Trastuzumab (T) detection in serum using signal amplification strategy for non-faradaic impedimetric sensing quartz crystal microbalance (QCM) based on peptide piezo-immunosensors and its role in breast cancer treatment.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e12502-e12502
Author(s):  
Mohammad Muhsin Chisti ◽  
Juan Liu ◽  
Justin Frank Antoni Klamerus ◽  
Ishmael A. Jaiyesimi ◽  
Syeda Hina Batool ◽  
...  
Keyword(s):  
Real Time ◽  
Signal Amplification ◽  
Limit Of Detection ◽  
Cell Immobilization ◽  
Breast Cancers ◽  
Label Free ◽  
Faradaic Impedance ◽  
Free Peptide ◽  
Capacitive Biosensor ◽  
Amplification Strategy

e12502 Background: Her2Neu (H) antigen, expressed on 20% of Breast cancers, is an established target for antibody therapy with T. Immunohistochemistry is still the most widely used technique to detect h level which is time consuming and does not reveal any details of interaction between the molecules. We have developed a new innovative biosensor based novel technique to study real time interaction of h antigens with T using QCM Piezo-immunosensor. This quantitative label free peptide based assay can be used to characterize cell surface antigen, to study antigen- antibody interactions and obtain understanding of mechanisms of resistance. Methods: A label free and reagent free peptide mimotope capacitive biosensor is developed for T quantification based on non-Faradaic readout. The low sensitivity issue of capacitive biosensor was overcome with two innovations: peptide mimotope mixed SAM biointerface and dilution of the testing buffer. Signal amplification was achieved through dilution of the PBS buffer to tune Cdl to dominate the overall capacitance change upon target binding. After 1000 times dilution, limit of detection is lowered 500 times (0.22 µg/mL) and the sensitivity increased 20 times (0.04192 (µg/mL)-1). Results: Binding was very specific. Signal amplification strategy is practical. Further applied to planar electrode for optimizing sensing, response time in less than 1 minute. Conclusions: This is the first report of T detection using electrochemical method based on non-Faradaic impedance. h antigen density and interactions of antigens will help physicians to determine the clinical efficacy and resistance mechanisms to targeted antibodies like T and ado-Trastuzumab.For the first time, we have established a low cost, highly sensitive, fast, synthetic, QCM assay which could be used as a basis for developing a new generation of affinity-based Immunosensor assays. This real time capability and its simplicity of operation are highly suitable for multipurpose studies on living cells including cell immobilization, cytotoxicity of drugs, and the cell action mechanisms

A label-free and enzyme-free signal amplification strategy for a sensitive RNase H activity assay

Nanoscale ◽  
2017 ◽  
Vol 9 (42) ◽  
pp. 16149-16153 ◽  
Author(s):  
Chang Yeol Lee ◽  
Hyowon Jang ◽  
Ki Soo Park ◽  
Hyun Gyu Park
Keyword(s):  
Signal Amplification ◽  
Rnase H ◽  
Label Free ◽  
Activity Assay ◽  
G Quadruplex ◽  
Catalytic Hairpin Assembly ◽  
Amplification Strategy

A target-triggered catalytic hairpin assembly with a G-quadruplex specific fluorescent binder, NMM, is employed to develop a novel and sensitive RNase H activity assay.

scholarly journals A novel electrochemical aptasensor for fumonisin B1 determination using DNA and exonuclease-I as signal amplification strategy

BMC Chemistry ◽  
2019 ◽  
Vol 13 (1) ◽  
Author(s):  
Min Wei ◽  
Fei Zhao ◽  
Shuo Feng ◽  
Huali Jin
Keyword(s):  
Incubation Time ◽  
Electrode Surface ◽  
Signal Amplification ◽  
Limit Of Detection ◽  
Fumonisin B1 ◽  
Electrochemical Aptasensor ◽  
Experimental Conditions ◽  
Exonuclease I ◽  
Double Stranded Dna ◽  
Amplification Strategy

Abstract In this work, using DNA and exonuclease-I (Exo-I) as signal amplification strategy, a novel and facile electrochemical aptasensor was constructed for fumonisin B1 (FB1) detection. The G-rich complementary DNA (cDNA) was immobilized onto the electrode surface. Then, aptamer of FB1 was hybridized with cDNA to form double-stranded DNA. In the absence of FB1, double-stranded DNA and G-rich cDNA on the electrode surface promoted effectively methylene blue (MB) enrichment and amplified the initial electrochemical response. In the presence of FB1, the combination of aptamer and FB1 led to the release of aptamer from the electrode surface and the expose of 3′ end of single-stranded cDNA. When Exo-I was added onto the electrode surface, the single-stranded cDNA was degraded in the 3′–5′ direction. The decrease of double-stranded DNA and G-rich cDNA resulted in the less access of MB to the electrode surface, which decreased the electrochemical signal. The experimental conditions including incubation time of FB1, the amount of Exo-I and incubation time of Exo-I were optimized. Under the optimal conditions, the linear relationship between the change of peak current and the logarithmic concentration of FB1 was observed in the range of 1.0 × 10−3–1000 ng mL−1 with a low limit of detection of 0.15 pg mL−1. The experimental results showed that the prepared aptasensor had acceptable specificity, reproducibility, repeatability and stability. Therefore, this proposed aptasensor has a potential application in the food safety detection.

A novel signal amplification strategy for highly specific and nonenzymatic isothermal electrochemiluminescence detection of tumour markers

2020 ◽  
Vol 12 (7) ◽  
pp. 938-942 ◽  
Author(s):  
Yan Liu ◽  
Xin Guo ◽  
Zhijin Fan ◽  
Yuhui Liao ◽  
Ying Yu ◽  
...  
Keyword(s):  
Signal Amplification ◽  
Limit Of Detection ◽  
Tumour Markers ◽  
Linear Dna ◽  
Amplification Strategy

A signal amplification strategy for highly specific and nonenzymatic isothermal electrochemiluminescence detection of microRNA was developed. The limit of detection was as low as 4 fmol, which was superior to that for the reported linear DNA method.

scholarly journals A lectin-coupled porous silicon-based biosensor: label-free optical detection of bacteria in a real-time mode

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mona Yaghoubi ◽  
Fereshteh Rahimi ◽  
Babak Negahdari ◽  
Ali Hossein Rezayan ◽  
Azizollah Shafiekhani
Keyword(s):  
Fourier Transform ◽  
Porous Silicon ◽  
Real Time ◽  
Limit Of Detection ◽  
Principal Component ◽  
The Other ◽  
Detection Methods ◽  
Carbohydrate Binding ◽  
Label Free ◽  
E Coli

Abstract Accuracy and speed of detection, along with technical and instrumental simplicity, are indispensable for the bacterial detection methods. Porous silicon (PSi) has unique optical and chemical properties which makes it a good candidate for biosensing applications. On the other hand, lectins have specific carbohydrate-binding properties and are inexpensive compared to popular antibodies. We propose a lectin-conjugated PSi-based biosensor for label-free and real-time detection of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) by reflectometric interference Fourier transform spectroscopy (RIFTS). We modified meso-PSiO2 (10–40 nm pore diameter) with three lectins of ConA (Concanavalin A), WGA (Wheat Germ Agglutinin), and UEA (Ulex europaeus agglutinin) with various carbohydrate specificities, as bioreceptor. The results showed that ConA and WGA have the highest binding affinity for E. coli and S. aureus respectively and hence can effectively detect them. This was confirmed by 6.8% and 7.8% decrease in peak amplitude of fast Fourier transform (FFT) spectra (at 105 cells mL−1 concentration). A limit of detection (LOD) of about 103 cells mL−1 and a linear response range of 103 to 105 cells mL−1 were observed for both ConA-E. coli and WGA-S. aureus interaction platforms that are comparable to the other reports in the literature. Dissimilar response patterns among lectins can be attributed to the different bacterial cell wall structures. Further assessments were carried out by applying the biosensor for the detection of Klebsiella aerogenes and Bacillus subtilis bacteria. The overall obtained results reinforced the conjecture that the WGA and ConA have a stronger interaction with Gram-positive and Gram-negative bacteria, respectively. Therefore, it seems that specific lectins can be suggested for bacterial Gram-typing or even serotyping. These observations were confirmed by the principal component analysis (PCA) model.

scholarly journals A novel electrochemical aptasensor for fumonisin B1 determination using DNA and exonuclease-I as signal amplification strategy

2019 ◽  
Author(s):  
Min Wei ◽  
Fei Zhao ◽  
Shuo Feng ◽  
Huali Jin
Keyword(s):  
Incubation Time ◽  
Electrode Surface ◽  
Signal Amplification ◽  
Limit Of Detection ◽  
Fumonisin B1 ◽  
Electrochemical Aptasensor ◽  
Experimental Conditions ◽  
Exonuclease I ◽  
Double Stranded Dna ◽  
Amplification Strategy

Abstract In this work, using DNA and exonuclease-I (Exo-I) as signal amplification strategy, a novel and facile electrochemical aptasensor was constructed for fumonisin B1 (FB1) detection. The G-rich complementary DNA (cDNA) was immobilized onto the electrode surface. Then, aptamer of FB1 was hybridized with cDNA to form double-stranded DNA. In the absence of FB1, double-stranded DNA and G-rich cDNA on the electrode surface promoted effectively methylene blue (MB) enrichment and amplified the initial electrochemical response. In the presence of FB1, the combination of aptamer and FB1 led to the release of aptamer from the electrode surface and the expose of 3' end of single-stranded cDNA. When Exo-I was added onto the electrode surface, the single-stranded cDNA was degraded in the 3’-5’ direction. The decrease of double-stranded DNA and G-rich cDNA resulted in the less access of MB to the electrode surface, which decreased the electrochemical signal. The experimental conditions including incubation time of FB1, the amount of Exo-I and incubation time of Exo-I were optimized. Under the optimal conditions, the linear relationship between the change of peak current and the logarithmic concentration of FB1 was observed in the range of 1.0×10-3-1000ng·mL−1 with a low limit of detection of 0.15 pg·mL−1. The experimental results showed that the prepared aptasensor had acceptable specificity, reproducibility, repeatability and stability. Therefore, this proposed aptasensor has a potential application in the food safety detection.

scholarly journals A novel electrochemical aptasensor for fumonisin B1 determination using DNA and exonuclease-I as signal amplification strategy

2019 ◽  
Author(s):  
Min Wei ◽  
Fei Zhao ◽  
Shuo Feng ◽  
Huali Jin
Keyword(s):  
Incubation Time ◽  
Electrode Surface ◽  
Signal Amplification ◽  
Limit Of Detection ◽  
Fumonisin B1 ◽  
Electrochemical Aptasensor ◽  
Experimental Conditions ◽  
Exonuclease I ◽  
Double Stranded Dna ◽  
Amplification Strategy

Abstract In this work, using DNA and exonuclease-I (Exo-I) as signal amplification strategy, a novel and facile electrochemical aptasensor was constructed for fumonisin B1 (FB1) detection. The G-rich complementary DNA (cDNA) was immobilized onto the electrode surface. Then, aptamer of FB1 was hybridized with cDNA to form double-stranded DNA. In the absence of FB1, double-stranded DNA and G-rich cDNA on the electrode surface promoted effectively methylene blue (MB) enrichment and amplified the initial electrochemical response. In the presence of FB1, the combination of aptamer and FB1 led to the release of aptamer from the electrode surface and the expose of 3' end of single-stranded cDNA. When Exo-I was added onto the electrode surface, the single-stranded cDNA was degraded in the 3’-5’ direction. The decrease of double-stranded DNA and G-rich cDNA resulted in the less access of MB to the electrode surface, which decreased the electrochemical signal. The experimental conditions including incubation time of FB1, the amount of Exo-I and incubation time of Exo-I were optimized. Under the optimal conditions, the linear relationship between the change of peak current and the logarithmic concentration of FB1 was observed in the range of 1.0×10-3-1000ng·mL−1 with a low limit of detection of 0.15 pg·mL−1. The experimental results showed that the prepared aptasensor had acceptable specificity, reproducibility, repeatability and stability. Therefore, this proposed aptasensor has a potential application in the food safety detection.

scholarly journals CRISPR/Cas13a signal amplification linked immunosorbent assay (CLISA)

2019 ◽  
Author(s):  
Qian Chen ◽  
Tian Tian ◽  
Erhu Xiong ◽  
Po Wang ◽  
Xiaoming Zhou
Keyword(s):  
Immunosorbent Assay ◽  
Signal Amplification ◽  
Limit Of Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Inflammatory Factor ◽  
Early Diagnosis Of Cancer ◽  
Low Concentrations ◽  
Conventional Elisa ◽  
Amplification Strategy ◽  
Endothelial Growth Factor

ABSTRACTThe enzyme-linked immunosorbent assay (ELISA) is a basic technique used in analytical and clinical investigations. However, conventional ELISA is still not sensitive enough to detect ultra-low concentrations of biomarkers for the early diagnosis of cancer, cardiovascular risk, neurological disorders, and infectious diseases. Herein we show a mechanism utilizing the CRISPR/Cas13a-based signal export amplification strategy, which double-amplifies the output signal by T7 RNA polymerase transcription and CRISPR/Cas13a collateral cleavage activity. This process is termed the CRISPR/Cas13a signal amplification linked immunosorbent assay (CLISA). The proposed method was validated by detecting an inflammatory factor, human interleukin-6 (human IL-6), and a tumor marker, human vascular endothelial growth factor (human VEGF), which achieved limit of detection (LOD) values of 45.81 fg/mL (2.29 fM) and 32.27 fg/m (0.81 fM), respectively, demonstrating that CLISA is at least 102-fold more sensitive than conventional ELISA.

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