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1.
Anal Chim Acta ; 1178: 338794, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34482876

RESUMO

Fluorescent materials with tunable optical properties are critical to their potential application. So far, the tuning of double-color luminescence has been easily achieved for many organic materials, but there are very few reports on multicolor luminescence materials. In this work, a multicolor emissions Schiff-base fluorescent compound 1,1'-{4,4'-Biphenyldiylbis[nitrilo(E)methylylidene]}di(2-naphthol) (BPDN) with an aggregation induced emission (AIE) characteristic was synthesized, and its luminescent characteristic was investigated. The BPDN molecules with low concentration in solution can emit faint light, but a new AIE phenomenon will appear when the BPDN molecules are aggregated in the solvent with low solubility or high concentration. The color and efficiency of the AIE of BPDN can be tuned by changing its aggregation state: the luminescence of the aggregate gradually redshifts (blue, green, to orange) as the solvent with poor solubility in the mixture increases or increasing the concentration of the BPDN. Based on the multicolor luminescence BPDN, a molecularly imprinted ratiometric fluorescent probe test strip (MIRF test strip) had been prepared and successfully applied to visual detection of pentachloronitrobenzene (PCNB). The color of test strip could change gradually from orange to yellow to green with the increase of the concentration of PCNB. This work shows the characteristic and application of multicolor luminescence BPDN.


Assuntos
Luminescência , Nitrobenzenos , Corantes Fluorescentes , Solventes
2.
Mater Sci Eng C Mater Biol Appl ; 128: 112355, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474903

RESUMO

Electrostatically driven self-assembly of [Au2L2]2+ (L is cyclic PNNP ligand) with [{Mo6I8}(L')6]2- (L' = I-, CH3COO-) in aqueous solutions is introduced as facile route for combination of therapeutic and cellular contrasting functions within heterometallic colloids (Mo6-Au2). The nature of L' affects the size and aggregation behavior of crystalline Mo6-Au2 aggregates, which in turn affect the luminescence of the cluster units incorporated into Mo6-Au2 colloids. The spin trap facilitated electron spin resonance spectroscopy technique indicates that the level of ROS generated by Mo6-Au2 colloids is also affected by their size. Both (L' = I-, CH3COO-) Mo6-Au2 colloids undergo cell internalization, which is enhanced by their assembly with poly-DL-lysine (PL) for L' = CH3COO-, but remains unchanged for L' = I-. The colloids PL-Mo6-Au2 (L' = CH3COO-) are visualized as huge crystalline aggregates both outside and inside the cell cytoplasm by confocal microscopy imaging of the incubated cells, while the smaller sized (30-50 nm) PL-Mo6-Au2 (L' = I-) efficiently stain the cell nuclei. Quantitative colocalization analysis of PL-Mo6-Au2 (L' = CH3COO-) in lysosomal compartments points to the fast endo-lysosomal escape of the colloids followed by their intracellular aggregation. The cytotoxicity of PL-Mo6-Au2 differs from that of Mo6 and Au2 blocks, predominantly acting through apoptotic pathway. The photodynamic therapeutic effect of the PL-Mo6-Au2 colloids on the cancer cells correlates with their intracellular trafficking and aggregation.


Assuntos
Fotoquimioterapia , Coloides , Luminescência , Polímeros , Água
3.
Talanta ; 235: 122749, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517617

RESUMO

Signal output mode is the important part of biosensor. In general, "signal on" and "signal off" are two common output modes. The development of dual signals-based ratio analysis as a powerful diagnostic tool has attracted widespread attention in the biosensor field in recent years. Dual signals ratio sensors with "signal on" and "signal off" are more favored because of their low background signal and better sensitivity and selectivity. In this study, inspired by the idea that EcoR V can cut specific sites of DNA to produce two corresponding fragments, and by using the capturing probe as guy wires, a reliable and sensitive method for EcoR V assay is developed based on the ratio of dual chemiluminescence (CL) signals for the first time. In particular, in the existence of the objective EcoR V, the substrate DNA would be degraded into two double stranded oligonucleotides with blunt ends which include the sequence I and the sequence II, then they can separately compete with two different corresponding capture probes on magnetic beads (MBs). One of capture probe hybridized with the sequence I containing more guanine (G) bases that reacted with the phenylglyoxal (PG) to produce chemical reaction which triggered a positive CL signal output I + CL as "signal-on"; another capture probe is priority to hybridize the sequence II, which triggered the weaker reporter DNA linked with horseradish peroxidase (HRP) probe to fall off the MBs, thereby outputting a negative CL signal I-CL as "signal-off". By comparing the linear relation and the correlation coefficient, the I-CL/I + CL ratio method has better linear relation (0.01-10 U/mL) and higher sensitivity (0.0045 U/mL). In addition, this developed strategy of high selectivity which can directly detect low concentration of target EcoR V in human serum, and thus this dual ratio biosensor might offer a promising detection approach for clinical diagnostics.


Assuntos
Técnicas Biossensoriais , DNA de Cadeia Simples , DNA/genética , DNA de Cadeia Simples/genética , Peroxidase do Rábano Silvestre , Humanos , Luminescência
4.
Talanta ; 235: 122783, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517641

RESUMO

As the light-harvesting "antenna", G-rich oligonucleotides (such as the G-quadruplex) can interact with lanthanide (III) to bring a luminescent enhancement response. In this study, phenomenon of luminescent enhancement of G-triplex/terbium (III) (G3/Tb3+) and interaction between G3 and Tb3+ were first reported and characterized. Based on G3/Tb3+ luminescence, a label-free aptasensor for the detection of ofloxacin (OFL) residues in the food was developed. The OFL triggered the action of rolling circle amplification (RCA) allowed for the amplification product of G3-forming sequences in the single-stranded DNA, which promoted the conformational transition of the G3/Tb3+ complexes once the addition of Tb3+. Under the optimal conditions, the logarithmic correlation between the G3/Tb3+ luminescence intensity and the concentration of OFL was found to be linear in the range of 5-1000 pmol L-1 (R2 = 0.9949). The limit of detection was 0.18 pmol L-1 (3σ/slope). Additionally, the good recoveries of 90.19-108.89 % and the relative standard deviations values of 0.59-5.87 % were obtained in the application of the aptasensor detecting OFL in the practical samples. These results confirmed that the present aptasensor has a good analytical performance and bright prospect for detecting ofloxacin residues in food.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , DNA de Cadeia Simples , Limite de Detecção , Luminescência , Ofloxacino , Térbio
5.
Talanta ; 235: 122798, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517656

RESUMO

Covalent organic frameworks (COFs) are considered to be a promising support material for catalyst due to their highly ordered porous structure. Here, a core-shell structured Fe3O4 magnetic covalent organic framework (Fe3O4@COF) was synthesized and employed to provide basic sites for immobilization of gold nanoparticles (AuNPs). The AuNPs was in-situ immobilized on the shell of Fe3O4@COF via a citrate reducing method. The Fe3O4@COF-AuNP had convenient magnetic separability and exhibited excellent mimicking peroxidase-like activity in catalyzing chemiluminescence (CL) reaction of luminol with hydrogen peroxide (H2O2). With acetylcholine chloride (ACh) as substrate of acetylcholinesterase (AChE), a CL method was exploited for sensitive detection of organophosphorus pesticide triazophos due to its irreversible inhibiting effect on the AChE activity and subsequently influences the production of H2O2 under the condition of choline oxidase (ChOx). This method gave a good linearity for triazophos in the range of 5.0-300.0 nmol L-1, and a limit of detection (LOD) of 1 nmol L-1 was acquired. The applicability of this method was verified by the determination of triazophos in different spiked vegetable samples.


Assuntos
Nanopartículas Metálicas , Estruturas Metalorgânicas , Praguicidas , Ouro , Peróxido de Hidrogênio , Luminescência , Compostos Organofosforados , Organotiofosfatos , Praguicidas/análise , Triazóis
6.
Talanta ; 235: 122811, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517668

RESUMO

Practical detection of single-component pesticide residue at ultra-low concentrations in agricultural products and environment is very important for assessment of environmental risks and protection of human health. Herein, a practical and highly sensitive chemiluminescence (CL) sensing acetamiprid in agricultural products and environmental media was constructed based on the synergistic co-catalysis of graphene oxide (GO)/gold nanoparticles (AuNPs) nanocomposites for luminol CL reaction and the smart interface engineering. ss-DNA could inhibit co-catalysis of GO/AuNPs for luminol CL reaction. Once acetamiprid was added, aptamer conformation changed in dimension and synergistically catalytic amplification signal of GO/AuNPs was restored significantly. The limit of detection was 8.9 pM. High sensitivity could be due to strong signal amplification from synergistic catalysis of GO/AuNPs for CL reaction and perfect regulation of composite interface by DNA dimension. Moreover, the used GO/AuNPs could be stably stored for six months, which was superior to previously reported AuNPs (only half a month). The analysis exhibited excellent selectivity for acetamiprid. The detection results for real samples confirmed reliability in practical application. This analysis is an extremely useful method for monitoring pesticide residues in environment and agricultural products. Synergetic co-catalysis of GO/AuNPs and ingenious interface engineering provide important ideas for other biosensors.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Nanopartículas Metálicas , Resíduos de Praguicidas , Ouro , Humanos , Limite de Detecção , Luminescência , Medições Luminescentes , Luminol , Neonicotinoides , Reprodutibilidade dos Testes
7.
Analyst ; 146(18): 5691-5703, 2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34515701

RESUMO

Platinum(II) complexes are the most commonly used anticancer drugs and potential optical materials, but the detectability of Pt(II) complex-based probes is seldom reported. In our previous work, a tetradentate Pt(II) complex Pt-CHO was utilised as a 'turn-off' probe to detect ClO- and image cancer cells. However, the recognition mechanism has not been completely clarified and there are still doubts. In this work, three Pt(II) complexes, Pt-H, Pt-CHO and Pt-COOH, were developed to elucidate the mechanism of this class of complexes and refine their property studies. As a result, the UV-visible absorption and luminescence emission experiments, as well as the mass spectrum, proved that the oxidation of Pt(II) to Pt(IV) was the real reason for luminescence quenching, which has nothing to do with aldehyde groups. This first reported mechanism introduces a new type of ClO- probe based on Pt(II) complexes, thereby expanding the application fields of platinum complexes. Moreover, the quantum yield measurements, the effect of biomolecules and reversibility were studied to improve the properties of the probes. Theoretical calculations were used to gain an in-depth understanding of optical characteristics and related mechanisms. The cell imaging of RAW264.7 cells under endogenous ClO- proved the potential of the probes in bioimaging.


Assuntos
Ácido Hipocloroso , Luminescência , Oxirredução , Estresse Oxidativo , Platina
8.
Nature ; 596(7871): 244-249, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34381236

RESUMO

Chemical reactions tend to be conceptualized in terms of individual molecules transforming into products, but are usually observed in experiments that probe the average behaviour of the ensemble. Single-molecule methods move beyond ensemble averages and reveal the statistical distribution of reaction positions, pathways and dynamics1-3. This has been shown with optical traps and scanning probe microscopy manipulating and observing individual reactions at defined locations with high spatial resolution4,5, and with modern optical methods using ultrasensitive photodetectors3,6,7 that enable high-throughput single-molecule measurements. However, effective probing of single-molecule solution chemistry remains challenging. Here we demonstrate optical imaging of single-molecule electrochemical reactions7 in aqueous solution and its use for super-resolution microscopy. The method utilizes a chemiluminescent reaction involving a ruthenium complex electrochemically generated at an electrode8, which ensures minimal background signal. This allows us to directly capture single photons of the electrochemiluminescence of individual reactions, and to develop super-resolved electrochemiluminescence microscopy for imaging the adhesion dynamics of live cells with high spatiotemporal resolution. We anticipate that our method will advance the fundamental understanding of electrochemical reactions and prove useful for bioassays and cell-imaging applications.


Assuntos
Eletroquímica , Imagem Individual de Molécula , Eletrodos , Células HEK293 , Humanos , Cinética , Luminescência , Imagem Óptica , Rutênio/química , Soluções , Processos Estocásticos , Fatores de Tempo
9.
Nat Commun ; 12(1): 4883, 2021 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-34385449

RESUMO

Pure organic room-temperature phosphorescent (RTP) materials have been suggested to be promising bioimaging materials due to their good biocompatibility and long emission lifetime. Herein, we report a class of RTP materials. These materials are developed through the simple introduction of an aromatic carbonyl to a tetraphenylpyrrole molecule and also exhibit aggregation-induced emission (AIE) properties. These molecules show non-emission in solution and purely phosphorescent emission in the aggregated state, which are desirable properties for biological imaging. Highly crystalline nanoparticles can be easily fabricated with a long emission lifetime (20 µs), which eliminate background fluorescence interference from cells and tissues. The prepared nanoparticles demonstrate two-photon absorption characteristics and can be excited by near infrared (NIR) light, making them promising materials for deep-tissue optical imaging. This integrated aggregation-induced phosphorescence (AIP) strategy diversifies the existing pool of bioimaging agents to inspire the development of bioprobes in the future.


Assuntos
Corantes Fluorescentes/química , Luminescência , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Nanopartículas/química , Pirróis/química , Imagem com Lapso de Tempo/métodos , Animais , Células HeLa , Humanos , Camundongos Endogâmicos BALB C , Camundongos Nus , Microscopia Confocal/métodos , Microscopia Eletrônica de Transmissão/métodos , Nanopartículas/ultraestrutura , Tamanho da Partícula
10.
Talanta ; 234: 122648, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364457

RESUMO

Herein, a novel paper-based chemiluminescence (CL) assay is reported using a smartphone readout for on-site and reliable analytical applications. The CL system was based on the high-performance improving effect of cobalt-imidazole metal-organic framework (CoMOF) on luminol-hydrogen peroxide (H2O2) CL emission. The CoMOF was grown on paper and used as a support for the CL reaction, which led to an intense CL emission and good reproducibility. More importantly, the stability of luminol, as the CL reagent, was greatly improved in the presence of CoMOF. This high stability, along with the high-yield CL emission, makes the device highly suitable for commercialization. Furthermore, using a smartphone as the detector for the developed device made the process easier and more accessible for public usage. In this work, the new paper-based CL smartphone device was used for the detection of the total phenolic content of food samples. Phenolic compounds (PC) are hydroxyl radical scavengers that can effectively quench the CL emission of the luminol-H2O2-CoMOF system. After optimizing the reaction conditions, the system could detect PC at the µg mL-1 level. Detection limits of 0.12, 0.28, 0.46, 0.85, and 1.23 µg mL-1 were obtained for gallic acid, quercetin, catechin, kaempferol, and caffeic acid, respectively. This work is the first report on the practical application of smartphone CL assays for the estimation of PC. The proposed assay is an easy-to-use, low-cost, portable, and suitable assay for on-site screening purposes.


Assuntos
Estruturas Metalorgânicas , Peróxido de Hidrogênio , Luminescência , Medições Luminescentes , Luminol , Reprodutibilidade dos Testes , Smartphone
11.
Clin Lab ; 67(8)2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34383424

RESUMO

BACKGROUND: Our study was undertaken to detect the prevalence of serum specific antibodies to TORCH agents in children by establishing the presence of the specific IgM antibodies with DiaSorin "Flash" chemiluminescence technology. MATERIALS AND METHODS: A total of 804 blood samples were collected for the detection of the Toxoplasma IgM; 2,048 cases were collected for CMV IgM, and 337 cases were collected for HSV-1/2 IgM, over a period of 9 months (from January 2019 to September 2019). RESULTS: In our cohort, a total of 103 samples (12.8%) were found to be seropositive for Toxoplasma, 1,551 samples (75.7%) were positive for CMV and 174 samples (51.6%) were positive for the HSV-1/2 infections. The perinatal CMV infection was observed in 11.9% of the patients with positive serology for CMV. CONCLUSIONS: The routine antenatal screening with chemiluminescence technology should be recommended in general population to avoid congenital malformations, as long as the prevalence of serum specific antibodies to TORCH agents is high and seropositivity rate increases with age.


Assuntos
Infecções por Citomegalovirus , Toxoplasmose , Criança , Infecções por Citomegalovirus/diagnóstico , Infecções por Citomegalovirus/epidemiologia , Feminino , Humanos , Imunoglobulina M , Luminescência , Gravidez , Prevalência , Tecnologia , Toxoplasmose/diagnóstico , Toxoplasmose/epidemiologia
12.
Anal Methods ; 13(34): 3785-3791, 2021 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-34350907

RESUMO

Olaquindox (OLA), a chemically synthesized antibacterial growth promoter, despite being strictly controlled, is illegally used in feed to improve feed conversion efficiency and increase the rate of weight gain for animals. However, it has become clear that OLA has toxic effects on human beings via the transmission of OLA through the food chain. Here, by employing terbium nitrate to provide metal ions and benzene-1,3,5-tricarboxylic acid (H3BTC) as an organic ligand, a simple, rapid, and easy scale-up synthetic method was presented for the fabrication of water-stable and highly luminescent rod-like metal-organic frameworks (Tb-BTC MOFs). Using the Tb-BTC MOFs as a luminescent probe, the luminescence quenching effect was obviously observed upon the addition of OLA, ascribed to the binding of OLA molecules on the surface of Tb-BTC and the existence of an inner-filter effect (IFE) mechanism. The correlation between the luminescence quenching ΔI and the concentration of OLA was found to be linear from 1.0 to 1000.0 µM with a detection limit of 20.6 nM. Furthermore, a Tb-BTC-loaded fiber paper was prepared and it is highly responsive (30 s) and suitable for visual OLA assay. The method described here can be successfully applied to the detection of OLA in animal feed and edible animal tissue samples.


Assuntos
Estruturas Metalorgânicas , Térbio , Animais , Humanos , Luminescência , Quinoxalinas
13.
Anal Chem ; 93(32): 11329-11336, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34342421

RESUMO

A class of water-soluble electrochemiluminescence (ECL) nanodots were prepared by encapsulating ECL-active iridium complexes into biocompatible horse spleen apoferritin (apoHSF) nanocages for immunoassays. The preparation feasibility was achieved based on the pH-induced disassembly/reassembly nature originated from apoHSF. Two iridium nanodots (1 and 2) with high ECL efficiency were separately prepared by directing the self-assembly of two water-insoluble luminescent complexes, Ir(ppy)3 (ppy = 2-phenylpyridine) and Ir(ppy)2(acac) (ppy = 2-phenylpyridine and acac = acetylacetonate), in the apoHSF cavity. Using tri-n-propylamine (TPrA) as a coreactant, the electrochemistry and "oxidative-reductive" ECL mechanisms for nanodots 1 and 2 were investigated, respectively. After demonstrating the spectroscopic property and relative ECL efficiency, the ECL emission of nanodots 1 and 2 quenched by TPrA• radicals at high potential was further studied and circumvented by optimizing the potential range and TPrA concentration for generating strong and stable ECL emission in aqueous media. The well-inherited biological functions of apoHSF in nanodots allow the convenient external modification of an antibody to act as a signal probe, thus a versatile ECL immunoassay paradigm was established. Acceptable results from this assay enabled the rapid and accurate detection of biomarkers in real samples. The unprecedented use of apoHSF is feasible and applicable for water-insoluble iridium complexes to fabricate a wide variety of biocompatible ECL nanodots for potential bioanalysis.


Assuntos
Apoferritinas , Irídio , Animais , Técnicas Eletroquímicas , Cavalos , Imunoensaio , Luminescência , Medições Luminescentes
14.
Radiol Phys Technol ; 14(3): 309-317, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34224082

RESUMO

The purpose of this study was to measure the surface dose and build-up region depth dose characteristics of 6 MV photon beams in Cyberknife and helical tomotherapy (HT) systems for non-standard small fields using parallel plate chambers (Roos and Markus), Gafchromic EBT3 films, and nanoDot optically stimulated luminescence dosimeters (OSLDs), as well as to investigate the effect of oblique incidence on the surface dose of the beam. All measurements were conducted in a virtual water phantom under machine-specific reference conditions. The Roos and OSLDs overestimated the surface dose when compared with the Markus chamber and EBT3 films by 20%. We applied water equivalent thickness (WET) correction to account for the intrinsic build-up thickness of the detectors from their effective point of measurement (EPOM). With WET correction, a reasonably close surface dose estimate was obtained for all detectors, within 1.9% agreement for the 60 mm collimator of Cyberknife and 3.1% agreement for the HT system, with a 5 × 10 cm2 field size. The surface dose increased from the normally incident Cyberknife and HT fields with increasing angle of incidence. The surface dose increased to twice its value at normal incidence for highly oblique angles of incidence above 55°. For the tested fields, a reasonable surface dose estimate could be measured with the detectors if the correction for intrinsic buildup thickness was applied. Nevertheless, the use of Roos chambers with large dimensions and nanoDot OSLDs is not recommended for estimating the surface dose for small fields.


Assuntos
Radioterapia de Intensidade Modulada , Luminescência , Imagens de Fantasmas , Fótons , Dosímetros de Radiação , Radiometria
15.
Colloids Surf B Biointerfaces ; 206: 111942, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34243033

RESUMO

Horseradish peroxidase (HRP) is usually used as a label enzyme in immunoassay so the method used for HRP detection in enzyme immunoassay (EIA) plays a key role in sensitivity and precision. The catalytic activity of HRP does not strictly follow classic Michaelis-Menten kinetics, probably due to the inactivation of the enzyme at high concentrations of H2O2. In this paper, a highly sensitive alternative procedure for the HRP assay using H2O2-sensitive CdTe quantum dots as a chemiluminescence (CL) system is reported. This method can measure a much more accurate and reliable value of Km (187 mM H2O2) in comparison with the standard detection method. This system also was applied to thyroid hormone (T4) detection using HRP-based immunoassay. The QD/H2O2 system exhibits a higher linear range of 0.2-16 µg/dL with the improved LOD value of 0.06 µg/dL and selective response to T4, which was better than the commercial colorimetric immunoassay. Meanwhile, the proposed method has been successfully applied to the clinical determination of T4 in the serum samples, and the results confirmed an excellent correlation with the conventional ELISA method (R2 = 0.9832), indicating the potential applications of the method for clinical diagnosis as well.


Assuntos
Compostos de Cádmio , Pontos Quânticos , Peroxidase do Rábano Silvestre , Peróxido de Hidrogênio , Imunoensaio , Luminescência , Medições Luminescentes , Telúrio
16.
Sensors (Basel) ; 21(13)2021 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-34202483

RESUMO

Since the introduction of paper-based analytical devices as potential diagnostic platforms a few decades ago, huge efforts have been made in this field to develop systems suitable for meeting the requirements for the point-of-care (POC) approach. Considerable progress has been achieved in the adaptation of existing analysis methods to a paper-based format, especially considering the chemiluminescent (CL)-immunoassays-based techniques. The implementation of biospecific assays with CL detection and paper-based technology represents an ideal solution for the development of portable analytical devices for on-site applications, since the peculiarities of these features create a unique combination for fitting the POC purposes. Despite this, the scientific production is not paralleled by the diffusion of such devices into everyday life. This review aims to highlight the open issues that are responsible for this discrepancy and to find the aspects that require a focused and targeted research to make these methods really applicable in routine analysis.


Assuntos
Técnicas Biossensoriais , Luminescência , Imunoensaio , Sistemas Automatizados de Assistência Junto ao Leito
17.
Talanta ; 233: 122563, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215059

RESUMO

Persistent luminescent nanoparticles (PLNPs) are a class of materials with excellent optical properties, which can continue to emit light for a long time after removing the excitation light source. This feature enables PLNPs to be used for development of biological detection modes without autofluorescence background. In this study, we prepared Zn2GeO4: Mn2+, Pr3+ (ZGOMP) nanorods through a one-pot hydrothermal method. Using the pH-responsive luminescence behavior of ZGOMP, we developed an autofluorescence-free biosensor using ZGOMP as a probe and gluconic acid as a quencher to detect prostate-specific antigen (PSA). Hybridization chain reaction (HCR) and magnetic separation system were introduced in the design to achieve efficient signal amplification. Under the optimal conditions, the as-designed autofluorescence-free sensing platform showed high selectivity, and showed a good luminescence response to PSA within the linear range of 0.001-10 ng/mL at a detection limit of 0.64 pg/mL. The excellent analytical performance shows that the current strategy provides an effective platform for clinical sample analysis.


Assuntos
Técnicas Biossensoriais , Nanopartículas , Nanotubos , Humanos , Luminescência , Masculino , Antígeno Prostático Específico
18.
Talanta ; 233: 122567, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215063

RESUMO

Photodynamic therapy (PDT) received great attention in cancer therapy due to the advantages of negligible drug resistance, low side effects, and minimal invasiveness. Development of theranostic nanoprobes with specific imaging-guided PDT is of great significance in the field. Herein we report the fabrication of a novel theranostic nanoprobe porphyrin/G-quadruplex conjugated gold/persistent luminescence nanocomposites for imaging-guided PDT. The developed nanoprobe contains NIR-emitting persistent luminescent nanoparticles (PLNP) as the core for autofluorescence-free bioimaging and Au coating on PLNP for facile subsequent DNA conjugation. The DNA sequence is designed to contain G-rich AS1411 aptamer for recognizing the over-expressed cellular nucleolin of cancer cell and forming a G-quadruplex structure to combine with tetrakis (4-carboxyphenyl) porphyrin (TCPP) to realize PDT. The AS1411 aptamer-contained DNA conjugated Au-coated PLNP is rapidly prepared via a freezing method with high content of DNA and good aqueous stability. Meanwhile, TCPP is easily loaded into the G-quadruplex structure formed from G-rich AS1411 aptamer on the surface of Au/PLNP in presence of K+. The theranostic nanoprobe gives integrated merits of PLNP for autofluorescence-free bioimging, TCPP for PDT and AS1411 aptamer-contained DNA for specific binding to cancer cells. This work provides a new specially designed imaging-guided PDT nanoplatform for theranostics.


Assuntos
Fotoquimioterapia , Porfirinas , Linhagem Celular Tumoral , Ouro , Luminescência , Medicina de Precisão
19.
Talanta ; 233: 122599, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215087

RESUMO

A method using a gas-phase microdialysis probe interfaced with a modified commercially available nitric oxide (NO) detector is shown to selectively measure aqueous NO at low µM levels with high selectivity. The detector measures chemiluminescence resulting from the gas-phase reaction of NO with ozone. The microdialysis probe is small enough (3 mm × 200 µm) to be used in vivo. Because the processes of extraction across the microdialysis membrane and transport from the probe to the detector are both very fast, the response time is shorter than 5 s. The method was verified using two different quantifiable sources of NO: nitrite and methylamine hexamethylene methylamine (MAHMA) NONOates. To demonstrate ruggedness and to show the impact of matrix on NO generation, the method was used to measure NO in a cell culture matrix. The continuous extraction, fast response time, and rugged nature make the method useful for monitoring NO in biological applications. Our results also show that predicting NO concentration for in vitro experiments based on NONOate concentration may be a poor assumption due to the pH dependence of NO formation and the rapid decline in NO concentration.


Assuntos
Óxido Nítrico , Ozônio , Luminescência , Microdiálise , Nitritos
20.
Talanta ; 233: 122522, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215137

RESUMO

Aldehydes are toxic carbonyl compounds that are identified in various matrices surrounding us. For instance, aldehydes could be formed during the cooking and frying of foods which affects the food quality and safety. Derivatization is a must for the determination of aldehydes as they lack intrinsic chromophoric groups. 2,4-Dinitrophenyl hydrazine (DNPH) is the most used derivatizing reagent for aldehydes and the formed hydrazones could be determined by either HPLC-UV or LC-MS. However, UV detection is non-sensitive, and the MS equipment is expensive and not widely available. Thus, herein we report a smart chemiluminescence (CL) detection method for the DNPH aldehydes derivatives. These derivatives are supposed to possess photosensitization ability due to the presence of strong chromophoric structures; nitrobenzene and phenyl hydrazone. Upon their UV irradiation, singlet oxygen is found to be produced which then converts the DNPH-aldehyde derivative into hydroperoxide. Next, the hydroperoxide reacts with luminol in an alkaline medium producing a strong CL. An HPLC system with online UV irradiation and online reaction with luminol followed by CL detection was constructed and used for the determination of aldehydes after their derivatization with DNPH. The developed method showed excellent sensitivity with detection limits down to 1.5-18.5 nM. The achieved sensitivity is superior to that obtained by HPLC-UV and LC-MS detection methods for DNPH-aldehydes derivatives. Additionally, our approach is an chemiluminogenic where the DNPH reagent itself does not produce CL which is an excellent advantage. The method was applied successfully for the determination of aldehydes in canola oil samples using simple liquid-liquid extraction showing good recovery (87.0-106.0%), accuracy (87.2-106.6), and precision (RSD≤10.2%). After analysis of fresh and heated oil samples, it was demonstrated that heating of oil, even for short time, strongly elevated the level of their aldehydes' content. At last, it was found that the results of the analysis of aldehydes in oil samples using the proposed method perfectly matched those obtained by a reference LC-MS method.


Assuntos
Aldeídos , Luminol , Cromatografia Líquida de Alta Pressão , Hidrazinas , Luminescência , Fenil-Hidrazinas
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