Molecular Recognition Technology Research Articles

Aptasensors and Advancement in Molecular Recognition Technology

AbstractSynthetic oligonucleic acids known as aptamers exhibit remarkable selectivity and affinity for target recognition and binding. Selected via an iterative process known as “selective evolution of ligands by exponential enrichment” (SELEX), aptamers fold into defined 3D conformations to interact with their targets. The incorporation of aptamers as recognition elements has driven notable progress in biosensors, giving rise to the development of aptasensors. Here, the process of aptamer discovery and the development of various types of aptasensors are summarized. The fundamental design principles of aptasensors are elaborated along with the superiority of aptamers compared to antibodies. The various modes employed by aptasensors, such as structure‐switching design, hybridization chain reaction amplification, enzyme‐assisted recycling, and split aptamer design are examined. Further light is shed on the diverse landscape of aptasensors, their adaptability to different analytes aptasensors as well as their potential to propel advancements in modern biosensor technology. As a nucleic acids‐based biosensor platform, aptasensors poise to become a next generation of sensitive and cost‐effective technology to shape the future of molecular recognition in biosensing.

Molecular recognition on the surface of concentrated hydrochloric acid: Hydration configuration-driven preferential recognition of Rh (III) anions with inner-coordinated water molecules

Comprehension of selective recognition of anions is confined to a phenomenological list of solvents, hardly surpassing Pedersen’s empirical observations of cationic-crown ether binding. In this work, a novel strategy employing thin-layer oil membrane extraction (TOMX) on the surface of concentrated hydrochloric acid is proposed for controllable recognition and separation of anions with different hydration configurations. Four typical chloric-complexing anions, RhCl63−, PdCl42−, PtCl62− and FeCl4−, usually coexisting in the concentrated hydrochloric acid leaching solutions of precious metal concentrates were focused. A surprising phenomenon was noticed that the octahedral RhCl5(H2O)2− anions with inner-coordinated water molecules were preferentially recognized by 18C6 macrocyclic molecule. However, the planar quadrilateral Pd (II) chloric-complexing anions with a hydration configuration via water molecules attacking the central Pd (II) atoms along the Z-axis direction can be separated subsequently. The Pt (IV) and Fe (III) chloric-complexing anions respectively with an octahedral and tetrahedral outer-coordinated hydration shell configuration were the last to be recognized. Such an order in extracting Rh (III) > Pd (II) > Pt (IV) > Fe (III) anions depends on their hydration capacity and the preferential affinity towards the interface, which is almost impossible during the conventional stirring and oil droplet dispersed extraction. Because of a lower concentration of dissociated hydrogen ions on the surface of concentrated hydrochloric acid compared to its bulk concentrations, the hydration of those chloric-complexing anions was enhanced. The Rh (III) anions with inner-coordinated water molecules exhibit a higher interfacial affinity than other anions. The water molecules entering the inner coordination layer of Rh (III) chloric-complexing anions, cooperating with its outer-coordinated hydration shell, act as a hydrogen bond “water bridge” to interact with 18C6 molecules, which makes it easier to feel the influence from the aqueous laminar shear flow under the thin-layer oil membrane, thereby driving the preferential recognition of easily hydrated Rh (III) anions at the interface. The controllable “water bridge” interactions driven by shear flow can be activated or deactivated on the surface of concentrated hydrochloric acid by adjusting the shear flow rate. This work lays a foundation for the future development of a controllable flexible molecular recognition technology at liquid–liquid interfaces.

De novo fabrication of higher arene ring incorporated contorted calix[2]phyrin(2.2.1.1.1) and its F- bound complex.

The rational design and synthesis of a novel contorted calix[2]phyrin(2.2.1.1.1) structure has been achieved, utilizing a terphenyl unit as a key building component. This terphenyl unit serves as a segment of the armchair periphery in a π-extended two-dimensional architecture. The resulting molecule exhibits remarkable properties, including the ability to self-assemble into solid-state supramolecular nanotubes. Additionally, it has demonstrated an affinity for complexation with fluoride anions, highlighting its potential for applications in molecular recognition and sensor technology. The incorporation of the terphenyl unit not only enhances the structural rigidity but also contributes to the unique electronic characteristics of the calix[2]phyrin.

Engineered olfactory system for in vitro artificial nose

• Artificial nose drew generous attention in the field of bionic organs • Construction with sensing module, recognition system and functional structure are introduced • Recognition technology, substrate materials and microarray integration in artificial nose are prospected The engineered biomimetic sensors can not only realize the action of organs, but also combine functional materials as in vitro organs by simulating the response of biological organs to different environmental signals. Artificial nose is a concept proposed by imitating biological olfactory system, simulating olfactory nerve cells, olfactory bulb and olfactory cortex through different materials to realize olfactory function. The sensor array used to sense external gas stimulation can be analyzed based on different recognition principles through different original signals such as optics, electricity, electrochemistry and bioelectricity. Furthermore, combined with pattern recognition and microarray technology, artificial nose can be highly integrated with biocompatible and other important properties to achieve in vitro application. The design principle and necessary components of artificial nose are introduced in this paper including sensing structure, recognition system and functional module. At the same time, the potential development prospects of molecular recognition technology, polymer-based materials and microarray integration in artificial nose are prospected.

PCR Mediated Nucleic Acid Molecular Recognition Technology for Detection of Viable and Dead Foodborne Pathogens.

Living foodborne pathogens pose a serious threat to public and population health. To ensure food safety, it is necessary to complete the detection of viable bacteria in a short time (several hours to 1 day). However, the traditional methods by bacterial culture, as the gold standard, are cumbersome and time-consuming. To break through the resultant research bottleneck, PCR mediated nucleic acid molecular recognition technologies, including RNA-based reverse transcriptase PCR (RT-PCR) and DNA-based viability PCR (vPCR) have been developed in recent years. They not only sensitively amplify detection signals and quickly report detection results, but also distinguish viable and dead bacteria. Therefore, this review introduces these PCR-mediated techniques independent of culture for viable and dead foodborne pathogen detection from the nucleic acid molecular recognition principal level and describes their whole-process applications in food quality supervision, which provides a useful reference for the development of detection of foodborne pathogens in the future.

Molecularly imprinted polymers as a selective sorbent for forensic applications in biological samples-a review.

Molecularly imprinted polymers (MIP) consist of a molecular recognition technology with applicability in different areas, including forensic chemistry. Among the forensic applications, the use of MIP in biological fluid analysis has gained prominence. Biological fluids are complex samples that generally require a pre-treatment to eliminate interfering agents to improve the results of the analyses. In this review, we address the development of this molecular imprinting technology over the years, highlighting the forensic applications of molecularly imprinted polymers in biological sample preparation for analysis of stimulant drugs such as cocaine, amphetamines, and nicotine.

Novel Hybrid Nanoparticles: Synthesis, Functionalization, Characterization, and Their Application in the Uptake of Scandium (III)Ions from Aqueous Media.

The aim of this study was to prepare novel supramolecular hybrid nanoparticles (HNPs) that can selectively separate and recover scandium metal ions, Sc(III), from an aqueous phase based on molecular recognition technology (MRT). Moreover, this approach is fully compatible with green chemistry principles. In this work, natural amorphous silica (SiO2) nanoparticles were prepared by a precipitation method from Iraqi rice husk (RH) followed by surface modification with 3-amino-propyl triethoxysilane (APTES) as coupling agent and Kryptofix 2.2.2 (K2.2.2) as polycyclic ligand. To evaluate the potential of the hybrid nanoparticles, the prepared HNPs were used for the solid–liquid extraction of scandium, Sc(III), ions from model solutions due to the fact that K2.2.2 are polycyclic molecules. These polycyclic molecules are able to encapsulate cations according to the corresponding cavity size with the ionic radius of metal by providing a higher protection due their cage-like structures. Moreover, the authors set the objectives to design a high-technology process using these HNPs and to develop a Sc recovery method from the aqueous model solution prior to employing it in industrial applications, e.g., for Sc recovery from red mud leachate. The concentrations of Sc model solutions were investigated using the UV-Vis spectrophotometer technique. Different characterization techniques were used including scanning electron microscope (SEM), atomic force microscopy (AFM), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), X-ray fluorescence (XRF), and Fourier transform infrared (FTIR). The extraction efficiency of Sc varied from 81.3% to 96.7%. Moreover, the complexed Sc ions were efficiently recovered by HCl with 0.1 mol/L concentration. The stripping ratios of Sc obtained ranged from 93.1% to 97.8%.

Synergy of flow injection system and molecular recognition technology products for rapid determination of 89,90Sr and 210Pb

A rapid, automated separation procedure was developed for radioactive strontium and lead isotope determination. This system includes a portable automated system for the preconcentration and sequential elution of targeting isotopes with an Na2H2EDTA solution from solid phase extraction materials, AnaLig®Sr-01 and SuperLig®620, provided by IBC Technologies. Strontium and lead were separated from the majority of matrix constituents to obtain pure fractions of Pb and Sr prior to radiometric detection. In case of barium presence, it can also be fully isolated and completely separated from Sr. The automated procedure can be successfully used for preconcentration and separation from high as well as low radioactivity samples. With only a 1 mL column filled with SuperLig®620, it is possible to isolate Sr and Pb with 100% recovery from 1 L to 2 L of sample at a flow rate of up to 10 mL min−1 within several hours. 89,90Sr isotopes can be further determined by Cherenkov counting, while 210Pb isotopes can be determined by either gamma spectrometry or liquid scintillation counter. The method was tested and validated using certified standard materials and proficiency test samples. The synergy of automated separation and detection procedures enables the determination of the low level activity of 90Sr and 210Pb in a short time with detection limits of 20 mBq L−1 for both isotopes. The proposed method enables lower labour costs, minimal size of apparatuses and columns, low separation time, and reduced secondary waste production. The automated procedure may be easily implemented in laboratories worldwide and can also be used at sampling sites.

Targeted Isolation of Cytotoxic Sesquiterpene Lactones from Eupatorium fortunei by the NMR Annotation Tool, SMART 2.0.

Small Molecular Accurate Recognition Technology (SMART 2.0) has recently been introduced as a NMR-based machine learning tool for the discovery and characterization of natural products. We attempted targeted isolation of sesquiterpene lactones from Eupatorium fortunei with the aid of structural annotation by SMART 2.0 and chemical profiling. Eight germacrene-type (1–7 and 10) and two eudesmane-type sesquiterpene lactones (8 and 9) were isolated from the whole plant of Eupatorium fortunei. With the guidance of the results of the subfractions from E. fortunei obtained by SMART 2.0, their cytotoxic activities were evaluated against five cancer cells (SKOV3, A549, PC3, HEp-2, and MCF-7). Compounds 4 and 8 exhibited IC50 values of 3.9 ± 1.2 and 3.9 ± 0.6 μM against prostate cancer cells, PC3, respectively. Compound 7 showed good cytotoxicity with IC50 values of 5.8 ± 0.1 μM against breast cancer cells, MCF-7. In the present study, the rapid annotation of the mixture of compounds in a fraction by the NMR-based machine learning tool helped the targeted isolation of bioactive compounds from natural products.

Sequential determination of 90Sr and 210Pb in bone samples using molecular recognition technology product AnaLig® Sr-01

Both radioactive isotopes, 210Pb and 90Sr, accumulate in bones and procedures for their determination usually include radiochemical methods prior their detection. This work describes a novel method for simultaneous determination of 210Pb and 90Sr in bone samples by using molecular recognition technology product AnaLig®Sr-01 gel, commercially available from IBC’s Technologies Inc. This material is initially used for strontium isolation. Important drawback is that it also binds lead ions. This fact is used to develop a simple and rapid method for their simultaneous determination. The use and effectiveness of AnaLig®Sr-01 gel was validated by analysis of certified reference animal bone material, supplied by International Atomic Energy Agency (IAEA A-12) and 210Pb reference sample. The developed single column method was used to determine the activity concentrations of 90Sr and 210Pb in bones of wild boars, deers and goats from different regions of Slovakia and Croatia. The proposed simple and effective method can easily be implemented in any radiochemical laboratory and the obtained results could be used for monitoring environmental areas of interest. The recoveries of both isotopes were high in all tested samples, 100% for Pb and around 80% for Sr, which is very important in sense of low activity concentration of radionuclides in environmental samples. The activity concentration of 210Pb correlated good with age of the animal (R2 = 0.94), whereas of 90Sr no correlation was found (R2 = 0.05).

A new rapid protocol for 226Ra separation and preconcentration in natural water samples using molecular recognition technology for ICP-MS analysis

A new rapid protocol for 226Ra separation and preconcentration in natural water samples was developed before its determination by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). For this purpose, the commercially available Ra specific resin AnaLig® Ra-01 was used. This resin shows a high selectivity for radium in a large range of acid concentrations and no affinity or possible elution of 226Ra interfering elements. The distribution coefficients of Ra and other elements over a wide range of acid (HCl and HNO3) concentrations were obtained. Due to the high radium selectivity, the new developed protocol uses only 50 mg of dry resin and its performance was evaluated using 100 mL of three natural waters with different ionic strengths, spiked with a known quantity of 226Ra. Radium was successfully separated and preconcentrated yielding recoveries ranging between 72% and 86%. In parallel with the characterisation of the resin sorption properties, a detailed study of polyatomic interferences was performed on our ICP-MS allowing to identify the prominent elements favouring interferences at m/z = 226. Furthermore, a 226Ra sensitivity comparison between different ICP-MS instruments and configurations was done in order to determine high sensitivity conditions for radium analysis.

“Off-On”switching electrochemiluminescence biosensor for mercury(II) detection based on molecular recognition technology

A novel “off-On” electrogenerated chemiluminescence (ECL) biosensor has been developed for the detection of mercury(II) based on molecular recognition technology. The ECL mercury(II) biosensor comprises two main parts: an ECL substrate and an ECL intensity switch. The ECL substrate was made by modifying the complex of Ruthenium(II) tris-(bipyridine)(Ru(bpy)32+)/Cyclodextrins-Au nanoparticles(CD-AuNps)/Nafion on the surface of glass carbon electrode (GCE), and the ECL intensity switch is the single hairpin DNA probe designed according to the “molecular recognition” strategy which was functionalized with ferrocene tag at one end and attached to Cyclodextrins (CD) on modified GCE through supramolecular noncovalent interaction. We demonstrated that, in the absence of Hg(II) ion, the probe keeps single hairpin structure and resulted in a quenching of ECL of Ru(bpy)32+. Whereas, in the presence of Hg(II) ion, the probe prefers to form the T-Hg(II)-T complex and lead to an obvious recovery of ECL of Ru(bpy)32+, which provided a sensing platform for the detection of Hg(II) ion. Using this sensing platform, a simple, rapid and selective “off-On” ECL biosensor for the detection of mercury(II) with a detection limit of 0.1 nM has been developed.

Determination of 90Sr in bone samples using molecular recognition technology product AnaLig®Sr-01

Activity concentrations of 90Sr in samples of wild boar bones hunted in different regions of Slovakia were determined. Molecular recognition technology product IBC´s AnaLig®Sr-01 and tributyl phosphate were used for strontium determination. From 7 to 10 g of bone ash was used for 90Sr analysis. Both separation methods were statistical tested and compared. The presented results were evaluated as correct for all experimental data for 90Sr determination in ash bone samples. Activity concentrations of 90Sr in bones were in the range of (4.5–69.0) Bq kg−1.

Synthesis and characterization of D-/L-methionine grafted PEDOTs for selective recognition of 3,4-dihydroxyphenylalanine enantiomers

Two pairs of amino-acid functionalized poly(3,4-ethylenedioxythiophene) (PEDOT) derivatives, namely, poly(N-(tert-butoxycarbonyl)-L-methionyl (3,4-ethylenedioxythiophene-2’-yl)methylamide) (L-PEDOT-Boc-Met) and poly(N-(tert-butoxycarbonyl)-D-methionyl (3,4-ethylenedioxythiophene-2’-yl)methylamide) (D-PEDOT-Boc-Met); poly(L-methionyl (3,4-ethylenedioxythiophene-2’-yl)methylamide) (L-PEDOT-Met) and poly(D-methionyl (3,4-ethylenedioxythiophene-2’-yl)methylamide) (D-PEDOT-Met) were synthesized via chemical oxidative polymerization of corresponding monomers. The structural characterization, spectroscopic properties and thermal stability of these monomers and polymers were systematically explored by FTIR spectra, Raman spectra, XRD spectra, UV-Vis spectra and thermogravimetric analysis. As chiral electrode materials, these polymers were employed to successfully recognize 3,4-dihydroxyphenylalanine (DOPA) enantiomers by cyclic voltammetry (CV) in sulphuric acid solution. The measurement results reveal that the tendency was hetero-chiral interaction between L-PEDOT-Met/PVA/GCE and D-DOPA, D-PEDOT-Met/PVA/GCE and L-DOPA, respectively. Also, the mechanism of chiral discrimination was discussed. All the results implied that the combination of electrochemical molecular recognition technology and chiral PEDOT materials can be a promising approach for chiral recognition and may open new opportunities for facile, biocompatible, sensitive and robust chiral assays in biochemical applications.

Determination of 226Ra using molecular recognition technology product AnaLig® Sr-01

A new method for determination of 226Ra using molecular recognition technology product AnaLig® Sr-01 was developed. For radium recovery, 133Ba tracer was used. The method’s performance was investigated by analysis of model gravel samples spiked with international intercomparison sample with known activity of 226Ra. The proposed method for the determination of 226Ra was applied for analysis of various admixtures of building materials from Slovakia and activity concentrations of 226Ra in the samples were in the range (5.2–165.0) Bq kg−1.

Recovery of metals from an acid leachate of spent hydrodesulphurization catalyst using molecular recognition technology

Acid leaching of spent hydrodesulphurization (HDS) catalysts solubilizes efficiently all metals present in the catalyst; however, this methodology poses subsequent difficulties in achieving metals separation with high purity. In the present work, molecular recognition technology, using SuperLig® 167 resin, was applied to recover Ni, Mo and Al from H2SO4 leachate of spent HDS catalyst.Batch tests showed a good resin affinity to Ni, in acid, with a maximum capacity of 1.35mmol/g. The separation of Al, which was in excess, was efficient, but Mo was also retained by the resin.Column studies, using 6g of resin and performed at three flow rates (1.0, 1.5 and 2.1mL/min), showed that the lower flow rate was better to treat a higher volume of solution. At 1.0mL/min, each gram of resin treated almost 40mL of solution with 97% and 100% of Ni and Mo retention, respectively. Elution with NaOH 0.25mol/L, followed by HNO3 4mol/L, both at 2.1mL/min, led to efficient separation of Mo and Ni.The use of SuperLig® 167 resin to treat the leaching solution enabled an easy and efficient separation of the metals present in the acid leachate into mono-metal solutions (Al in the raffinate, Mo and Ni in the alkaline and acid eluates, respectively) with high yield (99.7%, 100% and 87%, respectively) and purity (99.3%, 99.8% and 98.7%, respectively).

Industrial applications of molecular recognition technology to separations of platinum group metals and selective removal of metal impurities from process streams

Selective precious and specialty metal separations and recovery using molecular recognition processes are described for commercial mining and recycling operations.

Determination of difficult-to-measure actinides in evaporator concentrate

Radiochemical separation of americium, neptunium and plutonium was tested on model solution of evaporator concentrate sample for isolation of each of them for alpha-spectrometry analysis. A good chemical separation of radionuclides of interest from the matrix and interfering radionuclides is required, once the relatively small difference in alpha-particle energy makes it difficult to spectrometrically separate the peaks. This paper describes use of the molecular recognition technology product AnaLig®Pu-01 gel from IBC Advanced Technologies, Inc. to effectively and selectively pre-concentrate, separate and recover americium, neptunium and plutonium from model solution of evaporator concentrate samples from Nuclear Power Plant which belong to the most difficult matrices to analyse. The method is suitable for analysing highly contaminated samples of radioactive waste in a relatively short time. For counting the alpha activity of 241Am, 239,240Pu, 238Pu and 237Np ORTEC 576A alpha-spectrometer equipped with ULTRATM ion implanted silicon detectors (600 mm2 active area) was used. The spectra were processed by using the Alpha-visionTM 32-bit emulation software from the EG&G ORTEC company.

Determination of 90Sr in radioactive concentrate from Nuclear Power Plant Mochovce

This paper describes the use of molecular recognition technology product AnaLig®Sr-01 gel from IBC Advanced Technologies, Inc. to effectively and selectively pre-concentrate, separate and recover strontium from evaporator concentrate samples from Nuclear Power Plant Mochovce which belongs to the most difficult matrices to analyze. The method is suitable for analyzing highly contaminated samples of radioactive waste in a relatively short time and with high decontamination factors. Activity of 90Sr was measured using Cherenkov counting on TRI CARB 2900 TR liquid scintillation counter.

Selective Separation of Tri- and Pentavalent Arsenic in Aqueous Matrix with a Macrocycle-Immobilized Solid-Phase Extraction System

A simple flow-based method was developed for the selective separation of arsenic species (+3 and +5) using a macrocycle-immobilized solid phase extraction (SPE) system, commonly known as molecular recognition technology (MRT) gel. Arsenic species in solution or in the eluent were subsequently quantified with graphite furnace atomic absorption spectrometry. The separation behaviors of As(III) and As(V) on MRT–SPE were investigated. It was found that As(V) can be selectively collected on the SPE system within the range of pH 4 to 9, while As(III) was passed through the MRT–SPE. The retention capacity of the MRT–SPE material for As(V) was found to be 0.25 ± 0.04 mmol g−1. The detection limit of the method for As(V) was 0.06 μg L−1, and the relative standard deviation was 2.9 % (n = 10, C = 1 μmol L−1). Interference from the matrix ions was studied. In order to validate the developed method, certified reference materials of effluent wastewater and groundwater samples were analyzed, and the determined values were in good agreement with the certified values. The proposed method was successfully applied to the speciation analysis of tri- and pentavalent arsenic in natural water samples showing satisfactory recoveries (≥ 98.7 %).