RESUMO
Biosensors based on carbon nanotube field-effect transistors (CNT-FETs) have shown great potential in biomarker detection due to their high sensitivity because of appreciable semiconducting electrical properties. However, background signal interferences in complex mediums may results in low signal-to-noise ratio, which may impose challenges for precise biomarker detection in physiological fluids. In this work, we develop an enzymatic CNT-FET, with scalable production at wafer scale, for detection of trace sarcosine that is a biopsy-correlated biomarker of prostate cancer. Enzymatic cascade rectors are constructed on the CNT to improve the reaction efficiency, thereby, enhancing the signal transduction. As such, a limit of detection as low as 105 zM is achieved in buffer solution. Owing to the enhanced reaction efficiency, the testing of clinical serum samples yields significant signal difference to discriminate the prostate cancer (PCa) samples from the benign prostatic hyperplasia (BPH) samples (P = 1.07 × 10-5), demonstrating immense potential in practical applications.
Assuntos
Biomarcadores Tumorais , Técnicas Biossensoriais , Nanotubos de Carbono , Neoplasias da Próstata , Transistores Eletrônicos , Nanotubos de Carbono/química , Humanos , Masculino , Neoplasias da Próstata/diagnóstico , Neoplasias da Próstata/sangue , Técnicas Biossensoriais/instrumentação , Biomarcadores Tumorais/sangue , Limite de Detecção , Sarcosina/sangue , Sarcosina/análise , Desenho de Equipamento , Hiperplasia Prostática/diagnóstico , Hiperplasia Prostática/sangueRESUMO
BACKGROUND: Early prostatic cancer (PCa) diagnosis significantly improves the chances of successful treatment and enhances patient survival rates. Traditional enzyme cascade-based early cancer detection methods offer efficiency and signal amplification but are limited by cost, complexity, and enzyme dependency, affecting stability and practicality. Meanwhile, sarcosine (Sar) is commonly considered a biomarker for PCa development. It is essential to develop a Sar detection method based on cascade reactions, which should be efficient, low skill requirement, and suitable for on-site testing. RESULTS: To address this, our study introduces the synthesis of organic-inorganic self-assembled nanoflowers to optimize existing detection methods. The Sar oxidase (SOX)-inorganic hybrid nanoflowers (Cu3(PO4)2:Ce@SOX) possess inherent fluorescent properties and excellent peroxidase activity, coupled with efficient enzyme loading. Based on this, we have developed a dual-mode multi-enzyme cascade nanoplatform combining fluorescence and colorimetric methods for the detection of Sar. The encapsulation yield of Cu3(PO4)2:Ce@SOX reaches 84.5 %, exhibiting a remarkable enhancement in catalytic activity by 1.26-1.29 fold compared to free SOX. The present study employing a dual-signal mechanism encompasses 'turn-off' fluorescence signals ranging from 0.5 µM to 60 µM, with a detection limit of 0.226 µM, and 'turn-on' colorimetric signals ranging from 0.18 µM to 60 µM, with a detection limit of 0.120 µM. SIGNIFICANCE: Furthermore, our study developed an intelligent smartphone sensor system utilizing cotton swabs for real-time analysis of Sar without additional instruments. The nano-platform exhibits exceptional repeatability and stability, rendering it well-suited for detecting Sar in authentic human urine samples. This innovation allows for immediate analysis, offering valuable insights for portable and efficient biosensors applicable to Sar and other analytes.
Assuntos
Colorimetria , Oxirredução , Sarcosina , Smartphone , Sarcosina/urina , Sarcosina/análise , Sarcosina/química , Humanos , Nanoestruturas/química , Limite de Detecção , Espectrometria de Fluorescência , Neoplasias da Próstata/diagnóstico , Fluorescência , Técnicas Biossensoriais , Sarcosina Oxidase/químicaRESUMO
This article presents the development of a photothermal biosensing integrated with microfluidic paper-based analytical device (PT-µPAD) as a quantitative biosensor method for monitoring sarcosine in human control urine, plasma, and serum samples. The device utilizes gold nanoparticles (AuNPs) as both a peroxidase-like nanozyme and a photothermal substrate to enable sarcosine detection. In our PT-µPAD, hydrogen peroxide (H2O2) is generated through the oxidation of sarcosine by a sarcosine oxidase (SOx) enzyme. Subsequently, the H2O2 flows through the paper microchannels to the detection zone, where it etches the pre-deposited AuNPs, inducing a temperature change upon exposure by a 532 nm laser. The temperature variation is then measured using a portable and inexpensive infrared thermometer. Under optimized conditions, we obtained a linear range between 10.0 and 40.0 nmol L-1 (R2 = 0.9954) and a detection limit (LOD) of 32.0 pmol L-1. These values fall within the clinical range for sarcosine monitoring in prostate cancer diagnostics in humans. Moreover, our approach exhibits high selectivity without interfering effects. Recovery studies in various human control samples demonstrated a range of 99.05-102.11 % with the highest RSD of 2.25 %. The PT-µPAD was further validated for sarcosine determination in human control urine and compared with a commercial ELISA assay, revealing no significant difference between these two methods at a 95 % confidence level. Overall, our proposed sarcosine biosensor is well-suited for prostate cancer monitoring, given its affordability, sensitivity, and user-friendliness, even for unskilled individuals. Moreover, this strategy has promising prospects for broader applications, potentially detecting various biomarkers as a point-of-care (POC) diagnostic tool.
Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Neoplasias da Próstata , Masculino , Humanos , Sarcosina/análise , Ouro , Microfluídica , Peróxido de Hidrogênio , Neoplasias da Próstata/diagnóstico , Técnicas Biossensoriais/métodosRESUMO
An early diagnosis is the gold standard for cancer survival. Biosensors have proven their effectiveness in monitoring cancer biomarkers but are still limited to a series of requirements. This work proposes an integrated power solution, with an autonomous and self-signaling biosensing device. The biorecognition element is produced in situ by molecular imprinting to detect sarcosine, a known biomarker for prostate cancer. The biosensor was assembled on the counter-electrode of a dye-sensitized solar cell (DSSC), simultaneously using EDOT and Pyrrole as monomers for the biomimetic process and the catalytic reduction of triiodide in the DSSC. After the rebinding assays, the hybrid DSSC/biosensor displayed a linear behavior when plotting the power conversion efficiency (PCE) and the charge transfer resistance (RCT) against the logarithm of the concentration of sarcosine. The latter obtained a sensitivity of 0.468 Ω/decade of sarcosine concentration, with a linear range between 1 ng/mL and 10 µg/mL, and a limit of detection of 0.32 ng/mL. When interfacing an electrochromic cell, consisting of a PEDOT-based material, with the hybrid device, a color gradient between 1 ng/mL and 10 µg/mL of sarcosine was observed. Thus, the device can be used anywhere with access to a light source, completely equipment-free, suitable for point-of-care analysis and capable of detecting sarcosine within a range of clinical interest.
Assuntos
Técnicas Biossensoriais , Sarcosina , Masculino , Humanos , Sarcosina/análise , Técnicas Eletroquímicas , Limite de Detecção , Biomarcadores Tumorais , CorantesRESUMO
Herein, we report a facile and label-free method for sensitive and specific determination of prostate cancer biomarker sarcosine via using photoluminescent bimetallic Au/Cu nanoplatelets (AuCu NPs) to construct an inner filter effect (IFE)-based photoluminescence (PL) sensing platform. The AuCu NPs were formed by the cysteine-induced co-reduction reaction, which displayed bright PL with an emission peak at 560 nm. Meanwhile, the Cu(I) doping caused a maximum 25-fold enhancement of quantum yield (QY), compared with the native Au(I) complexes, i.e., from 0.85 to 21.5%. By integrating the AuCu NPs with p-phenylenediamine (PPD) oxidation reaction, an IFE-based sensor for sarcosine detection was constructed. In this method, sarcosine is oxidized under the catalysis of sarcosine oxidase (SOx) to yield H2O2. The latter further oxidizes PPD to form 2,5-diamino-N,N'-bis(p-aminophenyl)-l,4-benzoquinone di-imine (PPDox) in the presence of horseradish peroxidase (HRP). The UV-vis absorption spectrum of the PPDox can overlap well with the excitation and emission spectra of the AuCu NPs, resulting in the efficient quenching of the AuCu NPs via the IFE effect. Therefore, this IFE-based AuCu NPs/SOx/PPD/HRP sensing platform can be used for highly sensitive and specific sensing of sarcosine. The sensing platform showed two linear regions of the PL intensity of the AuCu NPs versus the concentration of sarcosine in the range of 0.5-5 µM and 5-100 µM with a detection limit (LOD) of 0.12 µM (S/N = 3). Furthermore, this IFE-based sensing platform could be developed into a paper-based biosensor for simple, instrument-free, and visual detection of sarcosine.
Assuntos
Técnicas Biossensoriais , Sarcosina , Biomarcadores Tumorais/análise , Peroxidase do Rábano Silvestre , Humanos , Peróxido de Hidrogênio , Masculino , Neoplasias da Próstata , Sarcosina/análise , Sarcosina OxidaseRESUMO
BACKGROUND: Sarcosine, also known as N-methyl glycine, is a natural amino acid that is an intermediate and by product in glycine synthesis and degradation. Recently found in many peptides, sarcosine has been researched as a newly accepted prostate cancer marker. The increased concentration of sarcosine in blood serum and the urine showed that malignancy of measured prostate cancer cells is active. OBJECTIVE: In this article, we aimed to design a potentiometric biosensor for detection of sarcosine with a low detection limit, high selectivity, short response time, wide linear range, and satisfactory long-term stability. METHODS: In this article, we developed a new Graphene oxide (GFOX) photosensitive cross-linker based potentiometric biosensor based on the AmiNoAcid (monomer) Decorated and Light Underpinning Conjugation Approach (ANADOLUCA) method. The functional groups determined using Raman, FT-IR, XPS analyzes, and surface characterization, the morphology of synthesized GFOX photosensitive cross-linker were determined by TEM and AFM studies. Then, the performance of the GFOX based potentiometric biosensor has been evaluated. RESULTS: When the usage of the developed GFOX doped potentiometric biosensor against sarcosine determination, it was found that 10-4 mM sarcosine was determined in 60 seconds in the solution. In addition, the detection limit of the GFOX doped potentiometric biosensor was found to be 9.45x10-7 mM, and the linear potentiometric biosensor was found to be in the concentration range of 10-1 to 10-5 mM. The selectivity studies of the developed potentiometric biosensor were investigated using glycine solutions, and it was determined that GFOX doped potentiometric biosensor was more selective against sarcosine. Besides this, a reusability test using 10-3 mM sarcosine solution showed that reproducible studies were performed without the loss of potential of designed potentiometric biosensor and no loss of sensitivity. CONCLUSION: After applying the framework, we get a new potentiometric biosensor for sarcosine determination. GFOX photosensitive cross-linker was used in designing potentiometric biosensors, and this increased the stability and efficiency of the biosensor. Therefore, the developed potentiometric biosensor for sarcosine determination could be easily used for the early diagnosis of prostate cancer.
Assuntos
Técnicas Biossensoriais , Grafite/química , Sarcosina/análise , Humanos , Masculino , Neoplasias da Próstata/sangue , Neoplasias da Próstata/diagnóstico , Sarcosina/sangueRESUMO
Coral reefs are naturally exposed to daily and seasonal variations in environmental oxygen levels, which can be exacerbated in intensity and duration by anthropogenic activities. However, coral's diel oxygen dynamics and fermentative pathways remain poorly understood. Here, continuous oxygen microelectrode recordings in the coral diffusive boundary layer revealed hyperoxia during daytime and hypoxia at nighttime resulting from net photosynthesis and net respiration, respectively. The activities of the metabolic enzymes citrate synthase (CS), malate dehydrogenase, and strombine dehydrogenase remained constant throughout the day/night cycle, suggesting that energy metabolism was regulated through adjustments in metabolite fluxes and not through changes in enzyme abundance. Liquid chromatography-mass spectrometry analyses identified strombine as coral's main fermentative end product. Strombine levels peaked as oxygen became depleted at dusk, indicating increased fermentation rates at the onset of nightly hypoxia, and again at dawn as photosynthesis restored oxygen and photosynthate supply. When these peaks were excluded from the analyses, average strombine levels during the day were nearly double those at night, indicating sifnificant fermentation rates even during aerobic conditions. These results highlight the dynamic changes in oxygen levels in the coral diffusive boundary layer, and the importance of fermentative metabolism for coral biology.
Assuntos
Antozoários/fisiologia , Oxigênio/análise , Sarcosina/análogos & derivados , Animais , Cromatografia Líquida , Recifes de Corais , Metabolismo Energético , Fermentação , Espectrometria de Massas , Microeletrodos , Fotossíntese , Sarcosina/análise , Estações do AnoRESUMO
The successful synthesis is reported of Mn, Fe, Co, Ni, Cu-doped g-C3N4 nanoflakes via a simple one-step pyrolysis method, respectively. Among them, the Fe-doped g-C3N4 nanoflakes exhibited the highest peroxidase-like activity, which can be used for colorimetric detection of hydrogen peroxide (H2O2) and sarcosine (SA), within the detection ranges of 2-100 µM and 10-500 µM and detection limits of 1.8 µM and 8.6 µM, respectively. The catalytic mechanism of the Fe-doped g-C3N4 nanoflake was also explored and verified the generation of hydroxyl radical (â¢OH) through fluorescence method. It is believed that the Fe-doped g-C3N4 nanoflakes as enzyme mimics will greatly promote the practical applications in a variety of fields in the future including biomedical science, environmental governance, antibacterial agent, and bioimaging due to their extraordinary catalytic performance and stability. Graphical abstract.
Assuntos
Colorimetria/métodos , Grafite/química , Peróxido de Hidrogênio/análise , Ferro/química , Nanopartículas/química , Compostos de Nitrogênio/química , Sarcosina/análise , Benzidinas/química , Catálise , Compostos Cromogênicos/química , Peróxido de Hidrogênio/química , Limite de Detecção , Oxirredução , Sarcosina/química , Sarcosina Oxidase/químicaRESUMO
Sarcosine is an amino acid derivative, which is considered as a key metabolite in various metabolic processes. Therefore, simple and sensitive detection methods are needed for further understanding its metabolic role and diagnostic value. In this study, we developed a novel method that meets the need for practical and sensitive detection in a complex medium mimicking urine conditions. For this aim, we selected sarcosine-specific DNA aptamers using graphene oxide-assisted systemic evolution of ligands by exponential enrichment (GO-SELEX). The candidate aptamers were labeled with 6-carboxyfluorescein (6-FAM) at their 5' ends. Two aptamers, namely 9S and 13S produced a significant fluorescence signal upon sarcosine binding. Both aptamers enabled a sensitive analysis with a detection limit of 0.5â¯pM. The linear detection ranged between 5â¯pM and 50⯵M for 9S aptamer, while 13S aptamer enabled a wider linear detection range between 5â¯pM and 500⯵M. The aptamer-based assay allowed rapid detection with no need for chemical derivatization of sarcosine and sophisticated instruments. Moreover, the aptamer-based assay was free of interference from urea and human serum albumin.
Assuntos
Aptâmeros de Nucleotídeos , Bioensaio , Técnicas Biossensoriais , Fluorescência , Sarcosina/análise , Aptâmeros de Nucleotídeos/química , Bioensaio/métodos , Bioensaio/normas , Técnicas Biossensoriais/métodos , Técnicas Biossensoriais/normas , Humanos , Conformação de Ácido Nucleico , Técnica de Seleção de Aptâmeros , Sensibilidade e EspecificidadeRESUMO
One consequence of the intensive use of glyphosate is the contamination of rivers by the active substance and its metabolites aminomethyl phosphonic acid (AMPA) and sarcosine, inducing river eutrophication. Biofilms are the predominant lifestyle for microorganisms in rivers, providing pivotal roles in ecosystem functioning and pollutant removal. The persistence of glyphosate in these ecosystems is suspected to be mostly influenced by microbial biodegradation processes. The present study aimed to investigate the tripartite relationship among biofilms, phosphorus and glyphosate in rivers. The first part consists of a co-occurrence analysis among glyphosate, AMPA and phosphorus using an extensive dataset of measurements (nâ¯=â¯56,198) from French surface waters between 2013 and 2017. The second part investigated the capacity of natural river biofilms to dissipate glyphosate, depending on phosphorus availability and the exposure history of the biofilm, in a microcosm study. A strong co-occurrence among glyphosate, AMPA and phosphorus was found in surface waters. More than two-thirds of samples contained phosphorous with glyphosate, AMPA or both compounds. Seasonal fluctuations in glyphosate, AMPA and phosphorus concentrations were correlated, peaking in spring/summer shortly after pesticide spreading. Laboratory experiments revealed that natural river biofilms can degrade glyphosate. However, phosphorus availability negatively influenced the biodegradation of glyphosate and induced the accumulation of AMPA in water. An increase in alkaline phosphatase activity and phosphorus uptake was observed in glyphosate-degrading biofilms, evidencing the tight link between phosphorus limitation and glyphosate degradation by biofilms. The results of the present study show that phosphorus not only is a key driver of river eutrophication but also can reduce complete glyphosate degradation by biofilms and favour the accumulation of AMPA in river water. The predominant role of biofilms and the trophic status of rivers must therefore be considered in order to better assess the fate and persistence of glyphosate.
Assuntos
Biofilmes , Monitoramento Ambiental , Glicina/análogos & derivados , Rios/química , Poluentes Químicos da Água/análise , Biodegradação Ambiental , Monitoramento Ambiental/métodos , Glicina/análise , Compostos Organofosforados/análise , Fósforo/análise , Sarcosina/análise , Estações do Ano , GlifosatoRESUMO
In 2009, Sreekumar found that sarcosine, as an effective biomarker, can be used to identify prostate cancer. However, it is difficult to detect sarcosine in urine or plasma because of its low concentration. In this work, we describe a simple strategy for the preparation of sarcosine biosensor based on platinum-loaded mesoporous nickel phosphonate (Pt/MNP) and subsequently apply it to detect sarcosine. Mesoporous structure could increase the active sites on the MNP surface, which makes the Pt/MNP have excellent electrochemical performance for detecting hydrogen peroxide, one of the enzymatic products, and the sarcosine biosensor exhibited a superior electrochemical performance. The linear range of sarcosine biosensor is from 5 to 40⯵M and the sensitivity is 123.51⯵Aâ¯mM-1â¯cm-2. The limit of detection is estimated to be 0.24⯵Mâ¯(S/Nâ¯=â¯3). Additionally, the sarcosine biosensor based on Pt/MNP also shows an excellent performance in the anti-interference test and the real serum sample. This work manifests the potential application of Pt/MNP as a novel biosensor material for sarcosine detection, which could be extended to other oxidase-based detection systems.
Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Níquel/química , Organofosfonatos/química , Platina/química , Sarcosina/análise , Humanos , Tamanho da Partícula , Porosidade , Propriedades de SuperfícieRESUMO
Peroxidase mimics have attracted increasing attention as emerging artificial enzymes due to their promising applications in many fields, including bionanotechnology, sustainable chemistry, and environmental remediation. Although many types of peroxidase mimics have been successfully exploited in the past decade, the development of an innovative peroxidase mimic that does not contain noble metals, but exhibits remarkable peroxidase-like activity and low cytotoxicity still remains a major challenge in this field. Herein, we present a bulk covalent triazine framework cleavage and metal atom anchoring strategy for the synthesis of iron-modified two-dimensional covalent triazine frameworks (2D Fe-CTFs) that demonstrate excellent peroxidase-like activity. Furthermore, three kinds of colorimetric sensing platforms for sarcosine, ochratoxin A, and fluoride ions were constructed based on the intrinsic peroxidase-like activity, salt-induced coagulation, and coordination competition of the 2D Fe-CTF, respectively. This work may provide a new synthetic method for peroxidase mimics that can be used in various colorimetric sensors.
Assuntos
Materiais Biocompatíveis/química , Colorimetria , Compostos Férricos/química , Nanoestruturas/química , Triazinas/química , Materiais Biocompatíveis/metabolismo , Técnicas Biossensoriais , DNA de Cadeia Simples/química , Fluoretos/análise , Ocratoxinas/análise , Peroxidase/química , Peroxidase/metabolismo , Sarcosina/análise , Água/químicaRESUMO
An improved amperometric sarcosine biosensor was constructed based on covalent immobilization of sarcosine oxidase nanoparticles (SOxNPs) onto gold electrode (AuE). The SOxNPs/AuE was characterized by scanning electron microscopy (SEM), fourier transform infrared (FTIR) spectroscopy and electrochemical impedance spectroscopy (EIS) at different stages of its construction. The biosensor worked optimally within 2â¯s at a potential of 1.0â¯V, against Ag/AgCl, pH 6.5 and 35⯰C. A linear relationship was observed between sarcosine concentration range, 0.1-100⯵M and the biosensor response i.e. current in mA under optimum conditions. The biosensor offered a low detection limit of 0.01⯵M and gratifying storage stability. The SOxNPs/AuE was unaffected by a number of serum substances at their physiological concentrations. The biosensor measured sarcosine level in sera collected from persons suffering from prostate cancer (mean13.5⯵M, nâ¯=â¯8), which was significantly higher (pâ¯<â¯0.01) than those in apparently healthy persons (mean 2.2⯵M, nâ¯=â¯8). The SOxNPs/Au electrode was reused 300- times during the span of 180 days, with only 10% loss in its initial activity while being stored dry at 4⯰C.
Assuntos
Técnicas Biossensoriais/métodos , Neoplasias da Próstata/sangue , Sarcosina/sangue , Bacillus/enzimologia , Eletrodos , Enzimas Imobilizadas/química , Ouro/química , Humanos , Limite de Detecção , Masculino , Nanopartículas/química , Nanopartículas/ultraestrutura , Sarcosina/análise , Sarcosina Oxidase/químicaRESUMO
This work reports the development of three-dimensional (3D) semiconducting polymer/graphene (SP/G) networks toward sensitive photocathodic enzymatic bioanalysis. Specifically, the porous 3D graphene was first synthesized via the hydrothermal and freeze-dry processes and then mixed with semiconducting polymer to obtain the designed hierarchical structure with unique porosity and large surface area. Afterward, the as-prepared hybrid was immobilized onto the indium tin oxide (ITO) for further characterizations. Exemplified by sarcosine oxidase (SOx) as a model biocatalyst, an innovative 3D SP/G-based photocathodic bioanalysis capable of sensitive and specific sarcosine detection was achieved. The suppression of cathodic photocurrent was observed in the as-developed photocathodic enzymatic biosystem due to the competition of oxygen consumption between the enzyme-biocatalyst process and O2-dependent photocathodic electrode. This work not only presented a unique protocol for 3D SP/G-based photocathodic enzymatic bioanalysis but also provided a new horizon for the design, development, and utilization of numerous 3D platforms in the broad field of general photoelectrochemical (PEC) bioanalysis.
Assuntos
Fluorenos/química , Grafite/química , Maleatos/química , Polímeros/química , Poliestirenos/química , Sarcosina Oxidase/química , Sarcosina/análise , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Eletrodos , Enzimas Imobilizadas/química , Fluorenos/efeitos da radiação , Grafite/síntese química , Luz , Maleatos/efeitos da radiação , Processos Fotoquímicos , Polímeros/efeitos da radiação , Poliestirenos/efeitos da radiação , Porosidade , Compostos de Estanho/químicaRESUMO
BACKGROUND: Plasma and serum are the most widely used matrices in clinical studies. However, some variability in absolute concentrations of metabolites are likely to be observed in these collection tubes matrices. METHODS: We analyzed 189 metabolites using the same protocol for quantitative targeted metabolomics (LC-MS/MS AbsoluteIDQ p180 Kit Biocrates) in three types of samples, serum, plasma EDTA and citrate, of 80 subjects from the Cooperative Health Research In South Tyrol cohort (40 healthy elderly and 40 healthy young). RESULTS: The concentration levels were higher in serum than citrate and EDTA, in particular for amino acids and biogenic amines. The average Pearson's correlation coefficients were however always higher than 0.7 for these two classes of metabolites. We could also demonstrate that blank EDTA vacutainer tubes contain a significant amount of sarcosine. Finally, we compared the metabolome of young people against elderly subjects and found that the highest number of metabolites significantly changing with age was detected in serum. CONCLUSION: Serum samples provide higher sensitivity for biomarker discovery studies. Due to the presence of spurious amount of sarcosine in vacutainer EDTA tubes, plasma EDTA is not suitable for studies requiring accurate quantification of sarcosine.
Assuntos
Coleta de Amostras Sanguíneas , Contaminação de Equipamentos , Metabolômica , Sarcosina/análise , Sarcosina/sangue , Aminas/metabolismo , Biomarcadores/sangue , Cromatografia Líquida , Ácido Cítrico/química , Ácido Edético/química , Humanos , Espectrometria de Massas em TandemRESUMO
In this study, on the basis of hierarchical CuInS2-based heterostructure, a novel cathodic photoelectrochemical (PEC) enzymatic bioanalysis of the sarcosine detection was reported. Specifically, heterostructured CuInS2/NiO/ITO photocathode was prepared and sarcosine oxidases (SOx) were integrated for the construction of the enzymatic biosensor. In the bioanalysis, the O2-dependent suppression of the cathodic photocurrent can be observed due to the competition between the as-fabricated O2-sensitive photocathode and the SOx-catalytic event toward O2 reduction. Based on the sarcosine-controlled O2 concentration, a novel photocathodic enzymatic biosensor could be realized for the sensitive and specific sarcosine detection. This work manifested the great potential of CuInS2-based heterostructure as a novel platform for future PEC bioanalytical development and also a PEC method for sarcosine detection, which could be easily extended to numerous other enzymatic systems and to our knowledge has not been reported. This work is expected to stimulate more interest in the design and implementation of numerous CuInS2-based heterostructured photocathodic enzymatic sensing.
Assuntos
Técnicas Biossensoriais/instrumentação , Cobre/química , Técnicas Eletroquímicas/instrumentação , Índio/química , Nanoestruturas/química , Sarcosina/análise , Sulfetos/química , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Eletrodos , Desenho de Equipamento , Nanoestruturas/ultraestrutura , Processos FotoquímicosRESUMO
Due to their central role in biochemical processes, fast separation and identification of amino acids (AA) is of importance in many areas of the biomedical field including the diagnosis and monitoring of inborn errors of metabolism and biomarker discovery. Due to the large number of AA together with their isomers and isobars, common methods of AA analysis are tedious and time-consuming because they include a chromatographic separation step requiring pre- or post-column derivatization. Here, we propose a rapid method of separation and identification of sarcosine, a biomarker candidate of prostate cancer, from isomers using differential ion mobility spectrometry (DIMS) interfaced with a tandem mass spectrometer (MS/MS) instrument. Baseline separation of protonated sarcosine from α- and ß-alanine isomers can be easily achieved. Identification of DIMS peak is performed using an isomer-specific activation mode where DIMS- and mass-selected ions are irradiated at selected wavenumbers allowing for the specific fragmentation via an infrared multiple photon dissociation (IRMPD) process. Two orthogonal methods to MS/MS are thus added, where the MS/MS(IRMPD) is nothing but an isomer-specific multiple reaction monitoring (MRM) method. The identification relies on the comparison of DIMS-MS/MS(IRMPD) chromatograms recorded at different wavenumbers. Based on the comparison of IR spectra of the three isomers, it is shown that specific depletion of the two protonated α- and ß-alanine can be achieved, thus allowing for clear identification of the sarcosine peak. It is also demonstrated that DIMS-MS/MS(IRMPD) spectra in the carboxylic C=O stretching region allow for the resolution of overlapping DIMS peaks. Graphical Abstract á .
Assuntos
Sarcosina/análise , Sarcosina/química , Espectrometria de Massas em Tandem/métodos , Isomerismo , Metabolômica , Modelos Moleculares , Espectrofotometria InfravermelhoRESUMO
Formation-free multi-level resistive switching characteristics by using 10 nm-thick polycrystalline GeOx film in a simple W/GeOx/W structure and understanding of switching mechanism through redox reaction in H2O2/sarcosine sensing (or changing Ge°/Ge4+ oxidation states under external bias) have been reported for the first time. Oxidation states of Ge0/Ge4+ are confirmed by both XPS and H2O2 sensing of GeOx membrane in electrolyte-insulator-semiconductor structure. Highly repeatable 1000 dc cycles and stable program/erase (P/E) endurance of >106 cycles at a small pulse width of 100 ns are achieved at a low operation current of 0.1 µA. The thickness of GeOx layer is found to be increased to 12.5 nm with the reduction of polycrystalline grain size of <7 nm after P/E of 106 cycles, which is observed by high-resolution TEM. The switching mechanism is explored through redox reaction in GeOx membrane by sensing 1 nM H2O2, which is owing to the change of oxidation states from Ge0 to Ge4+ because of the enhanced O2- ions migration in memory device under external bias. In addition, sarcosine as a prostate cancer biomarker with low concentration of 50 pM to 10 µM is also detected.
Assuntos
Biomarcadores Tumorais/análise , Testes Diagnósticos de Rotina/métodos , Peróxido de Hidrogênio/análise , Neoplasias da Próstata/diagnóstico , Neoplasias da Próstata/patologia , Sarcosina/análise , Testes Diagnósticos de Rotina/instrumentação , Humanos , Masculino , Oxidantes , OxirreduçãoRESUMO
Catalytic nanomaterials with intrinsic enzyme-like activities, called nanozymes, have recently attracted significant research interest due to their unique advantages relative to natural enzymes and conventional artificial enzymes. Among the nanozymes developed, particular interests have been devoted to nanozymes with peroxidase mimicking activities because of their promising applications in biosensing, bioimaging, biomedicine, etc. Till now, lots of functional nanomaterials have been used to mimic peroxidase. However, few studies have focused on the Ni-based nanomaterials for peroxidase mimics. In this work, we obtained the porous LaNiO3 nanocubes with high peroxidase-like activity by inducing its 3+ oxidation state in LaNiO3 perovskite and optimizing the morphology of LaNiO3 perovskite. The peroxidase mimicking activity of the porous LaNiO3 nanocubes with Ni3+ was about 58~fold and 22~fold higher than that of NiO with Ni2+ and Ni nanoparticles with Ni0. More, the porous LaNiO3 nanocubes exhibited about 2-fold higher activity when compared with LaNiO3 nanoparticles. Based on the superior peroxidase-like activity of porous LaNiO3 nanocubes, facile colorimetric assays for H2O2, glucose, and sarcosine detection were developed. Our present work not only demonstrates a useful strategy for modulating nanozymes' activities but also provides promising bioassays for clinical diagnostics.
Assuntos
Compostos de Cálcio/metabolismo , Nanopartículas/metabolismo , Níquel/metabolismo , Oxidantes/metabolismo , Óxidos/metabolismo , Titânio/metabolismo , Glucose/análise , Peróxido de Hidrogênio/análise , Oxirredução , Sarcosina/análiseRESUMO
Indicator displacement assay plays a fundamental role in the development of chemosensors. We explored here an ingenious yet effective strategy for amperometric assay of electrochemically inactive sarcosine based on an indicator displacement principle, in which 1,2-naphthoquinone-4-sulphonic acid sodium salt (NQS) was proposed as the receptor and the electroactive Ru(NH3)63+ cations used as an indicator. Due to the stronger binding affinity of the NQS toward sarcosine than toward Ru(NH3)63+, the developed amperometric indicator displacement assay (A-IDA) exhibits high selectivity and excellent sensitivity toward sarcosine determination as well as with a lower detection limit (30.00nM, S/N =3).