Electrochemical Detection Of Prostate Specific Antigen Research Articles

Disposal Immunosensor for Sensitive Electrochemical Detection of Prostate-Specific Antigen Based on Amino-Rich Nanochannels Array-Modified Patterned Indium Tin Oxide Electrode.

Sensitive detection of prostate-specific antigens (PSA) in serum is essential for the prevention and early treatment of prostate cancer. Simple and disposable electrochemical immunosensors are highly desirable for screening and mobile detection of PSAs in high-risk populations. Here, an electrochemical immunosensor was constructed based on amino-rich nanochannels array-modified patterned, inexpensive, and disposable indium tin oxide (ITO) electrodes, which can be employed for the sensitive detection of PSA. Using an amino-group-containing precursor, a vertically ordered mesoporous silica nanochannel film (VMSF) containing amino groups (NH2-VMSF) was rapidly grown on ITO. When NH2-VMSF contained template surfactant micelle (SM), the outer surface of NH2-VMSF was directionally modified by aldehyde groups, which enabled further covalent immobilization of the recognitive antibody to prepare the immuno-recognitive interface. Owing to the charge-based selective permeability, NH2-VMSF can electrostatically adsorb negatively charged redox probes in solution (Fe(CN)63-/4-). The electrochemical detection of PSA is realized based on the mechanism that the antigen-antibody complex can reduce the diffusion of redox probes in solution to the underlying electrode, leading to the decrease in electrochemical signal. The constructed immunosensor can achieve sensitive detection of PSA in the range from 10 pg/mL to 1 μg/mL with a limit of detection (LOD) of 8.1 pg/mL. Sensitive detection of PSA in human serum was also achieved. The proposed disposable immunosensor based on cheap electrode and nanochannel array is expected to provide a new idea for developing a universal immunosensing platform for sensitive detection of tumor markers.

DNA concatemer-silver nanoparticles as a signal probe for electrochemical prostate-specific antigen detection.

In this study, we report a metallobioassay for ultrasensitive electrochemical detection of prostate-specific antigen (PSA) based on DNA hybridization chain reaction (HCR) for amplifying the signal, which is derived from silver nanoparticles (Ag NPs) on DNA concatemers. The assay mainly consists of primary antibody (Ab1), secondary antibody (Ab2) with primer, and a signal probe. In the presence of PSA, a sandwich structure with DNA concatemers was formed, and numerous Ag NPs were loaded on the DNA concatemers, resulting in a strong signal, which appeared within the applied potential (-0.2 V to 0.3 V) in the phosphate-buffered saline (PBS). Differential pulse voltammetry (DPV) was employed to evaluate the analytical performance. Under optimal conditions, the DPV peak current of Ag NPs at about +0.09 V (vs. SCE) increased linearly as the logarithm of PSA concentration increased from 0.1 pg mL-1 to 75 ng mL-1, and the detection limit of PSA was estimated to be 0.033 pg mL-1 at the signal to noise ratio of 3. In addition, the assay was evaluated with human serum samples, and satisfying results were obtained, indicating that the assay can achieve PSA detection in the serum sample.

Green Synthesis and Layer-by-Layer Assembly of Amino-Functionalized Graphene Oxide/Carboxylic Surface Modified Trimetallic Nanoparticles Nanocomposite for Label-Free Electrochemical Biosensing

In this context, a novel, scalable and facile method for the green synthesis of graphene oxide (GO) to facilitate effective and safe oxidation of graphite using sodium periodate (NaIO4) is demonstrated. The optimized value of the oxidizing agent NaIO4 ensured effective oxidation, minimized defects on sp2 C-C plane (ID/IG = 0.645) and increased C/O atomic ratio of ∼5.146. Subsequently, we successfully synthesized the amino-functionalized reduced graphene oxide (NH2-rGO) and carboxylic surface modified AgPtPd (COOH-AgPtPd) trimetallic nanoparticles (TNPs), in order to fabricate a label-free electrochemical sensing platform using the conventional immersive layer-by-layer (LBL) assembly. The superior synergetic effect between LBL-assembled NH2-rGO and COOH-AgPtPd (COOH-AgPtPd/NH2-rGO) significantly boosts the electron transfer rate of the electrode as well as electrocatalytic efficiency. Therefore, the as-prepared COOH-AgPtPd/NH2-rGO nanocomposite-based sensing material was first employed for nonenzymatic electrochemical detection of H2O2, with a low detection limit of 0.2 nM. Moreover, COOH-AgPtPd/NH2-rGO nanocomposite can also be utilized as a sensing platform for label-free accurate electrochemical detection of prostate-specific antigen (PSA) over a large linear range of 4 fg mL−1 to 300 ng mL−1, with an ultra-low detection limit (LOD) of 4 fg mL−1.

Label-free electrochemical detection of prostate-specific antigen based on nucleic acid aptamer

We report a label-free aptasensor to make direct detection of prostate specific antigen (PSA, a biomarker of prostate cancer) using a quinone-containing conducting copolymer acting as redox transducer and grafting matrix for immobilization of the short aptamer strands. It is shown that capture of PSA generates a current decrease (signal-off) measured by Square Wave Voltammetry. This current decrease is specific for PSA above a limit of quantification in the ngmL−1 range. The change in current is used to determine the PSA–aptamer dissociation constant KD, of ca. 2.6nM. To consolidate the proof of concept, a heterogeneous competitive exchange with a complementary DNA strand which breaks PSA–aptamer interactions is studied. This double-check followed by a current increase provides full assurance of a perfectly specific recognition.

Ultrasensitive Electrochemical Detection of Prostate-Specific Antigen by Using Antibodies Anchored on a DNA Nanostructural Scaffold

The high occurrence of prostate cancer in men makes the prostate-specific antigen (PSA) screening test really important. More importantly, the recurrence rate after radical prostatectomy is high, whereas the traditional PSA immunoassay does not possess the sufficient high sensitivity for post-treatment PSA detection. In these assays, uncontrolled and random orientation of capture antibodies on the surface largely reduces their activity. Here, by exploiting the rapidly emerging DNA nanotechnology, we developed a DNA nanostructure based scaffold to precisely control the assembly of antibody monolayer. We demonstrated that the detection sensitivity was critically dependent on the nanoscale-spacing (nanospacing) of immobilized antibodies. In addition to the controlled assembly, we further amplified the sensing signal by using the gold nanoparticles, resulting in extremely high sensitivity and a low detection limit of 1 pg/mL. To test the real-world applicability of our nanoengineered electrochemical sensor, we evaluated the performance with 11 patients' serum samples and obtained consistent results with the "gold-standard" assays.

Electrochemical immunoassay for the prostate specific antigen using ceria mesoporous nanospheres

We report on a sensitive electrochemical immunoassay for the prostate specific antigen (PSA). An immunoelectrode was fabricated by coating a glassy carbon electrode with multiwalled carbon nanotubes, poly(dimethyldiallylammonium chloride), CeO2 and PSA antibody (in this order) using the layer-by-layer method. The immunosensor is then placed in a sample solution containing PSA and o-phenylenediamine (OPD). It is found that the CeO2 nanoparticles facilitate the electrochemical oxidation of OPD, and this produces a signal for electrochemical detection of PSA that depends on the concentration of PSA. There is a linear relationship between the decrease in current and the concentration of PSA in the 0.01 to 1,000 pg mL−1 concentration range, and the detection limit is 4 fg mL−1. The assay was successfully applied to the detection of PSA in serum samples. This new differential pulse voltammetric immunoassay is sensitive and acceptably precise, and the fabrication of the electrode is well reproducible.

Ultrasensitive electrochemical detection of prostate-specific antigen (PSA) using gold-coated magnetic nanoparticles as ‘dispersible electrodes’

Herein, we demonstrate the use of modified gold-coated magnetic nanoparticles as 'dispersible electrodes' which act as selective capture vehicles for electrochemical detection of prostate-specific antigen (PSA). A key advantage of this system is the ability to quantify non-electrochemical active analytes such as proteins with unprecedented detection limits and fast response times.

Electrochemical detection of prostate-specific antigen based on gold colloids/alumina derived sol-gel film

An electrochemical immunosensor for total prostate-specific antigen (PSA) was fabricated based on anti-PSA antibody-functionalized gold colloids/alumina sol-gel film. The presence of colloidal gold provides a good microenvironment for the immobilization of biomolecules. The fabrication process of the immunosensor was characterized by cyclic voltammetry. A direct electrochemical immunoassay format was employed to detect PSA on the basis of the potential change before and after the antigen–antibody interaction. Under optimal conditions, the potential change was proportional to PSA concentration ranging from 4.0 to 13 ng mL − 1 with a detection limit of 3.4 ng mL − 1 . In addition, the performance and factors influencing the performance of the immunosensor were investigated and optimized.