Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 33
Filter
1.
Molecules ; 27(22)2022 Nov 13.
Article in English | MEDLINE | ID: mdl-36431916

ABSTRACT

An amine-terminated polyamidoamine (PAMAM) dendron and two long alkyl groups were designed as a novel drug carrier that possesses an interior for the encapsulation of drugs and a biocompatible surface. We synthesized three dendron-bearing lipids, DL-G1, DL-G2, and DL-G3, which included first, second, and third generation polyamidoamine dendrons, respectively. The synthesized dendrimer encapsulating anticancer drug, 5-fluorouracil (5-FU), was prepared by extraction with chloroform from mixtures of the dendrimers and varying amounts of the drug. In vitro cytotoxicity of PAMAM conjugated di-n-dodecylamine micelles (G1, G2, G3) were analyzed on human gastric adenocarcinoma cells (AGS) by water-soluble tetrazolium-1 (WST-1) cell proliferation assay. Upon exposure to 5-FU loaded micelles, the viability of the cells decreased gradually in all generations. Cytotoxicity increased with increasing generation and reached its highest rate of 69.8 ± 3.2% upon 15 µM 5FU-loaded 25 µM PAMAM DL-3 micelle treatment. These results demonstrate that 5FU-loaded PAMAM conjugated di-n-dodecylamine treatment inhibits the proliferation of AGS cells in a generation-dependent manner.


Subject(s)
Dendrimers , Humans , Dendrimers/pharmacology , Excipients , Micelles , Lipids , Fluorouracil/pharmacology
2.
Anal Chem ; 92(11): 7746-7753, 2020 06 02.
Article in English | MEDLINE | ID: mdl-32367711

ABSTRACT

Abnormal dopamine neurotransmission is associated with several neurological and psychiatric disorders such as Parkinson's disease, schizophrenia, attention deficiency and hyperactivity disorder, and addiction. Developing highly sensitive, selective, and fast dopamine monitoring methods is of high importance especially for the early diagnosis of these diseases. Herein, we report a new ultrasensitive electrochemical sensing platform for in situ monitoring of cell-secreted dopamine using Au-coated arrays of micropyramid structures integrated directly into a Petri dish. This approach enables the monitoring of dopamine released from cells in real-time without the need for relocating cultured cells. According to the electrochemical analyses, our dopamine sensing platform exhibits excellent analytical characteristics with a detection limit of 0.50 ± 0.08 nM, a wide linear range of 0.01-500 µM, and a sensitivity of 0.18 ± 0.01 µA/µM. The sensor also has remarkable selectivity toward DA in the presence of different potentially interfering small molecules. The developed electrochemical sensor has great potential for in vitro analysis of neuronal cells as well as early diagnosis of different neurological diseases related to abnormal levels of dopamine.


Subject(s)
Biosensing Techniques , Dopamine/analysis , Electrochemical Techniques , Neuroblastoma/chemistry , Biosensing Techniques/instrumentation , Dopamine/metabolism , Electrochemical Techniques/instrumentation , Electrodes , Humans , Neuroblastoma/metabolism , Neuroblastoma/pathology , Tumor Cells, Cultured
3.
Anal Chem ; 92(18): 12347-12355, 2020 09 15.
Article in English | MEDLINE | ID: mdl-32786441

ABSTRACT

Parkinson's disease (PD) is a progressive neurodegenerative disorder involving dopaminergic neurons from the substantia nigra. The loss of dopaminergic neurons results in decreased dopamine (DA) release in the striatum and thus impaired motor functions. DA is one of the key neurotransmitters monitored for the diagnosis and during the progression and treatment of PD. Therefore, sensitive and selective DA detection methods are of high clinical relevance. In this study, a new microfluidic device utilized for electrochemical DA detection is reported. The microfluidic sensing device operates in the range of 0.1-1000 nM DA requiring only ∼2.4 µL sample volume, which corresponds to detectable 240 amol of DA. Using this sensor, we were able to monitor the changes in DA levels in cerebrospinal fluid and plasma of a mouse model of PD and following the treatment of drug l-3,4-dihydroxyphenylalanine.


Subject(s)
Cerebrospinal Fluid/chemistry , Disease Models, Animal , Dopamine/analysis , Electrochemical Techniques , Lab-On-A-Chip Devices , Parkinson Disease/diagnosis , Animals , Male , Mice , Parkinson Disease/blood
4.
Anal Bioanal Chem ; 411(13): 2925-2935, 2019 May.
Article in English | MEDLINE | ID: mdl-30957202

ABSTRACT

We present an electrochemical DNA detection strategy based on self-assembled ferrocene-cored poly(amidoamine) dendrimers for the detection of a gene relevant to breast cancer. The chemisorption of three ferrocene-cored poly(amidoamine) generations and hybridization of single-stranded DNA on a Au electrode were studied by cyclic voltammetry and differential pulse voltammetry. The biosensor demonstrated high sensitivity of 0.13 µA/(ng/ml) in the detection of the target DNA with a linear range of 1.3-20 nM and a detection limit of 0.38 nM. The DNA biosensor also has high selectivity for the target DNA, showing a clear signal difference from a noncomplementary sequence and a single-base-mismatch sequence, which was used as a model of BRAC1 gene mutation. The results shown are highly motivating for exploring DNA biosensing technology in the diagnosis of breast cancer caused by mutation of the BRAC1 gene. Graphical abstract.


Subject(s)
Biosensing Techniques/methods , Breast Neoplasms/genetics , DNA/genetics , Electrochemical Techniques/methods , Genes, BRCA1 , Biomarkers, Tumor/genetics , Breast Neoplasms/diagnosis , DNA Mutational Analysis/methods , DNA, Single-Stranded/genetics , Female , Ferrous Compounds/chemistry , Gold/chemistry , Humans , Immobilized Nucleic Acids/genetics , Metallocenes/chemistry , Mutation , Nucleic Acid Hybridization , Polyamines/chemistry
5.
Mikrochim Acta ; 186(12): 749, 2019 11 06.
Article in English | MEDLINE | ID: mdl-31696297

ABSTRACT

This review (with 160 ref.) summarizes the progress that has been made in the methods for chemical or biochemical sensing of hypoxanthine and xanthine, which are produced as part of purine metabolism and are precursors of uric acid. An introduction discusses the importance of hypoxanthine and xanthine as analytes due to their significance in the clinical and food science, together with the conventional methods of analysis. A large section covers methods for the electrochemical hypoxanthine and xanthine sensing. It is divided into subsections according to the nanomaterials used including carbon nanomaterials, meal oxide nanoparticles, metal organic frameworks, conductive polymers, and bio-nanocomposites. A further large section covers optical methods for hypoxanthine and xanthine sensing, with subsections on nanomaterials including carbon nanomaterials, nanosheets, nanoclusters, nanoparticles, and their bio-nanocomposites. A concluding section summarizes the current status, addresses current challenges, and discusses future perspectives. Graphical abstractSchematic representation of the hypoxanthine and xanthine electrochemical and optical sensors incorporating various nanomaterials like graphene, carbon nanotubes (CNT), quantum dots (QD), nanoparticles and polymers, which are implemented in clinical and food analysis.


Subject(s)
Electrochemical Techniques/methods , Hypoxanthine/analysis , Metal Nanoparticles/chemistry , Photometry/methods , Xanthine/analysis , Colorimetry/methods , Fluorescent Dyes/chemistry , Food Analysis/methods , Food Preservation , Graphite/chemistry , Metal-Organic Frameworks/chemistry , Nanotubes, Carbon/chemistry , Polymers/chemistry
6.
Biomedicines ; 12(2)2024 Jan 26.
Article in English | MEDLINE | ID: mdl-38397889

ABSTRACT

BACKGROUND: Multiple drug-delivery systems obtained by loading nanoparticles (NPs) with different drugs that have different physicochemical properties present a promising strategy to achieve synergistic effects between drugs or overcome undesired effects. This study aims to develop a new NP by loading quercetin (Que) and valproic acid (VPA) into chitosan. In this context, our study investigated the antioxidant activities of chitosan NPs loaded with single and dual drugs containing Que against oxidative stress. METHOD: The synthesis of chitosan NPs loaded with a single (Que or VPA) and dual drug (Que and VPA), the characterization of the NPs, the conducting of in vitro antioxidant activity studies, and the analysis of the cytotoxicity and antioxidant activity of the NPs in human neuroblastoma SH-SY5Y cell lines were performed. RESULT: The NP applications that protected cell viability to the greatest extent against H2O2-induced cell damage were, in order, 96 µg/mL of Que-loaded chitosan NP (77.30%, 48 h), 2 µg/mL of VPA-loaded chitosan NP (70.06%, 24 h), 96 µg/mL of blank chitosan NP (68.31%, 48 h), and 2 µg/mL of Que- and VPA-loaded chitosan NP (66.03%, 24 h). CONCLUSION: Our study establishes a successful paradigm for developing drug-loaded NPs with a uniform and homogeneous distribution of drugs into NPs. Chitosan NPs loaded with both single and dual drugs possessing antioxidant activity were successfully developed. The capability of chitosan NPs developed at the nanometer scale to sustain cell viability in SH-SY5Y cell lines implies the potential of intranasal administration of chitosan NPs for future studies, offering protective effects in central nervous system diseases.

7.
Laryngoscope Investig Otolaryngol ; 9(3): e1272, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38803458

ABSTRACT

Objective: Currently, diagnosis of cerebrospinal fluid (CSF) rhinorrhea relies on a multimodal approach, increasing costs and ultimately delaying diagnosis. In the United States and internationally, the crux of such a diagnosis relies on confirmation testing (via biomarkers) and localization (e.g., imaging). Biomarker testing may require analysis at an outside facility, resulting in delays diagnosis and treatment. In addition, specialized imaging may be nonspecific and often requires an active leak for diagnosis. There remains a clear need for innovative new technology. Methods: A comprehensive review was conducted on both foundational and innovative scholarly articles regarding current and emerging diagnosis modalities for CSF. Results: Current modalities in CSF rhinorrhea diagnosis and localization include laboratory tests (namely, B2T immunofixation), imaging (CT and/or MRI) with or without intrathecal administration, and surgical exploration. Each of these modalities carry flaws, risks, and benefits, ultimately contributing to delays in diagnosis and morbidity. Promising emerging technologies include lateral flow immunoassays (LFI) and biologically functionalized field-effect transistors (BioFET). Nevertheless, these carry some drawbacks of their own, and require further validation. Conclusion: CSF rhinorrhea remains a challenging diagnosis, requiring a multimodal approach to differentiate from nonpathologic causes of rhinorrhea. Current methods in diagnosis are imperfect, as the ideal test would be a readily accessible, inexpensive, rapid, highly accurate point-of-care test without the need for excess fluid or specialized processing. Critical work is being done to develop promising, new, improved tests, though a clear successor has not yet emerged. Level of Evidence: N/A.

8.
Bioprocess Biosyst Eng ; 36(12): 1807-16, 2013 Dec.
Article in English | MEDLINE | ID: mdl-23624729

ABSTRACT

Polyvinylimidazole (PVI)-grafted iron oxide nanoparticles (PVIgMNP) were prepared by grafting of telomere of PVI on the iron oxide nanoparticles. Different metal ions (Cu(2+), Zn(2+), Cr(2+), Ni(2+)) ions were chelated on polyvinylimidazole-grafted iron oxide nanoparticles, and then the metal-chelated magnetic particles were used in the adsorption of invertase. The maximum invertase immobilization capacity of the PVIgMNP-Cu(2+) beads was observed to be 142.856 mg/g (invertase/PVIgMNP) at pH 5.0. The values of the maximum reaction rate (V max) and Michaelis-Menten constant (Km) were determined for the free and immobilized enzymes. The enzyme adsorption-desorption studies, pH effect on the adsorption efficiency, affinity of different metal ions, the kinetic parameters and storage stability of free and immobilized enzymes were evaluated.


Subject(s)
Chelating Agents/chemistry , Copper/chemistry , Enzymes, Immobilized/chemistry , Ferric Compounds/chemistry , Imidazoles/chemistry , Metal Nanoparticles , Polyvinyls/chemistry , beta-Fructofuranosidase/chemistry , Adsorption , Hydrogen-Ion Concentration , Microscopy, Electron, Transmission , Temperature
9.
Biosensors (Basel) ; 13(3)2023 Mar 04.
Article in English | MEDLINE | ID: mdl-36979558

ABSTRACT

With the increasing number of patients suffering from Parkinson's disease, the importance of measuring drug levels in patient body fluids has increased exponentially, particularly for the drug clozapine. There is a growing demand for real-time analysis of biofluids on a single low-cost platform in ultra-low fluid volumes with robustness. This study aims to measure the level of clozapine (Clz) with a portable potentiostat using a practical approach. For this purpose, we developed an inexpensive, portable platform via electrochemistry on a commercial glucose test strip (CTS). CTSs were first modified by removing the enzyme mixture from the surface of the sensing zone, which was followed by modification with Multi walled carbon nanotube (MWCNT) and Nafion. The electrochemical characteristics of CTS electrodes were investigated using cyclic voltammetry (CV) and differential voltammetry (DPV) techniques. The designed sensor displayed decent linear range, detection limit, reproducibility, and reusability results. A linear dynamic range of 0.1-5 µM clozapine was observed under optimized conditions with a good sensitivity (1.295 µA/µM) and detection limit (83 nM). Furthermore, the designed sensing electrode was used to measure the amount of Clz in real samples.


Subject(s)
Antipsychotic Agents , Clozapine , Humans , Electrochemistry , Reproducibility of Results , Electrodes , Electrochemical Techniques/methods , Limit of Detection
10.
J Funct Biomater ; 13(3)2022 Aug 28.
Article in English | MEDLINE | ID: mdl-36135567

ABSTRACT

In this work, polyethyleneimine (PEI)-grafted chitosan (Chi-g-PEI) was prepared for the fabrication of layer-by-layer (LBL) films for use in sustained-drug-delivery applications. Chi-g-PEI and polyacrylic acid (PAA) multilayer films were formed using the LBL technique. Methylene blue (MB) was used as a model drug for the investigation of loading and release capabilities of the LBL films. Characterizations of the synthesized copolymer were performed using Fourier-transform infrared spectroscopy (FTIR), Nuclear magnetic resonance spectroscopy (NMR), Thermogravimetric analysis (TGA), and X-ray Powder Diffraction (XRD) techniques, and the thickness of the LBL films was measured using Atomic force microscopy (AFM). The drug-loading and -release behaviors of the LBL films were assessed using a UV-visible spectrophotometer. The results showed that the loading capacity and release rate of MB were affected by ionic strength and pH. In addition, it was demonstrated that PEI-grafted chitosan is a good candidate for the assembling of LBL films for drug-delivery applications.

11.
ACS Sens ; 7(1): 331-337, 2022 01 28.
Article in English | MEDLINE | ID: mdl-35006681

ABSTRACT

There is a growing demand for real-time analysis and sampling of biofluids on a single low-cost platform in ultralow fluid volumes with robustness. In this study, a microfluidic sensor was developed, manufactured through an additive manufacturing technique, and used for dopamine (DA) measurements. We implemented a biosensing system using pencil graphites (PGEs) integrated into a three-dimensional (3D) printed microfluidic syringe-type device (µSyringe). The amperometry technique was used to monitor the current changes associated with the electrooxidation of DA. The sensing signal was stable and linear in a concentration range of DA between the limit of quantification (0.1 nM) and the upper limit of linearity (500 nM). The µSyringe sensing device is simple, robust, and stable, making it suitable for real-time measurement of DA in cerebrospinal fluid (CSF) from freely moving mice.


Subject(s)
Biosensing Techniques , Graphite , Animals , Dopamine/analysis , Electrochemical Techniques , Mice , Syringes
12.
ACS Chem Neurosci ; 13(1): 158-165, 2022 01 05.
Article in English | MEDLINE | ID: mdl-34939797

ABSTRACT

l-3,4-Dihydroxyphenylalanine (l-DOPA), the dopamine precursor, remains the frontline treatment for Parkinson's disease (PD). With the treatment progress, l-DOPA efficacy decreases, necessitating higher and more frequent doses, with higher risks of dyskinesia. l-DOPA chelates iron through its catechol group, forming the l-DOPA:Fe complex; however, the fate of this complex is unknown. Catechol siderophore-like compounds are known to bind siderocalin (Scn)/lipocalin-2 to form stable siderophore:Fe:Scn complexes. Scn is upregulated in PD patients' substantia nigra and may play a role in PD pathophysiology. Therefore, in this study, we used the surface plasmon resonance (SPR) technique to examine the binding properties of l-DOPA to Scn. We found that l-DOPA formed a stable complex with Scn in the presence of Fe3+. Our analysis of the binding properties of l-DOPA precursors and metabolites indicates that the catechol group is necessary but not sufficient to form a stable complex with Scn. Finally, the affinity constant (Kd) of DOPA:Fe3+ binding with Scn (0.8 µM) was lower than l-DOPA plasma peak concentrations in l-DOPA preparations in the past six decades. Our results speculate a significant role for the l-DOPA-Scn complex in the decreased bioavailability of l-DOPA with the progress of PD.


Subject(s)
Parkinson Disease , Siderophores , Antiparkinson Agents , Humans , Iron/metabolism , Levodopa , Lipocalin-2 , Parkinson Disease/drug therapy , Surface Plasmon Resonance
13.
Lab Chip ; 21(2): 405-411, 2021 01 21.
Article in English | MEDLINE | ID: mdl-33331378

ABSTRACT

A novel lab-in-a-pencil graphite microfluidic sensing electrode (µFSE) was fabricated for real-time flow injection measurement of the antipsychotic drug clozapine (Clz). A simple, low-cost, and reusable µFSE was obtained by using 3D printing of a microfluidic chamber integrated with a flat pencil graphite without the need to utilize complex technologies. The µFSE has tubular geometry with 800 µm diameter, where the solution continuously flows in the holes of flat pencil graphite electrodes. Under optimized conditions, this device offers fast and effective Clz detection with good analytical features. A linear calibration curve in the range of 0.5 to 10 µM Clz was obtained with good sensitivity (0.01275 µA µM-1) and detection limit (24 nM). Finally, we demonstrate the applicability of our lab-fabricated microfluidic electrochemical device by monitoring Clz in serum samples at low concentrations.


Subject(s)
Antipsychotic Agents , Clozapine , Graphite , Electrochemical Techniques , Electrodes , Microfluidics , Printing, Three-Dimensional
14.
Int J Biol Macromol ; 143: 582-593, 2020 Jan 15.
Article in English | MEDLINE | ID: mdl-31812744

ABSTRACT

Nowadays, there is increasing number of electrochemical biosensors which utilize chitosan (Ch); as an enzyme immobilization matrix, and conductive nanomaterials; as electron carriers improving sensitivity of the biosensor. However, the challenge these sensors face is the lack of uniform dispersion of nanomaterials throughout the Ch film, which can negatively affect analytical performance of the biosensor. In this study, we report the development of an enzyme immobilization matrix that displays enhanced electrochemical performance thanks to a novel conductive thin film prepared via in situ electrocopolymerization of pyrrole (Py) and thiophene-grafted chitosan (Th-Ch). This is a simple thin film preparation method that can help overcome aforementioned challenges by providing a uniformly distributed conductive layer on the electrode. We are also for the first time reporting the synthesis and characterization of Th-Ch, where grafted Th plays an essential role as a linking group between Ch and Py. The resulting conductive Ch-based thin film was modified with glucose oxidase (GOx) which served as a model enzyme. In situ electrocopolymerization of Py with Th-Ch resulted in a highly conductive thin film enabling approximately 40% higher sensitivity when compared to a Py-Ch composite. This new type of composite thin film is promising in biosensor technology due to its biocompatibility, the chemically and physically modifiable structure, as well as its electrical conductivity.


Subject(s)
Biosensing Techniques , Chitosan/chemistry , Electrochemical Techniques , Membranes, Artificial , Pyrroles/chemistry , Thiophenes/chemistry , Electrodes
15.
3 Biotech ; 10(9): 407, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32904337

ABSTRACT

Breast cancer is a group of diseases in which cells divide out of controlled, typically resulting in a mass. Erlotinib is targeted cancer drug which functions as an inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase. It is used mainly to treat of non-small cell lung cancer patients and has an action against pancreatic cancer. Vorinostat (aka suberanilohydroxamic acid) is an inhibitor of histone deacetylases (HDAC), which has an epigenetic modulation activity. It is used to treat cutaneous T cell lymphoma. In the present study, the erlotinib (ERL) and vorinostat (SAHA) loaded TiO2 nanoparticles (NPs) were used for the treatment of the breast cancer cells (MDA-MB-231 and MCF-7) and human cancerous amniotic cells (WISH). Cell count and viability were negatively affected in all treatments compared to normal cells and bare TiO2 NPs. Apoptosis results indicated a significant increase in the total apoptosis in all treatments compared with control cells. ERL- and SAHA-loaded TiO2 NPs treatments arrested breast cancer cells at G2/M phase, which indicate the cytotoxic effect of these treatment. Partner and localizer of BRCA2 (PALB2) gene expression was assessed using qPCR. The results indicate that PLAB2 was upregulated in ERL- and SAHA-loaded TiO2 NPs compared with control cells and can be used as nanocarrier for chemotherapy drugs. However, this conclusion necessitates further confirmative investigation.

16.
Biosens Bioelectron ; 113: 25-31, 2018 Aug 15.
Article in English | MEDLINE | ID: mdl-29723772

ABSTRACT

In this study, a photo-bioelectrochemical fuel cell was constructed for photocurrent generation by illuminating the electrodes within an aqueous solution. In this purpose, gold electrode was coated with poly 4-(4H-Dithieno [3,2-b:2',3'-d]pyrol-4-yl) aniline, P(DTP-Ph-NH2) conductive polymer film by using electrochemical polymerization. Then, P(DTP-Ph-NH2) conductive polymer film coated surface was electrochemically modified with cytochrome C which covalently linked onto the surface via bis-aniline functionality of the polymer film and formed crosslinked-structure. The thylakoid membrane was attached on the surface of this electrode by using bissulfosaxinimidyl suberate (BS3) and used as photo-anode in photo-bioelectrochemical fuel cell. The photo-cathode of the photo-bioelectrochemical fuel cell fabrication was followed by the modification of conductive polymer poly[5-(4H-dithieno [3,2-b:2',3'-d]pyrol-4-yl) naphtalene-1-amine] film coating, glutaraldehyde activation, and bilirubin oxidase enzyme immobilization. During the photosynthesis occurring in thylakoid membrane under the light, water was oxidized and separated; while oxygen was released in anode side, the cathode side was reduced the oxygen gas into the water via a bio-electro-catalytic method. The cytochrome C was used for binding of thylakoid membrane to the electrode surface and play an important role for transferring of electrons released as a result of photosynthesis.


Subject(s)
Bioelectric Energy Sources , Cytochromes c/chemistry , Polymers/chemistry , Thylakoids/chemistry , Animals , Ascomycota/enzymology , Bioelectric Energy Sources/microbiology , Biosensing Techniques , Cattle , Electric Conductivity , Electron Transport , Enzymes, Immobilized/chemistry , Equipment Design , Oxidation-Reduction , Oxidoreductases Acting on CH-CH Group Donors/chemistry , Photosynthesis , Polymerization , Water/chemistry
17.
J Colloid Interface Sci ; 500: 105-112, 2017 Aug 15.
Article in English | MEDLINE | ID: mdl-28402842

ABSTRACT

The surface modification of nano-hydroxyapatite with polyamidoamine (PAMAM) dendrimer has potential for biomedical applications due to their unique and well-defined secondary structures. This paper presents a facile method to synthesize siloxane-cored PAMAM dendrons modified Hydroxyapatite nanoparticles. Firstly, the siloxane-cored PAMAM dendrons with different generations (G1 to G5, respectively) were synthesized using repetitive reactions between Michael addition and amidation starting from 3-aminopropyltriethoxysilane. Then, hydroxyapatite nanoparticles were synthesized by hydrothermal crystallization method and functionalized with siloxane-cored PAMAM dendrons. These synthesized materials were characterized by using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Thermogravimetric analysis (TGA). The results showed that the PAMAM dendrimer functionalization was carried out successfully and these materials may be applicable in biocomposite material and/or bone tissue engineering.

18.
Mater Sci Eng C Mater Biol Appl ; 72: 641-649, 2017 Mar 01.
Article in English | MEDLINE | ID: mdl-28024633

ABSTRACT

In this study we report a new, simple and first impedimetric biosensor based on 3-Thienyl boronic acid for dopamine detection. Biosensor electrode preparation is 1min long by simple electro-polymerization of 3-Thienyl boronic acid and copolymer Thiophene P(TBA0.50Th0.50). Strong interaction between dopamine and thin layer of boronic acid has provided bio-sensing electrode high selectivity and stability, linear range of 7.8 to 125µM, and detection limit of 0.3µM. Characterization and optimization studies were conducted using electrochemical impedance spectroscopy (EIS) and cyclic voltammogram (CV). In order to test reliability of proposed biosensor real sample application study has been conducted using non-diluted human urine and it has been found that biosensor selectivity and recovery is excellent. As well P(TBA0.50Th0.50) based electrode and dopamine interaction has been proven by single frequency impedance measurements. Biosensors acquired good reproducibility, stability, selectivity and very low interference.


Subject(s)
Biosensing Techniques , Dopamine/analysis , Polymers/chemistry , Thiophenes/chemistry , Biosensing Techniques/instrumentation , Dielectric Spectroscopy , Dopamine/urine , Electrodes , Humans , Limit of Detection , Microscopy, Electron, Scanning
19.
Food Chem ; 229: 358-365, 2017 Aug 15.
Article in English | MEDLINE | ID: mdl-28372186

ABSTRACT

An electrochemical immunosensor for the common food pathogen Escherichia coli O157:H7 was developed. This novel immunosensor based on the PPy/AuNP/MWCNT/Chi hybrid bionanocomposite modified pencil graphite electrode (PGE). This hybrid bionanocomposite platform was modified with anti-E. coli O157:H7 monoclonal antibody. The prepared bionanocomposite platform and immunosensor was characterized by using cyclic voltammetry (CV). Under the optimum conditions, the results have shown the order of the preferential selectivity of the method is gram negative pathogenic species E. coli O157:H7. Concentrations of E. coli O157:H7 from 3×101 to 3×107cfu/mL could be detected. The detection limit was ∼30cfu/mL in PBS buffer. Briefly, we developed a high sensitive electrochemical immunosensor for specific detection of E. coli O157:H7 contamination with the use of sandwich assay evaluated in this study offered a reliable means of quantification of the bacteria. For the applications in food quality and safety control, our immunosensor showed reproducibility and stability.


Subject(s)
Biosensing Techniques/methods , Chitosan/chemistry , Electrochemical Techniques/methods , Escherichia coli O157/chemistry , Gold/chemistry , Nanoparticles/chemistry , Polymers/chemistry , Pyrroles/chemistry
20.
Biosens Bioelectron ; 90: 6-12, 2017 Apr 15.
Article in English | MEDLINE | ID: mdl-27866080

ABSTRACT

The detection of cancer cells through important molecular recognition target such as sialic acid is significant for the clinical diagnosis and treatment. There are many electrochemical cytosensors developed for cancer cells detection but most of them have complicated fabrication processes which results in poor reproducibility and reliability. In this study, a simple, low-cost, and highly sensitive electrochemical cytosensor was designed based on boronic acid-functionalized polythiophene. In cytosensors fabrication simple single-step procedure was used which includes coating pencil graphite electrode (PGE) by means of electro-polymerization of 3-Thienyl boronic acid and Thiophen. Electrochemical impedance spectroscopy and cyclic voltammetry were used as an analytical methods to optimize and measure analytical performances of PGE/P(TBA0.5Th0.5) based electrode. Cytosensor showed extremely good analytical performances in detection of cancer cells with linear rage of 1×101 to 1×106 cellsmL-1 exhibiting low detection limit of 10 cellsmL-1 and incubation time of 10min. Next to excellent analytical performances, it showed high selectivity towards AGS cancer cells when compared to HEK 293 normal cells and bone marrow mesenchymal stem cells (BM-hMSCs). This method is promising for future applications in early stage cancer diagnosis.


Subject(s)
Biosensing Techniques , Cell Separation/methods , Neoplasms/diagnosis , Polymers/chemistry , Thiophenes/chemistry , Bone Marrow Cells/pathology , Boronic Acids/chemistry , Dielectric Spectroscopy , Gold/chemistry , Graphite , HEK293 Cells , Humans , Mesenchymal Stem Cells/pathology , Metal Nanoparticles , Neoplasms/pathology
SELECTION OF CITATIONS
SEARCH DETAIL