Recognition Properties Research Articles

A novel and quick egg yolk immunoglobulin y antibody extraction method leveraging the protein liquid-liquid phase separation principle.

This study presents a novel and efficient method for extracting immunoglobulin Y (IgY) antibodies from egg yolk based on the principle of liquid-liquid phase separation (LLPS) induced by polyethylene glycol 8000 (PEG 8000). Initial delipidation of egg yolk samples with varying PEG 8000 concentrations demonstrated optimal delipidation efficiency and protein recovery at 2.5 % PEG 8000 concentration. Subsequent IgY extraction involved inducing LLPS by raising PEG 8000 concentration to 6.5 %, resulting in turbid solutions and the formation of globular droplet-like condensates observed under a microscope. Unlike the PEG 6000 method that induced aggregation, the method developed here using PEG 8000 does not lead to the appearance of aggregates of IgY. SDS-PAGE analysis confirmed that IgY extracted was no different from the conventional PEG 6000 method, with similar purity levels (77 % vs 79 %). Enzyme-linked immunosorbent assay and western blot analysis confirmed the antigen recognition properties of the isolated IgY. This method significantly reduces the amount of PEG used, leading to substantial cost savings compared to PEG 6000. The method can be completed within one hour. Despite a slightly lower IgY yield by the method, the time- and cost-saving advantages of this method make it a promising alternative for IgY extraction in research. This proposed IgY extraction technique utilizing protein LLPS has the potential to improve the study of the physicochemical properties of IgY and optimized production, while offering a quicker and cost-effective solution for various applications in biomedical research.

Assembly-enhanced recognition: A biomimetic pathway to achieve ultrahigh affinities

On the one hand, nature utilizes hierarchical assemblies to create complex biological binding pockets, enabling ultrastrong recognition toward substrates in aqueous solutions. On the other hand, chemists have been fervently pursuing high-affinity recognition by constructing covalently well-preorganized stereoelectronic cavities. The potential of noncovalent assembly, however, for enhancing molecular recognition has long been underestimated. Inspired by (strept)avidin, an amphiphilic azocalix[4]arene derivative capable of assembly in aqueous solutions has been explored by us and demonstrated to exhibit ultrahigh binding affinity (up to 1012 M-1), which is almost four orders of magnitude higher than those reported for nonassembled azocalix[4]arenes. An ultrastable azocalix[4]arene/photosensitizer complex has been applied in hypoxia-targeted photodynamic therapy for tumors. These findings highlight the immense potential of an assembly-enhanced recognition strategy in the development of the next generation of artificial receptors with appropriate functionalities and extraordinary recognition properties.

Ultra-Sensitive Gaseous Styrene and Isoprene Detection with a Ratiometric Fluorescence Probe of Eu(III)-Incorporated UiO-67.

The development of probes for the efficient detection of volatile organic compounds is crucial for both human health protection and environmental monitoring. In this study, we successfully synthesized a ratiometric fluorescent sensing material [Eu-UiO-67 (1:1)], featuring dual-emission fluorescence peaks via a one-pot method. This material demonstrated exceptional ratiometric fluorescence recognition properties for liquid styrene and isoprene, achieving low limit of detections (LODs) of 6.2 and 20.24 ppb, respectively. Furthermore, we leveraged its outstanding photoluminescence properties to fabricate a Eu-UiO-67 film, which exhibited distinctive fluorescence responses toward gaseous styrene and isoprene. This unique behavior resulted in LODs of 12.42 ppb for gaseous styrene and 15.39 ppb for gaseous isoprene. The investigation into the sensing mechanisms revealed that the fluorescence response for styrene was mediated by an internal filtration effect, which arose from the competitive energy absorption between styrene and the Eu-UiO-67 (1:1) material. In contrast, fluorescence resonance energy transfer occurred between isoprene and the Eu-UiO-67 (1:1) materials. This approach offers a sensitive and reliable method for the detection of liquid/gaseous styrene and isoprene.

Salicylidene-based dual-responsive 'turn on' fluorometric chemosensors for the selective detection of Zn2+, Al3+ and F- ions: theoretical investigation and applications in the live cell imaging of zebrafish larvae and molecular logic gate operation.

Four salicylidene-based dual-responsive chemosensors 1,5-bis(5-bromosalicylaldehyde)carbohydrazone (R1), 1,5-bis(5-bromosalicylaldehyde)thiocarbohydrazone (R2), 1,5-bis(3-ethoxysalicylaldehyde)carbohydrazone (R3) and 1,5-bis(3-ethoxysalicylaldehyde)thiocarbohydrazone (R4) were synthesized and characterized. The molecular structures of R1 and R3 were confirmed by single crystal X-ray diffraction technique, which crystallized in the orthorhombic Pbcn and monoclinic P21/n space groups, respectively. The chemosensor molecules were investigated for their recognition properties against the selected cations (K+, Ca2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Fe3+ and Al3+) and anions (F-, Cl-, Br-, I-, HSO4-, H2PO4-, ClO4-, N3- and NO3-) by colorimetry, absorption spectroscopy, fluorescence spectroscopy, 1H NMR spectroscopy and theoretical studies. The sensor molecules showed colorimetric responses for the Co2+, Ni2+, Cu2+ and Fe3+ cations and the F- anion. Interestingly, the Zn2+ and Al3+ cations showed only the 'turn on' fluorometric response, whereas the F- anion showed both colorimetric and fluorometric responses. The binding constants were determined using the Benesi-Hildebrand (B-H) equation from the fluorescence titrations and found to be higher for R3 towards the Al3+ cation (2.03 × 106 M-1) with a low limit of detection (1.79 μM) and for R4 towards the F- anion (5.13 × 105 M-1) with a low limit of detection (5.23 μM). The chemosensors established 1 : 2 and 1 : 1 binding stoichiometries with the sensed cations and anion, respectively, as confirmed by Job's plots. The computational studies show a lower band gap of HOMO-LUMO when the chemosensors bind with the sensed inorganic ions compared to the free chemosensors. Furthermore, the observed fluorescent behaviour of the Zn2+ and Al3+ cations have motivated us to investigate the practical applications in the live cell-imaging of zebrafish larvae as well as in the development of a molecular logic gate.

Molecularly imprinted electrochemical sensor to sensitively detect tetramethylpyrazine in Baijiu.

Tetramethylpyrazine (TMP) is a compound known for its natural health benefits, but current detection methods for TMP are overly expensive and time-consuming. In this study, we developed functional materials with TMP molecular recognition properties using molecularly imprinted technology. As TMP does not produce electrochemical signals in the detection potential range, hexacyanoferrate was selected as a redox probe, combined with the highly conductive polymer PEDOT:PSS to enhance electrode conductivity. When coupled with the TMP-specific functional materials prepared through molecular imprinting, an electrochemical sensor specifically recognizing TMP was successfully developed, and this was confirmed through characterization techniques such as ultraviolet spectroscopy and scanning electron microscopy. Additionally, the crucial experimental parameters were optimized for improved performance. Under optimal conditions, the use of differential pulse voltammetry (DPV) to measure the peak currents of hexacyanoferrate showed a linear relationship with TMP concentrations from 0.50 × 10-6 to 5.00 × 10-3 M, achieving a detection limit of 2.1 × 10-7 M. This method proved effective for quantifying TMP in Baijiu samples, demonstrating good precision with relative standard deviations (RSD) ranging from 2.71% to 3.28%, and recovery percentages between 95.77% and 101.88%. These results indicate the potential of the molecularly imprinted polymer (MIP) sensor for accurately measuring TMP in actual samples.

Recognition of α-hydroxycarboxylates by N-heterocyclic boronic acids

Quinolineboronic and isoquinolineboronic acids were suggested earlier as receptors for sugars with fluorescence signaling properties. Here we report a detailed study of acid-base, optical, tautomeric and recognition properties of 3-quinolineboronic...

Efficient and Visual Detention of Ammonia and TNP Vapors by a Sustainable Highly Luminescent 1D Zn(II) Coordination Polymer.

To realize the aim of easy and accurate detection of ammonia and picric acid (PA) in both aqueous and vapor phases based on function-oriented investigation principles, in the present study, we include a luminescent performance with recognition performance, taking into account the application conditions. Zn(II) ions with luminescence qualities and an amine-substituted imidazole moiety with selective recognition properties towards picric acid and ammonia are coupled to generate a novel 1D luminous Zn(II) coordination polymer, Zn-CP [{Zn(II)( 2-ABZ)2(2-BDC)}].MeOH]∞, where 2-ABZ and 2-BDC stand for terephthalic acid and protonated 2 aminobenzimidazole, respectively. Tests for luminescence recognition demonstrate that Zn-CP has potent selectivity, and strong sensitivity to ammonia and PA in both media. In both detection processes, the limit of detection (LOD) values are determined to be 40 nm. Spectroscopic and DFT studies reveal that the detection of Trinitrophenol (TNP) primarily involves a synergistic mechanism of Photoinduced Electron Transfer (PET), Fluorescence Resonance Energy Transfer (FRET), and Charge Transfer (CT). In contrast, the detection of ammonia (NH3) vapor is predominantly driven by hydrogen bonding (H-bonding) formation. The constructed 1D luminous Zn-CP is a new material that guides the development of novel luminous sensors in the future.

Biomimetic prebiotic synthesis of homochiral peptides via a potential 5'-aa-AMP precursor.

Inspired by biosynthetic peptides, we investigate the chiral recognition properties of adenylate amidate (N-aa-AMP, a potential analog of 5'-aa-AMP) in prebiotic peptide formation. Our findings demonstrate that N-L-aa-AMP preferentially binds to L-aa, facilitating the formation of homochiral peptides, while N-D-aa-AMP shows a preference for D-aa, thereby achieving homochirality in peptide synthesis. Collectively, these results enhance our understanding of the evolutionary origins of homochirality on prebiotic Earth.

Bipyridine-Containing Optically Active π-Conjugated Polymers Derived from Amino Alcohols: Examination of the Higher-Order Structures, Chiral Recognition, and Metal Coordination Based on Quantum Mechanical and Molecular Dynamics Calculations.

Helical π-conjugated polymers are promising as optically active functional materials. The present paper reports the synthesis of novel bipyridine-containing π-conjugated polymers with optically active amino-alcohol-derived side chains, examination of their higher-order structures, chiral recognition, and metal coordination properties. The polymers adopt a folded helical conformation and aggregate in CHCl3/MeOH depending on the solvent composition, as supported by density functional theory calculations and molecular dynamics simulations. The polymer films showed differences in contact angles with aqueous solutions of (R)- and (S)-alcohols. Addition of some metal chlorides and perchlorates changed the intensity and color of the photoluminescence of the polymers.

Acetylated Globotetraose (Ac-Gb4) Suppresses Triple-Negative Breast Cancer Through FAK/AKT Signaling Pathway.

Triple-negative breast cancer (TNBC) remains a significant therapeutic challenge due to its unresponsiveness to hormone and HER2-targeted treatments. This study investigated the potential of acetylated globotetraose (Ac-Gb4) as a novel therapeutic approach targeting glycolipid-mediated signaling in breast cancer cells. We synthesized acetylated globotetraose (Gb4) to enhance its membrane permeability while preserving its biological recognition properties. Flow cytometry analysis revealed that Ac-Gb4 treatment significantly decreased SSEA3 and SSEA4 expression in MDA-MB-231 breast cancer cells, which are Globo-H-negative cells. Notably, Ac-Gb4 demonstrated selective cytotoxicity against cancer cells by significantly reducing proliferation and inducing apoptosis in MDA-MB-231 cells while sparing hTERT-HME1 normal breast epithelial cells. Mechanistic studies through Western blot analysis revealed that Ac-Gb4 simultaneously modulated multiple signaling pathways, including FAK cleavage, reduced AKT expression, and increased caspase-3 activation, particularly at the 4 mM concentration. These molecular changes correlated with decreased cancer cell invasion capability in a dose-dependent manner. Our findings demonstrated that Ac-Gb4 effectively targeted breast cancer cells through the modulation of critical signaling pathways involved in cell survival and invasion while maintaining a minimal impact on normal cells. This anti-cancer activity suggests that Ac-Gb4 represents a promising therapeutic candidate for breast cancer treatment, particularly for aggressive subtypes such as TNBC.

The Versatile Applications of Calix[4]resorcinarene-Based Cavitands.

The advancement of synthetic host-guest chemistry has played a pivotal role in exploring and quantifying weak non-covalent interactions, unraveling the intricacies of molecular recognition in both chemical and biological systems. Macrocycles, particularly calix[4]resorcinarene-based cavitands, have demonstrated significant utility in receptor design, facilitating the creation of intricately organized architectures. Within the realm of macrocycles, these cavitands stand out as privileged scaffolds owing to their synthetic adaptability, excellent topological structures, and unique recognition properties. So far, extensive investigations have been conducted on various applications of calix[4]resorcinarene-based cavitands. In this review, we will elaborate on their diverse functions, including catalysis, separation and purification, polymeric materials, sensing, battery materials, as well as drug delivery. This review aims to provide a holistic understanding of the multifaceted roles of calix[4]resorcinarene-based cavitands across various applications, shedding light on their contributions to advancing the field of supramolecular chemistry.

Partially Sulfated Pillar[5]Arenes: Synthesis and Molecular Recognition Properties.

We report the synthesis and characterization of sulfated pillar[5]arene hosts (P5S2-P5S10) that differ in the number of sulfate substituents. All five P5Sn hosts display high solubility in water (73-131 mM) and do not undergo significant self-association according to 1H NMR dilution experiments. The x-ray crystal structures of P5S6, P5S6 ⋅ Me6HDA, P5S8 ⋅ Me6HDA, and P5S10 ⋅ Me6HDA reveal one intracavity molecule of Me6HDA and several external molecules of Me6HDA which form a network of close methonium ⋅ ⋅ ⋅ sulfate interactions. The thermodynamic parameters of complexation between P5Sn and the panel of guests was measured by direct or competitive isothermal titration calorimetry. We find that the binding free energy toward a guest becomes more negative as the number of sulfate substituents increase. Conversely, the binding free energy of a specific sulfated pillar[5]arene toward a homologous series of guests becomes more negative as the number of NMe groups increases. The ability to tune the host ⋅ guest affinity by changing the number of sulfate substituents will be valuable in supramolecular polymers, separation materials, and latching applications.

Spc2 modulates substrate- and cleavage site-selection in the yeast signal peptidase complex.

Secretory proteins are critically dependent on the correct processing of their signal sequence by the signal peptidase complex (SPC). This step, which is essential for the proper folding and localization of proteins in eukaryotic cells, is still not fully understood. In eukaryotes, the SPC comprises four evolutionarily conserved membrane subunits (Spc1-3 and Sec11). Here, we investigated the role of Spc2, examining SPC cleavage efficiency on various models and natural signal sequences in yeast cells depleted of or with mutations in Spc2. Our data show that discrimination between substrates and identification of the cleavage site by SPC is compromised when Spc2 is absent or mutated. Molecular dynamics simulation of the yeast SPC AlphaFold2-Multimer model indicates that membrane thinning at the center of SPC is reduced without Spc2, suggesting a molecular explanation for the altered substrate recognition properties of SPC lacking Spc2. These results provide new insights into the molecular mechanisms by which SPC governs protein biogenesis.

Chiral helical polyaniline modified electrodes toward efficient enantioselective recognition of tyrosine

Enantiomeric analysis is a crucial aspect of the investigation of the properties of chiral substances, and it plays a pivotal role in the development and application of chiral substances. Therefore, the objective of this study was to develop a highly sensitive and user-friendly tyrosine (Tyr) enantiomer detector based on chiral helical polyaniline (PANI). In this study, the helical PANI was generated in an alcohol-water system and doped with Camphorsulfonic acid (CSA) to enhance its electrochemical properties. The chiral helical PANI was then obtained by eluting the CSA under alkaline conditions. The electrochemical sensors developed using this material enable selective recognition of Tyr enantiomers. The mechanism of enantioselective recognition was also explored from a molecular perspective with the help of modeling software. The chiral recognition ability and properties of the sensor were investigated using DPV, EIS, and CV. The surface characteristics of doped and de-doped chiral sensor were analyzed using FE-SEM, HR-TEM, AFM, CD, XPS, and FT-IR. Finally, an electrochemical analysis method for Tyr enantiomers was established using DPV, offering high sensitivity, superior anti-interference ability, quick analysis speed, and good long-term stability. The constructed chiral electrochemical sensor can be used for the detection of human serum and urine samples, which provides a new idea for the selective recognition of Tyr enantiomers in clinical sample.

Preparation of a 1,1'-Binaphthyl-based Chiral Polyimine Macrocycle Bonded Chiral Stationary Phase by Thiol-ene Click Reaction and Its Enantioseparation Performance in High-Performance Liquid Chromatography.

Chiral macrocycles have emerged as attractive media for chromatographic enantioseparation due to their excellent host-guest recognition properties. In this study, a new chiral stationary phase (CSP) based on 1,1'-binaphthyl chiral polyimine macrocycle (CPM) was reported. The CPM was synthesized by one-step aldehyde-amine condensation of (S)-2,2'-dihydroxy-[1,1'-binaphthalene]-3,3'-dicarboxaldehyde with 1,2-phenylenediamine and bonded on thiolated silica via the thiol-ene click reaction to afford the CSP. The enantioseparation performance of the CSP was evaluated by separating different types of racemates including alcohols, esters, ketones, amides, organic acids, and ethers in both normal-phase (NP) and reversed-phase (RP) elution modes. As a result, enantioseparations of 10 and 15 racemates were achieved in the two elution modes, respectively. Meanwhile, the effects of chromatographic conditions on separation, such as mobile phase composition and injection mass, were studied in detail. Moreover, a comparison of the proposed CSP for the separation of the tested racemates with commercial Chiralcel OD-H and Chiralpak AD-H columns was also conducted, and results revealed that the proposed CSP can achieve some enantioseparations that cannot be achieved by the two commercial columns. This study indicates that the chiral macrocycle is a promising chiral selector for high-performance liquid chromatography.

Molecularly imprinted polymers (MIPs) for SARS-CoV-2 omicron variant inhibition: An alternative approach to address the challenge of emerging zoonoses

Emerging zoonoses pose significant public health risks and necessitate rapid and effective treatment responses. This study enhances the technology for preparing Molecularly Imprinted Polymers (MIPs), which function as synthetic nanoparticles targeting SARS-CoV-2 receptor-binding domain (RBD), specifically the Omicron variant, thereby inhibiting its function. This study builds on previous findings by introducing precise adjustments in the formulation and process conditions to enhance particle stability and ensure better control over size and distribution, thereby overcoming the issues identified in earlier research. Following docking studies, imprinted nanoparticles were synthesized via inverse microemulsion polymerization and characterized in terms of size, morphology and surface charge. The selective recognition properties and ability of MIPs to obstruct the interaction between ACE2 and the RBD of SARS-CoV-2 were assessed in vitro, using Non-Imprinted Polymers (NIPs) as controls, and rebinding studies were conducted utilizing a Quartz Crystal Microbalance with Dissipation monitoring (QCM-D). The synthesized nanoparticles exhibited uniform dispersion and had a consistent diameter within the nanoscale range. MIPs demonstrated significant recognition properties and exhibited a concentration-dependent ability to reduce RBD binding to ACE2 without cytotoxic or sensitizing effects. MIPs-based platforms offer a promising alternative to natural antibodies for treating SARS-CoV-2 infections, therefore representing a versatile platform for managing emerging zoonoses.

Grafting a chromophore on AMD070 analogues for CXCR4 bioimaging: Chemical synthesis and in vitro assessment of the inhibition properties of the CXCR4 receptor

Thank to their particular pharmacokinetics, the use of small organic molecules can be a very promising alternative to macromolecular targeting biomolecules (i.e. antibodies, peptides…) for specific imaging of tumours. Herein, the potential of two AMD070-like inhibitors as CXCR4-targeting units for specific imaging of cancer cells, and the influence of chromophore-grafting on their recognition properties was investigated.

Engineered odorant receptors illuminate the basis of odour discrimination.

How the olfactory system detects and distinguishes odorants with diverse physicochemical properties and molecular configurations remains poorly understood. Vertebrate animals perceive odours through G protein-coupled odorant receptors (ORs)1. In humans, around 400 ORs enable the sense of smell. The OR family comprises two main classes: class I ORs are tuned to carboxylic acids whereas class II ORs, which represent most of the human repertoire, respond to a wide variety of odorants2. A fundamental challenge in understanding olfaction is the inability to visualize odorant binding to ORs. Here we uncover molecular properties of odorant-OR interactions by using engineered ORs crafted using a consensus protein design strategy3. Because such consensus ORs (consORs) are derived from the 17 major subfamilies of human ORs, they provide a template for modelling individual native ORs with high sequence and structural homology. The biochemical tractability of consORs enabled the determination of four cryogenic electron microscopy structures of distinct consORs with specific ligand recognition properties. The structure of a class I consOR, consOR51, showed high structural similarity to the native human receptor OR51E2 and generated a homology model of a related member of the human OR51 family with high predictive power. Structures of three class II consORs revealed distinct modes of odorant-binding and activation mechanisms between class I and class II ORs. Thus, the structures of consORs lay the groundwork for understanding molecular recognition of odorants by the OR superfamily.

Molecularly imprinted electrochemiluminescence sensor based on luminol functionalized Co-MOF for rifampicin detection.

A highly sensitive molecularly imprinted electrochemiluminescence (MIECL) sensor was developed for detecting rifampicin (RIF) based on luminol@Co-MOF. Co-MOF had a significant enhancement of ECL signaling in the luminol-O2 system. Molecular imprinted polymers (MIPs) with the introduction of RIF provide new properties for the specific recognition of RIF. A noteworthy decrease in ECL intensity was observed with higher concentrations of RIF. Consequently, the ECL signal was controlled by RIF elution from and adsorption by the MIP, thus establishing a new method for RIF detection. Under optimal conditions, this sensor exhibited linear detection ranges of RIF between 1.0 × 10-11mol L-1 and 1.0 × 10-6mol L-1, with a detection limit of 3.3 × 10-12mol L-1 (S/N = 3). The recoveries ranged between 98.1 and 106.0% in fish samples. This method can be used as a sensitive and rapid method to detect RIF in real samples.

Prenatal ethanol exposure impairs hippocampal plasticity and cognition in adolescent mice

BackgroundPrenatal alcohol exposure (PAE) induces a wide range of neurodevelopmental disabilities that are grouped under the term ‘fetal alcohol spectrum disorders’ (FASD). The effects of PAE on brain development are dependent on complex neurochemical events, including modification of AMPA receptors (AMPARs). We have recently found that chronic ethanol (EtOH) exposure decreases AMPA-mediated neurotransmission and expression through the overexpression of the specific microRNA (miR)137 and 501-3p, which target GluA1 AMPA subunit, in the developing hippocampus in vitro. Here, we explored how PAE mice may alter AMPAergic synapses in the hippocampus, and its effects on behavior. MethodsTo model PAE, we exposed C57Bl/6 pregnant mice to 10 % EtOH during during the first 10 days of gestation (GD 0–10; equivalent to the first trimester of pregnancy in humans). AMPA subunits postsynaptic expression in the hippocampus, electrical properties of CA1 neurons, memory recognition, and locomotor functions were then analyzed in adolescent PAE-exposed offspring. ResultsPAE adolescent mice showed dysregulation of AMPAergic neurotransmission, and increased miR 501-3p expression, associated with a significant reduction of spontaneous AMPA currents and intrinsic somatic excitability. In addition, PAE reduced the phosphorylation of AMPAR-containing GluA1 subunit, despite an increase in its total levels. Of note, the total levels of GluA2 and GluA3 AMPA receptors were enhanced as well. Consistently, at behavioral level, PAE reduced object recognition without altering locomotor activity. ConclusionsOur study shows that PAE leads to dysfunctional formation of AMPAergic synapses that could be responsible for neurobehavioral impairments, contributing to the understanding of the pathogenesis of FASD.