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A series of 73 ligands and 73 of their Cu+2 and Cu+1 copper complexes with different geometries, oxidation states of the metal, and redox activities were synthesized and characterized. The aim of the study was to establish the structure-activity relationship within a series of analogues with different substituents at the N(3) position, which govern the redox potentials of the Cu+2/Cu+1 redox couples, ROS generation ability, and intracellular accumulation. Possible cytotoxicity mechanisms, such as DNA damage, DNA intercalation, telomerase inhibition, and apoptosis induction, have been investigated. ROS formation in MCF-7 cells and three-dimensional (3D) spheroids was proven using the Pt-nanoelectrode. Drug accumulation and ROS formation at 40-60 μm spheroid depths were found to be the key factors for the drug efficacy in the 3D tumor model, governed by the Cu+2/Cu+1 redox potential. A nontoxic in vivo single-dose evaluation for two binuclear mixed-valence Cu+1/Cu+2 redox-active coordination compounds, 72k and 61k, was conducted.

We first report on constant potential (dc) amperometric flow-injection analysis (FIA) transduced by electroactive (conductive) polymers. Amperometric response is caused by the polymer recharging in order to maintain the electrode potential at a constant level when (i) ions are crossing the film|solution interface and polarizing electrode|film interface or (ii) ions or neutral molecules are specifically interacting with the polymer recharging it. The response under constant solution flow is a current peak and in flow-injection mode is a couple of current peaks directed opposite of the first sharp, analytically valuable peak. In both constant flow and flow-injection regimes, the peak current is dependent on analyte concentrations; obviously, the FIA mode provides more advantageous analytical characteristics. Constant potential amperometric flow-injection analysis is shown for boronate- and sulfate-functionalized polyanilines as well as for Prussian Blue, a member of the inorganic polymer family. As a proof of concept, the successful dc amperometric detection of lactate in human sweat with boronate-functionalized polyaniline has been shown. The proposed approach would revolutionize the field of conductive/electroactive polymer-supported ion sensing with the introduction of reliable and robust amperometry as a valuable alternative to existing potentiometry.

The review is dedicated to polymers of 2- and 3-aminophenylboronic acid. In contrast to the majority of other conducto- and impedimetric sensors, the ones developed by the authors can discriminate between specific and unspecific processes: conductivity as an analytical signal of the sensor is increasing upon specific binding being opposite to the result of an unspecific process. The increase of conductivity as a result of a specific process is demonstrated for the first time by our group, and the effect was confirmed by physicochemical investigations. The developed sensors are applicable to aerosol analysis as well as to aqueous media. Human whole sweat analysis performed by the sensors succeeded to determine the concentration of lactate (which is recognized as a hypoxia marker and the second important metabolite after in clinical diagnostics) in the range of 10−40 mM. The developed sensors are also applicable to reagentless mold detection in bioaerosols in the concentrations in the range 200−800 CFU/m3 that includes Russian hygienic standard for locality (500 CFU/m3).

The majority of reagentless affinity sensors suffer from poor selectivity because specific binding and non-specific interactions generate responses in the same direction, commonly causing resistance increase. We report on the advanced transducer, synthesized in course of molecular imprinting, which generates conductivity increase as a result of specific binding. Electropolymerization of 3-aminophenylboronic acid (3-APBA) known to yield conductive polyaniline only in the presence of F−, has been carried substituted the latter for hydroxy acids. The achieved synthesis of conductive polymer in course of fluoride-free 3-APBA electropolymerization indicates successful imprinting of hydroxy acids. Imprinting poly(3-APBA) provides as 10–15 times increased, as even decreased binding constants towards target analytes as compared to the non-imprinted polymer. This allows one to achieve the desired selectivity among polyols. Tuning binding properties of boronate functionalized polyaniline we’ve demonstrated the enzyme-free selective detection of saccharides and hydroxy acids via conductivity increase of the conductive polymer.

Electropolymerization of aminophenylboronic acids proceeds by the mechanism typical of conducting polyaniline, if the substituent in the ring is the electron donor and its position favors the electrophilic substitution into the para position with respect to the amino group in the ring. For the same reason, the polymerization of meta-aminophenylboronic acid requires the presence of fluoride ions to transform the weak electron acceptor, boronic acid group into the electron-donating trifluoroborate anion. It is shown that electropolymerization of ortho-aminophenylboronic acid can be carried out in strongly acidic media in the absence of fluoride ions, in analogy to unsubstituted polyaniline. The conductivity of the resulting polyanilineboronic acids synthesized under optimal conditions increases upon their binding with sugars and oxyacids, which allows detecting the specific interactions only, while the nonspecific interactions lower down the polymer conductivity.

In this work we propose a flow injection amperometry at constant potential as a perspective alternative to classical potentiometry for solid contact ion-selective electrodes (SC-ISEs). The amperometric readout mode eliminates the problem of background drift and potential instability – common limitations of potentiometry for SC-ISEs. The selectivity in flowinjection and constant flow amperometric modes is similar to the potentiometric one. Moreover, flow injection amperometry in comparison to potentiometry for ion-selective electrodes provides a shorter response time, within 15–30 s, by two orders of magnitude decreased detection limit and 5-6 fold increased signal-to-noise ratio. The proposed approach is an attractive readout mode that opens new horizons for the improvement of performance characteristics of solid contact ISEs.

The reduction of activated 5-(indol-3-yl)pyrrolidin-2-ones leading to a mixture of the respective indolyl pyrrolidines and their borane complexes, as well as several other transformations indicate that the electrophilicity of carbonyl group in 5-indolylpyrrolidin-2-ones is significantly decreased.

For noninvasive diagnostics of hypoxia, we propose the nonenzymatic sensor based on screen-printed structures with the working surface modified in course of electropolymerization of 3-aminophenylboronic acid (3-APBA) with imprinting of lactate. Impedimetric sensor allows lactate detection in the range from 3 mM to 100 mM with the detection limit of 1.5 mM; response time is 2–3 min. Sensor sensitivity remains unchanged within 6 months of storage unpacked in dry state at a room temperature, which is unachievable for enzyme based devices. Analysis of human sweat with poly(3-APBA) based sensor is possible due to (i) much higher lactate content compared to other polyols and (ii) high sensor selectivity (Klactateglucose 0.9). The attractive performance characteristics of poly(3-APBA) based ...