scholarly journals Optical Fiber Gratings Immunoassays

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2595 ◽  
Author(s):  
Médéric Loyez ◽  
Maxime Lobry ◽  
Ruddy Wattiez ◽  
Christophe Caucheteur
Keyword(s):  
Optical Fibers ◽  
Limit Of Detection ◽  
Ex Vivo ◽  
Point Of Care ◽  
Label Free ◽  
Intrinsic Properties ◽  
Fiber Gratings ◽  
The Core ◽  
Low Concentrations ◽  
Highly Sensitive

Optical fibers are of growing interest for biosensing, especially for point-of-care and biomedical assays. Their intrinsic properties bestow them sought-after assets for the detection of low concentrations of analytes. Tilted fiber Bragg gratings (TFBGs) photo-inscribed in the core of telecommunication-grade optical fibers are known to be highly-sensitive refractometers. In this work, we present different strategies to use them for label-free immunoassays. Bare, gold-sputtered, gold-electroless-plated (ELP) and hybrid configurations are biofunctionalized with antibodies, aiming at the detection of cancer biomarkers. We discuss the relative performances of the tested configurations and show that each leads to singular key features, which therefore drives their selection as a function of the target application. The most sensitive configuration presents a limit of detection of 10−12 g/mL in laboratory settings and was successfully used ex vivo in freshly resected lung tissues.

scholarly journals Trends in the Design of Intensity-Based Optical Fiber Biosensors (2010–2020)

Biosensors ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 197
Author(s):  
Nerea De Acha ◽  
Abián B. Socorro-Leránoz ◽  
César Elosúa ◽  
Ignacio R. Matías
Keyword(s):  
Optical Fiber ◽  
Limit Of Detection ◽  
Early Stage ◽  
Point Of Care ◽  
Research Groups ◽  
Fiber Sensors ◽  
Environment Quality ◽  
Low Concentrations ◽  
Highly Sensitive ◽  
Fiber Dimensions

There exists an increasing interest in monitoring low concentrations of biochemical species, as they allow the early-stage detection of illnesses or the monitoring of the environment quality. Thus, both companies and research groups are focused on the development of accurate, fast and highly sensitive biosensors. Optical fiber sensors have been widely employed for these purposes because they provide several advantages for their use in point-of-care and real-time applications. In particular, this review is focused on optical fiber biosensors based on luminescence and absorption. Apart from the key parameters that determine the performance of a sensor (limit of detection, sensibility, cross-sensibility, etc.), other features are analyzed, such as the optical fiber dimensions, the sensing set ups and the fiber functionalization. The aim of this review is to have a comprehensive insight of the different aspects that must be taken into account when working with this kind of sensors.

scholarly journals Demonstration of a Label-Free and Low-Cost Optical Cavity-Based Biosensor Using Streptavidin and C-Reactive Protein

Biosensors ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 4
Author(s):  
Donggee Rho ◽  
Seunghyun Kim
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Optical Cavity ◽  
Sample Volume ◽  
Small Sample ◽  
Label Free ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
Cavity Structure

An optical cavity-based biosensor (OCB) has been developed for point-of-care (POC) applications. This label-free biosensor employs low-cost components and simple fabrication processes to lower the overall cost while achieving high sensitivity using a differential detection method. To experimentally demonstrate its limit of detection (LOD), we conducted biosensing experiments with streptavidin and C-reactive protein (CRP). The optical cavity structure was optimized further for better sensitivity and easier fluid control. We utilized the polymer swelling property to fine-tune the optical cavity width, which significantly improved the success rate to produce measurable samples. Four different concentrations of streptavidin were tested in triplicate, and the LOD of the OCB was determined to be 1.35 nM. The OCB also successfully detected three different concentrations of human CRP using biotinylated CRP antibody. The LOD for CRP detection was 377 pM. All measurements were done using a small sample volume of 15 µL within 30 min. By reducing the sensing area, improving the functionalization and passivation processes, and increasing the sample volume, the LOD of the OCB are estimated to be reduced further to the femto-molar range. Overall, the demonstrated capability of the OCB in the present work shows great potential to be used as a promising POC biosensor.

A Highly Sensitive and Label-Free Microbead-Based ‘Turn-On’ Colorimetric Sensor for the Detection of Mercury(II) in Urine Using a Peroxidase-Like Split G-Quadruplex–Hemin DNAzyme

2018 ◽  
Vol 71 (12) ◽  
pp. 945
Author(s):  
Xin Fu ◽  
He Zhang ◽  
Jie Zhang ◽  
Shi-Tong Wen ◽  
Xing-Cheng Deng
Keyword(s):  
Standard Deviation ◽  
Base Pair ◽  
Limit Of Detection ◽  
Label Free ◽  
Turn On ◽  
Highly Sensitive ◽  
Relative Standard ◽  
G Quadruplex ◽  
Catalytically Active ◽  
Partial Cdna

A highly sensitive and label-free microbead-based ‘turn-on’ assay was developed for the detection of Hg2+ in urine based on the Hg2+-mediated formation of intermolecular split G-quadruplex–hemin DNAzymes. In the presence of Hg2+, T–T mismatches between the two partial cDNA strands were stabilized by a T–Hg2+–T base pair, and can cause the G-rich sequences of the two oligonucleotides to associate to form a split G-quadruplex which is able to bind hemin to form the catalytically active G-quadruplex–hemin DNAzyme. This microbead-based ‘turn-on’ process allows the detection of Hg2+ in urine samples at concentrations as low as 0.5 pM. The relative standard deviation and recovery are 1.2–3.9 and 98.7–103.2%, respectively. The remarkable sensitivity for Hg2+ is mainly attributed to the enhanced mass transport ability that is inherent in homogeneous microbead-based assays. Compared with previous developments of intermolecular split G-quardruplex–hemin DNAzymes for the homogeneous detection of Hg2+ (the limit of detection was 19nM), a signal enhancement of ~1000 times is obtained when such an assay is performed on the surface of microbeads.

scholarly journals Immunosensor Based on Long-Period Fiber Gratings for Detection of Viruses Causing Gastroenteritis

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 813 ◽  
Author(s):  
Marta Janczuk-Richter ◽  
Beata Gromadzka ◽  
Łukasz Richter ◽  
Mirosława Panasiuk ◽  
Karolina Zimmer ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Medical Diagnostics ◽  
Label Free ◽  
Fiber Gratings ◽  
Fast Detection ◽  
Long Period ◽  
Highly Sensitive ◽  
Protein Receptors ◽  
Long Period Fiber Gratings ◽  
Vaccine Testing

Since the norovirus is the main cause of acute gastroenteritis all over the world, its fast detection is crucial in medical diagnostics. In this work, a rapid, sensitive, and selective optical fiber biosensor for the detection of norovirus virus-like particles (VLPs) is reported. The sensor is based on highly sensitive long-period fiber gratings (LPFGs) coated with antibodies against the main coat protein of the norovirus. Several modification methods were verified to obtain reliable immobilization of protein receptors on the LPFG surface. We were able to detect 1 ng/mL norovirus VLPs in a 40-min assay in a label-free manner. Thanks to the application of an optical fiber as the sensor, there is a possibility to increase the user’s safety by separating the measurement point from the signal processing setup. Moreover, our sensor is small and light, and the proposed assay is straightforward. The designed LPFG-based biosensor could be applied in both fast norovirus detection and in vaccine testing.

scholarly journals Design and Development of Graphene FET Biosensor for the Detection of SARS-CoV-2

2021 ◽  
Author(s):  
B. Vamsi Krsihna ◽  
Shaik Ahmadsaidulu ◽  
Surapaneni Sai Tarun Teja ◽  
D Jayanthi ◽  
Alluri Navaneetha ◽  
...  
Keyword(s):  
Field Effect Transistor ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Drain Current ◽  
Label Free ◽  
Reduced Graphene ◽  
The World ◽  
Progressive Respiratory Failure ◽  
Effect Transistor ◽  
Graphene Fet

Abstract The most affected disease in recent years is Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-COV-2) that is notable as COVID-19. It has been started as a disease in one place and arisen as a pandemic throughout the world. A serious health problem is developed in the lungs due to the effect of this coronavirus. Sometimes it may result in death as a consequence of extensive alveolar damage and progressive respiratory failure. Hence, early detection and appropriate diagnosis of corona virus in patient’s body is very essential to save the lives of affected patients This work evolves a Silicon (Si) based label-free electrical device i.e. the reduced graphene oxide field-effect transistor (rGO FET) for SARS-CoV-2 detection. Firstly rGO FET functionalized with SARS-CoV-2 monoclonal antibodies (mAbs). Then the rGO FET characteristic response is observed to detect the antibody-antigen reaction of SARS-CoV-2 with different molar ranges. The developed GFET shows better performance towards the drain current and limit-of-detection (LoD) up to 2E-18 M. Therefore, we believe that an intense response was observed than the earlier developed devices and signifies impressive capability for subsequent implementation in point-of-care (PoC) diagnostic tests.

scholarly journals Label-Free Colorimetric Detection of Urine Glucose Based on Color Fading Using Smartphone Ambient-Light Sensor

Chemosensors ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 10 ◽  
Author(s):  
Wang ◽  
Guo ◽  
Hu ◽  
Liang ◽  
Li ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Point Of Care ◽  
Colorimetric Detection ◽  
Diabetic Patients ◽  
Ambient Light ◽  
Label Free ◽  
Urine Glucose ◽  
Light Sensor

In this work, a label-free colorimetric assay was developed for the determination of urine glucose using smartphone ambient-light sensor (ALS). Using horseradish peroxidase—hydrogen peroxide—3,3′,5,5′-tetramethylbenzidine (HRP-H2O2-TMB) colored system, quantitative H2O2 was added to samples to-be-determined for deepest color. The presence of glucose oxidase in urine led to the formation of H2O2 and the reduction of TMBred. As a result of this, the color of the urine faded and the solution changed from deep blue to light blue. We measured the illuminance of the transmitted light by a smartphone ambient light sensor, and thereby color changes were used to calculate the content of urine glucose. After method validation, this colorimetric assay was practically applied for the determination of urine samples from diabetic patients. Good linearity was obtained in the range of 0.039–10.000 mg/mL (R2 = 0.998), and a limit of detection was 0.005 mg/mL. Our method was had high accuracy, sensitivity, simplicity, rapidity, and visualization, providing a new sensor to be potentially applicable for point-of-care detection of urine glucose.

scholarly journals Analytical validation of a highly sensitive point-of-care system for cardiac troponin I determination

2019 ◽  
Vol 58 (1) ◽  
pp. 138-145 ◽  
Author(s):  
Federica Braga ◽  
Elena Aloisio ◽  
Andrea Panzeri ◽  
Takahito Nakagawa ◽  
Mauro Panteghini
Keyword(s):  
Cardiac Troponin ◽  
Troponin I ◽  
Limit Of Detection ◽  
Clinical Performance ◽  
Point Of Care ◽  
Total Error ◽  
Method Comparison ◽  
Reference Limit ◽  
Highly Sensitive ◽  
Limit Of Quantitation

Abstract Background Highly sensitive cardiac troponin assays (hs-cTn) are not available as point-of-care (POC) measurements. As rapid testing cannot be achieved at the expense of clinical performance, there is an urgent need to develop and rigorously validate POC hs-cTn. Konica Minolta (KM) has recently developed a surface plasmon-field enhanced fluorescence spectroscopy-based POC hs-cTn I system. Methods We validated the analytical characteristics of the KM POC system according to the international guidelines. Results Limit of blank (LoB) and limit of detection (LoD) were 0.35 and 0.62 ng/L, respectively, hs-cTn I concentrations corresponding to a total CV of 20%, 10% and 5% were 1.5, 3.9 and 11.0 ng/L, respectively. Method comparison studies showed that KM calibration was successfully traced to higher-order references. Limit of quantitation (LoQ), i.e. the hs-cTn I concentration having a total error of measurement of ≤34%, was 10.0 ng/L. The upper reference limit (URL) for 600 healthy blood donors was calculated at 12.2 ng/L (90% confidence interval [CI]: 9.2–39.2), while sex-partitioned URLs were 20.6 (males) and 10.7 ng/L (females), respectively (p < 0.0001). KM assay measured hs-cTn I concentrations >LoD in 65.7% of all reference individuals, in 76.7% of males and in 54.7% of females, respectively. Conclusions The KM system joins the characteristics of POC systems to the analytical performance of hs-cTn.

scholarly journals Recent Advances of Field-Effect Transistor Technology for Infectious Diseases

Biosensors ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 103
Author(s):  
Abbas Panahi ◽  
Deniz Sadighbayan ◽  
Saghi Forouhi ◽  
Ebrahim Ghafar-Zadeh
Keyword(s):  
Infectious Diseases ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Limit Of Detection ◽  
Point Of Care ◽  
High Sensitivity ◽  
Cmos Technology ◽  
Oxide Semiconductor ◽  
Label Free ◽  
Effect Transistor

Field-effect transistor (FET) biosensors have been intensively researched toward label-free biomolecule sensing for different disease screening applications. High sensitivity, incredible miniaturization capability, promising extremely low minimum limit of detection (LoD) at the molecular level, integration with complementary metal oxide semiconductor (CMOS) technology and last but not least label-free operation were amongst the predominant motives for highlighting these sensors in the biosensor community. Although there are various diseases targeted by FET sensors for detection, infectious diseases are still the most demanding sector that needs higher precision in detection and integration for the realization of the diagnosis at the point of care (PoC). The COVID-19 pandemic, nevertheless, was an example of the escalated situation in terms of worldwide desperate need for fast, specific and reliable home test PoC devices for the timely screening of huge numbers of people to restrict the disease from further spread. This need spawned a wave of innovative approaches for early detection of COVID-19 antibodies in human swab or blood amongst which the FET biosensing gained much more attention due to their extraordinary LoD down to femtomolar (fM) with the comparatively faster response time. As the FET sensors are promising novel PoC devices with application in early diagnosis of various diseases and especially infectious diseases, in this research, we have reviewed the recent progress on developing FET sensors for infectious diseases diagnosis accompanied with a thorough discussion on the structure of Chem/BioFET sensors and the readout circuitry for output signal processing. This approach would help engineers and biologists to gain enough knowledge to initiate their design for accelerated innovations in response to the need for more efficient management of infectious diseases like COVID-19.

scholarly journals Highly Sensitive Electrochemical Sensor for Diagnosis of Diabetic Ketoacidosis (DKA) by Measuring Ketone Bodies in Urine

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4902
Author(s):  
Anna Go ◽  
Sung Ryul Park ◽  
Yejin Ku ◽  
Mingge Sun ◽  
Sangho Yeon ◽  
...  
Keyword(s):  
Ketone Bodies ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Modified Electrodes ◽  
Electrochemical Measurement ◽  
Clinical Results ◽  
Current Increase ◽  
Sensing Material ◽  
Highly Sensitive ◽  
Good Agreement

In this report, we present an enzyme deposited Au electrode for an electrochemical measurement of acetylacetic acid (AcAc) in urine. The electrode has an immobilized layer of a mixture of D-β-hydroxybutyrate dehydrogenase (HBDH) and nicotinamide adenine dinucleotide (NADH) as sensing material to investigate its electroanalytical properties by means of cyclic voltammetry (CV). The modified electrodes are used for the detection of AcAc and present a linear current increase when the AcAc concentration increases. The electrode presents a limit of detection (LOD) of 6.25 mg/dL in the range of 6.25–100 mg/dL for investigation of clinical relevance. Finally, the electrode was evaluated using 20 patient samples. The measured results of urine ketone by the developed electrode were compared with the clinical results from a commercial kit, and the analysis showed good agreement. The proposed electrode was demonstrated to be a very promising platform as a miniaturized electrochemical analyzer for point-of-care monitoring of the critical biochemical parameters such as urine ketone.

Companion and Point-of-Care Sensor System for Rapid Multiplexed Detection of a Panel of Infectious Disease Markers

2017 ◽  
pp. 247263031769677
Author(s):  
Anjan Panneer Selvam ◽  
Shalini Prasad
Keyword(s):  
Whole Blood ◽  
Dynamic Range ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Lipoteichoic Acid ◽  
Impedance Change ◽  
Label Free ◽  
Nylon Membrane ◽  
Multiplexed Detection

A nanochannel-based electrochemical biosensor has been demonstrated for rapid and multiplexed detection of a panel of three biomarkers associated with rapid detection of sepsis. The label-free biosensor detected procalcitonin (PCT), lipoteichoic acid (LTA), and lipopolysaccharide (LPS) from human whole blood. The biosensor comprises a nanoporous nylon membrane integrated onto a microelectrode sensor platform for nanoconfinement effects. Charge perturbations due to biomarker binding are recorded as impedance changes using electrochemical impedance spectroscopy. The measured impedance change is used to quantitatively determine the concentration of the three biomarkers using antibody receptors from the tested sample. We were successful in detecting and quantifying the three biomarkers from whole blood. The limit of detection was 0.1 ng/mL for PCT and 1 µg/mL for LPS and LTA. The sensor was able to demonstrate a dynamic range of detection from 01.1 ng/mL to 10 µg/mL for PCT and from 1 µg/mL to 1000 µg/mL for LPS and LTA biomarkers. This novel technology has promising preliminary results toward the design of sensors for rapid and sensitive detection of the three panel biomarkers in whole blood toward diagnosis and classification of sepsis.

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