RESUMO
A heterometallic cluster [Ag6Au6(ethisterone)12] of an unprecedented topology was synthesized and characterized. A sensitive and specific probe for estrogen receptor α (ERα) has been developed for the first time based on the enhancement of the Ag6Au6 luminescence.
Assuntos
Receptor alfa de Estrogênio/metabolismo , Etisterona/metabolismo , Cobre , Ouro , Humanos , LuminescênciaRESUMO
In this study, a hyperbranched rolling circle amplification (HRCA)-based colorimetric biosensor for carcinoembryonic antigen (CEA) is developed with high sensitivity and specificity. A CEA aptamer can bind with its target (CEA) to form a complex due to their high affinity, and the introduced CDNA cannot hybridize with the aptamer. Thus, free CDNA can propagate the HRCA reaction to form a large number of single-stranded DNA (ss-DNA). ss-DNA can be easily adsorbed onto AuNPs and prevent salt-induced AuNPs aggregation, which causes the change in the color of the system. It is found that the absorbance intensity ratio (A520/A660) has a linear relationship with the concentration of the target in the range of 5 pM-0.5 nM, and the detection limit is as low as 2 pM (S/N = 3).
Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Antígeno Carcinoembrionário/análise , Técnicas de Amplificação de Ácido Nucleico/métodos , Biomarcadores Tumorais/análise , Colorimetria/métodos , DNA de Cadeia Simples/química , Ouro/química , Humanos , Limite de Detecção , Nanopartículas Metálicas/químicaRESUMO
Two novel luminescent hetero-trinuclear complexes [Pt2Ag(µ-dpppy)2(C≡CC6H4R-4)4](ClO4) (R = H, 1; R = CH3, 2; dpppy = 2,6-bis(diphenylphosphino)pyridine) were synthesized by the self-assembly reaction between [Pt(C[triple bond, length as m-dash]CC6H4R-4)4](2-) and [Ag2(µ-dpppy)3](2+) and characterized by elemental analyses, electrospray ionization mass spectrometry, and (1)H NMR and (31)P{(1)H} NMR spectroscopy and by X-ray crystallography for complex 2. Two Pt2Ag complexes show strong luminescence in the solid state, but exhibit weak emission in CH2Cl2 solution and in acetonitrile-water (1 : 1, v : v) solution at room temperature. To overcome the limitations of low water solubility and weak emission in solutions, a new kind of luminescent Pt2Ag@SiO2 nanoparticles was prepared by incorporating the new Pt2Ag acetylides into monodisperse silica nanoparticles. It is noted that Pt2Ag@SiO2 nanoparticles exhibit strong luminescence in aqueous solution, and cyanide anions tend to decrease their luminescence intensity in NaHCO3-NaOH buffer solution. Based on this, a novel nanosensor for highly sensitive detection of cyanide anions was developed in the range of 0.1-10.0 µM.
RESUMO
Three new mononuclear copper(II) complexes, [Cu(L2)](2+) (1), [Cu(acac)(L)](+) (2), and [Cu(acac-Cl)(L)](+) (3) (L = 2-(4-pyridine)oxazo[4,5-f]1,10-phenanthroline (4-PDOP); acac = acetylacetone; acac-Cl = 3-chloroacetylacetone), have been synthesized and characterized by elemental analysis, high resolution mass spectrometry (Q-TOF), and IR spectroscopy. Two of the complexes were structurally characterized by single-crystal X-ray diffraction techniques. Their interactions with DNA were studied by UV-vis absorption and emission spectra, viscosity, thermal melting, DNA unwinding assay and CD spectroscopy. The nucleolytic cleavage activity of the compounds was carried out on double stranded pBR322 circular plasmid DNA by using a gel electrophoresis experiment in the presence and absence of an oxidant (H2O2). Active oxygen intermediates such as hydroxyl radicals and hydrogen peroxide generated in the presence of L and complexes 1-3 may act as active species for the DNA scission. The cytotoxicity of the complexes against HepG2 cancer cells was also studied.
Assuntos
Complexos de Coordenação/síntese química , Complexos de Coordenação/farmacologia , Cobre/química , Clivagem do DNA/efeitos dos fármacos , DNA/química , DNA/metabolismo , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Bovinos , Técnicas de Química Sintética , Complexos de Coordenação/química , Complexos de Coordenação/metabolismo , Cristalografia por Raios X , Eletroquímica , Etídio/metabolismo , Sequestradores de Radicais Livres/farmacologia , Células Hep G2 , Humanos , Conformação de Ácido Nucleico , Desnaturação de Ácido NucleicoRESUMO
Graphitic-phase carbon nitride (g-C3N4) nanosheets, the newly emerging two-dimensional (2D) layered nanomaterials, have been demonstrated to be promising bioimaging agents due to their high photoluminescence (PL) quantum yields, good biocompatibility and low toxicity. However, the therapeutic applications of g-C3N4 nanosheets have not been explored until now. In this study, we have proven for the first time that g-C3N4 nanosheets can be used as efficient photosensitizers for photodynamic tumor therapy and as pH-responsive nanocarriers for drug delivery. On one hand, as photosensitizers, g-C3N4 nanosheets are able to generate reactive oxygen species (ROS) and kill cancer cells efficiently under low-intensity light irradiation (20 mW cm-2). On the other hand, as nanocarriers, g-C3N4 nanosheets possess an ultrahigh drug-loading capacity owing to their high surface-to-volume ratio. More importantly, g-C3N4 nanosheets loaded with the anticancer drug doxorubicin (DOX) exhibit a pH-responsive release property which is beneficial for the delivery of DOX into cancer cells for chemotherapy. Furthermore, due to their high PL quantum yields, the fluorescent g-C3N4 nanosheets can enable visualization of the delivery. These findings demonstrated the potential of g-C3N4 nanosheets as low-toxic and biocompatible photosensitizers and pH-responsive drug nanocarriers for biomedical applications.
RESUMO
A novel naphthalene-2,3-diamine-2-salicylaldehyde (NS) ligand and its mononuclear copper(II) complex (CuNS) have been synthesized and structurally characterized. The UVvis absorption and emission spectra of NS showed obvious changes on addition of Cu2+ solution. The interaction of the compounds with calf thymus DNA and G-quadruplex DNA were investigated by spectroscopic methods and thermal melting assay. The nucleolytic cleavage activity of the compounds was investigated on double-stranded circular pBR322 plasmid DNA and G-quadruplex DNA by electrophoretic mobility shift assay. The results show that CuNS has a greater ability to stabilize G-quadruplex DNA over calf-thymus DNA. The cytotoxicity of the compounds toward HpeG2 cancer cells was also studied, and they showed significant potential for antineoplastic effects.
Assuntos
Aldeídos/farmacologia , Antineoplásicos/farmacologia , Complexos de Coordenação/farmacologia , Cobre/farmacologia , DNA/metabolismo , Quadruplex G/efeitos dos fármacos , Aldeídos/síntese química , Aldeídos/química , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Bovinos , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Cobre/química , Cristalografia por Raios X , Células Hep G2 , Humanos , Ligantes , Modelos Moleculares , Neoplasias/tratamento farmacológicoRESUMO
A novel and general strategy is developed to design selective artificial enzyme inhibitor based on nanoparticleenzyme inter actions and molecular imprinting. Due to the creation of specific binding cavities, the resulting artificial inhibitor has high inhibition efficiency for the target enzyme, and shows great target-selectivity over other enzymes of similar function and proteins of compaable mole cular weight.
Assuntos
Quimotripsina/antagonistas & inibidores , Impressão Molecular , Nanopartículas/química , Polímeros/química , Polímeros/síntese química , Inibidores de Proteases/química , Inibidores de Proteases/síntese química , Desenho de Fármacos , Modelos Moleculares , Conformação Molecular , Nanotubos de Carbono/química , Polímeros/farmacologia , Inibidores de Proteases/farmacologiaRESUMO
In recent years, considerable efforts have been devoted to the construction of efficient enzyme mimetics, which have significant advantages of simple synthesis, good stability and design flexibility. In this paper, we described that graphene dots (GDs) possess highly-efficient peroxidase-like catalytic activity, and its activity is much higher than graphene oxide (GO) with large size. They can catalyze the oxidation of peroxidase substrate 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H2O2 to produce a blue product, which can be used for H2O2 detection by measuring the absorbance change. This catalytic reaction can be also used for other analyte detection by monitoring the generation or consumption of H2O2, such as glucose and reduced glutathione (GSH). The GDs-based system permits detection of as low as 10nM H2O2, which is much lower than that of other nanomaterials-catalyzed methods. Meanwhile, the detection limit of this system is 0.5 µM for glucose and 0.5 µM for GSH, respectively. Furthermore, the proposed system also shows high selectivity and is capable of sensing in complicated biological samples such as cell lysate. Due to their high catalytic activity, high diffusion and excellent biocompatibility, GDs can be expected to be applied in various fields, such as biotechnology, medical diagnostics and environmental monitoring.
Assuntos
Técnicas Biossensoriais/métodos , Glucose/análise , Glutationa/análise , Grafite/metabolismo , Peróxido de Hidrogênio/análise , Peroxidase/metabolismo , Animais , Benzidinas/metabolismo , Catálise , Glucose/metabolismo , Glutationa/metabolismo , Células HeLa , Humanos , Peróxido de Hidrogênio/metabolismo , Limite de Detecção , OxirreduçãoRESUMO
MicroRNAs (miRNAs), a kind of endogenous, noncoding RNAs (19-24 nucleotides), play vital roles in regulating gene expression and cellular processes. In recent years, it has been found that circulating miRNAs are differentially expressed in patients and healthy controls. This leads to the suggestion that circulating miRNAs are promising biomarkers for cancer classification and prognosis. However, it is still difficult to detect circulating miRNAs directly from real samples such as human serum without prior extraction and purification. In this work, we developed an ultrasensitive electrochemical biosensor for detection of cancer-associated circulating miRNAs based on DNA concatamers amplification. The proposed biosensor showed a high sensitivity for target miRNA-21 in a concentration range from 100 aM to 100 pM with a detection limit of 100 aM. Furthermore, the biosensor was successfully employed for direct detection of circulating miRNAs in human serum. Due to the high sensitivity, good selectivity and stability, the proposed electrochemical biosensor might have potential clinical application for circulating miRNAs in relation to diagnosis and prognosis.
Assuntos
Técnicas Biossensoriais/métodos , Neoplasias da Mama/sangue , MicroRNAs/sangue , Neoplasias da Mama/genética , Técnicas Eletroquímicas/métodos , Feminino , Humanos , Limite de DetecçãoRESUMO
Employing theranostic nanoparticles, which combine both therapeutic and diagnostic capabilities in one dose, has promise to propel the biomedical field toward personalized medicine. Here we investigate the theranostic properties of topological insulator bismuth selenide (Bi2Se3) in in vivo and in vitro system for the first time. We show that Bi2Se3 nanoplates can absorb near-infrared (NIR) laser light and effectively convert laser energy into heat. Such photothermal conversion property may be due to the unique physical properties of topological insulators. Furthermore, localized and irreversible photothermal ablation of tumors in the mouse model is successfully achieved by using Bi2Se3 nanoplates and NIR laser irradiation. In addition, we also demonstrate that Bi2Se3 nanoplates exhibit strong X-ray attenuation and can be utilized for enhanced X-ray computed tomography imaging of tumor tissue in vivo. This study highlights Bi2Se3 nanoplates could serve as a promising platform for cancer diagnosis and therapy.
Assuntos
Bismuto/química , Neoplasias Experimentais/diagnóstico , Neoplasias Experimentais/terapia , Selênio , Animais , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Transmissão , Selênio/química , Tomografia Computadorizada por Raios X , Difração de Raios XRESUMO
In this work, the electrochemical catalytic properties of the topological insulator bismuth selenide (Bi2Se3) were first studied. In the presence of Bi2Se3 the reduction current of dissolved O2 could be significantly enhanced. The electron transfer resistivity (Rct) was greatly reduced at the Bi2Se3-PVP modified electrode as evidenced by the electrochemical impedance spectrometry, implying that the topological insulator Bi2Se3 could facilitate the electron transfer at the interface due to the excellent surface conductivity. Based on the high electrochemical catalytic activity for the reduction of dissolved O2, the Bi2Se3-PVP modified electrode was used to detect glucose with the modification of glucose oxidase, and applied for the detection of glucose in human blood serum.
Assuntos
Técnicas Biossensoriais/métodos , Bismuto/química , Glicemia/análise , Técnicas Eletroquímicas/métodos , Selênio/química , Catálise , Eletrodos , Glucose Oxidase/química , Humanos , Oxirredução , Oxigênio/química , Povidona/química , Sensibilidade e EspecificidadeRESUMO
Bright blue fluorescent glutathione-functionalized graphene quantum dots (GQDs@GSH) were prepared by a one-step pyrolysis method with a fluorescence quantum yield as high as 33.6%. Futhermore, the obtained GQDs@GSH can be used as a probe to estimate the ATP level in cell lysates and human blood serum.
Assuntos
Trifosfato de Adenosina/sangue , Corantes Fluorescentes/química , Glutationa/metabolismo , Grafite/química , Pontos Quânticos , Espectrometria de Fluorescência , Trifosfato de Adenosina/metabolismo , Linhagem Celular Tumoral , Transporte de Elétrons , Glutationa/química , Humanos , Cinética , Teoria QuânticaRESUMO
In this paper, we reported a convenient fluorescence method for the detection of genetically modified organisms (GMOs). As it is known that the cauliflower mosaic virus (CaMV) 35S promoter is widely used in most transgenic plants (Schnurr and Guerra, 2000), we thus design a simple method based on the detection of a section target DNA (DNA-T) from the transgene CaMV 35S promoter. In this method, the full-length guanine-rich single-strand sequences were split into fragments (Probe 1 and 2) and each part of the fragment possesses two GGG repeats. In the presence of K(+) ion and berberine, if a complementary target DNA of the CaMV 35S promoter was introduced to hybridize with Probe 1 and 2, a G-quadruplex-berberine complex was thus formed and generated a strong fluorescence signal. The generation of fluorescence signal indicates the presence of CaMV 35S promoter. This method is able to identify and quantify Genetically Modified Organisms (GMOs), and it shows wide linear ranges from 5.0×10(-9) to 9.0×10(-7) mol/L with a detection limit of 2.0×10(-9) mol/L.
Assuntos
Técnicas Biossensoriais/instrumentação , Caulimovirus/genética , DNA de Plantas/genética , DNA Viral/genética , Plantas Geneticamente Modificadas/classificação , Plantas Geneticamente Modificadas/genética , Regiões Promotoras Genéticas/genética , Espectrometria de Fluorescência/instrumentação , DNA de Plantas/análise , DNA Viral/análise , Desenho de Equipamento , Análise de Falha de Equipamento , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Transgenes/genéticaRESUMO
Nowadays, bacterial infection is very common in the world. As a result of overusing antibiotics, several human pathogenic bacteria have become resistant to most of the clinically approved antibiotics. This has created an urgent need for the development of new methods to kill pathogenic bacteria. Here, we describe a novel method for the selective killing of pathogenic bacteria using antibody functionalized nanoscale reduced graphene oxide (NRGO). The antibody-NRGO complex exhibited little toxicity without near-infrared (NIR) irradiation. However, when irradiated with a NIR laser at a low power density (400 mW cm-2), the antibody-NRGO complex exhibited excellent photothermal properties and killed captured pathogenic bacteria specifically.
RESUMO
Graphene oxide (GO) has many exciting advantages such as easy preparation, low toxicity, good solubility and stability in aqueous solution. However, GO itself has a low near-infrared (NIR) absorption, and thus is not suitable for photothermal therapy and photoacoustic imaging. To overcome this limitation, a novel dye-enhanced GO is prepared utilizing the π-π stacking interactions between GO and indocyanine green (ICG). The ICG-GO complex has a high optical absorbance in the NIR region and exhibits excellent photothermal properties under NIR irradiation. In order to improve the cancer-targeting activity, GO was modified with folic acid (FA). In vitro experiments showed that the ICG-GO-FA nanocomposite could be used for targeted photothermal cancer cell destruction. Moreover, the application of the ICG-GO-FA nanocomposite for photoacoustic imaging was also demonstrated.
RESUMO
A simple, colorimetric, sensitive, cost-effective and high-throughput system based on a positively charged graphene oxide-enzyme complex was developed for bacterial detection and drug screening.
Assuntos
Colorimetria/métodos , Avaliação Pré-Clínica de Medicamentos/métodos , Grafite/química , Óxidos/química , Ânions , Anti-Infecciosos/farmacologia , Bactérias/metabolismo , Carbodi-Imidas/química , Análise Custo-Benefício , Eletroquímica/métodos , Monitoramento Ambiental/métodos , Escherichia coli/enzimologia , Escherichia coli/metabolismo , Corantes Fluorescentes/farmacologia , Ensaios de Triagem em Larga Escala , Microscopia de Força Atômica/métodos , Modelos Químicos , Complexos Multienzimáticos , Espectrofotometria/métodos , beta-Galactosidase/metabolismoRESUMO
A simple turn-on and homogeneous aptasensor, which relies on target induced formation of silver nanoclusters (Ag NCs), was developed for the determination of platelet-derived growth factor B-chain homodimer (PDGF-BB). The aptasensor contains two hairpin DNA probes termed as P1 and P2. P1 consists of the aptamer sequence of PDGF-BB. Meanwhile, P2 contains the Ag NCs nucleation sequence, which is blocked by the hairpin stem region. P1 and P2 can co-exist metastably in the absence of PDGF-BB and maintain hairpin structure. However, in the presence of PDGF-BB, the binding of PDGF-BB with aptamer will result in the hybridization between P1 and P2, and release the Ag NCs nucleation sequence. In this case, Ag NCs can be formed via the reduction of Ag(+) by NaBH(4). By monitoring the increase in fluorescence intensity, we could detect the target protein with high sensitivity. The detection limit of this aptasensor is 0.37 nM, which is comparable with that of other reported aptasensors. Furthermore, this proposed aptasensor shows high selectivity toward its target protein. Thus, the proposed aptasensor based on target induced formation of Ag NCs could be used as a sensitive and selective platform for the detection of target protein.
Assuntos
Aptâmeros de Nucleotídeos/química , Nanopartículas Metálicas/química , Prata/química , Aptâmeros de Nucleotídeos/metabolismo , Becaplermina , Sequências Repetidas Invertidas , Proteínas Proto-Oncogênicas c-sis/análise , Espectrometria de FluorescênciaRESUMO
Two hexanuclear clusters, [Pt(2)Ag(4)(C≡CC(6)H(4)R)(8)] (R = CH(3), 1; R = H, 2), together with dimer [Pt(2)Ag(4)(C≡CC(6)H(5))(8)](2) (3), have been synthesized and characterized by elemental analyses, electrospray ionization mass spectrometry, and (1)H NMR spectroscopy and by X-ray crystallography for 1 and 3. A considerable enhancement of photoluminescence (PL) and a notable red shift in the emission maximum of 1 (λ(max) 600 nm) relative to 2 (λ(max) 545 nm) are observed. Electrogenerated chemiluminescence (ECL) of 1 and 2 in the absence or presence of coreactant tri-n-propylamine (TPrA) or 2-(dibutylamino)ethanol (DBAE) at different working electrodes in different solvents (CH(2)Cl(2), CH(2)ClCH(2)Cl, or CH(3)CN) has been studied. The ECL spectra are identical with the PL spectra, indicating that ECL emissions are also due to a MLM'CT [Pt(d)/π (C≡CC(6)H(4)R-4) â Pt(p(z))/Ag(sp)/π* (C≡CC(6)H(4)R-4)] state modified by Pt···Ag and Ag···Ag contacts. ECL of 1- and 2/amine systems in CH(2)ClCH(2)Cl was produced at the potentials of 1.14-1.19 V vs SCE, notably negatively shifted by about 0.38 V compared to those of the Ru(bpy)(3)(2+)/amine system. In all cases, ECL quantum efficiencies of 2 are higher than those of 1 and on the same order of magnitude as that of the [Ru(bpy)(3)](PF(6))(2)/amine system. It is noted that Sudan I tends to decrease the ECL intensity of the 1/DBAE system in CH(2)ClCH(2)Cl at a platinum working electrode. A new ECL method for the determination of Sudan I was developed with a linear range of 2.5 × 10(-5)-1.0 × 10(-3) M and a detection limit of 8.0 × 10(-6) M based on 3 times the ratio of signal-to-noise.
RESUMO
Biosensors based on nanomaterials have been used for detection of various biological molecules with high sensitivity and selectivity. Herein, we developed a simple and ultrasensitive electrochemical DNA biosensor using long-range self-assembled DNA nanostructures as carriers for signal amplification, which can achieve an impressive detection limit of 5 aM human immunodeficiency virus (HIV) DNA even in complex biological samples. In this study, we designed two auxiliary probes. A cascade of hybridization events between the two auxiliary probes can lead to long-range self-assembly and form micrometer-long one-dimensional DNA nanostructures. In the presence of target DNA, each copy of the target can act as a trigger to connect a DNA nanostructure to a capture probe on the electrode surface. Then, a great amount of redox indicator [Ru(NH(3))(6)](3+) can be electrostatically bound to the DNA nanostructures and eventually result in significantly amplified electrochemical signals.
Assuntos
DNA Viral/análise , Técnicas Eletroquímicas , HIV-1/química , Nanoestruturas/análise , Técnicas Biossensoriais , Eletrodos , Células HeLa , HumanosRESUMO
A series of dinuclear compounds of [Ru(bpy)(2)(tpphz)Ln(TTA)(3)](PF(6))(2) (tpphz = tetrapyrido[3,2-a:2',3'-c:3'',2''-h:3''',4'''-j]phenazine; Ln = Er(III), Nd(III), Yb(III) and Gd(III); TTA = 2-thenoyltrifluoroacetone) have been prepared by attachment of a [Ln(TTA)(3)] fragment at the vacant diimine site of the luminescent mononuclear complex [Ru(bpy)(2)(tpphz)](PF(6))(2). In the solid state, in CH(2)Cl(2) solution and in Tris-HCl buffer solution of these dinuclear complexes Ru-Ln, sensitized near-infrared (NIR) luminescence is observed from Nd and Yb centres following excitation of the d-block unit, which results from the effective Ru â Ln (Ln = Nd, Yb) energy transfer, but no Er-based NIR luminescence is produced. The (3)MLCT (MLCT = metal to ligand charge transfer) emission is partly quenched in the Ru-Nd complex, slightly increased in the Ru-Yb complex, and is not changed in the Ru-Ercomplex. Interestingly, alpha-fetal protein (AFP) tends to decrease the NIR luminescence intensity of the Ru-Nd complex in Tris-HCl buffer solution. A novel NIR luminescent method for the determination of AFP was developed with a linear range of 0.5-18 ng mL(-1), and a detection limit of 0.2 ng mL(-1) based on 3 times the ratio of the signal-to-noise. Considering the attractive features, such as good selectivity, stability and rapidity, the proposed NIR luminescent method provides promising potential for AFP detection in clinical diagnosis and biomedical applications.