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1.
Mikrochim Acta ; 187(7): 397, 2020 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-32564257

RESUMO

Gold nanoparticle (AuNP)-anchored BP nanosheets were synthesized through in situ growth of AuNPs onto BP. Due to the strong chelating ability of P or phosphorus oxides with AuNPs, the stability of BP is improved. As proof-of-concept demonstration of the functionalized BP, electrochemical detection of circulating tumor cells (CTCs) based on BP@AuNPs@aptamer as a probe combined with immunomagnetic separation is reported. The aptamer can specifically bind with CTCs, while the phosphorus oxides including phosphite ion and phosphate ion (PxOy species) on BP and aptamer can react with molybdate to generate an electrochemical current, leading to dual signal amplification. The biosensor is applied to MCF-7 cell detection and displays good analytical performance with a detection limit of 2 cell mL-1. Furthermore, the practicality of this biosensor was validated through sensitive determination of MCF-7 cells in human blood. Therefore, the reported biosensor could be applied to detect other biomarkers, offering an ultrasensitive strategy for clinical diagnostics. Graphical abstract Electrochemical detection of circulating tumor cells based on gold nanoparticle-modified black phosphorus nanosheets is reported.

2.
Mikrochim Acta ; 187(5): 257, 2020 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-32246287

RESUMO

In this work, an aptamer-based photoelectrochemical (PEC) assay is reported for the determination of MCF-7 breast cancer cells using hexagonal carbon nitride tubes (HCNTs) as photoactive material. The aptamer immobilized on the HCNT surface can specifically bind with mucin 1 protein (MUC1) that is overexpressed on the surface of MCF-7 cell. Thus, the PEC assay has high specificity for the determination of MCF-7. The determination of MCF-7 is due to the binding of MCF-7 onto HCNT that suppressed the photocurrent intensity. The PEC assay displays good performances for MCF-7 determination with a linear range from 1 × 102 to 1 × 105 cell mL-1 and limit of detection down to 17 cells mL-1. Meanwhile, the PEC assay can distinguish MCF-7 from normal cells in blood samples, which may have potential applications in cancer diagnostics and therapeutics.

3.
Anal Chem ; 92(10): 7114-7122, 2020 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-32329601

RESUMO

Monitoring and early warning of spores germination is of great significance in avoiding their potential pathogenicity. Thus, effective monitoring of markers during spore germination is of great value. A ratio-dependent fluorescent probe based on in situ incorporation of fluorophores in a metal-organic framework (MOF) was designed to monitor a main component of bacterial spores, 2,6-pyridinedicarboxylic acid (DPA), with high sensitivity and specificity. The fluorescence of CdS quantum dots loaded on zeolitic imidazolate framework-8 (ZIF-8) nanocrystals is initially quenched by europium ions. The europium ions, however, can be seized by DPA, leading to restoring the fluorescence of quantum dots. Simultaneously, the fluorescence of another dye molecule, rhodamine 6G, loaded on the ZIF-8 is not affected by DPA and can serve as a stable internal fluorescence reference signal. On this basis, a ratio-dependent fluorescence method for rapid detection of DPA was established. The linear calibration ranged from 0.1 to 150 µM with a detection limit of 67 nM, which is much lower than the amount of DPA (60 µM) released by the contagious number of spores needed to cause anthrax. This analysis platform exhibits good anti-interference ability for monitoring spore germination. The practicable application of the method was verified by monitoring and imaging the release of DPA in the course of spore germination.

4.
Biosens Bioelectron ; 151: 111976, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31999584

RESUMO

In this work, a sensitive and reliable photoelectrochemical (PEC) biosensor was proposed based on hexagonal carbon nitride tubes (HCNT) as photoactive material for detection of circulating tumor cells (CTCs). Magnetic Fe3O4 nanospheres (MNs) and Cu2O nanoparticles (Cu2O NPs) were utilized for highly efficient magnetic capture of CTCs and for signal amplification, respectively. First, anti-epithelial cell adhesion molecule (EpCAM) antibody was linked onto MNs for capture and enrichment of CTCs. With the captured MCF-7 coated onto the electrode, the photocurrent intensity of HCNT was decreased due to the steric hindrance derived from MCF-7. Then, when the Cu2O-aptamer probe was bound onto the CTC surface, the photocurrent intensity was further decreased because Cu2O NPs competed with HCNT for absorption of exciting light and the aptamer molecules increased the steric hindrance, which leads to significantly decreased photocurrent response, thus realizing dual signal amplification. Using the breast cancer cell MCF-7 as a model, the proposed PEC biosensor displays good performances with a linear range from 3 to 3000 cell mL-1 and limit of detection down to 1 cell mL-1. The HCNT-based PEC biosensor shows good performance for detection of CTCs, which may have potential applications in cancer diagnostics and therapeutics.

5.
Mikrochim Acta ; 186(12): 856, 2019 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-31784833

RESUMO

A porous carbon nitride (PCN) modified with cobalt phosphides (CoP) was synthesized. In this nanocomposite, the CoP (in different weight fractions) serves (a) as the electron acceptor to accelerate the photoinduced charge separation, and (b) as the photosensitizer to increase the photoelectrochemical (PEC) response to visible light. Dissolved oxygen acts as the electron acceptor to generate PEC current. If glucose oxidase (GOx) catalyzes the oxidation of glucose, dissolved oxygen is consumed. This leads to the suppression of photocurrent. The photocathode biosensor has a linear response in the 0.05 to 0.7 mM glucose concentration range and a 1.1 µM limit of detection. Graphical abstractSchematic of a photoelectrochemical glucose biosensor based on the use of cobalt phosphide-modified porous carbon nitrides. PCN: porous carbon nitride; CoP: cobalt phosphide.


Assuntos
Glucose Oxidase/metabolismo , Glucose/análise , Luz , Nanocompostos/química , Nitrilos/química , Fosfinas/química , Biocatálise , Técnicas Biossensoriais , Técnicas Eletroquímicas , Glucose/metabolismo , Tamanho da Partícula , Processos Fotoquímicos , Porosidade , Propriedades de Superfície
6.
Mikrochim Acta ; 186(11): 735, 2019 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-31673799

RESUMO

Prussian Blue nanoparticles were deposited on g-C3N4 nanosheets. The resulting nanocomposite possesses peroxidase-like (POx) activity and can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine at room temperature in the presence of H2O2. This leads to formation of a blue product with an absorption maximum at 650 nm. The formation of the Prussian Blue nanoparticles on the g-C3N4 nanosheets, and the POx-like activity of the composite were characterized in detail. The POx mimic was used for determination of L-lactic acid via detection of H2O2 that is produced by the enzyme lactate oxidase (LOx). The assay has a linear range that extends from 5 to 100 µM, and the detection limit is 2.2 µM. The method was successfully applied to the determination of L-lactic acid in spiked human serum. Graphical abstract Ultra-small Prussian Blue (PB) nanoparticles were used to modify g-C3N4 nanosheets, and their peroxidase-like activity was explored for detection of L-lactic acid. LOx represent L-lactate oxidase, and TMB represents 3,3',5,5'-tetramethylbenzidine.

7.
Anal Bioanal Chem ; 411(26): 6889-6897, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31401668

RESUMO

Photoelectrochemical (PEC) sensor for sensitive detection of breast cancer biomarker human epidermal growth factor receptor 2 (HER2) utilizing hexagonal carbon nitride tubes (HCNT) as photoactive material is reported. The detection is based on suppression of the PEC current intensity of the sensor. HCNT were synthesized via a facile hydrothermal method with large specific surface area and low electron-hole recombination. Au nanoparticles (AuNPs) were deposited onto the surface of the HCNT, which enhanced the photocurrent intensity of the HCNT by one time. For HER2 detection, peptide specific to HER2 was immobilized on the AuNPs surface for capturing HER2 molecules. The following binding of HER2 with HER2 aptamer and the reaction of phosphate groups on aptamer with molybdate can form molybdophosphate precipitate, which sticks to the surface of HCNT and impedes electron transport. Thus, photocurrent intensity of the sensor was suppressed. Under optimal conditions, the linear relationship between the PEC intensity and the logarithm of HER2 concentration was from 0.5 to 1 ng mL-1 with low limit of detection (LOD) of 0.08 pg mL-1. Furthermore, the PEC sensor also displayed capability for detecting HER2 in human serum samples. This PEC sensor signal detection strategy can be easily adapted to other PEC sensors involving DNA and find wide applications. Graphical abstract.


Assuntos
Aptâmeros de Nucleotídeos/química , Neoplasias da Mama/sangue , Nitrilos/química , Receptor ErbB-2/sangue , Biomarcadores Tumorais/análise , Biomarcadores Tumorais/sangue , Técnicas Biossensoriais/métodos , Neoplasias da Mama/diagnóstico , Técnicas Eletroquímicas/métodos , Feminino , Ouro/química , Humanos , Limite de Detecção , Nanopartículas Metálicas/química , Peptídeos/química , Receptor ErbB-2/análise
8.
Mikrochim Acta ; 185(4): 229, 2018 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-29594805

RESUMO

A glassy carbon electrode was modified with an array of porous Ni3N nanosheets (Ni3N NA) and studied for its use in non-enzymatic electrochemical detection of glucose. The morphology and structure of the Ni3N NA were characterized by scanning electron microscopy and X-ray diffraction. Electrochemical studies demonstrated that the Ni3N NA acts as an efficient catalyst for the electro-oxidation of glucose at pH 13, best at a working voltage of 0.55 V (vs. Ag/AgCl). Figures of merit include (a) high sensitivity (39 µA·mM-1·cm-2), (b) a low limit of detection (0.48 µM), and (c) a linear range that extends from 2 µM to 7.5 mM. The sensor was applied to the determination of glucose levels in human serum, and satisfactory results were obtained. Graphical abstract Nonenzymatic electrochemical glucose sensor based on porous Ni3N nanosheet array. The arrow indicates the successive addition of glucose standard solutions.

9.
Anal Chem ; 89(19): 10264-10269, 2017 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-28859480

RESUMO

We have developed a new DNA self-assembly amplification technology that generates electric current for electrochemical biosensing. The new technology was used for detection of human epidermal growth factor receptor 2 (HER2). In our technology, an aptamer was utilized both as a ligand for recognition and as a signal generating reporter. The aptasensor is based on a sandwich format and a DNA primer on a HER2 aptamer initiates auxiliary DNA self-assembled on the electrode to form a long one-dimensional DNA. The resulting DNA is then reacted with molybdate to generate electrochemical current. The sensitivity of the aptasensor with DNA self-assembly was greater than that of the aptasensor without DNA self-assembly due to the extended length of the DNA strand. Aptasensor analysis of HER2 in serum of breast cancer patients and healthy individuals is highly correlated (R2 = 0.9924) with ELISA measurements, with a p value of 1.37 × 10-7. The analysis of HER2 in serum (confirmed by ELISA) suggests that HER2 levels in breast cancer patients are much higher than healthy individuals. For HER2 positive patients, the levels are higher than those of HER2 negative patients. After surgery, there is a drop of HER2 levels in serum, suggesting potential clinical applications of the new self-assembled DNA electric current generating biosensor. Unlike proteins, DNA is easily amplifiable. The DNA signal amplification method presented here enables effective current generation, which can find wide range of biomedical applications for protein detection.


Assuntos
Técnicas Biossensoriais/métodos , Primers do DNA/metabolismo , Receptor ErbB-2/sangue , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/metabolismo , Neoplasias da Mama/diagnóstico , Primers do DNA/química , Espectroscopia Dielétrica , Técnicas Eletroquímicas , Eletrodos , Feminino , Humanos , Molibdênio/química , Oxirredução , Ácidos Fosfóricos/química
10.
Zhongguo Gu Shang ; 27(11): 961-4, 2014 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-25577924

RESUMO

OBJECTIVE: To study technique and clinical therapeutic effects of internal fixation with three-column plates for the treatment of complex tibial plateau fractures through antero-midline and postero-medial approaches. METHODS: From January 2010 to December 2012, 28 patients with complex tibial plateau fractures were treated with internal fixation using three-column plates through antero-midline and postero-medial approaches. There were 17 males and 11 females, with an average age of 45.3 years old (ranged, 28 to 64 years old). Twelve patients had injuries in the left side and 16 patients had injuries in the right side. According to Schatzker classification, 12 patients were type V, 16 patients were type VI. According to three-column classification, all the patients had injuries of lateral, medial and posterior columns. The mean interval from injury to operation was 9.4 days (ranged, 6 to 15 days). The main clinical symptoms were knee joint swelling, deformity and limitation of motion before operation. The X-ray and CT showed all patients had complex tibial plateau fractures, which involved in the lateral, medial and posterior columns. The therapeutic effects were evaluated by fracture healing time, hospital for special surgery knee score (HSS) at one year after operation. The indexes such as tibial plateau-tibial shaft angle (TPA), posterior slope angle (PA) and femoral-tibial angle (FfA) were compared between immediate postoperation and one year after operation. RESULTS: All incisions primarily healed without postoperative complications such as infection and cutaneous necrosis. All the patients were followed up, and the duration ranged from 12 to 24 months, with a mean of 18.1 months. The bone union time ranged from 5 to 10 months (mean, 7.8 months) after operation. Knee joint swelling and pain disappeared after bony union, and joint function completely recovered. The results of hospital for special surgery knee score (HSS) was 27.81 ± 2.17 in pain, 19.52 ± 2.05 in function,15.82 ± 1.73 in passive range of motion, 8.51 ± 1.32 in muscle strength, 8.33 ± 1.08 in flexion deformity, 9.36 ± 0.52 in joint stability, and the total mean score was 89.35 ± 3.19. According to results of HSS, 20 patients got an excellent result, 5 good,2 fair and 1 poor. There were no significant differences in tibial plateau-tibial shaft angle (TPA), posterior slope angle (PA) and femoral-tibial angle (FTA) between immediate postoperation and one year after operation. CONCLUSION: Three-column plate internal fixation for the treatment of complex tibial plateau fractures through antero-midline and posteromedial approaches is effective to achieve anatomic reduction,rigid internal fixation and early functional exercise.


Assuntos
Placas Ósseas , Fixação Interna de Fraturas/métodos , Fraturas da Tíbia/cirurgia , Adulto , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Fraturas da Tíbia/fisiopatologia
11.
Zhongguo Gu Shang ; 24(2): 154-7, 2011 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-21442802

RESUMO

OBJECTIVES: To study the effect of Houxue Zhitong decoration on the expression of the mitochondria-initiated apoptosis pathway and transmembrane protein I an II of the epidural scar tissue. METHODS: A total of 60 New Zealand rabbits (weight: 2.5-3.0 kg) were randomly divided into four groups, sham operation group (D, n=15), control group (B, n=14), sodium hyaluronate group (C, n=15), Houxue Zhitong decoration group (D, n=15). Except for group A, 1.0 cm x 1.0 cm dura mater uncovered area laminectomy was performed at I (4) and I(5), covered with 0.5 ml sodium hyaluronate in group C, covered with same amount of saline in group B and D. First 2 weeks after operation, animals in group D were lavaged with 2.5 ml/kg Houxue Zhitong decoction by one a day for 14 days. Five rabbits of each group selected randomly were killed in the 2,4,8 weeks after laminectomy. The specimens were prepared for determination of the expression of Fas and FasL, at scar tissue by semiquantitative reserve transcription-polymerase chain reaction (RT-PCR). The degree of scar adhesion was evaluated according by Rydell method. RESULTS: The adhesion area in group B was larger than of group C and D in the 4th and 8th week. However, the number of fibroblasts and inflammantory cells in group D was the least among the three groups in the 8th week. At 2, 4, 8 weeks after operation, as compared with group B the expression of Fas, FasL of group C and D were decreased (P < 0.05). Especially, at 2 weeks, as compared with group B the expression of this two cytokines of group D was significant decreased (P < 0.05), too. In group C and D the duramater adhesion was decreased (P < 0.05). The proliferation of fibroblast and fibroblastic function were inhibited (P < 0.05). CONCLUSION: Huoxue Zhitong is able to down-regulated the expression of Fas, FasL, which inhibited the proliferation of fibroblast, the fibroblastic function and the synthesis of extracellular matrix in the epidural scar tissue. It is an effective way of reducing peridural scar formation and prevent the failed back surgery syndrome.


Assuntos
Apoptose/efeitos dos fármacos , Cicatriz/metabolismo , Cicatriz/patologia , Medicamentos de Ervas Chinesas/farmacologia , Proteína Ligante Fas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Receptor fas/metabolismo , Animais , Cicatriz/genética , Espaço Epidural/patologia , Proteína Ligante Fas/genética , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Coelhos , Receptor fas/genética
12.
Zhongguo Gu Shang ; 23(10): 776-9, 2010 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-21137294

RESUMO

OBJECTIVE: To study the effect of Huoxuezhitong recipe on the pathway of mitochondrial apoptosis and the expression of related gene (Caspase-3, -9, Bax, Bcl-2) in epidural scar tissue. METHODS: A total of 60 New Zealand rabbits, ranging in weight from 2.5 to 3.0 kg, were randomly divided into sham operative group (group A), control group (group B), sodium hyaluronate group (group C), Huoxuezhitong recipe group (group D, included Danggui 20 g, Chishao 20 g, Honghua 20 g, Ruxiang 15 g, Myrrh 15 g etc.) with 15 rabbits in each group. Except for group A, L4,5 vertebral plate were resected leading to 1.0 cm x 1.0 cm dura mater exposed area, which were covered with 0.5 ml sodium hyaluronate in group C, covered with same amount of saline in group B and D. At 2 weeks after operation, the rabbits of group D were administered with Huoxuezhitong recipe (2.5 ml/kg, once a day, continuous 14 d). Five rabbits of each group were selected randomly and were killed at 2, 4 and 8 weeks after operation; and the expression of Caspase-3, -9, Bax, Bcl-2 in scar tissue were surveyed by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The results by RT-PCR showed significant different in expressions of Caspase-3, -9, Bax, Bcl-2 of group A and others groups at each period (P < 0.01). At 2, 4, 8 weeks after operation, compared with group B, the expressions of Caspase-3, -9, Bcl-2 in group C and D were decreased (P < 0.05), but the expression of Bax in group C and D were increased (P < 0.05). At 8 weeks after operation, the expressions of Caspase-3, -9, Bax, Bcl-2 in group D was significant decreased compared with group C (P < 0.05). CONCLUSION: Huoxuezhitong recipe can regulate the levels of expression of Caspase-3, -9, Bax, Bcl-2 mRNA and further induce the pathway of mitochondrial apoptosis, thereby, achieve the effect of prophylaxis for the proliferation and conglutination of epidural scar tissue.


Assuntos
Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Caspase 9/metabolismo , Medicamentos de Ervas Chinesas/farmacologia , Genes bcl-2/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Actinas/genética , Actinas/metabolismo , Animais , Apoptose/genética , Carthamus tinctorius , Caspase 3/genética , Caspase 9/genética , Feminino , Genes bcl-2/genética , Mitocôndrias/patologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA Mensageiro/metabolismo , Coelhos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/metabolismo
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