Joanna Cabaj

Practical synthesis of bis-substituted tetrazines with two pendant 2-pyrrolyl or 2-thienyl groups, precursors of new conjugated polymers

Abstract Novel linear oligoheterocycles based on substituted tetrazines are described. The desired compounds have been accomplished by a variation of the original Pinner [Ann. Chem., 297 (1897) 221] synthesis in which the aromatic nitrile reacted with hydrazine in an aqueous solution to give bis(pyrrolyl)tetrazines or bis(phenyl)tetrazines. The bis(phenyl)tetrazines reacted with 3,4-ethylenedioxy-2-(trimethyltin)thiophene or 2-(trimethyltin)thiophene in the presence of Pd(PPh3)2Cl2 or Pd(PPh3)4 as catalyst to give the desired compounds. Quantum-chemical calculations were performed to assess the usefulness of the synthesized compounds for electropolymerization. Studies have indicated qualitative difference between bis-pyrrole tetrazine and bis-phenyl tetrazines regarding the electronic density rearrangement due to the loss of an electron.

Structure and Sensor Properties of Thin Ordered Solid Films

Miniaturized gas sensors and biosensors based on nanostructured sensing elements have attracted considerable interest because these nanostructured materials can be used to significantly improve sensor sensitivity and the response time. We report here on a generic, reversible sensing platform based on hybrid nanofilms. Thin ordered Langmuir-Blodgett (LB) films built of fluorene derivatives were used as effective gas sensors for both oxidative and reductive analytes. A novel immobilization method based on thin LB films as a matrix has been developed for construction of sensing protein layers. Biomolecules can often be incorporated into and immobilized on Langmuir-Blodgett films using adsorption methods or by covalent immobilization of proteins. The sensor sensitisation was achieved by an amphiphilic N-alkyl-bis(thiophene)arylenes admixed into the film. The interlaced derivative was expected to facilitate the electron transfer, thereby enhancing the sensor sensitivity. The results suggest that this may be very promising approach for exploring the interactions between proteins and high throughput detection of phenol derivatives in wastewater.

Electrochemical Nanosized Biosensors: Perspectives and Future of Biocatalysts

Electrochemical biological sensor device unite the sensitivity of classic instrumental techniques with the inseparable selectivity of the biological agent. The bio-element of the sensing device identifies the analyte following in a biocatalytic way and definitely generates an electrical response recorded by a transducing element. The signal is proportional to concentration of the analyzed substance. Certain of developed modern biosensors are commercial available and are regularly applied in clinical, environmental, or industrial arrangements. The enzymatic electrode is often the principal element of electrochemical biosensors. The choice of suitable composition of agents, in example: biocatalyst, mediators, semiconducting elements, supports, for design of enzymatic sensors directs an electrode activity according to electron transport rate, its stability, and vitality. Presented article underlined also the variety of technologies for creation of sensors basing on carbon nanotubes and their application in detecting of a numerous of biological molecules.

Comparative Study of Alternating Low-band-Gap Benzothiadiazole Co-oligomers

The benzothiadiazole – arylene alternating conjugated oligomers have been designed and synthesized via Suzuki coupling reaction. The structures and properties of the conjugated oligomers were characterized by 1HNMR, 13CNMR, UV–vis absorption spectroscopy, photoluminescence (PL) spectroscopy. The luminescent measurements demonstrate that polybenzothiadiazoles are good chromophores able to form thin films by Langmuir-Blodgett (LB) technique, making them suitable for further applications. Also the electrical properties of obtained films confirm the good potential of these novel aryl-based π-conjugated polymers for the development of various electrical and electrochemical solid-state devices.

Electrochemical and Optical Biosensors in Medical Applications

Analysis of many biochemical processes is of great significance for clinical, biological, food, environmental as well as bioterror applications. But, exchanging of the biochemical information to kind of electronic signal is a defiance due to connecting an electronic tool directly to a biological surrounding. Electrochemical detection instrument due to its advantageous to analyze the subject of a biological sample has a great potential in conversion of a biochemical occurrence to an electronic signal. In this chapter we presented the advancements made in the field of electrochemical biosensors targeted at medical field as well as optical elements used in modern biosensors. This material encompasses the technology, performance and commerci‐ alization of this brood of sensors. We have focused on the future development perspectives of this class of sensors, based on the experience gathered by different groups researching this field.

Conducting Polymers in Sensor Design

Conducting polymers (CPs) as well as conducting polymer nanoparticles seem to be very applicable for the development of various analyte-recognizing elements of sensors and biosensors. This chapter reviews mainly fabrication methods as well as application of conducting polymers in sensors. Conducting polymers (CPs) have been applied in the design of catalytic and affinity biosensors as immobilization matrixes, signal transduction systems, and even analyte-recognizing components. Various types of conducting and electrochemically generated polymer-based electrochemical sensors were developed including amperometric catalytic and potentiodynamic affinity sensors. A very specific interaction of analyte with immobilized biological element results in the formation of reaction products.

Optical biosensor with poly[N-nonyl-3,6-bis(ethylenedioxythiophene)carbazole] matrix for monitoring of phenol derivatives

The aim of the research was to develop an enzymatic, optical biosensor which provides quick and convenient determination of phenolic compounds in aqueous solutions. The biosensing strategy concerns design, fabrication and testing of a miniature ceramic-based biosensor which is destined for in-situ substrate monitoring. The base of the measuring system was fabricated using low temperature co-fired ceramics (LTCC) technology. The biocatalyst – laccase– was immobilized on the thin film of poly[N-nonyl-3,6-bis(ethylenedioxythiophene)carbazole] which provided good binding of the enzyme to the substrate and positively affected on the catalytic activity of the protein. In order to evaluate properties of the designed biosensor, its response for various concentrations of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diamonnium sal (ABTS) was measured. The optical biosensor produced by presented method could find applications in many fields, i.e. for detection of phenolic compounds in food products and beverages, in industry for control of technological processes or for environmental monitoring

Layered Biosensor Construction

In enzymatic devices, efforts have been concentrated on the control over enzyme activity, which is highly dependent on the interface between the electrode and the enzyme. Such con‐ trol has led to immobilization techniques suitable for anchoring the enzyme close to elec‐ trode with preservation of its biological activity. In these type of devices, where retaining of the enzyme activity at the electrode/enzyme interface is the key to design efficient electrode, charge transfer between enzyme and electrode should be fast and reversible. Moreover, the charge transfer may also be optimized with some mediating particles (i.e. conducting units) being used in conjunction with the biological molecules at the electrode surface. To the use of conducting polymers for the fabrication of various biosensors have been dedicated exten‐ sively study due to their redox, optical, mechanical and electrical properties, as well as to their unique capability to act both, as transducers, and an immobilization matrices for en‐ zyme retention [1].

A Fluorescent Biosensors for Detection Vital Body Fluids’ Agents

The clinical applications of sensing tools (i.e., biosensors) for the monitoring of physiologically important analytes are very common. Nowadays, the biosensors are being increasingly used to detect physiologically important analytes in real biological samples (i.e., blood, plasma, urine, and saliva). This review focuses on biosensors that can be applied to continuous, time-resolved measurements with fluorescence. The material presents the fluorescent biosensors for the detection of neurotransmitters, hormones, and other human metabolites as glucose, lactate or uric acid. The construction of microfluidic devices based on fluorescence uses a variety of materials, fluorescent dyes, types of detectors, excitation sources, optical filters, and geometrical systems. Due to their small size, these devices can perform a full analysis. Microfluidics-based technologies have shown promising applications in several of the main laboratory techniques, including blood chemistries, immunoassays, nucleic-acid amplification tests. Of the all technologies that are used to manufacture microfluidic systems, the LTCC technique seems to be an interesting alternative. It allows easy integration of electronic and microfluidic components on a single ceramic substrate. Moreover, the LTCC material is biologically and chemically inert, and is resistant to high temperature and pressure. The combination of all these features makes the LTCC technology particularly useful for implementation of fluorescence-based detection in the ceramic microfluidic systems.

Conjugated arylenes: their convenient synthesis, luminescence characteristics, and applications

Conjugated arylenes have significant perspectives as active materials useful in electronics, i.e. as semiconductors or solar cells. Organic semiconductors maintain the related processability, as with polymers, while retaining optoelectronic characteristics, i.e., high absorption coefficients of photons in the visible-region. This review summarizes recent developments in semiconducting polymers for electronic tools. This includes information on substitution and localization, branching, and its impact on functional materials.