targeted treatment of several diseases, including cancer. Indeed, the local administration of medications or chemicals in the area of interest may maximize the therapy efficacy, reducing side effects. Here, we report the concept and an early investigation of a novel intravascular steerable catheter powered by an on-board biohybrid actuator on its tip to navigate deep and tortuous regions within the cardiovascular systems. The catheter performance has been analyzed by analytical and numerical analyses, assessing the influence of the catheter geometrical (e.g., inner and outer radii, wall thickness) and physical (e.g., stiffness) parameters, the actuator geometrical parameters (e.g., length and positioning over the catheter tip) and contractile force. The findings demonstrate the necessity to lower the outer diameters and decrease wall thickness to maximize the catheter deflection. Also, we assessed the influence of the positioning of the biohybrid actuator as the applied forces. These preliminary results hold a lot of promise in light of future experiments using this type of actuation to drive microcatheters through the cardiovascular network, even though the performance of this concept still needs to be improved to match relevant anatomical targets, as the radius of curvature of the inner branches of organs.

The vast expansion of available synthetic biology tools has led to explosive developments in the field of materials science. The increased accessibility of these tools has pushed the frontier of materials science into the field of engineering biological and even living materials. By coupling the tunability of nanomaterials with the prospect of re-programming living devices, one can re-purpose biology to fulfil needs that are otherwise intractable using traditional engineering approaches.

Optical technologies in particular stand to benefit from the untapped potential in coupling the optical properties of nanomaterials with the specificity and scalability of biological materials. This presentation highlights applications in sensing and energy technologies that exploit the synergistic coupling of nanobio-hybrid materials. This talk will focus on the development of living electronics, such as photovoltaics based on photosynthetic organisms with augmented capabilities. The development include advancements in electrode engineering as well as biological engineering of living organisms. The talk will also discuss nanobionic approaches that focus oin infusing synthetic nanoparticle with living cells.

The control of biological functions is crucial for the in-depth understanding of physiological/pathogenic processes, as for the development of novel, ad hoc therapeutic modalities to fight specific diseases. In this regard, light-induced cell control is characterized by lower invasiveness, better space and time resolution, with respect to more traditional electrical-based methods. Exogenous inorganic and organic semiconducting materials have attracted considerable interest, since they can be employed as photoactive transducers to trigger the biological activity, without any need for viral transfection [1]. In particular, semiconducting polymers offer great biocompatibility and stability together with geometrical adaptability. Among them, the green light-absorbing poly(3-hexylthiophene) (P3HT) was successfully employed for the modulation of the physiological activity of different cell models [2-4], including the boosting of both proliferation and tubulogenesis of endothelial cells [5]. The latter result is particularly appealing in view of the regeneration of the cardiovascular tissue for application in cardiovascular disease therapies.

Here, we realize smart biointerfaces between red-light absorbing conjugated polymers and cardiovascular cells. The aim of our work is to study the cellular response both to the polymers alone and in combination with red light excitation. The latter is particularly favorable in view of in vivo applications, given the higher penetration of red light within living tissues, as compared to lower visible wavelengths. We show that conjugated polymers in form of nanoparticles lead to either enhancement or reduction of the angiogenic response of model endothelial cells, depending on the material type and the presence/absence of the light stimulus. Furthermore, we observe that semiconducting polymer thin films efficiently modulates, upon red light photoexcitation, the physiological properties of Cardiomyocytes. In particular, we demonstrate that polymer-mediated photostimulation modulates both the Ca²⁺ dynamics and the electrical properties of the cells. Very interestingly, we observe an anti-arrhythmogenic effect, unequivocally triggered by polymer photoexcitation.

Overall, our results support the possibility to employ red light-responsive conjugated polymers to regulate cardiovascular functions, in a drug-free, touchless, repeatable, and spatio-temporally controlled manner.