Unprocessed Human Plasma Samples Research Articles

Electrochemical sensing of doxorubicin hydrochloride under sodium alginate antifouling conditions using silver nanoparticles modified glassy carbon electrodes

Doxorubicin (DOX) is a highly effective anticancer drug with a narrow therapeutic window; thus, sensitive and timely detection of DOX is crucial. Using electrodeposition of silver nanoparticles (AgNPs) and electropolymerization of alginate (Alg) layers on the surface of a glassy carbon electrode, a novel electrochemical probe was constructed (GCE). The fabricated AgNPs/poly-Alg-modified GCE probe was utilized for the quantification of DOX in unprocessed human plasma samples. For the electrodeposition of AgNPs and electropolymerization of alginate (Alg) layers on the surface of GCE, cyclic voltammetry (CV) was used in the potential ranges of −2.0 to 2.0 V and −0.6 to 0.2 V, respectively. The electrochemical activity of DOX exhibited two oxidation processes at the optimum pH value of 5.5 on the surface of the modified GCE. The DPV spectra of poly(Alg)/AgNPs modified GCE probe toward consecutive concentrations of DOX in plasma samples demonstrated wide dynamic ranges of 15 ng/mL-0.1 μg/mL and 0.1–5.0 μg/mL, with a low limit of quantification (LLOQ) of 15 ng/mL. The validation results indicated that the fabricated electrochemical probe might serve as a highly sensitive and selective assay for the quantification of DOX in patient samples. As an outstanding feature, the developed probe could detect DOX in unprocessed plasma samples and cell lysates without the requirement for pretreatment.

An ultrasensitive and preprocessing-free electrochemical platform for the detection of doxorubicin based on tryptophan/polyethylene glycol-cobalt ferrite nanoparticles modified electrodes

Doxorubicin (DOX) is an anticancer drug which can effectively inhibit the growth of cancer cells and aids the immune-mediated elimination of tumoral cells. Developing a new technique for analysis of DOX in clinical fluids is highly required. Here, a novel electrochemical sensor was designed using tryptophan (Trp)/(polyethylene glycol)PEGylated-CoFe2O4 nanoparticles to modify glassy carbon electrodes’ surface and was utilized to determine DOX in unprocessed human plasma samples. PEGylated-CoFe2O4 nanoparticles were coated on the surface of the glassy carbon electrode to provide the PEGylated-CoFe2O4/GCE probe. Under optimized conditions, the low limit of quantification (LLOQ) of the proposed sensor was 30 ng/mL and the linear ranges for the determination of DOX were 30 ng/mL to 1.0 μg/mL and 1.0 μg/mL to 5.0 μg/mL, respectively. PEG molecules provided an antifouling effect to prevent precipitation of the macromolecules on the surface of the fabricated electrode. Obtained results indicated that the suggested electrochemical sensor can be utilized for specific and sensitive determination of DOX in plasma samples.

Chemical binding of horseradish peroxidase enzyme with poly beta-cyclodextrin and its application as molecularly imprinted polymer for the monitoring of H2 O2 in human plasma samples.

In this study, a selective and sensitive molecular imprinting-based electrochemical sensors, for horseradish peroxidase (HRP) entrapment was fabricated using electro polymerization of ß-Cyclodextrin (ß-CD) on the surface of glassy carbon electrode. Poly beta-cyclodextrin P(ß-CD) provide efficient surface area for self-immobilization of HRP as well as improve imprinting efficiency. The proposed imprinted biosensor successfully utilized for detection of HRP with excellent analytical results which linear range is 0.1 mg/mL to 10 ng/mL with LOD of 2.23 ng/mL. Furthermore, electrocatalytical activity of the prepared biosensor toward the reduction of hydrogen peroxide was investigated in the ranges of 1 to 15 μM with a detection limit of 0.4 μM by using chronoamperometry technique. The developed biosensor was used for the detection of hydrogen peroxide in unprocessed human plasma sample.

A novel immunosensor for the monitoring of PSA using binding of biotinylated antibody to the prostate specific antigen based on nano-ink modified flexible paper substrate: efficient method for diagnosis of cancer using biosensing technology

Prostate cancer is the most significant reason for deaths in men, outside of lung cancer. The clinical examination of cancer proteins or biomarkers is extremely significant in early examination and monitoring of recurrence of disease after treatment. Biomarkers have expanded great clinical significance owing to their extensive spectra in the identification, elimination, early diagnosis and cure of cancer. In this work, novel, ultrasensitive sandwich-type portable bio device based on citrate-capped silver nanoparticles (Citrate-AgNPs) modified graphene quantum dots (GQDs) nano ink for detection of Prostate specific antigen (PSA) was fabricated. Functionalized cysteamine with gold nanoparticles (Cys-AuNPs) was also utilized to amplify the signal. It provides a good and high external area for the immobilization biotinylated antibody of PSA in the large amount. For the first time, citrate-AgNPs-GQDs nano ink was directly written on the cellulose paper surface (ivory sheet and photographic paper) and modified by Cys-AuNPs. So, final structure of the immunodevices was completed after including of Ab1 and PSA (antigen). The immunosensors were used for the recognition of PSA by using DPVs (differential pulse voltammetry) technique. The obtained low limit of quantification (LLOQ) of the first immunodevice (ivory sheet/Citrate AgNPs-GQDs nano-ink/CysA-Au NPs/Ab1/BSA/PSA/Ab2) was 0.07 μg/L and the linear range for the calibration plot was from 0.07 to 60 μg/L. Also, the achieved LLOQ of the second immunodevice (photographic paper/Citrate AgNPs-GQDs nano-ink/Cys-Au NPs/Ab1/BSA/PSA/Ab2) was 0.05 μg/L with the linear range of 10 to 0.05 μg/L. It is noteworthy that, proposed immunoassay was effectively utilized to the monitoring of PSA glycoprotein in unprocessed human plasma sample. Obtained results show that the constructed immunosensor is able to apply as portable bio device for the clinical analysis of PSA in human plasma samples.

A novel bioassay for the monitoring of carcinoembryonic antigen in human biofluid using polymeric interface and immunosensing method.

Carcinoembryonic antigen (CEA) is a member of a family of cell surface glycoproteins. Recognition of CEA is needed to monitor the physiological status of the patient for treatment and also it is important to assess the severity of the disease. In this work, we reported a novel sandwich-type electrochemical immunosensor based on gold nanoparticles functionalized cysteamine-glutaraldehyde (AuNPs-CysA-GA) and it successfully designed to detection of the CEA biomarker in a human plasma sample. The AuNPs-CysA-GA provides a large surface area for the effective immobilization of CEA antibody, as well as it ascertains the bioactivity and stability of immobilized CEA antigens. Biotinylated-anti-CEA antibody (Ab1) was immobilized on the surface of glassy carbon electrode (GCE) modified AuNPs-CysA-GA. Also, secondary antibody (HRP-Ab2) was costed immobilized to complete the sandwich part of immunosensor. Field emission scanning electron microscope (FE-SEM and EDS), was employed to monitor the sensor fabrication procedure. The immunosensor was used for the detection of CEA using differential pulse voltammetry (DPVs) technique. The proposed interface led to enhancement of accessible surface area for immobilizing high amount of anti-CEA antibody, increasing electrical conductivity, boosting stability, and biocompatibility. Finally, the low limit of quantitation (LLOQ) of the proposed immunosensor was obtained as 7 ng/mL with the linear range of 0.001-5 μg/L. The proposed immunoassay was successfully applied for the monitoring of the CEA in unprocessed human plasma samples. Obtained results paved that the proposed bioassay can be used as a novel bioassay for the clinical diagnosis of cancer based on CEA monitoring.

A novel paper based immunoassay of breast cancer specific carbohydrate (CA 15.3) using silver nanoparticles-reduced graphene oxide nano-ink technology: A new platform to construction of microfluidic paper-based analytical devices (μPADs) towards biomedical analysis

The technology of ink-jet printing has been an appealing alternative to traditional photolithography for fabricating flexible and elastic circuits, having low-cost and ease of control. In this work, a novel, unique and sensitive immunoassay designed based on application of silver nanoparticles-reduced graphene oxide nanocomposite (Ag/RGO) ink for fabrication of paper based immunosensor, Cysteamine coped gold nanoparticles (CysA/Au NPs) as a signal amplification element for determination of CA15-3 protein. Fully electrochemically methodology was applied to prepare a new transducer based on the Ag/RGO surface which provides high surface area for CA15-3 antibody immobilization in high amount. Under optimized experimental conditions, the Ag-RGO/CysA-Au NPs based immunosensor shows good specificity and sensitivity. The obtained LLOQ of immunosensor for CA 15-3 biomarker was 15 U/mL as well as calibration curve was linear in the range of 15–125 U/mL. The technique was successfully employed assay of CA15-3 biomarker in unprocessed human plasma samples.

Ultrasensitive bioassay of epitope of Mucin-16 protein (CA 125) in human plasma samples using a novel immunoassay based on silver conductive nano-ink: A new platform in early stage diagnosis of ovarian cancer and efficient management

Ovarian cancer (OC) is known to be one of the most lethal malignancies associated with women disease. The CA-125 protein is a repetitive epitope of MUC-16, which plays key role in enhancing the proliferation of cancer cells and inhibiting anticancer immune responses. It is the most widely used biomarker for early stage diagnosis of OC. Also it is the only serum marker which currently used in clinical diagnosis. Monitoring of CA-125 protein in the serum sample is also valuable in evaluating the response of ovarian cancer to treatment. In this research, a novel immunoassay based on immobilization of CA-125 antibody on the biointerface of silver nanoparticles modified graphene quantum dots ink (Ag NPs-GQDs) was successfully designed to recognition of CA-125 protein in a human plasma sample. The supplied immunoassay presents the proper ability to detect and determine the amount of CA-125 biomarker in low concentrations of CA-125 biomarker. The proposed immunosensor was employed for the detection of CA-125 using differential pulse voltammetry (DPVs) and square wave voltammetry (SWVs) techniques. The proposed interface leads to enhancement of accessible surface area for immobilizing a high amount of anti-CA-125 antibody, increasing electrical conductivity, boosting stability, catalytic properties and biocompatibility. Under the optimized operating conditions, the low limit of quantitation (LLOQ) for the proposed immunosensor was recorded as 0.01 U/mL, which this evaluation was performed at highly linear range of 0.01–400 U/mL. The proposed immunoassay was successfully applied for the monitoring of CA-125 in unprocessed human plasma samples.

Sensitive detection and determination of benzodiazepines using silver nanoparticles-N-GQDs ink modified electrode: A new platform for modern pharmaceutical analysis

In this work, a unique conductive nano-ink based on silver nanoparticle‑nitrogen doped graphene quantum dots (Ag/N-GQD) was synthesized and utilized for development of a novel, unique and sensitive biosensor for determination of alprazolam, chlordiazepoxide bis, diazepam, oxazepam and clonazepam. Electrochemical deposition, as a well-controlled synthesis procedure, has been utilized for subsequently layer-by-layer preparation of Ag/N-GQD nano-ink on a chitosan (CS) electropolymerized on the surface of gold electrode using cyclic voltammetry techniques in the regime of −1 to +1 V. The modified electrode appeared as an efficient electroactive interface for detection of selected benzodiazepines by using cyclic voltammetry, differential pulse voltammetry, and square wave voltammetry. The prepared sensor showed a noticeably good electro-activity for electrooxidation of alprazolam, chlordiazepoxide bis, diazepam, oxazepam and clonazepam than bare CS and Ag/N-GQD modified electrodes. Enhancement of peak currents is ascribed to the fast heterogeneous electron transfer kinetics that arise from the synergistic coupling between unique features of CS such as high permeability, excellent film-forming capability, good adhesion, cheapness, nontoxicity, and a susceptibility to chemical modifications, Ag/N-GQD nano-ink as high electrical conductivity. Finally, application of the new sensor for determination of selected benzodiazepine group drugs in unprocessed human plasma samples was studied. In general, the simultaneous attachment of Ag/N-GQD nano-ink to structure of CS provides new opportunities toward biomedical analysis and the personal healthcare.

Application of bioactive cyclic oligosaccharide on the detection of doxorubicin hydrochloride in unprocessed human plasma sample: A new platform towards efficient chemotherapy

In this study, a novel nano-composite based on poly‑taurine/beta‑cyclodextrin and graphene quantum dot used for the modification of gold electrode by simple electrodeposition approach. The prepared interface was applied for the sensing of doxorubicin hydrochloride (DOX) in human plasma samples without any pretreatment procedure. The synergistic influence of poly-taurine, beta-cyclodextrin, and graphene quantum dot not only remarkably enhances electroactivity, but also speeds up the electron shift between DOX and the electrode substrates. Cyclic voltammetry results indicated that the DOX is oxidized via two electrons and two protons process at the optimum pH = 4 using poly-taurine/beta-cyclodextrin and graphene quantum dots thin film modified gold electrode. More momentously electrostatic repulsion takes place between the prepared polymeric film and DOX resulting in the signal amplification on oxidation of this drug and lowering its overpotential and thereby sensitive and selective detection of DOX in real samples. The apparent electron transfer rate constant and transfer coefficients were determined by cyclic voltammetry. Using differential-pulse voltammetric (DPV) technique sensitive determination of DOX in human plasma samples was performed with wide dynamic range and good limit of detection.

Ultrasensitive immunoassay of glycoprotein 125 (CA 125) in untreated human plasma samples using poly (CTAB‑chitosan) doped with silver nanoparticles

CA 125 is a Mucin glycoprotein and its concentration in human serum correlates with a woman's risk of developing ovarian cancer and also indicates response to therapy in diagnosed patients. Accurate detection of this large, complex protein in patient biofluids is of great clinical relevance. In this work, an innovative immunoassay for quantitation of CA 125 based on signal amplification strategy was proposed. In this work, Horseradish peroxidase (HRP) labeled CA 125-antibody (anti-CA 125) was immobilized onto a green and biocompatible nanocomposite containing poly cetyl trimethyl ammonium bromide (P (CTAB) as conductive matrix, chitosan (CS) as biocompatible agent and sliver nanoparticles (Ag NPs) as signal amplification element. Therefore, a novel nanocomposite film based P (CTAB-CS) and Ag NPs was exploited to develop a highly sensitive immunosensor for detection of CA 125 protein. Importantly, Ag NPs prepared by electrodeposition method which lead to compact morphology. Fully electrochemical methodology was used to prepare a new transducer on a glassy carbon surface which provided a high surface area to immobilize a high amount of the anti-CA 125. The surface morphology of electrode was characterized by high-resolution field emission scanning electron microscope (FE-SEM) and energy dispersive spectroscopy (EDS). The immunosensor was employed for the detection of CA 125 using cyclic voltammetry (CV) and differential pulse voltammetry (DPVs) techniques. Under optimized condition the calibration curve for CA 125 concentration by SWV and DPV was linear in 0.01–400 U/mL with lower limit of quantification of 0.001 U/mL. The method was successfully applied assay of the CA 125 in unprocessed human plasma samples.

Electrochemical recognition of taurine biomarker in unprocessed human plasma samples using silver nanoparticlebased nanocomposite: A new platform for early stage diagnosis of neurodegenerative diseases of the nervous system.

The rapid and accurate determination of the level of taurine biomarker in various tissues and body fluids can be of great interest in the early diagnosis of several important pathologies and diseases. In the present study, an innovative electrochemical interface for quantitation of taurine based on ternary signal amplification strategy was fabricated. In this work, silver nanoparticles were electrodeposited onto green and biocompatible nanocomposite containing α-cyclodextrin as conductive matrix. Therefore, a double layer film based on α-cyclodextrin and silver nanoparticles was exploited to develop a highly sensitive electrochemical sensor for detection of taurine. Fully electrochemical methodology was used to prepare a transducer on a glassy carbon electrode which provided a high surface area towards sensitive detection of taurine biomarker. The surface morphology of electrode surface was characterized by high-resolution field emission scanning electron microscope (FE-SEM). The proposed sensing platform provides a simple tool for taurine detection. The calibration curve for taurine concentration was linear in 0.7nM to 0.1mM with low limit of quantification of 0.7nM. The practical analytical utility of the modified electrode was illustrated by determination of taurine in unprocessed human plasma samples with recovery of 90.8% to 104%.

Sensitive monitoring of taurine biomarker in unprocessed human plasma samples using a novel nanocomposite based on poly(aspartic acid) functionalized by graphene quantum dots.

The rapid and accurate determination of the level of taurine biomarker in various tissues and body fluids can be of great interest in the early diagnosis of several important pathologies and diseases. For the first time, this study reports on the electropolymerization of a low toxic and biocompatible nanocomposite "poly(aspartic acid)-graphene quantum dots (GQDs)" as a novel strategy for surface modification of glassy carbon electrode and preparation a new interface for measurement of taurine. Electrochemical deposition, as a well-controlled synthesis procedure, has been used for subsequently layer-by-layer preparation of GQDs nanostructures on poly(aspartic acid) using cyclic voltammetry techniques in the regime of -1.5 to 2V. The field emission scanning electron microscopy indicated immobilization of uniformly GQDs onto poly(aspartic acid) film. The modified electrode appeared as an effective electroactivity for detection of taurine biomarker using cyclic voltammetry, chronoamperometry, and differential pulse voltammetry. Enhancement of peak currents is ascribed to the fast heterogeneous electron transfer kinetics that arise from the synergistic coupling between the excellent properties of poly(aspartic acid) as semiconducting polymer, GQDs as high density of edge plane sites, and subtle electronic characteristics to chemical modification. Under the optimized analysis conditions, the prepared sensor for detection of taurine showed a low limit of quantification 0.001mM. Finally, the resulting prepared sensor allow the quantification of these biomarkers directly in biological samples without need of derivatization schemes or sample pretreatment.

Immunosensing of breast cancer prognostic marker in adenocarcinoma cell lysates and unprocessed human plasma samples using gold nanostructure coated on organic substrate

Early stage diagnosis of cancer by monitoring the cancer biomarkers in human biological fluids is the excellent tool and the first step toward adopting efficient therapy, hindering metastasis and reducing mortality rate. An ultrasensitive electrochemical immunosensor for quantitation of tumor suppressor protein Carcinoma Antigen 15-3 (CA 15-3) based on ternary signal amplification strategy was fabricated. In this work, the antibody (horseradish peroxidase (HRP)-Labeled anti CA 15-3) was immobilized onto a green and biocompatible nanocomposite containing gold nano-shrub (Au NSs) electrochemically assembled onto thiolated graphene quantum dots (GQDs/CysA (Cysteamine)). Therefore, a novel multilayer film based on GQDs, CysA, and Au NSs was exploited to develop a highly sensitive immunosensor for detection of CA 15.3. Fully electrochemical methodology was used to prepare a new transducer on a gold surface which provided a high surface area to immobilize a high amount of the anti-CA 15.3. Under optimized condition the calibration curve for CA 15.3 concentration was linear in the range of 0.3–1 U/mL and 2–250 U/mL with detection limit of 0.011 U/mL. The method was applied to the assay of CA 15.3 in malignant cell line lysates of human breast adenocarcinoma cell line-MCF-7.

An innovative immunosensor for ultrasensitive detection of breast cancer specific carbohydrate (CA 15-3) in unprocessed human plasma and MCF-7 breast cancer cell lysates using gold nanospear electrochemically assembled onto thiolated graphene quantum dots

The accurate quantification of the level of breast cancer specific protein CA 15-3 in serum is crucial for cancer prognosis. This work, a novel and sensitive label-free immunoassay based on gold nanospear (Au NSs) electrochemically assembled onto thiolated graphene quantum dots (CysA/GQDs) for the detection of CA 15-3 antibodies. The CysA/Au NSs/GQDs hybrid interface provides a large surface area for the effective immobilization of CA 15-3 antigens, as well as it ascertains the bioactivity and stability of immobilized CA 15-3 antigens. Field emission scanning electron microscope (FE-SEM), and EDS photoelectron spectroscopies were used to monitor the sensor fabrication. Also, cyclic voltammetry was used to quantify the extent of Au NSs' surface coverage by CA 15-3 antigens. Square wave voltammetry (SWV) was employed to investigate the immunosensor fabrication and to monitor the binding events between CA 15–3 antigens-antibodies. Under optimized experimental conditions, the immunosensor displayed good sensitivity and specificity. The CA 15-3 were detected in a concentration as low as 0.11U/mL with a linear range from 0.16–125U/mL. The high sensitivity of the immunosensor may derive from the high loading of CA 15-3 antibodies on CysA/Au NSs/GQDs hybrid interface which increases the number of binding events. The method was successfully applied assay of the CA 15-3 in unprocessed human plasma samples. Also, proposed immunosensor was applied to the assay of CA 15-3 malignant cell line lysates (human breast adenocarcinoma cell line-MCF-7).

Non-enzymatic Determination of L-Proline Amino Acid in Unprocessed Human Plasma Sample Using Hybrid of Graphene Quantum Dots Decorated with Gold Nanoparticles and Poly Cysteine: A Novel Signal Amplification Strategy.

An innovative electrochemical interface for quantitation of L-proline (L-Pro) based on ternary amplification strategy was fabricated. In this work, gold nanoparticles prepared by soft template methodology were immobilized onto green and biocompatible nanocomposite containing poly as a conductive matrix and graphene quantum dots as the amplification element. Therefore, a novel multilayer film based on poly-L-cysteine, graphene quantum dots (GQDs), and gold nanoparticles (GNPs) was exploited to develop a highly sensitive electrochemical sensor for the detection of L-Pro. Fully electrochemical methodology was used to prepare a new transducer on a glassy carbon electrode, which provided a high surface area towards sensitive detection of L-Pro. The prepared electrode was employed for the detection of L-Pro. Under optimized conditions, the calibration curve for L-Pro concentration was linear in 0.5 nM - 10 mM with a low limit of quantification of 0.1 nM. The practical analytical utility of the modified electrode was illustrated by determination of L-Pro in unprocessed human plasma samples.

Aptamer based assay of plated-derived grow factor in unprocessed human plasma sample and MCF-7 breast cancer cell lysates using gold nanoparticle supported α-cyclodextrin

Platelet-derived growth factor (PDGF), a protein biomarker, is directly involved in many cell transformation processes, such as tumor growth and progression. Elevation platelet-derived growth factor (PDGF-BB) concentration in plasma could indicate the accelerating growth of metastatic breast tumors and angiogenesis. The development of an apta-assay for detection of PDGF-BB in is presented in this work. A highly specific DNA-aptamer, selected to PDGF-BB was immobilized onto a gold nanoparticles supported α-cyclodextrin and electrochemical measurements were performed in a solution containing the phosphate buffer solution with physiological pH. Variety of shapes of gold nanostructures with different sizes from zero-dimensional nanoparticles to spherical structures were prepared by one-step template (α-cyclodextrin)-assistant green electrodeposition method. Fully electrochemical methodology was used to prepare a new transducer on a gold surface which provided a high surface area to immobilize a high amount of the aptamer. The surface morphology of electrode was characterized by high-resolution field emission scanning electron microscope (FE-SEM) and energy dispersive spectroscopy (EDX). The prepared aptasensors represented different electrochemical activities toward the redox processes of PDGF-BB attributing to the size and shape of the gold nanoparticles. The aptasensor was employed for the detection of PDGF using square wave voltammetry (SWV) and Cyclic voltammetry (CV) techniques. Under optimized condition the calibration curve for PDGF-BB was linear in 0.52–1.52nM with low limit of quantification of 0.52nM. Also, under the optimized experimental conditions, the proposed aptasensor of GNPs-cubic-α-CD-Apt-Au electrode exhibited excellent analytical performance for MCF-7 cells determination, ranging from 328 TO 593 cells mL−1 with low limit of quantification of 328 cells mL−1. As a result, the electrochemical aptasensor was able to detect cancer-related targets in unprocessed human plasma samples.

An innovative immunosensor for detection of tumor suppressor protein p53 in unprocessed human plasma and cancer cell lysates

An innovative mediator-free electrochemical immunosensor for quantitation of p53 tumor suppressor protein based on signal amplification strategy was fabricated. In this work, biotin conjugated p53-antibody (anti-p53) was immobilized onto a green and biocompatible nanocomposite containing poly l-cysteine (P-Cys) as conductive matrix and 3D gold nanoparticles (GNPs) as signal amplification element. Therefore, a novel nanocomposite film based on P-Cys and GNPs was exploited to develop a highly sensitive immunosensor for detection of p53 protein. Importantly, GNPs prepared by sonoelectrodeposition method which lead to compact morphology. Fully electrochemical methodology was used to prepare a new transducer on a gold surface which provided a high surface area to immobilize a high amount of the anti-p53. The surface morphology of electrode was characterized by high-resolution field emission scanning electron microscope (FE-SEM) and energy dispersive spectroscopy (EDX). The immunosensor was employed for the detection of p53 in physiological pH using square wav voltammetry and differential pulse voltammetry (DPVs) techniques. Under optimized condition the calibration curve for p53 concentration by SWV and DPV was linear in 0.0369–50pM and 0.018–2.5pM with lower limit of quantification of 48fM and 18fM, respectively. The method was successfully applied assay of the p53 in unprocessed human plasma samples. Also, the method was applied to the assay of p53 in human plasma sample and normal and malignant cell line lysates such as (L929 normal cell Line from mouse C3H (L929), colon cancer cell-HCT, prostate cancer cell line PC-3, and human breast adenocarcinoma cell line-MCF7).

\u201cTORNADO\u201d \u2013 Theranostic One-Step RNA Detector; microfluidic disc for the direct detection of microRNA-134 in plasma and cerebrospinal fluid

Diagnosis of seizure disorders such as epilepsy currently relies on clinical examination and electroencephalogram recordings and is associated with substantial mis-diagnosis. The miRNA, miR-134 (MIR134 in humans), has been found to be elevated in brain tissue after experimental status epilepticus and in human epilepsy cells and their detection in biofluids may serve as unique biomarkers. miRNAs from unprocessed human plasma and human cerebrospinal fluid samples were used in a novel electrochemical detection based on electrocatalytic platinum nanoparticles inside a centrifugal microfluidic device where the sandwich assay is formed using an event triggered release system, suitable for the rapid point-of-care detection of low abundance biomarkers of disease. The device has the advantage of controlling the rotation speed of the centrifugal device to pump nanoliter volumes of fluid at a set time and manipulate the transfer of liquids within the device. The centrifugal platform improves reaction rates and yields by proposing efficient mixing strategies to overcome diffusion-limited processes and improve mass transport rates, resulting in reduced hybridization times with a limit of detection of 1 pM target concentration. Plasma and cerebrospinal fluid samples (unprocessed) from patients with epilepsy or who experienced status epilepticus were tested and the catalytic response obtained was in range of the calibration plot. This study demonstrates a rapid and simple detection for epilepsy biomarkers in biofluid.

Evaluation of Multiprotein Immunoaffinity Subtraction for Plasma Proteomics and Candidate Biomarker Discovery Using Mass Spectrometry

Strategies for removal of high abundance proteins have been increasingly utilized in proteomic studies of serum/plasma and other body fluids to enhance the detection of low abundance proteins and achieve broader proteome coverage; however, both the reproducibility and specificity of the high abundance protein depletion process still represent common concerns. Here we report a detailed evaluation of immunoaffinity subtraction performed applying the ProteomeLab IgY-12 system that is commonly used in human serum/plasma proteome characterization in combination with high resolution LC-MS/MS. Plasma samples were repeatedly processed using this approach, and the resulting flow-through fractions and bound fractions were individually analyzed for comparison. The removal of target proteins by the immunoaffinity subtraction system and the overall process was highly reproducible. Non-target proteins, including one spiked protein standard (rabbit glyceraldehyde-3-phosphate dehydrogenase), were also observed to bind to the column at different levels but also in a reproducible manner. The results suggest that multiprotein immunoaffinity subtraction systems can be readily integrated into quantitative strategies to enhance detection of low abundance proteins in biomarker discovery studies.

Physiological actions of taurine

Physiological actions of taurine