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1.
Nat Commun ; 15(1): 4733, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38830951

RESUMO

Polymyxins are gram-negative antibiotics that target lipid A, the conserved membrane anchor of lipopolysaccharide in the outer membrane. Despite their clinical importance, the molecular mechanisms underpinning polymyxin activity remain unresolved. Here, we use surface plasmon resonance to kinetically interrogate interactions between polymyxins and lipid A and derive a phenomenological model. Our analyses suggest a lipid A-catalyzed, three-state mechanism for polymyxins: transient binding, membrane insertion, and super-stoichiometric cluster accumulation with a long residence time. Accumulation also occurs for brevicidine, another lipid A-targeting antibacterial molecule. Lipid A modifications that impart polymyxin resistance and a non-bactericidal polymyxin derivative exhibit binding that does not evolve into long-lived species. We propose that transient binding to lipid A permeabilizes the outer membrane and cluster accumulation enables the bactericidal activity of polymyxins. These findings could establish a blueprint for discovery of lipid A-targeting antibiotics and provide a generalizable approach to study interactions with the gram-negative outer membrane.


Assuntos
Antibacterianos , Lipídeo A , Polimixina B , Ressonância de Plasmônio de Superfície , Polimixina B/farmacologia , Polimixina B/metabolismo , Lipídeo A/metabolismo , Lipídeo A/química , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/metabolismo , Testes de Sensibilidade Microbiana , Membrana Externa Bacteriana/metabolismo , Membrana Externa Bacteriana/efeitos dos fármacos , Cinética
2.
Methods Mol Biol ; 2796: 105-118, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38856898

RESUMO

Ion channels are transmembrane proteins essential for cellular functions and are important drug targets. Surface plasmon resonance (SPR) is a powerful technique for investigating protein-protein and protein-small molecule ligand interactions. SPR has been underutilized for studies of ion channels, even though it could provide a wealth of information on the mechanisms of ion channel regulation and aid in ion channel drug discovery. Here we provide a detailed description of the use of SPR technology for investigating inter-domain interactions in KCNH potassium-selective and voltage-gated ion channels.


Assuntos
Ressonância de Plasmônio de Superfície , Ressonância de Plasmônio de Superfície/métodos , Humanos , Ligação Proteica , Canais Iônicos/metabolismo , Canais Iônicos/química , Canais de Potássio Éter-A-Go-Go/metabolismo , Canais de Potássio Éter-A-Go-Go/química , Domínios e Motivos de Interação entre Proteínas , Ligantes , Animais
3.
Mol Biol Rep ; 51(1): 722, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38829419

RESUMO

BACKGROUND: Yersinia pestis is a bacterium that causes the disease plague. It has caused the deaths of many people throughout history. The bacterium possesses several virulence factors (pPla, pFra, and PYV). PFra plasmid encodes fraction 1 (F1) capsular antigen. F1 protein protects the bacterium against host immune cells through phagocytosis process. This protein is specific for Y. pestis. Many diagnostic techniques are based on molecular and serological detection and quantification of F1 protein in different food and clinical samples. Aptamers are small nucleic acid sequences that can act as specific ligands for many targets.This study, aimed to isolate the high-affinity ssDNA aptamers against F1 protein. METHODS AND RESULTS: In this study, SELEX was used as the main strategy in screening aptamers. Moreover, enzyme-linked aptamer sorbent assay (ELASA) and surface plasmon resonance (SPR) were used to determine the affinity and specificity of obtained aptamers to F1 protein. The analysis showed that among the obtained aptamers, the three aptamers of Yer 21, Yer 24, and Yer 25 were selected with a KD value of 1.344E - 7, 2.004E - 8, and 1.68E - 8 M, respectively. The limit of detection (LoD) was found to be 0.05, 0.076, and 0.033 µg/ml for Yer 21, Yer 24, and Yer 25, respectively. CONCLUSION: This study demonstrated that the synthesized aptamers could serve as effective tools for detecting and analyzing the F1 protein, indicating their potential value in future diagnostic applications.


Assuntos
Aptâmeros de Nucleotídeos , Proteínas de Bactérias , Técnica de Seleção de Aptâmeros , Yersinia pestis , Yersinia pestis/genética , Técnica de Seleção de Aptâmeros/métodos , Proteínas de Bactérias/genética , Ressonância de Plasmônio de Superfície/métodos , Humanos , Peste/diagnóstico , Peste/microbiologia , Antígenos de Bactérias
4.
Mikrochim Acta ; 191(7): 373, 2024 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-38842697

RESUMO

The design of surface plasmon resonance (SPR) sensors has been greatly enhanced in recent years by the advancements in the production and integration of nanostructures, leading to more compact and efficient devices. There have been reports of novel SPR sensors having distinct nanostructures, either as signal amplification tags like gold nanoparticles (AuNPs) or as sensing substrate-like two-dimensional (2D) materials including graphene, transition metal dichalcogenides (TMDCs), MXene, black phosphorus (BP), metal-organic frameworks (MOFs), and antimonene. Such 2D-based SPR biosensors offer advantages over conventional sensors due to significant increases in their sensitivity with a good figure of merit and limit of detection (LOD). Due to their atomically thin structure, improved sensitivity, and sophisticated functionalization capabilities, 2D materials can open up new possibilities in the field of healthcare, particularly in point-of-care diagnostics, environmental and food monitoring, homeland security protection, clinical diagnosis and treatment, and flexible or transient bioelectronics. The present study articulates an in-depth analysis of the most recent developments in 2D material-based SPR sensor technology. Moreover, in-depth research of 2D materials, their integration with optoelectronic technology for a new sensing platform, and the predicted and experimental outcomes of various excitation approaches are highlighted, along with the principles of SPR biosensors. Furthermore, the review projects the potential prospects and future trends of these emerging materials-based SPR biosensors to advance in clinical diagnosis, healthcare biochemical, and biological applications.


Assuntos
Ressonância de Plasmônio de Superfície , Técnicas Biossensoriais/métodos , Ouro/química , Grafite/química , Limite de Detecção , Nanopartículas Metálicas/química , Estruturas Metalorgânicas/química , Nanoestruturas/química , Fósforo/química , Ressonância de Plasmônio de Superfície/métodos
5.
Sci Rep ; 14(1): 13117, 2024 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-38849511

RESUMO

A surface plasmon resonance (SPR) phenomenon implemented via D-shaped polymer optical fiber (POF) is exploited to realize cortisol biosensors. In this work, two immonosensors are designed and developed for the qualitative as well as quantitative measurement of cortisol in artificial and real samples. The performances of the POF-based biosensors in cortisol recognition are achieved using different functionalization protocols to make the same antibody receptor layer over the SPR surface via cysteamine and lipoic acid, achieving a limit of detection (LOD) of 0.8 pg/mL and 0.2 pg/mL, respectively. More specifically, the use of cysteamine or lipoic acid changes the distance between the receptor layer and the SPR surface, improving the sensitivity at low concentrations of about one order of magnitude in the configuration based on lipoic acid. The LODs of both cortisol biosensors are achieved well competitively with other sensor systems but without the need for amplification or sample treatments. In order to obtain the selectivity tests, cholesterol and testosterone were used as interfering substances. Moreover, tests in simulated seawater were performed for the same cortisol concentration range achieved in buffer solution to assess the immunosensor response to the complex matrix. Finally, the developed cortisol biosensor was used in a real seawater sample to estimate the cortisol concentration value. The gold standard method has confirmed the estimated cortisol concentration value in real seawater samples. Liquid-liquid extraction was implemented to maximize the response of cortisol in liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis.


Assuntos
Aquicultura , Técnicas Biossensoriais , Hidrocortisona , Água do Mar , Ressonância de Plasmônio de Superfície , Hidrocortisona/análise , Água do Mar/análise , Técnicas Biossensoriais/métodos , Ressonância de Plasmônio de Superfície/métodos , Aquicultura/métodos , Limite de Detecção , Fibras Ópticas , Polímeros/química
6.
J Environ Manage ; 362: 121347, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38838534

RESUMO

The traditional homogenous and heterogenous Fenton reactions have frequently been restrained by the lower production of Fe2+ ions, which significantly obstructs the generation of hydroxyl radicals from the decomposition of H2O2. Thus, we introduce novel photo-Fenton-assisted plasmonic heterojunctions by immobilizing Fe3O4 and Bi nanoparticles onto 3D Sb2O3 via co-precipitation and solvothermal approaches. The ternary Sb2O3/Fe3O4/Bi composites offered boosted photo-Fenton behavior with a metronidazole (MNZ) oxidation efficiency of 92% within 60 min. Among all composites, the Sb2O3/Fe3O4/Bi-5% hybrid exhibited an optimum photo-Fenton MNZ reaction constant of 0.03682 min- 1, which is 5.03 and 2.39 times higher than pure Sb2O3 and Sb2O3/Fe3O4, respectively. The upgraded oxidation activity was connected to the complementary outcomes between the photo-Fenton behavior of Sb2O3/Fe3O4 and the plasmonic effect of Bi NPs. The regular assembly of Fe3O4 and Bi NPs enhances the surface area and stability of Sb2O3/Fe3O4/Bi. Moreover, the limited absorption spectra of Sb2O3 were extended into solar radiation by the Fe3+ defect of Fe3O4 NPs and the surface plasmon resonance (SPR) effect of Bi NPs. The photo-Fenton mechanism suggests that the co-existence of Fe3O4/Bi NPs acts as electron acceptor/donor, respectively, which reduces recombination losses, prolongs the lifetime of photocarriers, and produces more reactive species, stimulating the overall photo-Fenton reactions. On the other hand, the photo-Fenton activity of MNZ antibiotics was optimized under different experimental conditions, including catalyst loading, solution pH, initial MNZ concentrations, anions, and real water environments. Besides, the trapping outcomes verified the vital participation of •OH, h+, and •O2- in the MNZ destruction over Sb2O3/Fe3O4/Bi-5%. In summary, this work excites novel perspectives in developing boosted photosystems through integrating the photocatalysis power with both Fenton reactions and the SPR effects of plasmonic materials.


Assuntos
Peróxido de Hidrogênio , Metronidazol , Oxirredução , Metronidazol/química , Peróxido de Hidrogênio/química , Ressonância de Plasmônio de Superfície , Ferro/química , Poluentes Químicos da Água/química , Antimônio/química , Água/química
7.
Anal Chim Acta ; 1315: 342822, 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-38879216

RESUMO

In this study, a novel electrochemiluminescence (ECL) biosensor was developed to detect microRNA-21 (miRNA-21) with high sensitivity by leveraging the combined mechanisms of resonance energy transfer (RET) and surface plasmon coupling (SPC). Initially, the glassy carbon electrode (GCE) were coated with Cu-Zn-In-S quantum dots (CZIS QDs), known for their defect-related emission suitable for ECL sensing. Subsequently, a hairpin DNA H3 with gold nanoparticles (Au NPs) attached at the end was modified over the surface of the quantum dots. The Au NPs could effectively quench the ECL signals of CZIS QDs via RET. Further, a significant amount of report DNA was generated through the action of a 3D DNA walker. When the report DNA opened H3-Au NPs, the hairpin structure experienced a conformational change to a linear shape, increasing the gap between the CZIS QDs and the Au NPs. Consequently, the localized surface plasmon resonance ECL (LSPR-ECL) effect replaced ECL resonance energy transfer (ECL-RET). Moreover, the report DNA was released following the addition of H4-Au NPs, resulting in the formation of Au dimers and a surface plasma-coupled ECL (SPC-ECL) effect that enhanced the ECL intensity to 6.97-fold. The integration of new ECL-RET and SPC-ECL biosensor accurately quantified miRNA-21 concentrations from 10-8 M to 10-16 M with a limit of detection (LOD) of 0.08 fM, as well as successfully applied to validate human serum samples.


Assuntos
Técnicas Biossensoriais , DNA , Técnicas Eletroquímicas , Medições Luminescentes , MicroRNAs , Pontos Quânticos , Ressonância de Plasmônio de Superfície , MicroRNAs/análise , MicroRNAs/sangue , Humanos , Técnicas Eletroquímicas/métodos , Técnicas Biossensoriais/métodos , DNA/química , Pontos Quânticos/química , Ressonância de Plasmônio de Superfície/métodos , Medições Luminescentes/métodos , Ouro/química , Limite de Detecção , Transferência de Energia , Nanopartículas Metálicas/química
8.
Anal Biochem ; 692: 115580, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38825159

RESUMO

Ricin is one of the most toxic substances known and a type B biothreat agent. Shiga toxins (Stxs) produced by E. coli (STEC) and Shigella dysenteriae are foodborne pathogens. There is no effective therapy against ricin or STEC and there is an urgent need for inhibitors. Ricin toxin A subunit (RTA) and A1 subunit of Stx2a (Stx2A1) bind to the C-terminal domain (CTD) of the ribosomal P-stalk proteins to depurinate the sarcin/ricin loop. Modulation of toxin-ribosome interactions has not been explored as a strategy for inhibition. Therefore, development of assays that detect inhibitors targeting toxin-ribosome interactions remains a critical need. Here we describe a fluorescence anisotropy (FA)-based competitive binding assay using a BODIPY-TMR labeled 11-mer peptide (P11) derived from the P-stalk CTD to measure the binding affinity of peptides ranging from 3 to 11 amino acids for the P-stalk pocket of RTA and Stx2A1. Comparison of the affinity with the surface plasmon resonance (SPR) assay indicated that although the rank order was the same by both methods, the FA assay could differentiate better between peptides that show nonspecific interactions by SPR. The FA assay detects only interactions that compete with the labeled P11 and can validate inhibitor specificity and mechanism of action.


Assuntos
Polarização de Fluorescência , Ribossomos , Ricina , Ricina/antagonistas & inibidores , Ricina/metabolismo , Ricina/química , Polarização de Fluorescência/métodos , Ribossomos/metabolismo , Ressonância de Plasmônio de Superfície , Toxina Shiga/antagonistas & inibidores , Toxina Shiga/metabolismo , Toxina Shiga/química , Ligação Competitiva , Ligação Proteica , Toxina Shiga II/antagonistas & inibidores , Toxina Shiga II/metabolismo , Toxina Shiga II/química
9.
Int J Biol Macromol ; 272(Pt 1): 132624, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38838594

RESUMO

In this work, the interaction of chondroitin sulfate (CS) and dermatan sulfate (DS) with plant lectins was studied by affinity capillary electrophoresis (ACE), surface plasmon resonance (SPR) technology, molecular docking simulation, and circular dichroism spectroscopy. The ACE method was used for the first time to study the interaction of Ricinus Communis Agglutinin I (RCA I), Wisteria Floribunda Lectin (WFA), and Soybean Agglutinin (SBA) with CS and DS, and the results were in good agreement with those of the SPR method. The results of experiments indicate that RCA I has a strong binding affinity with CS, and the sulfated position does not affect the relationship, but the degree of sulfation can affect the combination of RCA I with CS to some extent. However, the binding affinity with DS is very weak. This study lays the foundation for developing more specialized analysis methods for CS and DS based on RCA I.


Assuntos
Sulfatos de Condroitina , Dermatan Sulfato , Simulação de Acoplamento Molecular , Lectinas de Plantas , Ligação Proteica , Sulfatos de Condroitina/química , Dermatan Sulfato/química , Dermatan Sulfato/metabolismo , Lectinas de Plantas/química , Lectinas de Plantas/metabolismo , Ressonância de Plasmônio de Superfície , Aglutininas/química , Aglutininas/metabolismo , Dicroísmo Circular , Eletroforese Capilar
10.
Opt Express ; 32(10): 17239-17254, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38858913

RESUMO

Doxorubicin (DOX) is an important drug for cancer treatment, but its clinical application is limited due to its toxicity and side effects. Therefore, detecting the concentration of DOX during treatment is crucial for enhancing efficacy and reducing side effects. In this study, the authors developed a biophotonic fiber sensor based on localized surface plasmon resonance (LSPR) with the multimode fiber (MMF)-four core fiber (FCF)-seven core fiber (SCF)-MMF-based direct-taper and anti-taper structures for the specific detection of DOX. Compared to other detection methods, it has the advantages of high sensitivity, low cost, and strong anti-interference ability. In this experiment, multi-walled carbon nanotubes (MWCNTs), cerium-oxide nanorods (CeO2-NRs), and gold nanoparticles (AuNPs) were immobilized on the probe surface to enhance the sensor's biocompatibility. MWCNTs and CeO2-NRs provided more binding sites for the fixation of AuNPs. By immobilizing AuNPs on the surface, the LSPR was stimulated by the evanescent field to detect DOX. The sensor surface was functionalized with DOX aptamers for specific detection, enhancing its specificity. The experiments demonstrated that within a linear detection range of 0-10 µM, the sensitivity of the sensor is 0.77 nm/µM, and the limit of detection (LoD) is 0.42 µM. Additionally, the probe's repeatability, reproducibility, stability, and selectivity were evaluated, indicating that the probe has high potential for detecting DOX during cancer treatment.


Assuntos
Doxorrubicina , Ouro , Nanopartículas Metálicas , Ressonância de Plasmônio de Superfície , Doxorrubicina/farmacologia , Humanos , Ressonância de Plasmônio de Superfície/instrumentação , Ouro/química , Nanopartículas Metálicas/química , Neoplasias/tratamento farmacológico , Nanotubos de Carbono/química , Técnicas Biossensoriais/instrumentação , Fibras Ópticas , Desenho de Equipamento , Antibióticos Antineoplásicos/análise , Cério/química , Tecnologia de Fibra Óptica/instrumentação
11.
Opt Express ; 32(11): 20024-20034, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38859121

RESUMO

An optical fiber sensing probe using a composite sensitive film of polyacrylonitrile (PAN) nanofiber membrane and gold nanomembrane is presented for the detection of a carcinoembryonic antigen (CEA), a biomarker associated with colorectal cancer and other diseases. The probe is based on a tilted fiber Bragg grating (TFBG) with a surface plasmon resonance (SPR) gold nanomembrane and a functionalized polyacrylonitrile (PAN) PAN nanofiber coating that selectively binds to CEA molecules. The performance of the probe is evaluated by measuring the spectral shift of the TFBG resonances as a function of CEA concentration in buffer. The probe exhibits a sensitivity of 0.46 dB/(µg/ml), a low limit of detection of 505.4 ng/mL in buffer, and a good selectivity and reproducibility. The proposed probe offers a simple, cost-effective, and a novel method for CEA detection that can be potentially applied for clinical diagnosis and monitoring of CEA-related diseases.


Assuntos
Resinas Acrílicas , Antígeno Carcinoembrionário , Ouro , Nanofibras , Fibras Ópticas , Ressonância de Plasmônio de Superfície , Antígeno Carcinoembrionário/análise , Ouro/química , Nanofibras/química , Ressonância de Plasmônio de Superfície/instrumentação , Ressonância de Plasmônio de Superfície/métodos , Resinas Acrílicas/química , Humanos , Técnicas Biossensoriais/instrumentação , Membranas Artificiais , Nanopartículas Metálicas/química , Reprodutibilidade dos Testes , Tecnologia de Fibra Óptica/instrumentação
12.
Opt Express ; 32(9): 16040-16051, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38859241

RESUMO

Chiral materials are essential to perceive photonic devices that control the helicity of light. However, the chirality of natural materials is rather weak, and relatively thick films are needed for noticeable effects. To overcome this limitation, artificial photonic materials were suggested to affect the chiral response in a much more substantial manner. Ideally, a single layer of such a material, a metasurface, should already be sufficient. While various structures fabricated with top-down nanofabrication technologies have already been reported, here we propose to utilize scaffolded DNA origami technology, a scalable bottom-up approach for metamolecule production, to fabricate a chiral metasurface. We introduce a chiral plasmonic metamolecule in the shape of a tripod and simulate its optical properties. By fixing the metamolecule to a rectangular planar origami, the tripods can be assembled into a 2D DNA origami crystal that forms a chiral metasurface. We simulate the optical properties but also fabricate selected devices to assess the experimental feasibility of the suggested approach critically.


Assuntos
DNA , DNA/química , Ressonância de Plasmônio de Superfície/instrumentação , Nanotecnologia , Nanoestruturas/química
13.
Opt Express ; 32(8): 13783-13796, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38859339

RESUMO

The conical fiber SPR sensor is easy to manufacture and has been used in biochemical detection research, but it has the problem of structural fragility. This article proposes a spiral cone fiber SPR sensor, which introduces a spiral structure on the 76µm fiber coarse cone, achieving good coupling of the core mode into the cladding mode, and improving the physical strength and practicality of the cone-shaped fiber SPR sensor. By modifying the target protein on the surface of the sensor gold film, specific detection of ginsenoside Rg1, an active ingredient of traditional Chinese medicine ginseng, was achieved. The detection sensitivity was 0.138 nm/(µm/ml) and the detection limit was 0.22µm/ml. The proposed spiral cone fiber SPR sensor provides a new scheme for the specific detection of active ingredients in traditional Chinese medicine, which is structurally stable and physically strong.


Assuntos
Ginsenosídeos , Ressonância de Plasmônio de Superfície , Ginsenosídeos/análise , Ressonância de Plasmônio de Superfície/métodos , Técnicas Biossensoriais/instrumentação , Desenho de Equipamento , Tecnologia de Fibra Óptica/instrumentação , Limite de Detecção
14.
Nano Lett ; 24(22): 6480-6487, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38771966

RESUMO

The metal plasmonic nanostructure has the optical property of plasmon resonance, which holds great potential for development in nanophotonics, bioelectronics, and molecular detection. However, developing a general and straightforward method to prepare metal plasmonic nanostructures with a controllable size and morphology still poses a challenge. Herein, we proposed a synthesis strategy that utilized a customizable self-assembly template for shape-directed growth of metal structures. We employed gold nanoparticles (AuNPs) as connectors and DNA nanotubes as branches, customizing gold nanoparticle-DNA origami composite nanostructures with different branches by adjusting the assembly ratio between the connectors and branches. Subsequently, various morphologies of plasmonic metal nanostructures were created using this template shape guided strategy, which exhibited enhancement of surface-enhanced Raman scattering (SERS) signals. This strategy provides a new approach for synthesizing metallic nanostructures with multiple morphologies and opens up another possibility for the development of customizable metallic plasmonic structures with broader applications.


Assuntos
DNA , Ouro , Nanopartículas Metálicas , Ouro/química , Nanopartículas Metálicas/química , DNA/química , Ressonância de Plasmônio de Superfície , Análise Espectral Raman , Nanotecnologia/métodos , Tamanho da Partícula , Nanoestruturas/química , Propriedades de Superfície
15.
ACS Appl Mater Interfaces ; 16(22): 28162-28171, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38767334

RESUMO

This study investigated the suitability of surface modification for a long-range surface plasmon (LRSP) aptasensor using two different hydrogels, aiming at real-time monitoring of vancomycin (VCM) in undiluted serum and blood. Three different layer structures were formed on a gold surface of LRSP sensor chip using poly[2-methacryloyloxyethyl phosphorylcholine (MPC)-co-N-methacryloyl-(L)-tyrosinemethylester (MAT)] (PMM) and poly[MPC-co-2-ethylhexyl methacrylate (EHMA)-co-MAT] (PMEM). The peptide aptamer for VCM was immobilized in PMM and PMEM via MAT. Among four differently prepared sensor chips, the LRSP hydrogel aptasensor with PMM, referred to as the PMM hydrogel, exhibited the highest sensor output and superior antifouling properties. Following the optimization of the PMM hydrogel preparation conditions, the shelf life of the PMM hydrogel was determined to exceed 2 weeks, and the same sensor chip could be used for 102 days without significant performance deterioration. The PMM hydrogel was then applied for VCM measurement in undiluted serum in vitro, where it demonstrated a limit of detection of 0.098 µM and a dynamic range of 0.18-100 µM, covering the therapeutic range. Additionally, the PMM hydrogel enabled the continuous measurement of various VCM concentrations in serum without rinsing and showed a concentration-dependent output in undiluted blood. These findings underscore the potential of the PMM hydrogel for real-time and direct monitoring of VCM in body fluids.


Assuntos
Hidrogéis , Ressonância de Plasmônio de Superfície , Vancomicina , Vancomicina/sangue , Vancomicina/química , Vancomicina/farmacologia , Humanos , Hidrogéis/química , Técnicas Biossensoriais/métodos , Técnicas Biossensoriais/instrumentação , Aptâmeros de Peptídeos/química , Ouro/química , Aptâmeros de Nucleotídeos/química , Antibacterianos/sangue , Antibacterianos/química , Antibacterianos/farmacologia , Fosforilcolina/química , Fosforilcolina/análogos & derivados , Metacrilatos/química
16.
Anal Methods ; 16(22): 3539-3550, 2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38780022

RESUMO

Dengue virus (DENV) is the most prevalent global arbovirus, exhibiting a high worldwide incidence with intensified severity of symptoms and alarming mortality rates. Faced with the limitations of diagnostic methods, an optical and electrochemical biosystem was developed for the detection of DENV genotypes 1 and 2, using cysteine (Cys), cadmium telluride (CdTe) quantum dots, and anti-DENV antibodies. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), surface plasmon resonance (SPR), atomic force microscopy (AFM), and Fourier transform infrared spectroscopy (FTIR) were employed to characterize the immunosensor. The AFM and SPR results demonstrated discernible topographic and angular changes confirming the biomolecular recognition. Different concentrations of DENV-1 and DENV-2 were evaluated (0.05 × 106 to 2.0 × 106 PFU mL-1), resulting in a maximum anodic shift (ΔI%) of 263.67% ± 12.54 for DENV-1 and 63.36% ± 3.68 for DENV-2. The detection strategies exhibited a linear response to the increase in viral concentration. Excellent linear correlations, with R2 values of 0.95391 for DENV-1 and 0.97773 for DENV-2, were obtained across a broad concentration range. Data analysis demonstrated high reproducibility, displaying relative standard deviation values of 3.42% and 3.62% for Cys-CdTe-antibodyDENV-1-BSA and Cys-CdTe-antibodyDENV-2-BSA systems. The detection limits were 0.34 × 106 PFU mL-1 and 0.02 × 106 PFU mL-1, while the quantification limits were set at 1.49 × 106 PFU mL-1 and 0.06 × 106 PFU mL-1 for DENV-1 and DENV-2, respectively. Therefore, the biosensing apparatus demonstrates analytical effectiveness in viral screening and can be considered an innovative solution for early dengue diagnosis, contributing to global public health.


Assuntos
Técnicas Biossensoriais , Vírus da Dengue , Dengue , Telúrio , Vírus da Dengue/isolamento & purificação , Vírus da Dengue/imunologia , Técnicas Biossensoriais/métodos , Telúrio/química , Humanos , Dengue/diagnóstico , Técnicas Eletroquímicas/métodos , Técnicas Eletroquímicas/instrumentação , Pontos Quânticos/química , Ressonância de Plasmônio de Superfície/métodos , Cisteína/química , Compostos de Cádmio/química , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/análise , Imunoensaio/métodos , Imunoensaio/instrumentação , Limite de Detecção , Microscopia de Força Atômica
17.
Colloids Surf B Biointerfaces ; 239: 113964, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38761495

RESUMO

Delamanid is an anti-tuberculosis drug used for the treatment of drug-resistant tuberculosis. Since delamanid has a high protein bound potential, even patients with low albumin levels should experience high and rapid delamanid clearance. However, the interaction between delamanid and albumin should be better controlled to optimize drug efficacy. This study was designed to evaluate the binding characteristics of delamanid to human serum albumin (HSA) using various methods: fluorescence spectroscopy, circular dichroism (CD), surface plasmon resonance (SPR), and molecular docking simulation. The fluorescence emission band without any shift indicated the interaction was not affected by the polarity of the fluorophore microenvironment. The reduction of fluorescence intensity at 344 nm was proportional to the increment of delamanid concentration as a fluorescence quencher. UV-absorbance measurement at the maximum wavelength (λmax, 280 nm) was evaluated using inner filter effect correction. The HSA conformation change was explained by the intermolecular energy transfer between delamanid and HSA during complex formation. The study, which was conducted at temperatures of 298 K, 303 K, and 310 K, revealed a static quenching mechanism that correlated with a decreased of bimolecular quenching rate constant (kq) and binding constant (Ka) at increased temperatures. The Ka was 1.75-3.16 × 104 M-1 with a specific binding site with stoichiometry 1:1. The negative enthalpy change, negative entropy change, and negative Gibbs free energy change demonstrated an exothermic-spontaneous reaction while van der Waals forces and hydrogen bonds played a vital role in the binding. The molecular displacement approach and molecular docking confirmed that the binding occurred mainly in subdomain IIA, which is a hydrophobic pocket of HSA, with a theoretical binding free energy of -9.33 kcal/mol. SPR exhibited a real time negative sensorgram that resulted from deviation of the reflex angle due to ligand delamanid-HSA complex forming. The binding occurred spontaneously after delamanid was presented to the HSA surface. The SPR mathematical fitting model revealed that the association rate constant (kon) was 2.62 × 108 s-1M-1 and the dissociation rate constant (koff) was 5.65 × 10-3 s-1. The complexes were performed with an association constant (KA) of 4.64 × 1010 M-1 and the dissociation constant (KD) of 2.15 × 10-11 M. The binding constant indicated high binding affinity and high stability of the complex in an equilibrium. Modified CD spectra revealed that conformation of the HSA structure was altered by the presence of delamanid during preparation of the proliposomes that led to the reduction of secondary structure stabilization. This was indicated by the percentage decrease of α-helix. These findings are beneficial to understanding delamanid-HSA binding characteristics as well as the drug administration regimen.


Assuntos
Dicroísmo Circular , Simulação de Acoplamento Molecular , Albumina Sérica Humana , Espectrometria de Fluorescência , Ressonância de Plasmônio de Superfície , Termodinâmica , Humanos , Albumina Sérica Humana/química , Albumina Sérica Humana/metabolismo , Cinética , Conformação Proteica , Ligação Proteica , Oxazóis/química , Oxazóis/metabolismo
18.
ACS Appl Mater Interfaces ; 16(23): 29645-29656, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38809175

RESUMO

The cell-SELEX method enables efficient selection of aptamers that bind whole bacterial cells. However, after selection, it is difficult to determine their binding affinities using common screening methods because of the large size of the bacteria. Here we propose a simple surface plasmon resonance imaging method (SPRi) for aptamer characterization using bacterial membrane vesicles, called nanosomes, instead of whole cells. Nanosomes were obtained from membrane fragments after mechanical cell disruption in order to preserve the external surface epitopes of the bacterium used for their production. The study was conducted on Bacillus cereus (B. cereus), a Gram-positive bacterium commonly found in soil, rice, vegetables, and dairy products. Four aptamers and one negative control were initially grafted onto a biochip. The binding of B. cereus cells and nanosomes to immobilized aptamers was then compared. The use of nanosomes instead of cells provided a 30-fold amplification of the SPRi signal, thus allowing the selection of aptamers with higher affinities. Aptamer SP15 was found to be the most sensitive and selective for B. cereus ATCC14579 nanosomes. It was then truncated into three new sequences (SP15M, SP15S1, and SP15S2) to reduce its size while preserving the binding site. Fitting the results of the SPRi signal for B. cereus nanosomes showed a similar trend for SP15 and SP15M, and a slightly higher apparent association rate constant kon for SP15S2, which is the truncation with a high probability of a G-quadruplex structure. These observations were confirmed on nanosomes from B. cereus ATCC14579 grown in milk and from the clinical strain B. cereus J066. The developed method was validated using fluorescence microscopy on whole B. cereus cells and the SP15M aptamer labeled with a rhodamine. This study showed that nanosomes can successfully mimic the bacterial membrane with great potential for facilitating the screening of specific ligands for bacteria.


Assuntos
Aptâmeros de Nucleotídeos , Bacillus cereus , Ressonância de Plasmônio de Superfície , Ressonância de Plasmônio de Superfície/métodos , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/metabolismo , Bacillus cereus/metabolismo , Bacillus cereus/química , Técnica de Seleção de Aptâmeros
19.
Mikrochim Acta ; 191(6): 335, 2024 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-38760484

RESUMO

The release of tire wear substances in the environment is raising concerns about potential impacts on aquatic ecosystems. The purpose of this study was to develop a quick and inexpensive screening test for the following tire wear substances: 6-phenylphenyldiamine quinone (6-PPD quinone), hexamethoxymethylmelamine (HMMM), 1-3-diphenylguanidine (1,3-DPG), and melamine. A dual strategy consisting of nanogold (nAu) signal intensity and the plasmonic ruler principle was used based on the spectral shift from the unaggregated free-form nAu from 525 nm to aggregated nAu at higher wavelengths. The shift in resonance corresponded to the relative sizes of the tire wear substances at the surface of nAu: 6-PPD (560 nm), HMMM (590 nm), 1,3-DPG (620 nm), and melamine (660 nm) in a concentration-dependent manner. When present in mixtures, a large indiscriminate band between 550 and 660 nm with a maximum corresponding to the mean intermolecular distance of 0.43 nm from the tested individual substances suggests that all compounds indiscriminately interacted at the surface of nAu. An internal calibration methodology was developed for mixtures and biological extracts from mussels and biofilms and revealed a proportional increase in absorbance at the corresponding resonance line for each test compound. Application of this simple and quick methodology revealed the increased presence of melamine and HMMM compounds in mussels and biofilms collected at urban sites (downstream city, road runoffs), respectively. The data also showed that treated municipal effluent decreased somewhat melamine levels in mussels.


Assuntos
Ouro , Nanopartículas Metálicas , Triazinas , Ouro/química , Nanopartículas Metálicas/química , Triazinas/análise , Triazinas/química , Ressonância de Plasmônio de Superfície/métodos , Poluentes Químicos da Água/análise
20.
Zhongguo Zhong Yao Za Zhi ; 49(7): 1848-1864, 2024 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-38812197

RESUMO

Elucidating the quality markers(Q-markers) of traditional Chinese medicines is essential for understanding the mechanisms of action and promoting the rational use of traditional Chinese medicines as well as for developing traditional Chinese medicine-derived drugs. Studies have shown that surface plasmon resonance(SPR) is promising in this field. This study proposed a method based on pull-down with SPR chips to predict the Q-markers of Angong Niuhuang pills(AGNHP). Firstly, 71 main chemical components of AGNHP were analyzed by UPLC-Q-TOF-MS, and then network pharmacology was employed to predict the potential targets of AGNHP against stroke. Secondly, the STAT3 protein chip was constructed, and the extract of AGNHP was recovered by pull-down of the SPR system for STAT3 ligand. The potential active ingredients were collected, enriched, and identified as coptisine, palmatine, epiberberine, berberine, worenine, demethyleneberberine, jatrorrhizine, tetrahydrocoptisine, baicalein, and baicalin methyl ester. Next, the affinity constants of the 10 active ingredients were determined as 44.7, 44, 58.1, 51.3, 39.7, 32.1, 49.2, 69.1, 19.7, and 24.9 µmol·L~(-1), respectively. The molecular docking results showed that the 10 compounds could compete for binding with STAT3. This is the first report that SPR combined with UPLC-Q-TOF-MS is reliable and feasible for determining the active ingredients of AGNHP at the molecular level from complex systems. STAT3 could be used as a potential target for the biological quality evaluation of AGNHP.


Assuntos
Medicamentos de Ervas Chinesas , Espectrometria de Massas , Ressonância de Plasmônio de Superfície , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/análise , Espectrometria de Massas/métodos , Fator de Transcrição STAT3/metabolismo , Fator de Transcrição STAT3/química , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida/métodos , Controle de Qualidade , Humanos , Espectrometria de Massa com Cromatografia Líquida
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