Detection of epidermal growth factor receptor (EGFR) in biological fluids is of paramount importance, since it has significant application in cancer diagnosis, drug development, and therapy ...monitoring. EGFR is a cancer biomarker, and its overexpression is associated with the development of some types of cancer. Herein, we report on the development of a sensitive and selective electrochemical aptamer/antibody (Apt/Ab) sandwich immunosensor for detection of EGFR. In this study, a biotinylated anti-human EGFR Apt was immobilized on streptavidin-coated magnetic beads (MB) and served as a capture probe. A polyclonal anti-human EGFR Ab was conjugated to citrate-coated gold nanoparticles (AuNPs) and used as a signaling probe. In the presence of EGFR, an Apt-EGFR-Ab sandwich was formed on the MB surface. The extent of the complexation was evaluated by differential pulse voltammetry of AuNPs after their dissolution in HCl. Under optimal conditions, the dynamic concentration range of the immunosensor for EGFR spanned from 1 to 40ng/mL, with a low detection limit of 50pg/mL, and RSD percent of less than 4.2%. The proposed approach takes advantage of sandwich assay for high specificity, MBs for fast separation, and electrochemical method for cost-effective and sensitive detection. In this proof-of-principle study, we demonstrate the potential clinical efficacy of the immunosensor for monitoring of chemotherapy effectiveness in breast cancer samples.
•We fabricated a new electrochemical Apt/Ab-based sandwich EGFR immunosensor.•EGFR aptamer, immobilized on MB, served as an EGFR-recognition element.•We quantified EGFR by following the DPV signal of AuNPs, conjugated to anti-EGFR Ab.•The proposed immunosensor can detect EGFR with detection limit of 50pg/mL.•In this proof-of-principle study, we detected the EGFR in serums of breast cancer patients.
•A three-layer device is designed and fabricated for electrochemical detection of DNA.•The detection conditions are optimized to achieve desired selectivity and sensitivity.•The proposed DNA ...biosensor is able to distinguish the base-mismatch DNA sequence.
The development of new rapid and reliable detection technology of Cryptosporidium, a deadly waterborne pathogen, using a three-dimensional micro total analysis systems (3D μTAS) is the main goal of this work. An approach to enhance DNA detection on a patterned configurable 3D μTAS electrochemical DNA biosensor to human genotype of Cryptosporidium was successfully developed in present study. A novel 3D μTAS, comprising three layers, was fabricated to achieve better result comparing to the commercial SPE. The first layer was comprised of a circular gold coated area (gold dot) in the center of a PI sheet and the third layer consisted of a common homemade screen printed electrode (SPE). The second layer was included PDMS channels and reservoir for sample delivery. The biosensor was fabricated on the gold dot of the first layer and electrochemical signal was recorded using the differential pulse voltammetry (DPV) and impedance methods on the third layer and the results were compared with biosensor fabricated on commercial SPE. The calibration curve of 3D μTAS DNA biosensor shows a detection limit of 1.8 ng/mL and a sensitivity of 12.844 μA/(μg mL−1) in a linear range of 2.5 ng/mL to 0.1 μg/mL, which are 6 times lower detection limit and 23 times higher sensitivity of commercial SPE in a similar linear range. The specificity of prepared DNA sensor was conducted by using non-complementary, single, three and five mismatches strands and the potential of the biosensor in discriminating single mismatch detection was experimentally appraised.
Porosity is a key property that plays a crucial role in enhancing the performance of solid oxide fuel cell (SOFC) electrodes. The addition of pyrolyzable pore-formers to the electrode materials of ...SOFCs can generate suitable porous microstructures with the required porosity, pore sizes, and morphology. The present review provides details on the characterization and microstructural analysis, firing profile, electrical conductivity, mechanical strength, and gas permeability of the porous electrodes of SOFCs. A better understanding of these relationships can help to design optimized porous microstructures for generating higher power densities of the cells.
The aim of this study was to fabricate a novel electrochemical-based DNA-sensing device for Ebola virus DNA diagnostic by an enzyme-amplified detection, which improves the sensitivity and selectivity ...of the sensor. A thiolated DNA capture probe sequence was immobilized on the screen printed electrode surface and hybridized with biotinylated target strand DNA for the fabrication of Ebola DNA-sensing devices. Prior to the electrochemical detection of the enzymatic product by differential pulse voltammetry (DPV) method, the biotinylated hybrid was labeled with a streptavidin-alkaline phosphatase conjugate on the surface of the working electrode. All the experiment steps were optimized using electrochemical impedance spectroscopy (EIS) and the optimum condition for biosensor fabrication was achieved. A detection limit of 4.7 nM complementary oligonucleotides was obtained using the fabricated biosensor and the standard deviation of the blank solution. The last step, the selectivity and reproducibility of fabricated electrochemical DNA biosensor was obtained.
•A novel biosensor was fabricated for the enzyme-amplified detection of Ebola virus DNA.•The biosensor fabrication conditions were optimized by electrochemical methods.•The optimization was performed for all fabrication steps of the electrochemical DNA biosensor.•The fabricated electrochemical DNA biosensor exhibited high selectivity and sensitivity.
Safe administration of highly cytotoxic chemotherapeutic drugs is a challenging problem in cancer treatment due to the adverse side effects and collateral damage to non-tumorigenic cells. To mitigate ...these problems, promising new approaches, based on the paradigm of controlled targeted drug delivery (TDD), and utilizing drug nanocarriers with biorecognition ability to selectively target neoplastic cells, are being considered in cancer therapy. Herein, we report on the design and testing of a nanoparticle-grid based biosensing platform to aid in the development of new targeted drug nanocarriers. The proposed sensor grid consists of superparamagnetic gold-coated core-shell Fe
Ni@Au nanoparticles, further functionalized with folic acid targeting ligand, model thiolated chemotherapeutic drug doxorubicin (DOX), and a biocompatibility agent, 3,6-dioxa-octanethiol (DOOT). The employed dual transduction method based on electrochemical and enhanced Raman scattering detection has enabled efficient monitoring of the drug loading onto the nanocarriers, attaching to the sensor surface, as well as the drug release under simulated intracellular conditions. The grid's nanoparticles serve here as the model nanocarriers for new TDD systems under design and optimization. The superparamagnetic properties of the Fe
Ni@Au NPs aid in nanoparticles' handling and constructing a dense sensor grid with high plasmonic enhancement of the Raman signals due to the minimal interparticle distance.
Biotemplated metal nanoclusters have garnered much attention owing to their wide range of potential applications in biosensing, bioimaging, catalysis, and nanomedicine. Here, we report the synthesis ...of stable, biocompatible, watersoluble, and highly fluorescent bovine serum albumin-templated cadmium nanoclusters （CdNcs） through a facile one-pot green method. We covalently conjugated hyaluronic acid （HA） to the CdNcs to form a pH-responsive, tumor- targeting theranostic nanocarrier with a sustained release profile for doxorubicin （DOX）, a model anticancer drug. The nanocarrier showed a DOX encapsulation efficiency of about 75.6%. DOX release profiles revealed that 74% of DOX was released at pH 5.3, while less than 26% of DOX was released at pH 7.4 within the same 24-h period. The nanocarrier selectively recognized MCF-7 breast cancer cells expressing CD44, a cell surface receptor for HA, whereas no such recognition was observed with HA receptor-negative HEK293 cells. Biocompatibility of the nanocarrier was evaluated through cytotoxicity assays with HEK293 and MCF-7 ceils. The nanocarrier exhibited very low to no cytotoxicity, whereas the DOX-loaded nanocarrier showed considerable cellular uptake and enhanced MCF-7 breast cancer cell-killing ability. We also confirmed the feasibility of using the highly fluorescent nanoconjugate for bioimaging of MCF-7 and HeLa cells. The superior targeted drug delivery efficacy, cellular imaging capability, and low cytotoxicity position this nanoconjugate as an exciting new nanoplatform with promising biomedical applications.
Porous ceramic microstructures play an important role in enhancing the performance of solid oxide fuel cells (SOFCs). The development of SOFCs that can generate high power densities requires ...improvements in the electrodes. The engineering of the highly porous electrodes is required to maximize the number of electrochemical reaction sites and to facilitate the gas diffusion. Various sacrificial template methods are capable of generating appropriate porous microstructures and can give a strict control over the porosity amount, pore sizes, and morphology. The present review provides a broad overview on SOFCs from the perspectives of creating porous electrodes using sacrificial template methods as a state of the art strategy. In addition, the manufacturing processes for the production of SOFCs are overviewed and described with focus on the advantages and limitations of each method.
In this study, we have designed and realized three simple electrochemical bioassays for the detection of the human epidermal growth factor receptor 2 (HER2) cancer biomarker using magnetic beads ...coupling screen-printed arrays. The different approaches were based on a sandwich format in which affibody (Af) or antibody (Ab) molecules were coupled respectively to streptavidin or protein A-modified magnetic beads. The bioreceptor-modified beads were used to capture the HER2 protein from the sample and sandwich assay was performed by adding the labeled secondary affibody or the antibody. An enzyme-amplified detection scheme based on the coupling of secondary biotinylated bioreceptor with streptavidin-alkaline phosphatase enzyme conjugate was then applied. The enzyme catalyzed the hydrolysis of the electro-inactive 1-naphthyl-phosphate to the electro-active 1-naphthol, which was detected by means of differential pulse voltammetry (DPV). Each developed assay has been studied and optimized. Furthermore, a thorough comparison of the analytical performances of developed assays was performed. Finally, preliminary experiments using serum samples spiked with HER2 protein were also carried out.
The rapid spread of the SARS-CoV-2 virus that caused the COVID-19 disease, has highlighted our urgent need for sensitive, fast and accurate diagnostic technologies. In fact, one of the main ...challenges for flatting COVID-19 spread charts is the ability to accurately and rapidly identify asymptomatic cases that result in spreading the virus to close contacts. SARS-CoV-2 virus mutation is also relatively rapid, which makes the detection of COVID-19 diseases still crucial even after the vaccination. Conventional techniques, which are commercially available have focused on clinical manifestation, along with molecular and serological detection tools that can identify the SARS-CoV-2 virus however, owing to various disadvantages including low specificity and sensitivity, a quick, low cost and easy approach is needed for diagnosis of COVID-19. Scientists are now showing extensive interest in an effective portable and simple detection method to diagnose COVID-19. There are several novel methods and approaches that are considered viable advanced systems that can meet the demands. This study reviews the new approaches and sensing technologies that work on COVID-19 diagnosis for easy and successful detection of SARS-CoV-2 virus.
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•Reviewing all the published manuscripts focusing on COVID-19 detection and monitoring.•Studying and classifying the applied methods for COVID-19 detection and monitoring.•Studying and classifying the biomolecules and analytes that are targeted for COVID-19 detection and monitoring.•Investigation the pros and cons of applied methods and offering new detection and monitoring methods for future studies.
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