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New representatives of 2,4,7‐trisubstituted 9,9‐dialkyl‐9H‐fluorenes were prepared and used for crystallographic investigations as well as initial binding studies towards metal ions and carbohydrates. The binding studies, which included 1H NMR spectroscopic titrations and fluorescence measurements, demonstrated the ability of the tested fluorene‐based compounds to act as complexing agents for ionic and neutral substrates. Depending on the nature of the subunits of the fluorene derivatives, "turn on" or "turn off" fluorescent chemosensors can be developed. Compounds composed of 4,6‐dimethylpyridin‐2‐yl‐aminomethyl moieties have the potential to be used as sensitive "turn‐on" chemosensors for some metal ions. [ABSTRACT FROM AUTHOR]

Abstract New representatives of 2,4,7‐trisubstituted 9,9‐dialkyl‐9H‐fluorenes were prepared and used for crystallographic investigations as well as initial binding studies towards metal ions and carbohydrates. The binding studies, which included 1H NMR spectroscopic titrations and fluorescence measurements, demonstrated the ability of the tested fluorene‐based compounds to act as complexing agents for ionic and neutral substrates. Depending on the nature of the subunits of the fluorene derivatives, “turn on” or “turn off” fluorescent chemosensors can be developed. Compounds composed of 4,6‐dimethylpyridin‐2‐yl‐aminomethyl moieties have the potential to be used as sensitive “turn‐on” chemosensors for some metal ions.

The detection of human serum albumin (HSA) is of significant clinical importance in disease diagnoses. In this work, polymer-based synthetic receptors are designed by incorporating Ag-ZnS microspheres in molecularly imprinted poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MIPs) for the gravimetric detection of HSA. Among different compositions of Ag-ZnS@MIPs, MIPs having methacrylic acid and ethylene glycol dimethacrylate volume ratio of 3:2 exhibit enhanced HSA sensitivity in the concentration range of 5–200 ng/mL. A remarkably low threshold limit of detection (LOD = 0.364 ng/mL) is achieved with quartz crystal microbalance (QCM) based gravimetric sensors. Furthermore, the Ag-ZnS@MIPs/QCM sensors show high selectivity for HSA compared to other proteins, e.g., bovine serum albumin (BSA), glycoprotein, ribonuclease, and lysozyme. Hence, the gravimetric quantification of HSA realizes a highly sensitive, selective, and label-free detection mechanism with a limit of quantification down to 1.1 ng/mL. [ABSTRACT FROM AUTHOR]

Molecularly imprinted polymers (MIPs) have gained growing interest among researchers worldwide, due to their key features that make these materials interesting candidates for implementation as receptors into sensor applications. In fact, MIP-based glucose sensors could overcome the stability issues associated with the enzymes present in commercial glucose devices. Various reports describe the successful development of glucose MIPs and their coupling to a wide variety of transducers for creating sensors that are able to detect glucose in various matrices. In this review, we have summarized and critically evaluated the different production methods of glucose MIPs and the different transducer technologies used in MIP-based glucose sensors, and analyzed these from a commercial point of view. In this way, this review sets out to highlight the most promising approaches in MIP-based sensing in terms of both manufacturing methods and readout technologies employed. In doing so, we aim at delineating potential future approaches and identifying potential obstacles that the MIP-sensing field may encounter in an attempt to penetrate the commercial, analytical market. [ABSTRACT FROM AUTHOR]

The paper is a self-review of works on development of new approaches to formation of mimics of receptor and catalytic sites of biological macromolecules in the structure of highly cross-linked polymer membranes and thin films. The general strategy for formation of the binding sites in molecularly imprinted polymer (MIP) membranes and thin films was described. A selective recognition of a number of food toxins, endocrine disruptors and metabolites is based on the results of computational modeling data for the prediction and optimization of their structure. A strategy proposed for the design of the artificial binding sites in MIP membranes was supported by the research performed by the authors on development of a number of the MIP membrane-based affinity and catalytic biosensors for selective and sensitive measurement (detection limits 0.3–100 nM) of the target analytes. Novel versatile approaches aimed at improving sensitivity of the developed biosensor systems were discussed.

A method for encrypting messages using engineered bacteria and different fluorescently labeled synthetic receptors is described. We show that the binding of DNA-based artificial receptors to E. coli expressing His-tagged outer membrane protein C (His-OmpC) induces a Förster resonance energy transfer (FRET) between the dyes, which results in the generation of a unique fluorescence fingerprint. Because the bacteria continuously divide, the emission pattern generated by the modified bacteria dynamically changes, enabling the system to produce encryption keys that change with time. Thus, this development indicates the potential contribution of live-cell-based encryption systems to the emerging area of information protection at the molecular level.

Abstract A series of new 9,9‐diethylfluorenes consisting of three side‐arms each bearing a heterocyclic, bis(carboxymethyl)amino, bis(carbamoylmethyl)amino, bis(ethoxycarbonylmethyl)amino or an amino group were prepared on the basis of 2,4,7‐tris(bromomethyl)‐9,9‐diethylfluorene. Imidazolyl, benzimidazolyl, pyrazolyl, pyrrolyl, 1,3‐dioxoisoindolyl and pyridinium groups were taken into account as heterocyclic units, attached to the aromatic skeleton via −CH2−, −CH2NHCH2− or −CH2N=CH− linkers. In addition to the seventeen 2,4,7‐trisubstituted 9,9‐diethylfluorenes, two macrocyclic compounds were prepared on the basis of 2,7‐bis(aminomethyl)‐9,9‐diethylfluorene. The excellent yield of the macrocyclization reaction is worth a special mention. Both the acyclic and the macrocyclic fluorene‐based compounds have, among other things, the potential to act as artificial receptors for different substrates in analogy to the known receptors consisting of a benzene or biphenyl core.

Abstract Artificial receptor‐based protein assays have various attractive features such as a long‐term stability, a low‐cost production process, and the ease of tuning the target specificity. However, such protein sensors are still immature compared with conventional immunoassays. To enhance the application potential of synthetic sensing materials, organic field‐effect transistors (OFETs) are some of the suitable platforms for protein assays because of their solution processability, durability, and compact integration. Importantly, OFETs enable the electrical readout of the protein recognition phenomena of artificial receptors on sensing electrodes. Thus, we believe that OFETs functionalized with artificial protein receptors will be a powerful tool for the on‐site analyses of target proteins. In this Minireview, we summarize the recent progress of the OFET‐based protein assays including the rational design strategies for devices and sensing materials.

The detection of human serum albumin (HSA) is of significant clinical importance in disease diagnoses. In this work, polymer-based synthetic receptors are designed by incorporating Ag-ZnS microspheres in molecularly imprinted poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MIPs) for the gravimetric detection of HSA. Among different compositions of Ag-ZnS@MIPs, MIPs having methacrylic acid and ethylene glycol dimethacrylate volume ratio of 3:2 exhibit enhanced HSA sensitivity in the concentration range of 5–200 ng/mL. A remarkably low threshold limit of detection (LOD = 0.364 ng/mL) is achieved with quartz crystal microbalance (QCM) based gravimetric sensors. Furthermore, the Ag-ZnS@MIPs/QCM sensors show high selectivity for HSA compared to other proteins, e.g., bovine serum albumin (BSA), glycoprotein, ribonuclease, and lysozyme. Hence, the gravimetric quantification of HSA realizes a highly sensitive, selective, and label-free detection mechanism with a limit of quantification down to 1.1 ng/mL.

Molecularly imprinted polymers (MIPs) have gained growing interest among researchers worldwide, due to their key features that make these materials interesting candidates for implementation as receptors into sensor applications. In fact, MIP-based glucose sensors could overcome the stability issues associated with the enzymes present in commercial glucose devices. Various reports describe the successful development of glucose MIPs and their coupling to a wide variety of transducers for creating sensors that are able to detect glucose in various matrices. In this review, we have summarized and critically evaluated the different production methods of glucose MIPs and the different transducer technologies used in MIP-based glucose sensors, and analyzed these from a commercial point of view. In this way, this review sets out to highlight the most promising approaches in MIP-based sensing in terms of both manufacturing methods and readout technologies employed. In doing so, we aim at delineating potential future approaches and identifying potential obstacles that the MIP-sensing field may encounter in an attempt to penetrate the commercial, analytical market.

Sucrose is a primary metabolite in plants, a source of energy, a source of carbon atoms for growth and development, and a regulator of biochemical processes. Most of the traditional analytical chemistry methods for sucrose quantification in plants require sample treatment (with consequent tissue destruction) and complex facilities, that do not allow real-time sucrose quantification at ultra-low concentrations (nM to pM range) under in vivo conditions, limiting our understanding of sucrose roles in plant physiology across different plant tissues and cellular compartments. Some of the above-mentioned problems may be circumvented with the use of bio-compatible ligands for molecular recognition of sucrose. Nevertheless, problems such as the signal-noise ratio, stability, and selectivity are some of the main challenges limiting the use of molecular recognition methods for the in vivo quantification of sucrose. In this review, we provide a critical analysis of the existing analytical chemistry tools, biosensors, and synthetic ligands, for sucrose quantification and discuss the most promising paths to improve upon its limits of detection. Our goal is to highlight the criteria design need for real-time, in vivo, highly sensitive and selective sucrose sensing capabilities to enable further our understanding of living organisms, the development of new plant breeding strategies for increased crop productivity and sustainability, and ultimately to contribute to the overarching need for food security.

Abstract The design of a fully synthetic, chemical “apoptosis‐inducing receptor” (AIR) molecule is reported that is anchored into the lipid bilayer of cells, is activated by the incoming biological input, and responds with the release of a secondary messenger—a highly potent toxin for cell killing. The AIR molecule has four elements, namely, an exofacial trigger group, a bilayer anchor, a toxin as a secondary messenger, and a self‐immolative scaffold as a mechanism for signal transduction. Receptor installation into cells is established via a robust protocol with minimal cell handling. The synthetic receptor remains dormant in the engineered cells, but is effectively triggered externally by the addition of an activating biomolecule (enzyme) or in a mixed cell population through interaction with the surrounding cells. In 3D cell culture (spheroids), receptor activation is accessible for at least 5 days, which compares favorably with other state of the art receptor designs.

The design of a fully synthetic, chemical "apoptosis‐inducing receptor" (AIR) molecule is reported that is anchored into the lipid bilayer of cells, is activated by the incoming biological input, and responds with the release of a secondary messenger—a highly potent toxin for cell killing. The AIR molecule has four elements, namely, an exofacial trigger group, a bilayer anchor, a toxin as a secondary messenger, and a self‐immolative scaffold as a mechanism for signal transduction. Receptor installation into cells is established via a robust protocol with minimal cell handling. The synthetic receptor remains dormant in the engineered cells, but is effectively triggered externally by the addition of an activating biomolecule (enzyme) or in a mixed cell population through interaction with the surrounding cells. In 3D cell culture (spheroids), receptor activation is accessible for at least 5 days, which compares favorably with other state of the art receptor designs. [ABSTRACT FROM AUTHOR]

Abstract The newest generation of cell‐based technologies relies heavily on methods to communicate to the engineered cells using artificial receptors, specifically to deactivate the cells administered to a patient in the event of adverse effects. Herein, artificial synthetic internalizing receptors are engineered that function in mammalian cells in 2D and in 3D and afford targeted, specific intracellular drug delivery with nanomolar potency in the most challenging cell type, namely primary, donor‐derived T cells. Receptor design comprises a lipid bilayer anchor for receptor integration into cell membrane and a small xenobiotic molecule as a recognition ligand. Artificial receptors are successfully targeted by the corresponding antibody–drug conjugate (ADC) and exhibit efficient cargo cell entry with ensuing intracellular effects. Receptor integration into cells is fast and robust and affords targeted cell entry in under 2 h. Through a combination of the receptor design and the use of ADC, combined benefits previously made available by chimeric artificial receptors (performance in T cells) and the chemical counterpart (robustness and simplicity) in a single functional platform is achieved. Artificial synthetic receptors are poised to facilitate the maturation of engineered cells as tools of biotechnology and biomedicine.

A series of new 9,9‐diethylfluorenes consisting of three side‐arms each bearing a heterocyclic, bis(carboxymethyl)amino, bis(carbamoylmethyl)amino, bis(ethoxycarbonylmethyl)amino or an amino group were prepared on the basis of 2,4,7‐tris(bromomethyl)‐9,9‐diethylfluorene. Imidazolyl, benzimidazolyl, pyrazolyl, pyrrolyl, 1,3‐dioxoisoindolyl and pyridinium groups were taken into account as heterocyclic units, attached to the aromatic skeleton via −CH2−, −CH2NHCH2− or −CH2N=CH− linkers. In addition to the seventeen 2,4,7‐trisubstituted 9,9‐diethylfluorenes, two macrocyclic compounds were prepared on the basis of 2,7‐bis(aminomethyl)‐9,9‐diethylfluorene. The excellent yield of the macrocyclization reaction is worth a special mention. Both the acyclic and the macrocyclic fluorene‐based compounds have, among other things, the potential to act as artificial receptors for different substrates in analogy to the known receptors consisting of a benzene or biphenyl core. [ABSTRACT FROM AUTHOR]

The newest generation of cell‐based technologies relies heavily on methods to communicate to the engineered cells using artificial receptors, specifically to deactivate the cells administered to a patient in the event of adverse effects. Herein, artificial synthetic internalizing receptors are engineered that function in mammalian cells in 2D and in 3D and afford targeted, specific intracellular drug delivery with nanomolar potency in the most challenging cell type, namely primary, donor‐derived T cells. Receptor design comprises a lipid bilayer anchor for receptor integration into cell membrane and a small xenobiotic molecule as a recognition ligand. Artificial receptors are successfully targeted by the corresponding antibody–drug conjugate (ADC) and exhibit efficient cargo cell entry with ensuing intracellular effects. Receptor integration into cells is fast and robust and affords targeted cell entry in under 2 h. Through a combination of the receptor design and the use of ADC, combined benefits previously made available by chimeric artificial receptors (performance in T cells) and the chemical counterpart (robustness and simplicity) in a single functional platform is achieved. Artificial synthetic receptors are poised to facilitate the maturation of engineered cells as tools of biotechnology and biomedicine. [ABSTRACT FROM AUTHOR]

Artificial receptor‐based protein assays have various attractive features such as a long‐term stability, a low‐cost production process, and the ease of tuning the target specificity. However, such protein sensors are still immature compared with conventional immunoassays. To enhance the application potential of synthetic sensing materials, organic field‐effect transistors (OFETs) are some of the suitable platforms for protein assays because of their solution processability, durability, and compact integration. Importantly, OFETs enable the electrical readout of the protein recognition phenomena of artificial receptors on sensing electrodes. Thus, we believe that OFETs functionalized with artificial protein receptors will be a powerful tool for the on‐site analyses of target proteins. In this Minireview, we summarize the recent progress of the OFET‐based protein assays including the rational design strategies for devices and sensing materials. [ABSTRACT FROM AUTHOR]

Peptide based lectin mimetics represent an attractive approach for the development of artificial carbohydrate receptors that might find application in bio-analytical and medicinal fields. Taking into consideration the structure of typical lectin binding site, we have designed a novel artificial receptor molecule possessing a rigid three-dimensional structure, hydrogen-bonding site and lipophilic binding pocket to promote hydrophobic interaction and hydrogen-bonding. A new solid-phase synthetic approach that allows complete synthesis of desired bicyclic peptide 1 on the solid support was developed. CD spectra of peptides 1 and 2 indicate that the structure of 1 is rather rigid and preorganised for the three-dimensional monosaccharide substrates binding. The binding affinities of bicyclic peptide receptor 1 toward various carbohydrate substrates at physiologically relevant conditions were estimated by UV/vis and fluorimetric titration experiments, and the observed values are in the millimolar range. With these results we have demonstrated that the bicyclic peptide 1 represent a promising basis for the design of new and more efficient carbohydrate receptors that may have broader application in bio-analytical or medicinal field. [ABSTRACT FROM AUTHOR]

In terms of the thermodynamics of solutions (using the density functional theory (DFT) method at RwB97XD/6-31G(d) level of the theory) the influence of the environment, as well as type of functional monomers and a ratio of "template molecule (melamine) to monomer molecules" on the recognition properties of pre-polymerization complexes of "artificial receptor" against melamine has been explored. The geometries and energy characteristics of the "functional monomer-template" pre-polymerization complexes with the ratios 1:1, 2:1, 3:1 were obtained. There are acrylamido-2-methyl-1-propanesulfonic acid (AMPSA), ethylene glycol methacrylate phosphate, itaconic acid and acrylic acids were considered as functional monomers. It is shown that for all environments and there is a pattern, namely, the most energetically favorable monomer in the formation of pre-polymerization complexes with melamine is AMPSA. It is followed by itaconic and acrylic acid. In addition, the same sequence is stored at increase of the ratio between the molecules of monomers and melamine. [ABSTRACT FROM AUTHOR]

The paper is a self-review of works on development of new approaches to formation of mimics of receptor and catalytic sites of biological macromolecules in the structure of highly cross-linked polymer membranes and thin films. The general strategy for formation of the binding sites in molecularly imprinted polymer (MIP) membranes and thin films was described. A selective recognition of a number of food toxins, endocrine disruptors and metabolites is based on the results of computational modeling data for the prediction and optimization of their structure. A strategy proposed for the design of the artificial binding sites in MIP membranes was supported by the research performed by the authors on development of a number of the MIP membrane-based affinity and catalytic biosensors for selective and sensitive measurement (detection limits 0.3-100 nM) of the target analytes. Novel versatile approaches aimed at improving sensitivity of the developed biosensor systems were discussed., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Authors.)

Abstract: A new type of molecularly imprinted polymer (MIP)-based fluorescent artificial receptor was developed by anchoring MIP on the surface of denatured bovine serum albumin (dBSA) modified CdTe quantum dots (QDs) using the surface molecular imprinting process. The approach combined the merits of molecular imprinting technology and the fluorescent property of the CdTe QDs. The dBSA was used not only to modify the surface defects of the CdTe QDs, but also as assistant monomer to create effective recognition sites. Three different proteins, namely lysozyme (Lyz), cytochrome c (Cyt) and methylated bovine serum albumin (mBSA), were tested as the template molecules and then the receptors were synthesized by sol–gel reaction (imprinting process). The results of fluorescence and binding experiments demonstrated the recognition performance of the receptors toward the corresponding template. Under optimum conditions, the linear range for Lyz was from 1.4×10−8 to 8.5×10−6 M, and the detection limit was 6.8nM. Moreover, the new artificial receptors were applied to separate and detect Lyz in real samples. This fluorescent artificial receptor may serve as a starting point in the design of highly effective synthetic fluorescent receptor for recognition of target protein. [Copyright &y& Elsevier]

Molecular Imprinting Technology (MIT) is a technique to design artificial receptors with a predetermined selectivity and specificity for a given analyte, which can be used as ideal materials in various application fields. Molecularly Imprinted Polymers (MIPs), the polymeric matrices obtained using the imprinting technology, are robust molecular recognition elements able to mimic natural recognition entities, such as antibodies and biological receptors, useful to separate and analyze complicated samples such as biological fluids and environmental samples. The scope of this review is to provide a general overview on MIPs field discussing first general aspects in MIP preparation and then dealing with various application aspects. This review aims to outline the molecularly imprinted process and present a summary of principal application fields of molecularly imprinted polymers, focusing on chemical sensing, separation science, drug delivery and catalysis. Some significant aspects about preparation and application of the molecular imprinting polymers with examples taken from the recent literature will be discussed. Theoretical and experimental parameters for MIPs design in terms of the interaction between template and polymer functionalities will be considered and synthesis methods for the improvement of MIP recognition properties will also be presented. [ABSTRACT FROM AUTHOR]

Binding mode calculations for complexes between an artificial paracyclophane receptor and digoxins, cholic acids as well as cortisone steroids show encapsulation of different ring combinations. Docking experiments were performed between the 26-10 antibody and digoxins. Coordination affinity arises from hydrophobic desolvation and van der Waals interactions rather than from hydrogen bonds. The specificity and affinity arises mainly from shape complementarity. Computed binding free energies and Kohonen neural network computations both point to physicochemical and structural similarities of natural antibodies and artificial receptors. [ABSTRACT FROM AUTHOR]

The electrostatic potential surface (EPS) is calculated for molecular tweezers, clips, and bowls at different levels of theory (semiempirical AM1, ab initio HF/6-31G*, and density functional theory pBP/DN**). According to these calculations, the molecular electrostatic potential (MEP) on the concave side of the molecular tweezers and clips is suprisingly negative for hydrocarbons. This finding seems to be a general phenomenon in nonconjugated π-electron systems with concave-convex topology and it explains the receptor properties of the molecular tweezers and clips. Analogous calculations performed for the conjugated aromatic molecular bowls show different results. The DFT calculations predict that in these systems the more negative MEP lies on the concave side similar to the findings for the nonconjugated molecular tweezer- and clip-systems, whereas the AM1 calculation leads to the opposite result that the MEP is more negative on convex side of the bowl-systems. [ABSTRACT FROM AUTHOR]

In the study, we have developed an efficient and robust method using dual modes of fluorescence sensing and smartphone readout for the detection of pyrethroids using artificial receptors inside a covalent organic framework. Carbazole-conjugated frameworks (CCFs) were used to prepare efficient fluorescent probes that combine stability with light-emitting activity. C N linkages between aldehydes and amines formed Schiff bases, allowing the development of layered structures, creating exceptionally stable frameworks. Artificial receptors that can bind compounds inside the CCFs with high affinity, for both the detection and absorption of λ-cyhalothrin (LC), were constructed using room-temperature reverse microemulsion polymerization. Under optimum conditions, the fluorescence sensing correlation with the concentration of LC showed good linearity in the range of 0.8–175 μg L−1 with a detection limit of 0.368 μg L−1. The smartphone-based visible readout exhibited a good effect, with a detection limit of 4.067 μg L−1, and recovery of 88 %–103% in food samples. A parallel analysis in food samples was conducted by high-performance liquid chromatography, the results showed good consistency, indicating the practicability of the developed method. Dual mode analysis can avoid the disadvantages of a single response, providing excellent sensitivity, specificity, and efficiency through a strong binding force between the target and the artificial receptors. [Display omitted] • Efficient and robust dual modes of fluorescence sensing and smartphone readout for the detection of pyrethroids. • Dual mode analysis using artificial receptors bound inside a covalent organic framework. • Carbazole-conjugated frameworks were used to prepare efficient fluorescent probes. • The on/off fluorescence of the target-CCFs complex was reversible. • Dual mode analysis provide excellent sensitivity, specificity, and efficiency. [ABSTRACT FROM AUTHOR]

A robust and highly specific sensor based on electroactive molecularly imprinted polymer nanoparticles (nanoMIP) was developed. The nanoMIP tagged with a redox probe, combines both recognition and reporting capabilities. The developed nanoMIP replaces enzyme-mediator pairs used in traditional biosensors thus, offering enhanced molecular recognition for insulin, improving performance in complex biological samples, and yielding high stability. Also, most of existing sensors show poor performance after storage. To improve costs of the logistics and avoid the need of cold storage in the chain supply, we developed an alternative to biorecognition system that relies on nanoMIP. NanoMIP were computationally designed using "in-silico" insulin epitope mapping and synthesized by solid phase polymerisation. The characterisation of the polymer nanoparticles was performed by transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier-transform Infrared (FT-IR) and surface plasmon resonance (SPR). The electrochemical sensor was developed by chemical immobilisation of the nanoMIP on screen printed platinum electrodes. The insulin sensor displayed satisfactory performances and reproducible results (RSD = 4.2%; n = 30) using differential pulse voltammetry (DPV) in the clinically relevant concentration range from 50 to 2000 pM. The developed nanoMIP offers the advantage of large number of specific recognition sites with tailored geometry, as the resultant, the sensor showed high sensitivity and selectivity to insulin with a limit of detection (LOD) of 26 and 81 fM in buffer and human plasma, respectively, confirming the practical application for point of care monitoring. Moreover, the nanoMIP showed adequate storage stability of 168 days, demonstrating the robustness of sensor for several rounds of insulin analysis. • The molecularly imprinted polymer nanoparticles tagged with a redox probe, combines both recognition and reporting functions. • The electroactive nanoparticles system replaces enzyme-mediator pairs used in classic biosensors. • Nanoparticles were computationally designed to selectively bind insulin epitopes. • The sensor devised provides adequate selectivity, low cross-reactivity and high sensitivity in plasma. • This technology is robust and can be potentially applied to a broad range of targets. [ABSTRACT FROM AUTHOR]

Phenolic compounds are secondary metabolites frequently found in plants that exhibit many different effects on human health. Because of the relevant bioactivity, their identification and quantification in agro-food matrices as well as in biological samples are a fundamental issue in the field of quality control of food and food supplements, and clinical analysis. In this review, a critical selection of sensors and biosensors for rapid and selective detection of phenolic compounds is discussed. Sensors based on electrochemistry, photoelectrochemistry, fluorescence, and colorimetry are discussed including devices with or without specific recognition elements, such as biomolecules, enzymes and molecularly imprinted materials. Systems that have been tested on real matrices are prevalently considered but also techniques that show potential development in the field. [ABSTRACT FROM AUTHOR]

Synthetic sensing materials (artificial receptors) are some of the most attractive components of chemical/biosensors because of their long-term stability and low cost of production. However, the strategy for the practical design of these materials toward specific molecular recognition in water is not established yet. For the construction of artificial material-based chemical/biosensors, the bottom-up assembly of these materials is one of the effective methods. This is because the driving forces of molecular recognition on the receptors could be enhanced by the integration of such kinds of materials at the 'interfaces', such as the boundary portion between the liquid and solid phases. Additionally, the molecular assembly of such self-assembled monolayers (SAMs) can easily be installed in transducer devices. Thus, we believe that nanosensor platforms that consist of synthetic receptor membranes on the transducer surfaces can be applied to powerful tools for high-throughput analyses of the required targets. In this review, we briefly summarize a comprehensive overview that includes the preparation techniques for molecular assemblies, the characterization methods of the interfaces, and a few examples of receptor assembly-based chemical/biosensing platforms on each transduction mechanism. [ABSTRACT FROM AUTHOR]

A method for encrypting messages using engineered bacteria and different fluorescently labeled synthetic receptors is described. We show that the binding of DNA-based artificial receptors to E. coli expressing His-tagged outer membrane protein C (His-OmpC) induces a Förster resonance energy transfer (FRET) between the dyes, which results in the generation of a unique fluorescence fingerprint. Because the bacteria continuously divide, the emission pattern generated by the modified bacteria dynamically changes, enabling the system to produce encryption keys that change with time. Thus, this development indicates the potential contribution of live-cell-based encryption systems to the emerging area of information protection at the molecular level., (Copyright © 2020, Kishore Prasad et al.; licensee Beilstein-Institut.)