Organic thin films as active materials in field effect transistors and electrochemical sensing

This PhD thesis is focused on Organic Electronics, an emerging field where different disciplines converge to gain insights into the properties of organic materials and their applications. Under the present work different organic materials have been realized and analysed for application both in Organic Field Effect Transistors and electrochemical sensing with Organic Electrochemical Transistors. An overview about Organic Electronic is reported with the most recent advancement of the last years: a state of the art of research about Organic Field Effect Transistors (OFETs) and Organic Electrochemical Transistors (OECTs) is given, with an overview on the emerging Organic Bioelectronics. The main motifs of the research performed are reported along the discussion. In the application of the supersonic molecular beam epitaxy method, thin films of Copper Phthalocyanine have been grown, reaching an unprecedented order in the crystalline structure, as the characterization by Raman spectroscopy and AFM have shown. A modified-pentacene molecule (2,3-CN2-TIPS-Pn films) has been used as active layer for the building of an OFET device, which showed an ambipolar behaviour with balanced electrons and holes mobility on the order of 2⋅10-3cm2/Vs. The charge transport properties of 2,3-CN2-TIPS-Pn films show the effectiveness of TIPS-Pn functionalization with cyano e− withdrawing groups to promote e- transport while maintaining equivalent h− transport. A second OFET device has been realized with tetracene organic thin films deposited on different dielectrics substrates: the devices have been characterized and the mobility measured. For the tetracene film deposited on the polystyrene substrate, we have found a mobility of 2⋅10-1 cm2/Vs, the highest retrieved up to now in literature for tetracene. The molecular structures of all the organic molecules used, have been deeply investigated by means AFM analysis and XRD-advanced algorithm tools. For the films made with the TIPS molecule, the GIXRD analysis revealed a favourable arrangement of the molecules in the TFT channel. The XRD analysis performed on the tetracene films revealed interesting correlation between the mobility of the film and the AFM and structural parameters: in particular the polystyrene film shows the best surface coverage and the highest alpha phase percentage of the molecular structure. New insights into the device physics of OECT have been discovered: in the sensing experiments with OECTs, the role of the gate electrode has been investigated. This clarified the two working principles an OECT can operate (faradaic or non-faradaic mode). We found that an OECT can switch between these two modes of operation simply changing the metal wire acting as gate electrode. In particular the faradaic operational mode lead to the possibility to exploit the transistor as a halide sensor, able to detect Na+ ions in solution with a sensibility up to 10μM. Then the role of electrolyte has been studied with micellar structures, which open unexplored horizons for the application of OECT with a new class of electrolytes. The ability of micelles to dope/dedope efficiently the PEDOT:PSS permitted to investigate the doping process of the polymer, that is one of the main issue today in organic electronics. The modulation signals have been correlated with the surface charge of the micelles, measured by the zeta-potential techniques and the injection of micelles into the polymer structure has been probed by an optical spectroscopy measurement, performed in-situ during the OECT current acquisition. As a consequence of the micelle experiment, bilayer structure, like liposomes, have been tested and detected for the first time with an OECT. Although this experiment is currently in progress, it seems particularly promising, mainly because the opportunity to exploit the ability of liposomes to trap and release drugs in a controlled way. A new nanoparticles-based sensor has been developed, able to detect the presence in solution of iron-oxide magnetic nanoparticles functionalised with different polymeric coatings: we provide the ability of OECTs to detect and monitor selectively, with an appropriate choice of the electrolyte, different nanosystems. We demonstrate an on-line sensing based on OECTs, with an easy sampling/sample preparation, for the detection of functionalized magnetic nanoparticles. OECTs have promising applications in bioelectronics as well as in nanomedicine or neuroscience. They are becoming an ideal platform for both in-vitro and in-vivo biomedical applications, as well as for the development of protocells inside miniaturized electro-chemical laboratory

A review on the protocols for the synthesis of proteinoids

Protocells are a type of synthetic cells, which, if engineered to have properties similar to a natural cell, can have immense applications in synthetic biology and bioengineering communities. Proteinoids are one of the leading contenders for protocells discovered by Sidney H. Fox in 1950s as the protein-like molecules which are made out of amino acids. Proteinoids, if made in a right way, can show electrical excitability patterns on its surface with inflow and outflow of acidic and basic ions giving rise to a oscillatory charge behaviour similar to a neuronal spiking potential. The right protocol for the preparation of proteinoids can be hard to find, given that the literature for proteinoid is widely distributed across different scientific subdisciplines - origin of life, synthetic cell engineering, application of proteinoid NPs etc. This review attempts to enlist most of the relevant protocols published in the literature, each catering to different application, whether motivated by fundamental sciences or basic sciences perspective. The article also suggests the best set of protocol that could be followed by the readers to synthesise proteinoid powder as a potential experimental system for proto-cognitive, cosmetic, biomedical, or synthetic biology applications. An overarching picture of proteinoid as a potential system to study the chemical evolution during the transition from abiotic to prebiotic life, in the history of Earth, is also presented in the end.Comment: 1 figur

Transistor tridimensionale del tipo Organic ElectroChemical Transistor (OECT) e relativo metodo di fabbricazione.

La presente invenzione riguarda un metodo di fabbricazione di un transistor polimerico 3D

Author correction: Kombucha electronics: Electronic circuits on kombucha mats

Correction to: Scientific Reports, published online 09 June 2023 The original version of this Article contained an error in the spelling of the author Pasquale D’Angelo which was incorrectly given as Passquale D’Angelo. The original Article has been corrected

PEDOT:PSS interfaces support the development of neuronal synaptic networks with reduced neuroglia response in vitro

The design of electrodes based on conductive polymers in brain-machine interface technology offers the opportunity to exploit variably manufactured materials to reduce gliosis, indeed the most common brain response to chronically implanted neural electrodes. In fact, the use of conductive polymers, finely tailored in their physical-chemical properties, might result in electrodes with improved adaptability to the brain tissue and increased charge-transfer efficiency. Here we interfaced poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) doped with different amounts of ethylene glycol (EG) with rat hippocampal primary cultures grown for 3 weeks on these synthetic substrates. We used immunofluorescence and scanning electron microscopy combined to single cell electrophysiology to assess the biocompatibility of PEDOT:PSS in terms of neuronal growth and synapse formation. We investigated neuronal morphology, density and electrical activity. We reported the novel observation that opposite to neurons, glial cell density was progressively reduced, hinting at the ability of this material to down regulate glial reaction. Thus PEDOT:PSS is an attractive candidate for the design of new implantable electrodes, controlling the extent of glial reactivity without affecting neuronal viability and function

A bio-inspired memory device based on interfacing Physarum polycephalum with an organic semiconductor

The development of devices able to detect and record ion fluxes is a crucial point in order to understand the mechanisms that regulate communication and life of organisms. Here, we take advantage of the combined electronic and ionic conduction properties of a conducting polymer to develop a hybrid organic/living device with a three-terminal configuration, using the Physarum polycephalum Cell (PPC) slime mould as a living bio-electrolyte. An over-oxidation process induces a conductivity switch in the polymer, due to the ionic flux taking place at the PPC/polymer interface. This behaviour endows a current-depending memory effect to the device

A bio-inspired memory device based on interfacing Physarum polycephalum with an organic semiconductor

The development of devices able to detect and record ion fluxes is a crucial point in order to understand the mechanisms that regulate communication and life of organisms. Here, we take advantage of the combined electronic and ionic conduction properties of a conducting polymer to develop a hybrid organic/living device with a three-terminal configuration, using the Physarum polycephalum Cell (PPC) slime mould as a living bio-electrolyte. An over-oxidation process induces a conductivity switch in the polymer, due to the ionic flux taking place at the PPC/polymer interface. This behaviour endows a current-depending memory effect to the device

Silk Fibroin Materials: Biomedical Applications and Perspectives

The golden rule in tissue engineering is the creation of a synthetic device that simulates the native tissue, thus leading to the proper restoration of its anatomical and functional integrity, avoiding the limitations related to approaches based on autografts and allografts. The emergence of synthetic biocompatible materials has led to the production of innovative scaffolds that, if combined with cells and/or bioactive molecules, can improve tissue regeneration. In the last decade, silk fibroin (SF) has gained attention as a promising biomaterial in regenerative medicine due to its enhanced bio/cytocompatibility, chemical stability, and mechanical properties. Moreover, the possibility to produce advanced medical tools such as films, fibers, hydrogels, 3D porous scaffolds, non-woven scaffolds, particles or composite materials from a raw aqueous solution emphasizes the versatility of SF. Such devices are capable of meeting the most diverse tissue needs; hence, they represent an innovative clinical solution for the treatment of bone/cartilage, the cardiovascular system, neural, skin, and pancreatic tissue regeneration, as well as for many other biomedical applications. The present narrative review encompasses topics such as (i) the most interesting features of SF-based biomaterials, bare SF’s biological nature and structural features, and comprehending the related chemo-physical properties and techniques used to produce the desired formulations of SF; (ii) the different applications of SF-based biomaterials and their related composite structures, discussing their biocompatibility and effectiveness in the medical field. Particularly, applications in regenerative medicine are also analyzed herein to highlight the different therapeutic strategies applied to various body sectors

Nicolaes Tulp: The Overshadowed Subject in The Anatomy Lesson of Dr. Nicolaes Tulp

In and out of prison most of his life, Aris Kindt [12] was known as a petty thief prone to violence. Such a misery was Kindt that he was even banned from his hometown of Leiden in South Holland. In the winter of 1632, Kindt was back in a Holland prison for assault and robbery, having been apprehended while stealing a man’s cloak [10]. Worse yet for the jailed thief, the Amsterdam Guild of Surgeons’ annual ‘‘anatomy lesson’’ was fast approaching, and the Guild needed a body