RESUMO
Homogeneous electrochemiluminescence (ECL) has gained attention for its simplicity and stability. However, false positives due to solution background interference pose a challenge. To address this, magnetic ECL nanoparticles (Fe3O4@Ru@SiO2 NPs) were synthesized, offering easy modification, magnetic separation, and stable luminescence. These were utilized in an ECL sensor for miRNA-155 (miR-155) detection, with locked DNAzyme and substrate chain (mDNA) modified on their surface. The poor conductivity of long-chain DNA significantly impacts the conductivity and electron transfer capability of Fe3O4@Ru@SiO2 NPs, resulting in weaker ECL signals. Upon target presence, unlocked DNAzyme catalyzes mDNA cleavage, leading to shortened DNA chains and reduced density. In contrast, the presence of short-chain DNA has minimal impact on the conductivity and electron transfer capability of Fe3O4@Ru@SiO2 NPs. Simultaneously, the material surface's electronegativity decreases, weakening the electrostatic repulsion with the negatively charged electrode, resulting in the system detecting stronger ECL signals. This sensor enables homogeneous ECL detection while mitigating solution background interference through magnetic separation. Within a range of 100 fM to 10 nM, the sensor exhibits a linear relationship between ECL intensity and target concentration, with a 26.91 fM detection limit. It demonstrates high accuracy in clinical sample detection, holding significant potential for clinical diagnostics. Future integration with innovative detection strategies may further enhance sensitivity and specificity in biosensing applications.
Assuntos
DNA , Técnicas Eletroquímicas , Medições Luminescentes , MicroRNAs , Dióxido de Silício , MicroRNAs/análise , Técnicas Eletroquímicas/métodos , DNA/química , Dióxido de Silício/química , Humanos , Técnicas Biossensoriais/métodos , Propriedades de Superfície , DNA Catalítico/química , DNA Catalítico/metabolismo , Nanopartículas de Magnetita/química , Limite de Detecção , Rutênio/químicaRESUMO
The electrochemiluminescence (ECL) intensity can be regulated by ionic current passing through the microchannel, which broadened the regulation of the ECL sensors. But in the early reported sensors, the electrostatic repulsion and steric hindrance caused few targets to approach the interface of the microchannel driven by concentration difference, which reduced the detection efficiency and prolonged the detection period. In this study, different accumulation strategies, such as a positive electric field and different polarity electric fields, were designed to accumulate targets in the microchannel. The interaction of azide groups and hydrogen sulfide served as a research model. Hydrogen sulfide can react with the negatively charged azide groups in the microchannel surface to produce positively charged amino groups, decreasing the negative charge density of the microchannel and thus altering the ionic current and ECL intensity. The accumulation of hydrogen sulfide at the microchannel tip can increase the collision probability with azide groups to improve the detection efficiency, and the integration of accumulation and reaction can shorten the detection period to 28 min. The hydrogen sulfide concentration on the microchannel tip accumulated by applying different polarity electric fields was 22.3-fold higher than that accumulated by applying a positive electric field. The selected research model broadened the application range of a microchannel-based ECL sensor and confirmed the universality of the microchannel-based ECL sensor.
RESUMO
Halide perovskites have emerged as a highly promising class of photoelectric materials. However, the application of lead-based perovskites has been hindered by their toxicity and relatively weak stability. In this work, a composite material comprising a lead-free perovskite cesium copper iodide (CsCu2I3) nanocrystal and a metal-organic framework (MOF-801) has been synthesized through an in situ growth approach. The resulting composite material, denoted as CsCu2I3/MOF-801, demonstrates outstanding stability and exceptional optoelectronic characteristics. MOF-801 may serve a dual role by acting as a protective barrier between CsCu2I3 nanocrystals and the external environment, as well as promoting the efficient transfer of photogenerated charge carriers, thereby mitigating their recombination. Consequently, CsCu2I3/MOF-801 demonstrates its utility by providing both stability and a notably high initial photocurrent. Leveraging the inherent reactivity between H2S and the composite material, which results in the formation of Cu2S and structural alteration, an exceptionally sensitive photoelectrochemical sensor for H2S detection has been designed. This sensor exhibits a linear detection range spanning from 0.005 to 100 µM with a remarkable detection limit of 1.67 nM, rendering it highly suitable for precise quantification of H2S in rat brains. This eco-friendly sensor significantly broadens the application horizon of perovskite materials and lays a robust foundation for their future commercialization.
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The detection of trypsin is significantly important for both clinical diagnosis and disease treatment. In this study, an innovative multicolor sensor for trypsin detection has been established based on the regulation of the peroxidase activity of bovine serum albumin-coated gold nanoclusters (BSA-Au NCs) and efficient etching of gold nanobipyramids (Au NBPs). BSA-Au NCs have slight peroxidase enzyme activity and can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to generate TMB+, while trypsin can hydrolyze BSA ligands on the surface of BSA-Au NCs, thus exposing more catalytic active sites of BSA-Au NCs and resulting in the enhancement of the peroxidase activity of BSA-Au NCs, hence more TMB+ is generated. Under acidic conditions, TMB+ can etch Au NBPs efficiently, consequently affecting the aspect ratio of Au NBPs accompanied by the ultraviolet-visible (UV-vis) spectra blue shifting of the system. Furthermore, this also results in color variations that can be distinguished and recognized by naked eyes without any expensive and sophisticated instruments. This multicolor sensor has an available linear relationship with the logarithm of the trypsin concentration in the range of 0.1-100 µg/mL, and the detection limit is 0.045 µg/mL. The designed sensor has been used to detect the concentration of trypsin in human serum samples from healthy individuals and pancreatitis patients with satisfactory results.
Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Humanos , Tripsina/química , Soroalbumina Bovina/química , Ouro/química , Peroxidases , Nanopartículas Metálicas/químicaRESUMO
In this work, combined with the high amplification efficiency of hybridization chain reaction (HCR), high specificity of the CRISPR/Cas12a system, and convenience of the homogeneous electrochemiluminescence (ECL) assay based on the regulation of negative charge on the reporting probes, a sensitive ECL biosensor for hepatitis B virus DNA (chosen as a model target) had been developed. The initiator chain trigger DNA that can induce HCR amplification is modified on the surface of ruthenium bipyridine-doped silica nanoparticles (Ru@SiO2 NPs) first, and large amounts of negative charges modified on the particles were achieved through the HCR amplification reaction. The efficiency of the nanoparticles reaching the negatively charged working electrode can be regulated and realize the change of the ECL signal. In addition, long DNA on the surface of the luminescent body may prevent the coreactant from entering the pore to react with ruthenium bipyridine. These factors combine to produce a low-background system. The presence of the target can activate the CRISPR/Cas12a system and make trigger DNA disappear from the nanoparticle surface, and strong ECL can be detected. The sensor does not require a complex electrode modification; therefore, it has better reproducibility. Additionally, due to dual signal amplification, the sensor has a high sensitivity. In the range of 10 fM to 10 nM, the ECL intensity exhibits a strong linear relationship with the logarithm of the target concentration, and the detection limit is 7.41 fM. This sensor has shown high accuracy in detecting clinical samples, which holds significant potential for application in clinical testing.
Assuntos
Nanopartículas , Rutênio , Vírus da Hepatite B/genética , Sistemas CRISPR-Cas , Reprodutibilidade dos Testes , Dióxido de Silício , DNARESUMO
For rapid and sensitive detection of miRNA-210, which is important for improving the reliability of clinical diagnosis of breast cancer, a dual-signal mode ratiometric photoelectrochemical (PEC) sensor based on a Au/GaN photoanode is proposed. First, a DNA probe was designed that could complement the target miRNA-210. Then, another G-rich DNA sequence was designed to mismatch the probe and form a double-stranded DNA (dsDNA). Upon addition of the target, the dsDNA unwinds from its binding site and releases G-rich single-stranded DNA. In the presence of Mg2+ and K+, this single-stranded DNA molecule spontaneously forms a G-quadruplex structure, facilitating the rapid transport of photogenerated holes, thereby increasing the photocurrent response of Au/GaN and enabling sensitive label-free detection of miRNA-210. By control of different pH values, a response signal was generated at pH 8, while a reference signal was produced at pH 5. The designed PEC system shows a high potential for the development of miRNA-210 detection. Ultimately, the response signal-to-reference signal ratio was used as the variable, and a broad linear span ranging from 10 fM to 1 nM (R2 = 0.993) has been exhibited, with a detection threshold of 3 fM (S/N = 3). The designed PEC platform shows potential for the development of other disease markers.
Assuntos
Técnicas Biossensoriais , MicroRNAs , DNA de Cadeia Simples , Reprodutibilidade dos Testes , Ouro/química , DNA/química , Limite de Detecção , Técnicas EletroquímicasRESUMO
Terminal deoxynucleotidyl transferase (TdT) is upregulated in several types of leukemia and is considered a disease biomarker and a potential therapeutic target for leukemia. In this research, a homogeneous electrochemiluminescence (ECL) method based on the control of surface charge and morphology of tris (2,2'-bipyridine) ruthenium(II) chloride hexahydrate-doped silica nanoparticles (Ru@SiO2 NPs) has been designed for TdT activity detection. A small amount of short single-stranded DNA (ssDNA) was modified onto the surface of Ru@SiO2 NPs, and the nanoparticles with a slight positive charge experienced electrostatic attraction with the indium tin oxide (ITO) electrode with a negative charge, so relatively high ECL signals had been detected. Under the action of TdT, the ssDNA was significantly elongated, carrying numerous negative charges on its phosphate backbone, so the overall negative charge of the reporter nanoparticles was enhanced, resulting in a strong electrostatic repulsion with the ITO electrode. Simultaneously, the long ssDNA wrapped around the nanoparticles hindered the approach of the coreactant. Due to the dual effects, the ECL response of the system decreased. The constructed biosensor exhibited excellent sensitivity toward TdT over a range spanning from 1 to 100 U/L. The limit of detection is as low as 1.78 U/L. The developed approach was effectively applied to detect TdT activity in leukemic patients' leukocyte extracts.
Assuntos
Técnicas Biossensoriais , Leucemia , Nanopartículas , Humanos , DNA Nucleotidilexotransferase , Dióxido de Silício , Técnicas Eletroquímicas/métodos , Medições Luminescentes/métodos , DNA de Cadeia Simples , Técnicas Biossensoriais/métodosRESUMO
A novel photoelectrochemical (PEC) sensor was constructed for the highly sensitive detection of reduced glutathione (GSH) based on the multiple catalytic properties of phosphotungstic acid (PTA). In this work, the catalytic properties of PTA were applied to PEC sensing for the first time and interpreted in detail. First, PTA as an electron acceptor can inhibit the complexation of photogenerated electron-hole pairs in p-Cu2O, thus significantly increasing the photogenerated current of p-type semiconductor material Cu2O. Secondly, when GSH is oxidized to oxidized glutathione (GSSG) by photogenerated holes on the photocathode, PTA is able to reduce GSSG to GSH by transferring protons, forming a redox cycle regeneration process of GSH. Finally, the relatively large amount of PTA in the background solution was able to pre-oxidize interfering substances such as L-cysteine and ascorbic acid, which improved the selectivity of the method. Under the optimal experimental conditions, the linear range of the PEC sensor response to GSH was 0.050-100 nmol L-1, with a detection limit as low as 0.017 nmol L-1 (S/N = 3), which can be applied to the detection of GSH content in cell lysate samples.
Assuntos
Técnicas Biossensoriais , Glutationa , Dissulfeto de Glutationa , Ácido Fosfotúngstico , Semicondutores , Oxirredução , Técnicas Eletroquímicas/métodos , Técnicas Biossensoriais/métodos , Limite de DetecçãoRESUMO
Two-dimensional (2D) layered MoS2 has good dispersion and adsorption properties, but being a narrow bandgap semiconductor limits its application in photoelectric sensing. In this study, a homogeneous photoelectrochemical sensor based on three-dimensional (3D) ZnO/Au/2D MoS2 is proposed for the ultrasensitive detection of tetracycline (TET). MoS2 is uniformly embedded on the 3D ZnO/Au surface by ordered self-assembly. The physical method of π-π interaction of MoS2 replaces the conventional use of chemically modifying aptamers on the electrode material surface. Under optimal conditions, this method has been successfully applied to the detection of TET in milk, honey, pig kidney and pork samples with reliable results. We believe that this study presents a method for the preparation of sensing carriers and target detection with great potential for application.
RESUMO
The discrepancy of the electrostatic interaction of negatively charged signal molecules to long and short DNA strands of the modified electrode surface has been used for the first time to the develop an electrochemiluminescence (ECL) biosensor for human papillomavirus 16 (HPV 16) DNA detection. The short single-stranded capture probe (CP) was modified first on the surface of the gold electrode, which only has a small amount of negative charge. The electrostatic interaction between the negatively charged tris(2,2'-bipyridyl) ruthenium(II) chloride hexahydrate-doped SiO2 nanoparticles (Ru@SiO2 NPs) and CP is weak, hence Ru@SiO2 NPs easily diffuse to the surface of the electrode to generate a strong ECL signal. Hybrid chain reaction (HCR) amplification products (long strand dsDNA) were prepared in homogeneous solution in advance. When the target was present, the dsDNA can be connected on the electrode surface and cause the enhancement of the negative charge on the electrode surface. Owing to electrostatic interaction and steric hindrance, Ru@SiO2 NPs are difficult to diffuse to the electrode surface, resulting in a significantly reduced ECL signal. The decrease of ECL signal is linearly correlated with the logarithm of the HPV concentration under optimal conditions, with the detection range being 0.1 fM -5 pM with a limit of 1.41 aM. This innovative methodology expands the application of electrostatic interaction in ECL sensing, but can also easily develop biosensors for detecting other targets by changing the DNA sequence used in this strategy.
Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Técnicas Biossensoriais/métodos , DNA , Técnicas Eletroquímicas/métodos , Eletrodos , Humanos , Medições Luminescentes/métodos , Dióxido de Silício , Eletricidade EstáticaRESUMO
Alkaline phosphatase (ALP) plays a vital role in clinical diagnoses and biomedical research. It is important to develop some convenient but sensitive methods for ALP activity detection. In this study, a multicolor biosensor for ALP activity has been developed based on the peroxidase activity of copper nanoclusters (CuNCs) and etching of gold nanorods (AuNRs). The presence of CuNCs can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to produce blue TMB+. In acid solution, TMB+ can cause the etching of AuNRs accompanied by a significant color change of the system. The presence of sodium pyrophosphate (PPi) can inhibit the peroxidase activity of CuNCs, which can be recovered after the addition of ALP. Different ALP added results in the recovery of the catalytic activity of CuNCs to different degrees and generates different amounts of TMB+. This consequently affected the morphology of the AuNRs in the system and results in the output of a vivid color change, which can be recognized with the naked eyes easily without any complicated instruments. The biosensor has a linear relationship with ALP activity in the range of 10.0-80.0 U L-1, and the detection limit is 4.6 U L-1. The proposed method has been applied to detect ALP activity in human serum samples with satisfactory results.
Assuntos
Técnicas Biossensoriais , Nanotubos , Fosfatase Alcalina , Técnicas Biossensoriais/métodos , Colorimetria/métodos , Cobre , Ouro , Humanos , Limite de Detecção , PeroxidasesRESUMO
The change of surface charge density can cause many changes in physical or chemical properties and has been applied to design many sensitive sensors. Ochratoxin A (OTA) is a negatively charged target in neutral or alkaline solutions. In this work, a microchannel-based electrochemiluminescence (ECL) aptasensor for OTA detection based on this character had been designed. The charged target directly combined with functionalization layers of the microchannels, which caused surface charge density variation and therefore resulted in the change of ECL intensity of the (1,10-phenanthroline)ruthenium(II)/tripropylamine system. The decrease of ECL intensity is linearly dependent on OTA concentration ranging from 0.5 to 4 ng mL-1 with a detection limit down to 0.17 ng mL-1. This strategy has the advantages of simple interface chemistry design and universality, which offers a guiding significance for the charged target assay.
Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Rutênio , Técnicas Eletroquímicas , Medições LuminescentesRESUMO
Infectious diseases are a long-standing and severe global public health problem. The rapid diagnosis of infectious diseases is an urgent need to solve this problem. MicroRNA (miRNA) plays an important role in the intervention of some infectious diseases and is expected to become a potential biomarker for the diagnosis and prognosis of infectious diseases. It is of great significance to develop rapid and sensitive methods for detecting miRNA for effective control of infectious diseases. In this study, a simple and highly sensitive homogeneous electrochemical method for microRNAs using enzyme-driven cascaded signal amplification has been developed. In the presence of target miRNA, the reaction system produced plenty of MB-labeled single-nucleotide fragments (MB-MF) containing a few negative charges, which can diffuse to the negative surface of the ITO electrode easily, so an obvious electrochemical signal enhancement was obtained. Without the target, MB-HP contains a relatively large amount of negative charges due to the phosphates on the DNA chain, which cannot be digested by the enzyme and cannot diffuse freely to the negatively charged ITO electrode, so only a small signal was detected. The enhanced electrochemical response has a linear relationship with the logarithm of miRNA concentration in the range of 10 fM to 10 nM and the limit of detection as low as 3.0 fM. Furthermore, the proposed strategy showed the capability of discriminating single-base mismatch and performed eligibly in the analysis of miRNA in cell lysates, exhibiting great potential for disease diagnosis and biomedical research. Graphical abstract.
Assuntos
Técnicas Biossensoriais/instrumentação , Técnicas Eletroquímicas/instrumentação , Enzimas/metabolismo , MicroRNAs/análise , Linhagem Celular , Humanos , Limite de DetecçãoRESUMO
BACKGROUND: To evaluate the prognostic significance of pretreatment quality of life for patients with nasopharyngeal carcinoma treated with intensity-modulated radiotherapy. METHODS: We performed a prospective, longitudinal study on 554 newly diagnosed patients with NPC from April 2011 to January 2015. A total of 501 consecutive NPC patients were included. Patients were asked to complete the EORTC QLQ-C30 (version 3.0) and QLQ-H&N35 questionnaires before treatment. RESULTS: Global health status among QLQ-C30 correlates with EBV DNA(P = 0.019). In addition, pretreatment appetite loss was significantly correlated with EBV DNA(P = 0.02). Pretreatment teeth, opening mouth, feeding tube was significantly correlated with EBV DNA, with P value of 0.003, < 0.0001, and 0.031, respectively. In multivariate analysis, pretreatment cognitive functioning of QLQ-C30 was significantly associated with LRFS, with HR of 0.971(95%CI 0.951-0.990), P = 0.004. Among scales of QLQ-H&N35 for multivariate analysis, pretreatment teeth (P = 0.026) and felt ill (P = 0.012) was significantly associated with PFS, with HR of 0.984 (95%CI 0.971-.998) and 1.004 (95%CI 1.001-1.007), respectively. Felt ill of QLQ-H&N35 was significantly associated with DMFS, with HR of 1.004(95%CI 1.000-1.007), P = 0.043. There is no QoL scale significantly associated with OS after multivariate analysis. CONCLUSIONS: In conclusion, our analysis confirms that pretreatment teeth and felt ill was significantly associated with PFS in NPC patients treated with IMRT. In addition, the posttreatment EBV DNA was significantly associated with OS.
Assuntos
Carcinoma/epidemiologia , Carcinoma/radioterapia , Neoplasias Nasofaríngeas/epidemiologia , Neoplasias Nasofaríngeas/radioterapia , Prognóstico , Radioterapia de Intensidade Modulada , Adolescente , Adulto , Idoso , Carcinoma/tratamento farmacológico , Carcinoma/patologia , Criança , Feminino , Nível de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas/tratamento farmacológico , Neoplasias Nasofaríngeas/patologia , Estudos Prospectivos , Qualidade de Vida , Inquéritos e Questionários , Adulto JovemRESUMO
A highly sensitive and selective fluorescence biosensor for inorganic pyrophosphatase (PPase) activity has been developed based on special click ligation trigger hyperbranched rolling circle amplification (CLT-HRCA). Pyrophosphate ion (PPi) can coordinate with Cu2+ to form stable PPi/Cu2+ complex and Cu2+ in the complex cannot be reduced to Cu+. The addition of PPase causes the hydrolysis of PPi into orthophosphate (Pi) and therefore induces the releasing of Cu2+ from the stable PPi/Cu2+ complex, and the free Cu2+ is easily reduced to Cu+ by sodium ascorbate. Then Cu+ catalyzes the cyclization reaction between the specially designed 5'-azide and 3'-alkyne tagged padlock probes through Cu+ catalyzed azide-alkyne cycloaddition (CuAAC), which in turn initiates the hyperbranched rolling circle amplification (HRCA). Given that the CLT-HRCA products contain large amounts of double-stranded DNAs (dsDNAs), the addition of SYBR Green I resulted in the enhanced fluorescence signal. There was a linear relationship between the enhanced fluorescence intensity and the logarithm PPase activity ranging from 0.05 to 25 mU with a detection limit of 0.02 mU. Such proposed biosensor has been successfully applied to screen the potential PPase inhibitors and has accessed the related inhibit ability with high efficiency.
Assuntos
Técnicas Biossensoriais , Corantes Fluorescentes/química , Pirofosfatase Inorgânica/análise , Reação de Cicloadição , Pirofosfatase Inorgânica/antagonistas & inibidores , Limite de Detecção , Espectrometria de FluorescênciaRESUMO
Changes in the charge density on the inner surface of the microchannel can modulate the ion concentration at the tip, thus causing changes in the resistance of the system. In this study, this property is adopted to construct a portable sensor using a multimeter and aflatoxin B1 (AFB1) is used as the model target. Initially, the cDNA/aptamer complex is modified in the microchannel. The inner microchannel surface's charge density is then altered by the recognition of the target, leading to a change in the system's resistance, which can be conveniently monitored using a multimeter. Critical parameters influencing the performance of the system are optimized. Under optimum conditions, the resistance is linearly related to the logarithm of AFB1 concentration in the range of 100 fM-10 nM and the detection limit is 46 fM (S/N = 3). The resistive measurement is separated from the recognition reaction of the target, reducing the matrix interference during the detection process. This sensor boasts high sensitivity and specificity coupled with commendable reproducibility and stability. It is applied to assay the AFB1 content successfully in an actual sample of corn. Moreover, this approach is cost-effective, user-friendly, and highly accurate.
Assuntos
Aflatoxina B1 , Aptâmeros de Nucleotídeos , Aflatoxina B1/análise , Reprodutibilidade dos Testes , Limite de Detecção , DNA ComplementarRESUMO
In this work, an electrochemiluminescence (ECL) biosensor with dual signal enhancement was constructed and used for DNA adenine methylation methyltransferase (Dam MTase) detection. At present of Dam MTase, restriction endonuclease (DPnI) cleaves hairpin DNA (HP) and releases the HP stem end as a single strand that can activate CRISPR/Cas12a trans-cleavage activity. Assisted by trans-cleavage, the distance between the signal quenching factor ferrocene (Fc) and the ECL signal unit increased, and the repulsion between the signal unit and the Indium Tin Oxides (ITO) electrode decreased. The above results resulted in an enhanced ECL signal. ECL intensity has a good linear relationship with the logarithm of Dam MTase concentration in the range of 5-70 U/mL with a detection limit of 23.4 mU/mL. The proposed biosensor was successfully utilized to detect of Dam MTase in serum samples.
Assuntos
Técnicas Biossensoriais , Sistemas CRISPR-Cas , Adenina , Técnicas Biossensoriais/métodos , DNA , Metilação de DNA , Enzimas de Restrição do DNA , Índio , Metalocenos , Metiltransferases , Óxidos , EstanhoRESUMO
Point-of-care testing (POCT) has experienced rapid development owing to its advantages of rapid testing, low cost and strong operability, making it indispensable for analyte detection in outdoor or rural areas. In this study, we propose a novel method for the detection of aflatoxin B1 (AFB1) using a dual-signal readout approach within a unified system. This method employs dual channel modes, namely visual fluorescence and weight measurements, as the signal readouts. Specifically, a pressure-sensitive material is utilized as a visual fluorescent agent, its signal can be quenched in the presence of high oxygen pressure. Additionally, an electronic balance, commonly used for weight measurement, is adopted as another signal device, where the signal is generated through the catalytic decomposition of H2O2 by platinum nanoparticles. The experimental results demonstrate that the proposed device enables accurate AFB1 detection within the concentration range of 1.5-32 µg mL-1, with a detection limit of 0.47 µg mL-1. Moreover, this method has been successfully applied for practical AFB1 detection with satisfactory results. Notably, this study pioneers the use of a pressure-sensitive material as a visual signal in POCT. By addressing the limitations of single-signal readout approaches, our method fulfills requirements of intuitiveness, sensitivity, quantitative analysis and reusability.
Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Nanopartículas Metálicas , Aflatoxina B1/análise , Platina , Peróxido de Hidrogênio , Limite de Detecção , Fluorometria , Testes Imediatos , Técnicas Biossensoriais/métodosRESUMO
The sensing performance of a microchannel-based electrochemiluminescence (ECL) biosensor is related to the change ratio of charge density on the surface of microchannels caused by a target recognition reaction. In this study, adenosine triphosphate (ATP) served as a model target. The dsDNA superstructures containing a capture probe (CP, containing an ATP aptamer sequence) and alternating units of ssDNA probes of P1 and P2, CP/(P1/P2)n, were grafted onto the inner wall of microchannels first. The CP in dsDNA superstructures captured ATP molecules, causing the release of dsDNA fragments containing alternating units of P1 and P2, (P1/P2)n. The target recognition reaction significantly changed the charge density of microchannels, which altered the ECL intensity of the (1,10-phenanthroline)ruthenium(II)/tripropylamine system in the reporting interface. The ECL intensity of the constructed system had a linear relationship with the logarithm of ATP concentration ranging from 1 fM to 100 pM with a detection limit of 0.32 fM (S/N = 3). The biosensor was successfully applied to detect ATP in rat brains.
Assuntos
Trifosfato de Adenosina/análise , Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , DNA/análise , Trifosfato de Adenosina/genética , Animais , Aptâmeros de Nucleotídeos/química , Encéfalo , Química Encefálica , DNA/química , Técnicas Eletroquímicas , Medições Luminescentes , RatosRESUMO
Hydrogen sulfide (H2S) has emerged as an important indicator in the spoilage process of meat. In this study, a mimetic enzyme based on Cu2+-modified boron nitride nanosheets-supported gold nanoparticles (AuNPs/Cu2+-BNNS) was synthesized, which can be used to catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB). The H2S gas can inhibit the activity of AuNPs/Cu2+-BNNS toward catalytic oxidation of TMB. Meanwhile, the usage of headspace method could avoid most interferences in the rotten sample. Various concentrations of TMB+ could change the aspect ratio of the gold nanoroads (AuNRs), which results in vivid color changing and UV-vis spectra shifting. The sensor had a good linear relationship with H2S concentration ranging from 10.0 to 90.0 µmol/L, and the detection limit is 7.8 µmol/L. The AuNPs/Cu2+-BNNS sensors were successfully applied to detect H2S produced by meat spoilage with satisfying results.