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Advanced Bioelectronic Platforms for Biomedical Engineering and E-Healthcare
No full textLa ricerca oggetto approfondisce la convergenza tra scienza dei materiali, elettronica e biologia attraverso lo sviluppo di piattaforme bioelettroniche basate su transistor elettrochimici organici (OECT). Adottando un approccio interdisciplinare, l’obiettivo è realizzare dispositivi innovativi che avanzino l’ingegneria biomedica, migliorando l’efficacia e l’accessibilità delle soluzioni di e-healthcare. Tra i vantaggi degli OECT vi sono basse tensioni di funzionamento, stabilità in ambienti acquosi, scalabilità per l'integrazione in sistemi elettronici su larga scala e facilità di fabbricazione. Operando come dispositivi a tre terminali, la conduttività del canale è modulata dal movimento di ioni attraverso il canale, guidato da cambiamenti di tensione all'interfaccia volumetrica tra l'elettrolita e il polimero conduttivo. Imitando i processi di trasporto ionico propri dei sistemi biologici, gli OECT si integrano perfettamente con i tessuti corporei e ambienti fisiologici, rilevando e amplificando i flussi ionici in segnali elettrici misurabili. Il Capitolo 1 fornisce una panoramica sugli OECT, evidenziando come questa tecnologia si allinei con lo sviluppo di piattaforme bioelettroniche per applicazioni biomediche. Il Capitolo 2 introduce un processo fotolitografico scalabile per la produzione di OECT ad alte prestazioni, utilizzando il polimero conduttivo poli(3,4-etilenediossitiophene) drogato con poli(stirene sulfonato) (PEDOT:PSS). Il metodo sfrutta una tecnica basata sulla deposizione di due strati di fotoresist con cross-linking controllato per definire le geometrie del canale e incapsulare gli elettrodi. Inoltre, al fine di ridurre la citotossicità e migliorare le prestazioni dei dispositivi, questo capitolo analizza l’uso di materiali alternativi per il gate polarizzabile, migliorando la sensibilità nella rilevazione degli ioni a basse tensioni di alimentazione. Questi sviluppi delineano una trasformazione nella bioelettronica integrata e nei sistemi neuromorfici. I risultati sono pubblicati nell'articolo "Microfabrication of Organic Electrochemical Transistors for High-Performance Integrated Bioelectronics" su Advanced Materials Technologies. Il Capitolo 3 introduce l’architettura ion-selective floating-gate OECT (ISFG-OECT), per eliminare la complessità e l’ingombro dei dispositivi tradizionali per il rilevamento ionico selettivo. Il nuovo design consente un accoppiamento ionico-elettronico efficiente, permettendo il rilevamento selettivo degli ioni senza l’impiego di serbatoi di liquidi. Questo capitolo evidenzia il potenziale degli ISFG-OECT come soluzione scalabile e affidabile per il monitoraggio degli ioni in settori come la diagnostica medica, l'agricoltura di precisione e il monitoraggio ambientale. I risultati sono stati pubblicati su Advanced Materials Technologies. Nel Capitolo 4, l’obiettivo è sviluppare OECT ad architettura verticale totalmente stampati in 3D (vOECT). Questo capitolo esplora un approccio di stampa 3D additiva che ottimizza la struttura del dispositivo e integra membrane ionoselettive, al fine di realizzare dispositivi miniaturizzati ad alte prestazioni. Viene dimostrato il loro potenziale per l'integrazione in applicazioni biomediche che richiedono alta sensibilità e selettività. Il Capitolo 5 presenta la realizzazione di una piattaforma bioelettronica ad alta efficienza e sensibilità per la quantificazione di vescicole extracellulari (EV). Il sistema integra matrici di OECT funzionalizzati in configurazione 3×4, utilizzando la click-chemistry per rilevare le EV con proteine di membrana, consentendo la quantificazione in tempo reale. Questa configurazione rappresenta una soluzione robusta, ad alta sensibilità e facile da usare per la sanità di precisione, la ricerca sulle EV e l’indagine diagnostica, affrontando le sfide della eterogeneità e la necessità di una quantificazione affidabile dei biomarcatori nelle applicazioni biomedicheThis thesis examines the convergence of materials science, electronics and biology through the development of bioelectronic platforms based on organic electrochemical transistors (OECTs). By fostering interdisciplinary research, it aims to develop innovative devices that advance biomedical engineering and significantly enhance the effectiveness and accessibility of e-healthcare solutions. Among the benefits of OECTs are their low operating voltages, stability in aqueous environments, scalability for integration into large-scale electronic systems and ease of processing and fabrication. Operating as three-terminal devices, OECTs channel conductivity is modulated by driving ions in and out of the channel, which is gated by voltage changes at the volumetric interface between the electrolyte and the conducting polymer film. By mimicking the ion transport processes inherent in biological systems, OECTs can seamlessly integrate with living tissues and physiological environments detecting and amplifying ion fluxes into measurable electrical signals.
Chapter 1 details highlighting their unique properties and capabilities that align with the goals of developing advanced bioelectronic platforms for biomedical applications. Chapter 1 highlights the OECTs properties that support the development of advanced bioelectronic platforms for biomedical applications.
Chapter 2 introduces a scalable photolithographic fabrication process for high-performance OECTs using the prototypical conductive polymer poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS). The method employs a two-layer photoresist approach with controlled cross-linking to pattern the polymeric channel and encapsulate the electrodes. This work explores alternative polarizable gate materials to mitigate cytotoxicity while enhancing device performance, achieving unprecedented ion detection sensitivity at low supply voltages. These advancements open opportunities for next-generation integrated bioelectronics, and neuromorphics. The results are reported in the paper “Microfabrication of Organic Electrochemical Transistors for High-Performance Integrated Bioelectronics” to be submitted to peer-review on Advanced Materials Technologies.
Chapter 3 focuses on advancing ion-selective sensing with the introduction of ion-selective floating-gate OECTs (ISFG-OECTs) architecture. With the aim of overcoming the complexity and bulk of traditional ion-selective sensing devices, the novel architecture paradigm achieves efficient ionic-electronic coupling within a compact design, enabling selective ion detection without liquid reservoirs. Theoretical and practical guidelines for ISFG-OECT implementation are provided. This chapter highlights the ISFG-OECT’s potential as a scalable and reliable solution for ion monitoring in fields such as medical diagnostics, precision agriculture, and environmental sensing. This chapter’s findings are published on Advanced Materials Technologies.
In Chapter 4, the objective is to develop fully 3D-printed vertical OECTs (vOECTs). This chapter explores a direct-write additive 3D printing approach that optimizes device structure and integrates ion-selective membranes to yield high-performance, miniaturized devices. It demonstrates their potential for integration in biomedical applications that require high sensitivity and selectivity.
Chapter 5 outlines the development of a high-throughput bioelectronic platform for extracellular vesicle (EV) quantification. The system integrates channel-functionalized OECT arrays in a 3×4 matrix configuration, using click chemistry to detect EVs with transmembrane proteins, allowing real-time quantification. This configuration represents a robust, high-sensitivity, and user-friendly solution for precision healthcare, EV research, and screening diagnostics, addressing the challenges of heterogeneity and the need for reliable biomarker quantification in biomedical applications
Selective and Real‐Time Ion Monitoring with Integrated Floating‐Gate Organic Electrochemical Transistor Sensing Circuits
No full textIon-selective transistor-based sensors play a pivotal role in quantifying ion concentrations in aqueous media. Existing solutions rely on direct coupling between ion-selective membrane and channel, requiring bulky electrolyte reservoirs or complex technological approaches and material interfaces. This work introduces a transformative paradigm with ion-selective floating-gate organic electrochemical transistors (ISFG-OECTs) and their integration in sensing circuits. ISFG-OECTs feature spatial separation between ion-selective gating and ionic-electronic current modulation. Leveraging volumetric capacitance and solid-state ionic liquid, efficient ionic coupling with the channel is obtained. These distinctive features make them an ideal solution for streamlined materials integration, eliminating the need for liquid reservoirs. Theoretical foundations and design guidelines for efficient ISFG-OECT implementation are elucidated. Experimental results demonstrate the effectiveness of ISFG-OECTs in both transistor-sensors and current-driven circuit configurations, revealing highly selective detection of K+ ions with a limit of detection as low as 11 x 10-6 m, even in the presence of interfering Na+ ions at concentrations two orders of magnitude higher. The proposed approach is simple, reliable, and scalable, offering opportunities for a broad range of fields, such as medical diagnostics, precision agriculture, and environmental monitoring.This work introduces ion-selective integrated circuit sensors with floating-gate organic electrochemical transistors allowing together ionic coupling and spatial separation of ion-selective membrane and channel, with no need of bulky reservoirs and simplifying materials integration. Results demonstrate highly selective K+ ion monitoring with a low 11 x 10-6 m limit of detection, opening opportunities for various application fields, from medical diagnostics to precision agriculture. imag
Microfabrication of Organic Electrochemical Transistors for High‐Performance Integrated Bioelectronics
No full textIn bioelectronics, organic electrochemical transistors (OECTs) are pivotal in bridging electronic devices and biological systems, especially in sensing, neuromorphic interfacing, and biological monitoring. Current OECT fabrication methods face challenges due to conductive polymers incompatibility with photoresist solvents and the complexity of multi-step parylene-C coatings. This work introduces a scalable photolithographic fabrication process for high-performance OECTs using the prototypical conductive polymer poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS). The method employs a two-layer photoresist approach with controlled cross-linking, incorporating (3-glycidyloxypropyl)trimethoxysilane to pattern polymeric channel and encapsulate electrodes. This process yields high-performance OECTs with highly reproducible characteristics, typical ON/OFF current modulation of 5 103, and transconductance normalized to channel thickness > 200 S cm−1. To avoid cytotoxic Ag/AgCl pellets, the impact of scaling polarizable gates is analyzed on device performance, including bare Au, protein-functionalized, and PEDOT:PSS gates. The analysis provides design rules to tailor OECT performance for diverse applications. The effectiveness of the approach is demonstrated by integrating OECTs with polarizable gates in current-driven circuit configuration, allowing ion detection at a supply voltage as low as 0.4 V with a sensitivity of up to 2620 mV dec−1, the highest ever reported. These advancements open opportunities for next-generation integrated bioelectronics and neuromorphic biosensing
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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