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1.
ACS Sens ; 9(6): 3290-3295, 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38832719

RESUMO

Superchiral fields, supported by chiral plasmonic structures, have shown outstanding performance for chiral molecule sensing via enhanced chiral light-matter interaction. However, this sensing capability cannot fully reveal the chiral origin of the molecules as the chiroptic response of the molecules is intertwined with the chiroptic response of the chiral plasmonic nanostructures, which can potentially be excluded by using a plasmonic racemic mixture. Such a plasmonic racemic mixture is not easily attainable, as it normally requires complex fabrication and expensive instrumentation, whose structural fineness is limited by the fabrication precision. Here, we demonstrate trace-amount chiral molecule detection with plasmonic racemic arrays fabricated by direct laser writing with vector beams, which is facile, cost-effective, and highly controllable. The racemic arrays present no inherent circular differential scattering but a large local superchiral field, which reflects the intrinsic chiral features of the chiral molecules. They are further applied to discriminate enantiomers of phenylalanine with a limit of detection (LOD) of 10.0 ± 2.8 µM, which is an order of magnitude smaller than the LOD of conventional circular dichroism spectroscopy. The strong local superchiral field provided by the plasmonic racemic arrays enlightens the design of a superior sensing platform, which holds promising applications for biomedical detection and enantioselective drug development.


Assuntos
Lasers , Estereoisomerismo , Fenilalanina/química , Fenilalanina/análise , Limite de Detecção , Ouro/química , Nanoestruturas/química , Ressonância de Plasmônio de Superfície/métodos
2.
ACS Sens ; 9(6): 3027-3036, 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38864606

RESUMO

Surface plasmon (SP) excitation in metal-coated tilted fiber Bragg gratings (TFBGs) has been a focal point for highly sensitive surface biosensing. Previous efforts focused on uniform metal layer deposition around the TFBG cross section and temperature self-compensation with the Bragg mode, requiring both careful control of the core-guided light polarization and interrogation over most of the C + L bands. To circumvent these two important practical limitations, we studied and developed an original platform based on partially coated TFBGs. The partial metal layer enables the generation of dual-comb resonances, encompassing highly sensitive (TM/EH mode families) and highly insensitive (TE/HE mode families) components in unpolarized transmission spectra. The interleaved comb of insensitive modes acts as wavelength and power references within the same spectral region as the SP-active modes. Despite reduced fabrication and measurement complexity, refractometric accuracy is not compromised through statistical averaging over seven individual resonances within a narrowband window of 10 nm. Consequently, measuring spectra over 60 nm is no longer needed to compensate for small temperature or power fluctuations. This sensing platform brings the following important practical assets: (1) a simpler fabrication process, (2) no need for polarization control, (3) limited bandwidth interrogation, and (4) maintained refractometric accuracy, which makes it a true game changer in the ever-growing plasmonic sensing domain.


Assuntos
Fibras Ópticas , Ressonância de Plasmônio de Superfície , Ressonância de Plasmônio de Superfície/instrumentação , Ressonância de Plasmônio de Superfície/métodos , Técnicas Biossensoriais/métodos , Técnicas Biossensoriais/instrumentação , Tecnologia de Fibra Óptica/instrumentação
3.
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
4.
Curr Protoc ; 4(6): e1030, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38923763

RESUMO

Functional characterization of enzymes/proteins requires determination of the binding affinity of small molecules or other biomolecules with the target proteins. Several available techniques, such as proteomics and drug discovery strategies, require a precise and high-throughput assay for rapid and reliable screening of potential candidates for further testing. Surface plasmon resonance (SPR), a well-established label-free technique, directly measures biomolecular affinities. SPR assays require immobilization of one interacting component (ligand) on a conductive metal (mostly gold or silver) and a continuous flow of solution containing potential binding partner (analyte) across the surface. The SPR phenomenon occurs when polarized light excites the electrons at the interface of the metal and the dielectric medium to generate electromagnetic waves that propagate parallel to the surface. Changes in the refractive index due to interaction between the ligand and analyte are measured by detecting the reflected light, providing real-time data on kinetics and specificity. A prominent use of SPR is identifying compounds in crude plant extracts that bind to specific molecules. Procedures that utilize SPR are becoming increasingly applicable outside the laboratory setting, and SPR imaging and localized SPR (LSPR) are cheaper and more portable alternative for in situ detection of plant or mammalian pathogens and drug discovery studies. LSPR, in particular, has the advantage of direct attachment to test tissues in live-plant studies. Here, we describe three protocols utilizing SPR-based assays for precise analysis of protein-ligand interactions. © 2024 Wiley Periodicals LLC. Basic Protocol 1: SPR comparison of binding affinities of viral reverse transcriptase polymorphisms Basic Protocol 2: SPR screening of crude plant extract for protein-binding agents Basic Protocol 3: Localized SPR-based antigen detection using antibody-conjugated gold nanoparticles.


Assuntos
Ressonância de Plasmônio de Superfície , Ressonância de Plasmônio de Superfície/métodos , Ligantes , Ligação Proteica , Proteínas/química , Proteínas/metabolismo , Ouro/química
5.
Int J Mol Sci ; 25(12)2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38928409

RESUMO

The beta-galactoside-binding mammalian lectin galectin-1 can bind, via its carbohydrate recognition domain (CRD), to various cell surface glycoproteins and has been implicated in a range of cancers. As a consequence of binding to sugar residues on cell surface receptors, it has been shown to have a pleiotropic effect across many cell types and mechanisms, resulting in immune system modulation and cancer progression. As a result, it has started to become a therapeutic target for both small and large molecules. In previous studies, we used fluorescence polarization (FP) assays to determine KD values to screen and triage small molecule glycomimetics that bind to the galectin-1 CRD. In this study, surface plasmon resonance (SPR) was used to compare human and mouse galectin-1 affinity measures with FP, as SPR has not been applied for compound screening against this galectin. Binding affinities for a selection of mono- and di-saccharides covering a 1000-fold range correlated well between FP and SPR assay formats for both human and mouse galectin-1. It was shown that slower dissociation drove the increased affinity at human galectin-1, whilst faster association was responsible for the effects in mouse galectin-1. This study demonstrates that SPR is a sound alternative to FP for early drug discovery screening and determining affinity estimates. Consequently, it also allows association and dissociation constants to be measured in a high-throughput manner for small molecule galectin-1 inhibitors.


Assuntos
Galectina 1 , Ligação Proteica , Ressonância de Plasmônio de Superfície , Galectina 1/metabolismo , Galectina 1/antagonistas & inibidores , Galectina 1/química , Ressonância de Plasmônio de Superfície/métodos , Humanos , Animais , Camundongos , Cinética , Bibliotecas de Moléculas Pequenas/farmacologia , Bibliotecas de Moléculas Pequenas/química , Polarização de Fluorescência/métodos
6.
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
7.
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
8.
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
9.
Sci Rep ; 14(1): 14303, 2024 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-38906902

RESUMO

Dopamine is one of the significant neurotransmitters and its monitoring in biological fluids is a critical issue in healthcare and modern biomedical technology. Here, we have developed a dopamine biosensor based on surface plasmon resonance (SPR). For this purpose, the carboxymethyl dextran SPR chip was used as a surface to immobilize laccase as a bioaffinity recognition element. Data analysis exhibited that the acidic pH value is the optimal condition for dopamine interaction. Calculated kinetic affinity (KD) (48,545 nM), obtained from a molecular docking study, showed strong association of dopamine with the active site of laccase. The biosensor exhibited a linearity from 0.01 to 189 µg/ml and a lower detection limit of 0.1 ng/ml (signal-to-noise ratio (S/N) = 3) that is significantly higher than the most direct dopamine detecting sensors reported so far. Experiments for specificity in the presence of compounds that can co-exist with dopamine detection such as ascorbic acid, urea and L-dopa showed no significant interference. The current dopamine biosensor with high sensitivity and specificity, represent a novel detection tool that offers a label-free, simple procedure and cost effective monitoring system.


Assuntos
Técnicas Biossensoriais , Dopamina , Simulação de Acoplamento Molecular , Ressonância de Plasmônio de Superfície , Ressonância de Plasmônio de Superfície/métodos , Dopamina/análise , Dopamina/metabolismo , Técnicas Biossensoriais/métodos , Lacase/metabolismo , Lacase/química , Limite de Detecção , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Cinética , Concentração de Íons de Hidrogênio , Dextranos/química
10.
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
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(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
13.
Molecules ; 29(12)2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38930876

RESUMO

In this study, we report the successful development of a novel high-sensitivity intensity-based Surface Plasmon Resonance imaging (SPRi) biosensor and its application for detecting molecular interactions. By optimizing the excitation wavelength and employing a wavelength division multiplexing (WDM) algorithm, the system can determine the optimal excitation wavelength based on the initial refractive index of the sample without adjusting the incidence angle. The experimental results demonstrate that the refractive index resolution of the system reaches 1.77×10-6 RIU. Moreover, it can obtain the optimal excitation wavelength for samples with an initial refractive index in the range of 1.333 to 1.370 RIU and accurately monitor variations within the range of 0.0037 RIU without adjusting the incidence angle. Additionally, our new SPRi technique realized real-time detection of high-throughput biomolecular binding processes, enabling analysis of kinetic parameters. This research is expected to advance the development of more accurate SPRi technologies for molecular interaction analysis.


Assuntos
Técnicas Biossensoriais , Ressonância de Plasmônio de Superfície , Ressonância de Plasmônio de Superfície/métodos , Técnicas Biossensoriais/métodos , Algoritmos , Refratometria , Ensaios de Triagem em Larga Escala/métodos , Cinética
14.
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
15.
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
16.
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
17.
Talanta ; 276: 126234, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38749161

RESUMO

Glutathione (GSH) is an essential antioxidant in the human body, but its detection is difficult due to the interference of complex components in serum. Herein, hollow double-layer Pt@CeO2 nanospheres were developed as oxidase mimetics, and the light-assisted oxidase mimetics effects were found. The oxidase activity was enhanced significantly by utilizing the synergistic effect of Schottky junction and the localized surface plasmon resonance (LSPR) of Pt under UV light. A novel GSH colorimetric-fluorescent-SERS sensing platform was established, with the sensing performance notably boosted by using the light-assisted oxidase mimetics effects. This platform boasts an exceptionally low detection limit (LOD) of 0.084 µM, while the detection time was shortened from 10 min to just 2 min. The anti-interference detection with high recovery rate (96.84%-107.4 %) in real serum made it be promising for practical application.


Assuntos
Cério , Colorimetria , Glutationa , Nanosferas , Oxirredutases , Platina , Ressonância de Plasmônio de Superfície , Glutationa/sangue , Glutationa/química , Colorimetria/métodos , Platina/química , Humanos , Cério/química , Nanosferas/química , Oxirredutases/química , Ressonância de Plasmônio de Superfície/métodos , Limite de Detecção , Materiais Biomiméticos/química , Espectrometria de Fluorescência/métodos
18.
Nanotechnology ; 35(35)2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38821044

RESUMO

Recent studies have shown that abnormalmiRNA-378expression is a rule, rather than an exception, in cervical cancer and can be used as a diagnostic and prognostic biomarker to assess tumor initiation. In this study, we developed a general, sensitive strategy for detectingmiRNA-378using catalytic hairpin self-assembly (CHA) combined with gold nanoparticles (AuNP) colorimetry. The presence ofmiRNA-378triggers the repeated self-assembly of two designed hairpin DNAs (H1 and H2) into dsDNA polymers, which leads to changes in the surface plasmon resonance absorption band and the macroscopic color of the AuNP colloids due to the formation of nanoparticle-DNA conjugates. This experimental phenomenon can be observed by ultraviolet-visible spectrometry or even with the naked eye. Using this method,miRNA-378could be quantitatively detected at the picomolar level (as low as 20.7 pM). Compared with traditional methods, such as quantitative polymerase chain reaction and RNA blotting, this strategy has a simple operation, low cost, and high sensitivity and selectivity, and thus, exhibits significant potential for miRNA detection.


Assuntos
Colorimetria , Ouro , Nanopartículas Metálicas , MicroRNAs , MicroRNAs/genética , MicroRNAs/análise , Ouro/química , Nanopartículas Metálicas/química , Humanos , Colorimetria/métodos , Ressonância de Plasmônio de Superfície/métodos , DNA/química , DNA/genética , Catálise
19.
J Agric Food Chem ; 72(19): 11259-11267, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38691423

RESUMO

Peanut allergen monitoring is currently an effective strategy to avoid allergic diseases, while food matrix interference is a critical challenge during detection. Here, we developed an antifouling surface plasmon resonance sensor (SPR) with stratified zwitterionic peptides, which provides both excellent antifouling and sensing properties. The antifouling performance was measured by the SPR, which showed that stratified peptide coatings showed much better protein resistance, reaching ultralow adsorption levels (<5 ng/cm2). Atomic force microscopy was used to further analyze the antifouling mechanism from a mechanical perspective, which demonstrated lower adsorption forces on hybrid peptide coatings, confirming the better antifouling performance of stratified surfaces. Moreover, the recognition of peanut allergens in biscuits was performed using an SPR with high efficiency and appropriate recovery results (98.2-112%), which verified the feasibility of this assay. Therefore, the fabrication of antifouling sensors with stratified zwitterionic peptides provides an efficient strategy for food safety inspection.


Assuntos
Alérgenos , Arachis , Peptídeos , Ressonância de Plasmônio de Superfície , Ressonância de Plasmônio de Superfície/métodos , Arachis/química , Arachis/imunologia , Peptídeos/química , Peptídeos/imunologia , Alérgenos/análise , Alérgenos/imunologia , Alérgenos/química , Incrustação Biológica/prevenção & controle , Contaminação de Alimentos/análise , Proteínas de Plantas/imunologia , Proteínas de Plantas/química , Proteínas de Plantas/análise , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Adsorção
20.
Talanta ; 276: 126249, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38743970

RESUMO

The adoption of biophotonic sensing technologies holds significant promise for application in health care and biomedical industries in all aspects of human life. Then, this piece of writing employs the powerful effective medium theory and FDTD simulation to anticipate the most favorable state and plasmonic attributes of a magnificent nanocomposite, comprising carboxylate functionalized carbon nanotubes and chitosan (CS). Furthermore, it thoroughly explores the exhibited surface plasmon resonance behaviors of this composite versus the quantity of CS variation. Subsequently, enlightening simulations are conducted on the nanocomposite with a delicate layer and a modified golden structure integrating as a composite. The intricate simulations eventually unveil an optimal combination to pave the way for crafting an exceptional specific biosensor that far surpasses its counterpart as a mere Au thin layer in terms of excellence. The proposed biosensor demonstrated linear behavior across a wide range from 0.01 µM to 150 µM and achieved a detection limit of 10 nM, with a sensitivity of 134◦RIU-1.


Assuntos
Anlodipino , Quitosana , Nanotubos de Carbono , Ressonância de Plasmônio de Superfície , Quitosana/química , Nanotubos de Carbono/química , Ressonância de Plasmônio de Superfície/métodos , Anlodipino/análise , Anlodipino/química , Ácidos Carboxílicos/química , Técnicas Biossensoriais/métodos , Limite de Detecção , Humanos
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