Selective PQQPFPQQ Gluten Epitope Chemical Sensor with a Molecularly Imprinted Polymer Recognition Unit and an Extended-Gate Field-Effect Transistor Transduction Unit.

A molecularly imprinted polymer (MIP) recognition system was devised for selective determination of an immunogenic gluten octamer epitope, PQQPFPQQ. For that, a thin MIP film was devised, guided by density functional theory calculations, and then synthesized to become the chemosensor recognition unit. Bis(bithiophene)-based cross-linking and functional monomers were used for this synthesis. An extended-gate field-effect transistor (EG-FET) was used as the transduction unit. The EG-FET gate surface was coated with the PQQPFPQQ-templated MIP film, by electropolymerization, to result in a complete chemosensor. X-ray photoelectron spectroscopy analysis confirmed the presence of the PQQPFPQQ epitope, and its removal from the MIP film. The chemosensor selectively discriminated between the octamer analyte and another peptide of the same number of amino acids but with two of them mismatched (PQQQFPPQ). The chemosensor was validated with respect to both the PQQPFPQQ analyte and a real gluten extract from semolina flour. It was capable to determine PQQPFPQQ in the concentration range of 0.5-45 ppm with the limit of detection (LOD) = 0.11 ppm. Moreover, it was capable of determining gluten in real samples in the concentration range of 4-25 ppm with LOD = 4 ppm, which is a value sufficient for discriminating between gluten-free and non-gluten-free food products. The gluten content in semolina flour determined with the chemosensor well correlated with that determined with a commercial ELISA gluten kit. The Langmuir, Freundlich, and Langmuir-Freundlich isotherms were fitted to the epitope sorption data. The sorption parameters determined from these isotherms indicated that the imprinted cavities were quite homogeneous and that the epitope analyte was chemisorbed in them

Potential-driven Chirality manifestations and impressive enantioselectivity by inherently chiral electroactive films

Molecular materials coupling electroactivity with enantiorecognition capability are an attractive objective in materials research. The usual strategy, hinging on attaching chiral pendants to an electroactive polyconjugated backbone, generally results in modest chirality manifestations. We have thus designed electroactive chiral polyheterocycles, where chirality is not external to the electroactive backbone, but inherent to it, resulting from a tailored torsion produced by the presence of atropisomeric, conjugatively active biheteroaromatic scaffolds. The coincidence of the stereogenic element with the whole electroactive backbone affords by electrooligomerization enantiopure electroactive films of impressive chiroptical activity, which can be finely and reversibly tuned by the electric potential, since injection of positive charges results in decrease of the atropisomeric scaffold angle to favour delocalization, as revealed by CD spectroelectrochemistry, suggesting us the image of a "breathing chirality". To test the enantiorecognition ability of the new inherently chiral conducting films we have developed an efficient protocol in ionic liquid affording preparation of very reproducible electrode surfaces by electrooxidation of the enantiopure monomers on screen printed electrode supports. The resulting specular R and S electrodes have been tested with (R)-(+)- and S-(-)-N,N-dimethyl-1-ferrocenylethylamine specular probes. The response is highly and reproducibly enantioselective (with \uf07e100 mV separation between R and S probes with single enantiomers and even more with the racemate), specular for R vs S surfaces with respect to S and R probes, and reversible in repeated alternating sequences of S and R probe sensing on a single electrode.[1] With the contribution of Fondazione Cariplo, grant no. 2011-0417. [1] F. Sannicol\uf2, S. Arnaboldi, T. Benincori, V. Bonometti, R. Cirilli, L. Dunsch, W. Kutner, G. Longhi, P.R. Mussini, M. Panigati, M. Pierini, S. Rizzo, Angew. Chemie 2014, 53, 2623-2627

The thiophene-based inherently chiral monomer family grows: molecular design and electrochemical properties

Our group has recently presented electroactive thiophenebased polyconjugated films of unprecedented chirality manifestations and enantiorecognition ability,[1] based on the "inherent chirality" concept, implying that the whole electroactive backbone coincides with the stereogenic element, consisting in a tailored torsion induced by an atropisomeric bi-benzothiophene scaffold. Such films are easily prepared as enantiopure electrode surfaces by electrooligomerization of (R) and (S) enantiopure monomer 1. Now, concurrently with the exploration of the applicative potentialities of this "parent" molecular material, both racemic and enantiopure, we are widening the class of available monomers designed according the same strategy, but with different atropisomeric heteroaromatic scaffolds, different side chains, and/or with the addition of a further stereogenic element. The electrochemical properties of a selection of the new inherently chiral monomers now available will be presented in detail and rationalized as a function of their molecular structure, also in the perspective of potential applications. With the contribution of Fondazione Cariplo, grant no. 2011-0417. [1] F. Sannicol\uf2, S. Arnaboldi, T. Benincori, V. Bonometti, R. Cirilli, L. Dunsch, W. Kutner, G. Longhi, P.R. Mussini, M. Panigati, M. Pierini, S. Rizzo, Angew. Chemie 2014, 53, 2623-2627

Model of a passenger lift with control system programmable logically

W artykule przedstawiono model zlecenia produkcyjnego stanowiącego podstawę integracji systemów Proedims i KbRS w zakresie harmonogramowania produkcji dyskretnej. Model zlecenia umożliwia planowanie produkcji złożonych wyrobów posiadających wielopoziomowe struktury procesów technologicznych zarówno w systemach o konfiguracji przepływowej jak i gniazdowej z maszynami równoległymi. W przyjętym modelu systemu produkcyjnego oraz zlecenia wyszczególniono etapy decyzyjne wymagane przy budowie harmonogramu. Opisano sposób współpracy przy wymianie danych pomiędzy omawianymi systemami.The paper presents the model of a production order, which is the basis of Proedims and KbRS software systems integration, used in scheduling of discrete manufacturing systems. The model enables planning of production orders for complex products with multi-level structure of the processes in flow shop and job shop production system configuration with parallel machines. Required decision-making stages for schedule construction of the given model of the production system and production order were presented. Principles of cooperation in exchanging data between Proedims and KbRS were discussed

Determination of Asymmetric Dimethylarginine by Using Organic Semiconductor-Based Molecularly Imprinted Polymer Film

This article describes simple, fast and cheap procedure of Asymmetric dimethylarginine (ADMA) determination using a new chemosensor with an artificial recognition unit

Inherently chiral electrodes, the effective tool for chiral voltammetry

An attractive issue in electroanalysis is the development of artificial \u201cintelligent\u201d electrodes, capable to discriminate as well as quantify the enantiomers of chiral analytes, particularly of biological and pharmaceutical interest. For this aim, many approaches have been proposed in the last years. However, even the most successful attempts at chiral discrimination almost invariably resulted in the detection of a difference in current intensity between the signals of the two antipodes of a chiral probe, without differentiation of their redox potentials; the chiral enantioselective layer is in many instances not of general use, but tailored for a given probe; many preparation procedures are very sophisticated and/or the active films fragile. A winning solution comes from a new class, which we have recently presented and patented1, of \u201cinherently chiral\u201d molecular semiconductors, in which the coincidence of the element granting both electroactivity and chirality with the entire molecular backbone results in extraordinary chiroptical manifestations, which can be finely and reversibly tuned by the electric potential. Above all, enantiopure electrode surfaces can be easily prepared e.g. by electrooligomerization; they mostly consist of cyclic oligomers, highly electroactive and chiral, idealizing conducting polymers without ends and of high complexing ability. Such electrode surfaces are able to discriminate enantiomers of chiral molecules in terms of large peak potential differences (80-200 mV and more), with linear dynamic ranges for peak currents, thus affording enantiomeric ratio evaluation. The same spectacular enantioselectivity is obtained on chemically different surfaces of the same structural concept, which demonstrates the general validity of our proposed strategy. A simple reconditioning protocol affords performing more experiments on a single electrode.The new electrodes have been tested with very good results on chiral probes even very different and of applicative interest2 (Dopa, methyl-Dopa, ofloxacin, norepinephrine, tyrosine, naproxen, catechines, ascorbic acid...), on different supports, including commercial screen printed ones, and in different media (aqueous and nonaqueous ones, as well as small ionic liquid drops on SPEs). As an interesting alternative strategy to effective enantiodiscrimination, preliminary results about inherently chiral ionic liquid media applied on achiral electrodes will be also presented. This work was supported by Fondazione Cariplo (Grants no. 2011-0417 and 2011-1851) References (1) Sannicol\uf2, F. et al., Angew. Chem. Int. Ed. 2014, 53, 2623; Sannicol\uf2, F. et al., Chem. Eur. J. 2014, 20, 15296; Sannicol\uf2 F. et al., Patent appl. MI2014A000948 (2014). (2) Arnaboldi S., Benincori T., Cirilli R., Kutner W., Magni M., Mussini P.R., Noworyta K., Sannicol\uf2 F., Chemical Science, 2015, 6, 2041

Inherently chiral electrodes, tool for chiral voltammetry

Recently we have devised an innovative approach to chiral conducting thiophene oligomers, based on the concept of "inherent chirality": the stereogenic element is a tailored torsion intrinsic to the whole electroactive backbone, arising from insertion of atropisomeric biheteroaromatic scaffolds, rather than stereocentres localized in attached pendants. [1] Thus the stereogenic element responsible for chirality is also responsible for electroactivity, since it constitutes the conjugated backbone. An example are the films obtained by electrooligomerization of the 2,2-bis[2-(5,2-bithienyl)]3,3-bithianaphthene (BT2-T4) parent monomer, mostly yielding cyclic oligomers (BT2-T4)n, predominantly dimers and trimers. They constitute rings of fully conjugated thiophene units, idealizing conducting polymers without ends. [2] This outstanding feature combination endows the electroactive films with exceptional chirality manifestations, like e.g. circularly polarized luminescence, and, above all, the capability, as electrode materials, to pronouncedly separate (in many cases by 100-200 mV and even more) voltammetry peaks of enantiomers of chiral probes of quite different chemical and electrochemical properties, and of quite different structural features, including pharmaceutically and/or biological relevant ones, like DOPA, ofloxacin and many others. Concurrently, peak currents display a linear dynamic range, to be exploited e.g. to quantify enantiomeric excesses on disposable SPEs. [3] Similar enantioselectivity is also shown by oligomer films obtained by electrooligomerization of other inherently chiral monomers, having different chemical and structural features. This proves the general validity of this approach to obtain highly enantioselective enantiopure surfaces, attractive tools for chiral voltammetry. [1] Angew.Chem. 2014, 53, 2623 [2] Chem.Eur. J. 2014, 20, 5298 [3] Chem.Sci. 2015, 6,1706 Keywords: chiral electrodes, chiral voltammetry, inherently chiral oligomer films, enantioselectivity in electroanalysis Acknowledgements: The Authors gratefully acknowledge the support provided by FONDAZIONE CARIPLO (grant no. 2011-0417

Molecularly imprinted polymer based extended-gate field-effect transistor chemosensors for phenylalanine enantioselective sensing

This article discusses the design and synthesis of molecularly imprinted polymers, guided by DFT calculations

Inherent Chirality in Electrochemically Active Molecular Materials: Strategy and Panoramic Overview

The introduction of chirality in organic conjugated polymers has been considered for a wide variety of purposes and applications, i.e., in optics and sensoristics. In this frame, the possibility of coupling electroactivity and enantiorecognition capability is an ambitious objective of the modern chemical research. As commonly reported in literature, chirality in organic semiconductors has mostly been introduced by attaching chiral pendants to the electroactive conjugated backbone through suitable linkers; however, this approach usually leads to poor chirality manifestations. In our strategy, instead, chirality results from a tailored torsion internally produced along the conjugated backbone, and it is not due to the presence of any external stereogenic element. The general structure is here illustrated: the stereogenic core responsible for chirality interconnects two bithiophene pendants and the connectivity of the bi-heteroaromatic scaffold maintains the conjugation between the bithiophene termini. The symmetry of the monomer is C2, and the thiophene a\u2013positions involved in the electrochemical polymerization are homotopic, so full regioregularity of the polymers is guaranteed. Several members of this innovative class of inherently chiral molecules have been designed, synthesized, characterized and submitted to electrochemical polymerization. Chirality is maintained even in the solid state, as proved by CD experiments carried out on polymer films. CD investigations performed under different polarization states revealed a tendency of the structure to flatten when the polymer is p-doped. This phenomenon is reversible and suggested the image of a breathing system. The electrochemical properties and the polymerization ability of a complete series of inherently chiral thiophene- and pyrrole-based monomers, both as racemates and as pure enantiomers, will be described and discussed