polaron pair vs. bipolaron

The molecular structure of a cyclic oligothiophene, C10T, has been determined by single-crystal X-ray structure analysis. The exclusive syn-conformation of all thiophene units as confirmed in the solid state and the ring strain in this macrocycle result in its unusual and optoelectronic properties. This does not only apply to neutral C10T but also to its oxidized states, as demonstrated by absorption and ESR spectroscopy, supporting the formation of a polaron-pair structure upon oxidation of C10T to C10T2(·+) as has been discussed for linear oligothiophenes. To the best of our knowledge, C10T2(·+) represents an unambiguous example comprising a two-polaron structure (polaron- pair) of a thiophene-based conjugated macrocycle

Label-free electrochemical DNA sensor using "click"-functionalized PEDOT electrodes

Here we describe a label-free electrochemical DNA sensor based on poly(3,4-ethylenedioxythiophene)-modified (PEDOT-modified) electrodes. An acetylene-terminated DNA probe, complementary to a specific "Hepatitis C" virus sequence, was immobilized onto azido-derivatized conducting PEDOT electrodes using "click" chemistry. DNA hybridization was then detected by differential pulse voltammetry, evaluating the changes in the electrochemical properties of the polymer produced by the recognition event. A limit of detection of 0.13. nM was achieved using this highly selective PEDOT-based genosensor, without the need for labeling techniques or microelectrode fabrication processes. These results are promising for the development of label-free and reagentless DNA hybridization sensors based on conducting polymeric substrates. Biosensors can be easily prepared using any DNA sequence containing an alkyne moiety. The data presented here reveal the potential of this DNA sensor for diagnostic applications in the screening of diseases, such as "Hepatitis C", and genetic mutations.The authors would like to thank the ICTS “NANBIOSIS”, more specifically to the Nanotechnology Platform, unit of the Networking Biomedical Research Center in Bioengineering, Biomaterials & Nanomedicine (CIBER-BBN) at the Institute for Bioengineering of Catalonia (IBEC) and also to the Serveis Cientificotècnics (SCT) of the Universitat de Barcelona (UB) for their assistance in XPS and ToF-SIMS analyses. This work was supported by Networking Biomedical Research Center in Bioengineering, Biomaterials & Nanomedicine (CIBER-BBN), Spain. The Nanobioengineering group at IBEC receives support from the Spanish Ministry of Science and Education and the Commission for Universities and Research of the Department of Innovation, Universities and Enterprise of the Generalitat de Catalunya (No. 2009 SGR 505). In addition, the research received support from the Spanish Ministry of Science and Education, CICYT (CTQ2009-07758), and the Fundación Botín, Santander, Spain.Peer reviewe

Impact of Record-Linkage Errors in Covid-19 Vaccine-Safety Analyses using German Health-Care Data: A Simulation Study

With unprecedented speed, 192,248,678 doses of Covid-19 vaccines were administered in Germany by July 11, 2023 to combat the pandemic. Limitations of clinical trials imply that the safety profile of these vaccines is not fully known before marketing. However, routine health-care data can help address these issues. Despite the high proportion of insured people, the analysis of vaccination-related data is challenging in Germany. Generally, the Covid-19 vaccination status and other health-care data are stored in separate databases, without persistent and database-independent person identifiers. Error-prone record-linkage techniques must be used to merge these databases. Our aim was to quantify the impact of record-linkage errors on the power and bias of different analysis methods designed to assess Covid-19 vaccine safety when using German health-care data with a Monte-Carlo simulation study. We used a discrete-time simulation and empirical data to generate realistic data with varying amounts of record-linkage errors. Afterwards, we analysed this data using a Cox model and the self-controlled case series (SCCS) method. Realistic proportions of random linkage errors only had little effect on the power of either method. The SCCS method produced unbiased results even with a high percentage of linkage errors, while the Cox model underestimated the true effect

"clickable" Organic Electrochemical Transistors

Interfacing the surface of an organic semiconductor with biological elements is a central quest when it comes to the development of efficient organic bioelectronic devices. Here, we present the first example of "clickable"organic electrochemical transistors (OECTs). The synthesis and characterization of an azide-derivatized EDOT monomer (azidomethyl-EDOT, EDOT-N3) are reported, as well as its deposition on Au-interdigitated electrodes through electropolymerization to yield PEDOT-N3-OECTs. The electropolymerization protocol allows for a straightforward and reliable tuning of the characteristics of the OECTs, yielding transistors with lower threshold voltages than PEDOT-based state-of-the-art devices and maximum transconductance voltage values close to 0 V, a key feature for the development of efficient organic bioelectronic devices. Subsequently, the azide moieties are employed to click alkyne-bearing molecules such as redox probes and biorecognition elements. The clicking of an alkyne-modified PEG4-biotin allows for the use of the avidin-biotin interactions to efficiently generate bioconstructs with proteins and enzymes. In addition, a dibenzocyclooctyne-modified thrombin-specific HD22 aptamer is clicked on the PEDOT-N3-OECTs, showing the application of the devices toward the development of organic transistors-based biosensors. Finally, the clicked OECTs preserve their electronic features after the different clicking procedures, demonstrating the stability and robustness of the fabricated transistors.Fil: Fenoy, Gonzalo Eduardo. Austrian Institute Of Technology; Austria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Hasler, Roger. AIT Austrian Institute of Technology GmbH; AustriaFil: Quartinello, Felice. Institute of Environmental Biotechnology; AustriaFil: Marmisollé, Waldemar Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Lorenz, Christoph. Universitat Ulm; AlemaniaFil: Azzaroni, Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Bäuerle, Peter. Universitat Ulm; AlemaniaFil: Knoll, Wolfgang. Danube Private University; Austria. Austrian Institute Of Technology; Austri

Interface Engineering of “Clickable” Organic Electrochemical Transistors toward Biosensing Devices

“Clickable” organic electrochemical transistors (OECTs) allow the reliable and straightforward functionalization of electronic devices through the well-known click chemistry toolbox. In this work, we study various aspects of the click chemistry-based interface engineering of “clickable” OECTs. First, different channel architectures are investigated, showing that PEDOT-N3 films can properly work as a channel of the transistors. Furthermore, the Cu(I)-catalyzed click reaction of ethynyl-ferrocene is studied under different reaction conditions, endowing the spatial control of the functionalization. The strain-promoted and catalyst-free cycloaddition of a dibenzocyclooctyne-derivatized poly-l-lysine (PLL-DBCO) is also performed on the OECTs and validated by a fiber optic (FO)-SPR setup. The further immobilization of an azido-modified HD22 aptamer yields OECT-based biosensors that are employed for the recognition of thrombin. Finally, their performance is evaluated against previously reported architectures, showing higher density of the immobilized HD22 aptamer, and originating similar KD values and higher maximum signal change upon analyte recognition.</p

Dual fluorescence of 9-anthryl-substituted oligothiophenes in nonpolar environment

9-Anthryl-oligothiophenes (9A-Tn, n = 1–4) have been studied in n-hexane solution between helium and room temperature using absorption, fluorescence emission and excitation spectra and time resolved fluorescence measurements. These compounds are reference systems for studies on intramolecular energy and charge transfer in donor/acceptor-substituted conjugated chain molecules. The absorption spectra show contribution of both substituents anthracene and oligothiophene, but no additional bands due to mixed electronic states. Dual fluorescence is observed at Tgreater-or-equal, slanted 120 K for the compounds 9A-Tn (n = 1–3), but not for 9A-T4. Time resolved spectroscopy reveals a dynamical coupling between the two emission components whose relative quantum yields are strongly temperature dependent. The occurrence of the dual fluorescence is explained by an intramolecular torsional motion between the two molecular subunits

Cyclopentadithiophene-based Co-oligomers for Solution-processed Organic Solar Cells

A new family of low band-gap co-oligomers based on 4H-cyclopenta[2,1-b:3,4-b']dithiophene (CPDT) and thieno[3,2-b]thiophene (TT) units as central electron-donor cores has been synthesized and characterized for use as electron-donor materials in solution-processed bulk-heterojunction organic solar cells. An in-depth study into the role played by the hexyl chains 5 linked to the thienylenevinylene-based π-bridge has been carried out. Power conversion efficiencies (PCE) of up to 4% and external quantum efficiencies as high as 50% have been achieved. Experiments carried out after solvent vapor annealing (SVA) as a post-treatment led to a doubling of the fill factor (FF) and PCE