A miniaturized electrochemical assay for homocysteine using screen-printed electrodes with cytochrome c anchored gold nanoparticles

Thangamuthu, Madasamy; Santschi, Christian; Martin, Olivier J. F.

doi:10.1039/c5an00752f

Cited by 26 publications

(38 citation statements)

References 51 publications

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“…The current in the AuNPs modified SPE is reduced by 13 μA (from 33 μA to 20 μA), whereas the bare SPE shows only a 3 μA current reduction (from 16 μA to 13 μA). The more pronounced current reduction on anti-CRP-SAM-AuNPs-SPE can be attributed to the larger amounts of immobilized antibodies, which is confirmed by the estimated surface coverage values using the Randles-Sevcik’s equation [ 31 , 32 ].

where, C and D correspond to the concentration and diffusion coefficient of Fe(CN) 6 4− , respectively.…”

Section: Resultsmentioning

confidence: 77%

“…The parameters I p , n , γ, and A are attributed to the maximum current response, the number of transferred electrons per molecule, the scan rate, and the effective surface area. The calculated surface coverage of anti-CRP on SAM-AuNPs-SPE was 22.6 nmol cm −2 , which is about 13 times higher than for the bare SPE (1.7 nmol cm −2 ), suggesting that the enhanced immobilization of anti-CRP is related to the larger surface area and the higher electron transfer rate that is offered by the spherically shaped AuNPs (20–60 nm) [ 31 ].…”

Section: Resultsmentioning

confidence: 99%

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Label-Free Electrochemical Immunoassay for C-Reactive Protein

Thangamuthu

Santschi

Martin³

2018

Biosensors

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C-reactive protein (CRP) is one of the most expressed proteins in blood during acute phase inflammation, and its minute level increase has also been recognized for the clinical diagnosis of cardio vascular diseases. Unfortunately, the available commercial immunoassays are labour intensive, require large sample volumes, and have practical limitations, such as low stability and high production costs. Hence, we have developed a simple, cost effective, and label-free electrochemical immunoassay for the measurement of CRP in a drop of serum sample using an immunosensor strip made up of a screen printed carbon electrode (SPE) modified with anti-CRP functionalized gold nanoparticles (AuNPs). The measurement relies on the decrease of the oxidation current of the redox indicator Fe3+/Fe2+, resulting from the immunoreaction between CRP and anti-CRP. Under optimal conditions, the present immunoassay measures CRP in a linear range from 0.4–200 nM (0.047–23.6 µg mL−1), with a detection limit of 0.15 nM (17 ng mL−1, S/N = 3) and sensitivity of 90.7 nA nM−1, in addition to a good reproducibility and storage stability. The analytical applicability of the presented immunoassay is verified by CRP measurements in human blood serum samples. This work provides the basis for a low-priced, safe, and easy-to-use point-of-care immunosensor assay to measure CRP at clinically relevant concentrations.

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where, C and D correspond to the concentration and diffusion coefficient of Fe(CN) 6 4− , respectively.…”

Section: Resultsmentioning

confidence: 77%

Section: Resultsmentioning

confidence: 99%

Label-Free Electrochemical Immunoassay for C-Reactive Protein

Thangamuthu

Santschi

Martin³

2018

Biosensors

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“…Before nanomaterials deposition, SPE was pre-treated, as described in our earlier report [ 33 ], to remove the organic ink constituents or contaminants and to increase the surface functionalities. Then, the amine (-NH 2 ) functionalized carbon surface was formed by electro-oxidation in 0.1 M ammonium carbamate solution applying a constant potential of 1.0 V for 10 min.…”

Section: Methodsmentioning

confidence: 99%

Electrochemical Sensor for Bilirubin Detection Using Screen Printed Electrodes Functionalized with Carbon Nanotubes and Graphene

Thangamuthu

Gabriel

Santschi

et al. 2018

Sensors

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Practice oriented point-of-care diagnostics require easy-to-handle, miniaturized, and low-cost analytical tools. In a novel approach, screen printed carbon electrodes (SPEs), which were functionalized with nanomaterials, are employed for selective measurements of bilirubin, which is an important biomarker for jaundice. Multi-walled carbon nanotubes (MWCNT) and graphene separately deposited on SPEs provide the core of an electrochemical sensor for bilirubin. The electrocatalytic activity towards bilirubin oxidation (bilirubin to biliverdin) was observed at +0.25 V. In addition, a further peak corresponding to the electrochemical conversion of biliverdin into purpurin appeared at +0.48 V. When compared to MWCNT, the graphene type shows a 3-fold lower detection limit (0.3 ± 0.022 nM and 0.1 ± 0.018 nM, respectively), moreover, the graphene type exhibits a larger linear range (0.1–600 µM) than MWCNT (0.5–500 µM) with a two-fold better sensitivity, i.e., 30 nA µM−1 cm−2, and 15 nA µM−1 cm−2, respectively. The viability is validated through measurements of bilirubin in blood serum samples and the selectivity is ensured by inhibiting common interfering biological substrates using an ionic nafion membrane. The presented approach enables the design and implementation of low cost and miniaturized electrochemical sensors.

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“…Considering the DNA Methylation is an important epigenetic marker associated with cancer, we aimed to detect hypermethylation of GSTP‐1 electrochemically via hybridization between probe and target DNA by using MWCNT modified Screen Printed Electrodes (SPEs) for point of care diagnostics purposes. Screen printing technology is widely used for fabrication of disposable electrochemical biosensors that can be easily adapted in portable systems 13–15. These electrodes need low sample volumes, allow complex surface modifications and have good reproducibility.…”

Section: Introductionmentioning

confidence: 99%

Prostate Cancer Biomarker Detection with Carbon Nanotubes Modified Screen Printed Electrodes

Topkaya

Ozkan-Ariksoysal

2015

Electroanalysis

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DNA hypermethylation is an epigenetic alteration and a promising biomarker for early prostate cancer detection. Simple, sensitive, easy to handle and rapid detection methodologies are imperative for point of care diagnostics especially for cancer. Herein, we describe for the first time a regenerable and compatible electrochemical biosensor for detection of Glutathione S‐Transferase P‐1 (GSTP‐1) gene hypermethylation related to prostate cancer via DNA hybridization onto the disposable Carbon and Multi Walled Carbon Nanotubes (MWCNT) Screen Printed Electrodes (SPEs). In the study, capture probes were adsorbed onto the SPEs by simple passive adsorption and then hybridization was achieved by sending the complementary target onto the probe‐modified electrodes. The selectivity of the biosensor was proved by control studies. Differential Pulse Voltammetry (DPV) technique was used to detect hybridization via guanine oxidation signals changes. The total time of the optimized method was nearly 1h, measurements took for less than 1 min, and the biosensor response was stable up to 40 days of storage period at 4 °C. The main advantages of the biosensor are very low detection limit (picomolar range) and capability of reusing the biosensor for at least 3 times after very simple regeneration process that is a unique property to reduce the cost of the assay. In addition, this is the first study that demonstrates the detection of GSTP‐1 hypermethylation electrochemically by using SPEs in order to create point of care diagnostics. The optimum parameters for the biosensor, as well as its future prospects to enhance the performance of DNA biosensors were also presented.

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A miniaturized electrochemical assay for homocysteine using screen-printed electrodes with cytochrome c anchored gold nanoparticles

Cited by 26 publications

References 51 publications

Label-Free Electrochemical Immunoassay for C-Reactive Protein

Label-Free Electrochemical Immunoassay for C-Reactive Protein

Electrochemical Sensor for Bilirubin Detection Using Screen Printed Electrodes Functionalized with Carbon Nanotubes and Graphene

Prostate Cancer Biomarker Detection with Carbon Nanotubes Modified Screen Printed Electrodes

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