A label-free logic gate hairpin aptasensor for sensitive detection of ATP based on graphene oxide and PicoGreen dye

Abstract Background In this paper, a simple, enzyme-free, label-free fluorescence, high sensitivity logic gate hairpin aptasensor was developed for adenosine triphosphate (ATP) detection based on graphene oxide (GO) and PicoGreen dye. Methods Using single-strand deoxyribonucleic acid (DNA) and adenosine triphosphate (ATP) as input signal and fluorescence signal as output signal, if single-strand DNA (DNA-L), single-strand DNA (DNA-S), and ATP were present at the same time, one segment of DNA-L formed a hairpin ring with ATP, and the other segment of DNA-L formed a completely complementary hairpin stem with DNA-S. The hairpin DNA was detached from the GO surface, and PicoGreen dye was embedded into the hairpin stem, and the fluorescence signal was enhanced. The molecular logic gate was constructed through the establishment of logic histogram, logic circuit, truth table, and logic formula. The biosensor-related performances including sensitivity, selectivity, and linearity were investigated, respectively. Results We have successfully constructed a AND logic gate. The detection limit of ATP is 138.0 pmol/L (3σ/slope) with detection range of 50–500 nmol/L (R2 = 0.98951), and its sensitivity is 4.748 × 106–6.875 × 108 a.u. (mol/L)−1. Conclusions The logic gate hairpin aptamer sensor has the advantages of high sensitivity, low detection limit, and low cost, and can be successfully applied to the detection of adenosine triphosphate (ATP) in actual human urine samples.

Download Full-text

A Label-Free Fluorescent AND Logic Gate Aptasensor for Carbohydrate Antigen 15-3 Detection Based on Graphene Oxide

Combinatorial Chemistry & High Throughput Screening ◽

10.2174/1386207324666210216095053 ◽

2021 ◽

Vol 24 ◽

Author(s):

Wenxiao Hu ◽

Yafei Dong ◽

Luhui Wang ◽

Yue Wang ◽

Mengyao Qian ◽

...

Keyword(s):

Fluorescent Dyes ◽

Logic Gate ◽

High Sensitivity ◽

Carbohydrate Antigen ◽

Fluorescence Signal ◽

Label Free ◽

Molecular Logic ◽

Long Stem ◽

Middle Ring ◽

Fluorescent Aptasensor

Background: Molecular logic gate always used fluorescent dyes to realize fluorescence signal. The labeling of the fluorophore is relatively expensive, low yield and singly labeled impuritiesaffects the affinity between the target and the aptamer. Label-free fluorescent aptamer biosensor strategy has attracted widespread interest due to lower cost and simple. Objective: Herein, we have designed a AND logic gate fluorescent aptasensor for detecting carbohydrate antigen 15-3(CA15-3) based on label-free fluorescence signal output. Materials and Methods: A hairpin DNA probe consists of CA15-3 aptamer and partly anti-CA15-3 aptamer sequences as a long stem and G-rich sequences of the middle ring as a quadruplex-forming oligomer. G-rich sequences can fold into a quadruplex by K+, and then G-quadruplex interacts specifically with N-methylmesoporphyrin IX(NMM), leading to a dramatic increase in fluorescence of NMM. With CA15-3 and NMM as the two inputs, the fluorescence intensity of the NMM is the output signal. Lacking of CA15-3 or NMM, there is no significant fluorescence enhancing, and the output of the signal is “0”. The fluorescence signal was dramatically increasing and the output of the signal is “1” only when CA15-3 protein and NMM were added at the same time. Results: This biosensor strategy possessed selectivity, high sensitivity for detecting CA15-3 protein from 10 to 500 U mL-1 and the detection limit was 10 U mL-1, and also showed good reproducibility in spiked human serum. Conclusion: In summary, the proposed AND logic gate fluorescent aptasensor could specifically detect CA15-3.

Download Full-text

Sensitive and In Situ Hemoglobin Detection Based on a Graphene Oxide Functionalized Microfiber

Nanomaterials ◽

10.3390/nano10122461 ◽

2020 ◽

Vol 10 (12) ◽

pp. 2461

Author(s):

Fang Fang ◽

Yanpeng Li ◽

Liuyang Yang ◽

Liangye Li ◽

Zhijun Yan ◽

...

Keyword(s):

Graphene Oxide ◽

Detection Limit ◽

Light Field ◽

Low Cost ◽

High Sensitivity ◽

Optical Microscope ◽

Wavelength Shift ◽

Compact Structure ◽

Blood Diseases ◽

Evanescent Light

The determination of hemoglobin (Hb) level is indispensable in the pathological study of many blood diseases. Graphene oxide (GO), with its excellent optical properties and great biocompatibility, has attracted significant attention and been widely utilized in biochemical detection. Here, we report an ultrasensitive Hb sensor based on a graphene oxide (GO)-coated microfiber. The GO was utilized as a linking layer deposited on the microfiber surface, which can provide an enhanced local evanescent light field and abundant bonding sites for Hb molecules. The optical microfiber with a compact structure and a strong evanescent light field served as the platform for biosensing. The surface morphology characterized by optical microscope, scanning electron microscope, and Raman spectroscopy offers detailed evidence for the success of GO deposition. The dynamic bonding between GO and target Hb molecules was monitored in real-time through an optical spectrum analyzer. An ultrahigh sensitivity of 6.02 nm/(mg/mL) with a detection limit of 0.17 μg/mL was achieved by tracking the resonant wavelength shift of spectra. It is important to highlight that the detection limit of GO-coated microfiber is 1–2 orders of magnitude lower than other reported fiber optic Hb sensors. Benefiting from high sensitivity, low cost, small size, and fast response, the proposed sensing microfiber coated with GO could be a competitive alternative in the diagnosis of blood diseases and a subject of further research in the medical field.

Download Full-text

Cocaine detection using aptamer and molybdenum disulfide-gold nanoparticle-based sensors

Nanomedicine ◽

10.2217/nnm-2019-0046 ◽

2020 ◽

Vol 15 (4) ◽

pp. 325-335

Author(s):

Li Gao ◽

Wenwen Xiang ◽

Zebin Deng ◽

Keqing Shi ◽

Huixing Wang ◽

...

Keyword(s):

Gold Nanoparticles ◽

Detection Limit ◽

Molybdenum Disulfide ◽

Low Cost ◽

High Sensitivity ◽

Label Free ◽

Sensing System ◽

Plasmon Resonance Band ◽

Resonance Band ◽

Cocaine Detection

Aim: The current work highlighted a novel colorimetric sensor based on aptamer and molybdenum disulfide (MoS2)-gold nanoparticles (AuNPs) that was developed for cocaine detection with high sensitivity. Materials & methods: Due to the presence of the plasmon resonance band on the surface of AuNPs, AuNPs aggregated and the color was changed from red to blue after adding a certain concentration of NaCl. We used MoS2 to optimize the sensing system of AuNPs. The folded conformation of the aptamer in combination with cocaine enhanced the salt tolerance of the MoS2-AuNPs, effectively preventing their aggregation. Results & conclusion: The detection limit of cocaine was 7.49 nM with good selectivity. The method based on MoS2-AuNPs colorimetry sensor is simple, quick, label-free and low cost.

Download Full-text

A Label-Free Fluorescent AND Logic Gate Aptasensor for Sensitive ATP Detection

Sensors ◽

10.3390/s18103281 ◽

2018 ◽

Vol 18 (10) ◽

pp. 3281 ◽

Cited By ~ 1

Author(s):

Jingjing Zhang ◽

Chunzheng Yang ◽

Chaoqun Niu ◽

Chen Liu ◽

Xuepin Cai ◽

...

Keyword(s):

Deoxyribonucleic Acid ◽

Limit Of Detection ◽

Low Cost ◽

Logic Gate ◽

Label Free ◽

Detection Range ◽

Sensitivity Range ◽

Highly Sensitive ◽

Input Signals ◽

Atp Detection

In this study, a label-free fluorescent, enzyme-free, simple, highly sensitive AND logic gate aptasensor was developed for the detection of adenosine triphosphate (ATP). Double-stranded deoxyribonucleic acid (DNA) with cohesive ends was attached to graphene oxide (GO) to form an aptasensor probe. ATP and single-stranded DNA were used as input signals. Fluorescence intensity of PicoGreen dye was used as an output signal. The biosensor-related performances, including the logic gate construction, reaction time, linearity, sensitivity, and specificity, were investigated and the results showed that an AND logic gate was successfully constructed. The ATP detection range was found to be 20 to 400 nM (R2 = 0.9943) with limit of detection (LOD) of 142.6 pM, and the sensitivity range was 1.846 × 106 to 2.988 × 106 M−1. This method for the detection of ATP has the characteristics of being simple, low cost, and highly sensitive.

Download Full-text

Integrating high-performing electrochemical transducers in lateral flow assay

Analytical and Bioanalytical Chemistry ◽

10.1007/s00216-021-03301-y ◽

2021 ◽

Author(s):

Antonia Perju ◽

Nongnoot Wongkaew

Keyword(s):

High Performance ◽

Point Of Care ◽

Low Cost ◽

High Sensitivity ◽

Lateral Flow ◽

Analytical Performance ◽

Label Free ◽

High Performing ◽

Lateral Flow Assays ◽

Electrochemical Transducers

AbstractLateral flow assays (LFAs) are the best-performing and best-known point-of-care tests worldwide. Over the last decade, they have experienced an increasing interest by researchers towards improving their analytical performance while maintaining their robust assay platform. Commercially, visual and optical detection strategies dominate, but it is especially the research on integrating electrochemical (EC) approaches that may have a chance to significantly improve an LFA’s performance that is needed in order to detect analytes reliably at lower concentrations than currently possible. In fact, EC-LFAs offer advantages in terms of quantitative determination, low-cost, high sensitivity, and even simple, label-free strategies. Here, the various configurations of EC-LFAs published are summarized and critically evaluated. In short, most of them rely on applying conventional transducers, e.g., screen-printed electrode, to ensure reliability of the assay, and additional advances are afforded by the beneficial features of nanomaterials. It is predicted that these will be further implemented in EC-LFAs as high-performance transducers. Considering the low cost of point-of-care devices, it becomes even more important to also identify strategies that efficiently integrate nanomaterials into EC-LFAs in a high-throughput manner while maintaining their favorable analytical performance.

Download Full-text

An Electrochemically Reduced Copper/Reduced Graphene Oxide Film Modified Electrode for Sensitive Non-Enzymatic Glucose Detection in Human Serum

10.21203/rs.3.rs-264254/v1 ◽

2021 ◽

Author(s):

Sopit Phetsang ◽

Pinit Kidkhunthod ◽

Narong Chanlek ◽

Jaroon Jakmunee ◽

Pitchaya Mungkornasawakul ◽

...

Keyword(s):

Graphene Oxide ◽

Human Serum ◽

Reduced Graphene Oxide ◽

Modified Electrode ◽

Electrocatalytic Activity ◽

Glucose Sensor ◽

Electrochemical Sensors ◽

High Sensitivity ◽

Detection Range ◽

Reduced Graphene

Abstract Numerous studies suggest that modification with functional nanomaterials can enhance the electrode electrocatalytic activity, sensitivity, and selectivity of the electrochemical sensors. Here, a highly sensitive and cost-effective disposable non-enzymatic glucose sensor based on copper(II)/reduced graphene oxide modified screen-printed carbon electrode is demonstrated. Facile fabrication of the developed sensing electrodes is carried out by the adsorption of copper(II) onto graphene oxide modified electrode, then following the electrochemical reduction. The proposed sensor illustrates good electrocatalytic activity toward glucose oxidation with a wide linear detection range from 0.10 mM to 12.5 mM, low detection limit of 65 µM, and high sensitivity of 172 µA mM− 1 cm− 2 along with satisfactory anti-interference ability, reproducibility, stability, and the acceptable recoveries for the detection of glucose in a human serum sample (95.6–106.4%). The copper(II)/reduced graphene oxide based sensor with the superior performances is a great potential for the quantitation of glucose in real samples.

Download Full-text

Quantification of Neuropeptide Y with Picomolar Sensitivity Enabled by Guided-Mode Resonance Biosensors

Sensors ◽

10.3390/s20010126 ◽

2019 ◽

Vol 20 (1) ◽

pp. 126 ◽

Cited By ~ 3

Author(s):

Mohammad G. Abdallah ◽

Joseph A. Buchanan-Vega ◽

Kyu J. Lee ◽

Brett R. Wenner ◽

Jeffery W. Allen ◽

...

Keyword(s):

Neuropeptide Y ◽

Near Infrared ◽

Single Point ◽

High Sensitivity ◽

Quantitative Detection ◽

Label Free ◽

Sensor Surface ◽

Detection Range ◽

Guided Mode ◽

Guided Mode Resonance

Assessing levels of neuropeptide Y (NPY) in the human body has many medical uses. Accordingly, we report the quantitative detection of NPY biomarkers applying guided-mode resonance (GMR) biosensor methodology. The label-free sensor operates in the near-infrared spectral region exhibiting distinctive resonance signatures. The interaction of NPY with bioselective molecules on the sensor surface causes spectral shifts that directly identify the binding event without additional processing. In the experiments described here, NPY antibodies are attached to the sensor surface to impart specificity during operation. For the low concentrations of NPY of interest, we apply a sandwich NPY assay in which the sensor-linked anti-NPY molecule binds with NPY that subsequently binds with anti-NPY to close the sandwich. The sandwich assay achieves a detection limit of ~0.1 pM NPY. The photonic sensor methodology applied here enables expeditious high-throughput data acquisition with high sensitivity and specificity. The entire bioreaction is recorded as a function of time, in contrast to label-based methods with single-point detection. The convenient methodology and results reported are significant, as the NPY detection range of 0.1–10 pM demonstrated is useful in important medical circumstances.

Download Full-text

Label-Free Split Aptamer Sensor for Femtomolar Detection of Dopamine by Means of Flexible Organic Electrochemical Transistors

Materials ◽

10.3390/ma13112577 ◽

2020 ◽

Vol 13 (11) ◽

pp. 2577 ◽

Cited By ~ 5

Author(s):

Yuanying Liang ◽

Ting Guo ◽

Lei Zhou ◽

Andreas Offenhäusser ◽

Dirk Mayer

Keyword(s):

Detection Limit ◽

Electrochemical Sensors ◽

Limit Of Detection ◽

High Sensitivity ◽

Label Free ◽

Dopamine Detection ◽

Electrochemical Transistor ◽

Sensitivity And Selectivity

The detection of chemical messenger molecules, such as neurotransmitters in nervous systems, demands high sensitivity to measure small variations, selectivity to eliminate interferences from analogues, and compliant devices to be minimally invasive to soft tissue. Here, an organic electrochemical transistor (OECT) embedded in a flexible polyimide substrate is utilized as transducer to realize a highly sensitive dopamine aptasensor. A split aptamer is tethered to a gold gate electrode and the analyte binding can be detected optionally either via an amperometric or a potentiometric transducer principle. The amperometric sensor can detect dopamine with a limit of detection of 1 μM, while the novel flexible OECT-based biosensor exhibits an ultralow detection limit down to the concentration of 0.5 fM, which is lower than all previously reported electrochemical sensors for dopamine detection. The low detection limit can be attributed to the intrinsic amplification properties of OECTs. Furthermore, a significant response to dopamine inputs among interfering analogues hallmarks the selective detection capabilities of this sensor. The high sensitivity and selectivity, as well as the flexible properties of the OECT-based aptasensor, are promising features for their integration in neuronal probes for the in vitro or in vivo detection of neurochemical signals.

Download Full-text

Compact Inner-Wall Grating Slot Microring Resonator for Label-Free Sensing

Sensors ◽

10.3390/s19225038 ◽

2019 ◽

Vol 19 (22) ◽

pp. 5038 ◽

Cited By ~ 3

Author(s):

Hongjun Gu ◽

He Gong ◽

Chunxue Wang ◽

Xiaoqiang Sun ◽

Xibin Wang ◽

...

Keyword(s):

Refractive Index ◽

Sodium Chloride ◽

High Sensitivity ◽

Microring Resonator ◽

Silicon On Insulator ◽

Label Free ◽

Detection Range ◽

Sodium Chloride Solutions ◽

Sensing Application ◽

Index Unit

In this paper, we present and analyze a compact inner-wall grating slot microring resonator (IG-SMRR) with the footprint of less than 13 μm × 13 μm on the silicon-on-insulator (SOI) platform for label-free sensing, which comprises a slot microring resonator (SMRR) and inner-wall grating (IG). Its detection range is significantly enhanced without the limitation of the free spectral region (FSR) owing to the combination of SMRR and IG. The IG-SMRR has an ultra-large quasi-FSR of 84.5 nm as the detection range, and enlarged factor is up to over 3 compared with the conventional SMRR. The concentration sensitivities of sodium chloride solutions and D-glucose solutions are 996.91 pm/% and 968.05 pm/%, respectively, and the corresponding refractive index (RI) sensitivities are 559.5 nm/RIU (refractive index unit) and 558.3 nm/RIU, respectively. The investigation on the combination of SMRR and IG is a valuable exploration of label-free sensing application for ultra-large detection range and ultra-high sensitivity in future.

Download Full-text

Improved Detection of Hg2+ in Aqueous Solution with High Sensitivity and Selectivity by Using Mercury-Specific DNA, Sybr Green I and Gold Nanoparticles

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.239-242.934 ◽

2011 ◽

Vol 239-242 ◽

pp. 934-939

Author(s):

Hui Xu ◽

Shuli Gao ◽

Jian Nong Chen ◽

Quan Wen Liu

Keyword(s):

Gold Nanoparticles ◽

High Sensitivity ◽

Sybr Green ◽

Sybr Green I ◽

Fluorescence Signal ◽

Potassium Ions ◽

Label Free ◽

Turn On ◽

Sensitivity And Selectivity ◽

Fluorescence Turn On

We report a label-free, fast, fluorescence turn on assay for Hg2+detecton by using mercury-specific DNA (MSD), Sybr Green I (SG) and gold nanoparticles (AuNPs). SG efficiently discriminates MSD and MSD/Hg2+complex. The addition of gold nanoparticle decreases the background fluorescence signal further for MSD. The fluorescence intensity of MSD/Hg2+complex keeps constant after addition of AuNPs. This property improves the signal-to-background ratio and decreases the detection limitation further. In addition, the method shows improved selectivity compared with that in the absence of AuNPs. This strategy could be applied to the detection of potassium ions and showed good generality.

Download Full-text