scholarly journals Advances in Label-Free Detections for Nanofluidic Analytical Devices

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 885 ◽  
Author(s):  
Thu Le ◽  
Hisashi Shimizu ◽  
Kyojiro Morikawa
Keyword(s):  
Single Molecule ◽  
Detection Methods ◽  
Label Free ◽  
Practical Applications ◽  
Detection Techniques ◽  
Kinetic Information ◽  
Label Free Detection ◽  
Nanofluidic Devices ◽  
Nanofluidic Device ◽  
New Research

Nanofluidics, a discipline of science and engineering of fluids confined to structures at the 1–1000 nm scale, has experienced significant growth over the past decade. Nanofluidics have offered fascinating platforms for chemical and biological analyses by exploiting the unique characteristics of liquids and molecules confined in nanospaces; however, the difficulty to detect molecules in extremely small spaces hampers the practical applications of nanofluidic devices. Laser-induced fluorescence microscopy with single-molecule sensitivity has been so far a major detection method in nanofluidics, but issues arising from labeling and photobleaching limit its application. Recently, numerous label-free detection methods have been developed to identify and determine the number of molecules, as well as provide chemical, conformational, and kinetic information of molecules. This review focuses on label-free detection techniques designed for nanofluidics; these techniques are divided into two groups: optical and electrical/electrochemical detection methods. In this review, we discuss on the developed nanofluidic device architectures, elucidate the mechanisms by which the utilization of nanofluidics in manipulating molecules and controlling light–matter interactions enhances the capabilities of biological and chemical analyses, and highlight new research directions in the field of detections in nanofluidics.

scholarly journals Affinity Sensors for the Diagnosis of COVID-19

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 390
Author(s):  
Maryia Drobysh ◽  
Almira Ramanaviciene ◽  
Roman Viter ◽  
Arunas Ramanavicius
Keyword(s):  
Field Effect Transistors ◽  
Resonance Field ◽  
Analytical Signal ◽  
Nucleic Acid Hybridization ◽  
Detection Methods ◽  
Label Free ◽  
Infected People ◽  
Label Free Detection ◽  
Main Instrument ◽  
Antigen Antibody

The coronavirus disease 2019 (COVID-19) outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was proclaimed a global pandemic in March 2020. Reducing the dissemination rate, in particular by tracking the infected people and their contacts, is the main instrument against infection spreading. Therefore, the creation and implementation of fast, reliable and responsive methods suitable for the diagnosis of COVID-19 are required. These needs can be fulfilled using affinity sensors, which differ in applied detection methods and markers that are generating analytical signals. Recently, nucleic acid hybridization, antigen-antibody interaction, and change of reactive oxygen species (ROS) level are mostly used for the generation of analytical signals, which can be accurately measured by electrochemical, optical, surface plasmon resonance, field-effect transistors, and some other methods and transducers. Electrochemical biosensors are the most consistent with the general trend towards, acceleration, and simplification of the bioanalytical process. These biosensors mostly are based on the determination of antigen-antibody interaction and are robust, sensitive, accurate, and sometimes enable label-free detection of an analyte. Along with the specification of biosensors, we also provide a brief overview of generally used testing techniques, and the description of the structure, life cycle and immune host response to SARS-CoV-2, and some deeper details of analytical signal detection principles.

scholarly journals Biological Nanopores: Engineering on Demand

Life ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 27
Author(s):  
Ana Crnković ◽  
Marija Srnko ◽  
Gregor Anderluh
Keyword(s):  
Molecular Biology ◽  
Single Molecule ◽  
Enzymatic Reactions ◽  
Label Free ◽  
Natural Sources ◽  
On Demand ◽  
Label Free Detection ◽  
Long Read ◽  
Inorganic Molecules ◽  
Standard Molecular Biology

Nanopore-based sensing is a powerful technique for the detection of diverse organic and inorganic molecules, long-read sequencing of nucleic acids, and single-molecule analyses of enzymatic reactions. Selected from natural sources, protein-based nanopores enable rapid, label-free detection of analytes. Furthermore, these proteins are easy to produce, form pores with defined sizes, and can be easily manipulated with standard molecular biology techniques. The range of possible analytes can be extended by using externally added adapter molecules. Here, we provide an overview of current nanopore applications with a focus on engineering strategies and solutions.

scholarly journals Label-free detection techniques for protein microarrays: Prospects, merits and challenges

PROTEOMICS ◽  
2009 ◽  
Vol 10 (4) ◽  
pp. 731-748 ◽  
Author(s):  
Sandipan Ray ◽  
Gunjan Mehta ◽  
Sanjeeva Srivastava
Keyword(s):  
Protein Microarrays ◽  
Label Free ◽  
Detection Techniques ◽  
Label Free Detection

scholarly journals Single-Molecule Detection of DNA in a Nanochannel by High-Field Strength-Assisted Electrical Impedance Spectroscopy

Micromachines ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 189 ◽  
Author(s):  
Porpin Pungetmongkol ◽  
Takatoki Yamamoto
Keyword(s):  
Single Molecule ◽  
High Intensity ◽  
High Sensitivity ◽  
Electrical Impedance Spectroscopy ◽  
Random Coil ◽  
Label Free ◽  
Electrode Gap ◽  
Label Free Detection ◽  
Intensity Field ◽  
Nanogap Electrodes

Many researchers have fabricated micro and nanofluidic devices incorporating optical, chemical, and electrical detection systems with the aim of achieving on-chip analysis of macromolecules. The present study demonstrates a label-free detection of DNA using a nanofluidic device based on impedance measurements that is both sensitive and simple to operate. Using this device, the electrophoresis and dielectrophoresis effect on DNA conformation and the length dependence were examined. A low alternating voltage was applied to the nanogap electrodes to generate a high intensity field (>0.5 MV/m) under non-faradaic conditions. In addition, a 100 nm thick gold electrode was completely embedded in the substrate to allow direct measurements of a solution containing the sample passing through the gap, without any surface modification required. The high intensity field in this device produced a dielectrophoretic force that stretched the DNA molecule across the electrode gap at a specific frequency, based on back and forth movements between the electrodes with the DNA in a random coil conformation. The characteristics of 100 bp, 500 bp, 1 kbp, 5 kbp, 10 kbp, and 48 kbp λ DNA associated with various conformations were quantitatively analyzed with high resolution (on the femtomolar level). The sensitivity of this system was found to be more than about 10 orders of magnitude higher than that obtained from conventional linear alternating current (AC) impedance for the analysis of bio-polymers. This new high-sensitivity process is expected to be advantageous with regard to the study of complex macromolecules and nanoparticles.

scholarly journals Electrochemical DNA Detection Methods to Measure Circulating Tumour DNA for Enhanced Diagnosis and Monitoring of Cancer

Proceedings ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 15
Author(s):  
Bukola Attoye ◽  
Matthew Baker ◽  
Chantevy Pou ◽  
Fiona Thomson ◽  
Damion K. Corrigan
Keyword(s):  
Point Of Care ◽  
Low Cost ◽  
Detection Methods ◽  
Clinical Samples ◽  
Label Free ◽  
Ambient Conditions ◽  
Liquid Biopsies ◽  
Current Time ◽  
Electrochemical Approach ◽  
Label Free Detection

Liquid biopsies are becoming increasingly important as a potential replacement for existing biopsy procedures which can be invasive, painful and compromised by tumour heterogeneity. This paper reports a simple electrochemical approach tailored towards point-of-care cancer detection and treatment monitoring from biofluids using a label-free detection strategy. The mutations under test were the KRAS G12D and G13D mutations, which are both important in the development and progression of many human cancers and which have a presence that correlates with poor outcomes. These common circulating tumour markers were investigated in clinical samples and amplified by standard and specialist PCR methodologies for subsequent electrochemical detection. Following pre-treatment of the sensor to present a clean surface, DNA probes developed specifically for detection of the KRAS G12D and G13D mutations were immobilized onto low-cost carbon electrodes using diazonium chemistry and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride/N-hydroxysuccinimide coupling. Following the functionalisation of the sensor, it was possible to sensitively and specifically detect a mutant KRAS G13D PCR product against a background of wild-type KRAS DNA from the representative cancer sample. Our findings give rise to the basis of a simple and very low-cost system for measuring ctDNA biomarkers in patient samples. The current time to result of the system was 3.5 h with considerable scope for optimisation, and it already compares favourably to the UK National Health Service biopsy service where patients can wait weeks for their result. This paper reports the technical developments we made in the production of consistent carbon surfaces for functionalisation, assay performance data for KRAS G13D and detection of PCR amplicons under ambient conditions.

scholarly journals Silicene Quantum Capacitance Dependent Frequency Readout to a Label-free Detection of DNA Hybridization

2021 ◽  
Author(s):  
Sazzadur Rahman ◽  
Rokaia Laizu Naima ◽  
Khatuna Jannatun Shetu ◽  
Mahabub Hossain ◽  
M. Shamim Kaiser ◽  
...  
Keyword(s):  
Band Gap ◽  
Dna Hybridization ◽  
Glucose Sensor ◽  
Detection Method ◽  
Genetic Research ◽  
Ph Sensor ◽  
Detection Methods ◽  
Quantum Capacitance ◽  
Label Free ◽  
Label Free Detection

Two-dimensional silicon allotrodes– also called Sinicene– have recently experienced intensive scientific research interest due to their unique electrical, mechanical, and sensing characteristics. A novel silicene based nano-material has been enticed great amenities, partially because of its uniformity with graphene. Silicene is a highly sensitive for numerous sensors based on molecular sensing as pH sensor, gas sensor, ion sensor and biosensing are Deoxyribonucleic acid (DNA) nucleobase sensor, photonic sensor, cell-based biosensor, glucose sensor, and bioelectric nose sensor. Nowadays genetic research based on DNA hybridization, which is a vital tools for sensing material and it has various detection methods. Among of them, the detection method is frequency readout used to a label-free detection of DNA hybridization. In this paper we have compared the graphene and silicene quantum capacitance that has been proposed for a DNA hybridization detection method on wireless readout. These method shows, the strands of mismatched and complementary DNA have in different range of frequency to identify output efficiency. With respect to DNA concentration the output of silicene is almost sharply linear than graphene. In addition of field effect transistor, silicene opens a new opportunities due to its band gap whereas graphene indicates zero band gap. It can be stated that silicene is much more reliable as well as much stronger than multi-layered graphene.

Bifunctional Nanoparticles as a Recyclable Fluorescent Sensor for pH and Cu2+ Detection and Removal of Heavy Metal Ions

NANO ◽  
2020 ◽  
Vol 15 (04) ◽  
pp. 2050048
Author(s):  
Yong Qian ◽  
Xiangfu Meng ◽  
Hongji Liu ◽  
Xingyu Wang ◽  
Hui Wang
Keyword(s):  
Aqueous Solution ◽  
Heavy Metal Ions ◽  
High Efficiency ◽  
Fluorescent Sensor ◽  
High Sensitivity ◽  
Label Free ◽  
Practical Applications ◽  
Surrounding Environment ◽  
Label Free Detection ◽  
Recyclable Adsorbent

Magnetic and fluorescent-based sensors have demonstrated widely applications due to their easily recycle and quickly optical response. However, the complex synthesis and weaker function of these sensors limit their practical applications. Herein, an unmodified, magnetic-functionalized carbon dots-based fluorescent sensor has been developed for label-free detection of pH and Cu[Formula: see text] with high sensitivity. The sensors can not only reversibly quench and recover the fluorescence signals in response to the variation of surrounding environment including pH and Cu[Formula: see text], but also be used as a high-efficiency recyclable adsorbent for removing Cu[Formula: see text], Hg[Formula: see text], Cr[Formula: see text] and Pb[Formula: see text] from aqueous solution.

scholarly journals An Aptamer-Based Biosensor for Direct, Label-Free Detection of Melamine in Raw Milk

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3227 ◽  
Author(s):  
Naoto Kaneko ◽  
Katsunori Horii ◽  
Joe Akitomi ◽  
Shintaro Kato ◽  
Ikuo Shiratori ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Background Noise ◽  
Colorimetric Detection ◽  
Raw Milk ◽  
Detection Methods ◽  
Label Free ◽  
Label Free Detection ◽  
High Concentrations ◽  
Direct Label ◽  
Urinary Problems

Melamine, a nitrogen-rich compound, has been used as a food and milk additive to falsely increase the protein content. However, melamine is toxic, and high melamine levels in food or in milk can cause kidney and urinary problems, or even death. Hence, the detection of melamine in food and milk is desirable, for which numerous detection methods have been developed. Several methods have successfully detected melamine in raw milk; however, they require a sample preparation before the analyses. This study aimed to develop an aptamer-DNAzyme conjugated biosensor for label-free detection of melamine, in raw milk, without any sample preparation. An aptamer-DNAzyme conjugated biosensor was developed via screening using microarray analysis to identify the candidate aptamers followed by an optimization, to reduce the background noise and improve the aptamer properties, thereby, enhancing the signal-to-noise (S/N) ratio of the screened biosensor. The developed biosensor was evaluated via colorimetric detection and tested with raw milk without any sample preparation, using N-methylmesoporphyrin IX for fluorescence detection. The biosensor displayed significantly higher signal intensity at 2 mM melamine (S/N ratio, 20.2), which was sufficient to detect melamine at high concentrations, in raw milk.

scholarly journals Using Laser Interference Lithography in the Fabrication of a Simplified Micro- and Nanofluidic Device for Label-free Detection

2017 ◽  
Vol 33 (10) ◽  
pp. 1197-1199 ◽  
Author(s):  
Taiga AJIRI ◽  
Haruya KASA ◽  
Masatoshi MAEKI ◽  
Akihiko ISHIDA ◽  
Hirofumi TANI ◽  
...  
Keyword(s):  
Interference Lithography ◽  
Laser Interference Lithography ◽  
Label Free ◽  
Laser Interference ◽  
Label Free Detection ◽  
Nanofluidic Device

A nanofluidic device for ultrasensitive and label-free detection of tetracycline in association with γ-cyclodextrin and GO

2021 ◽  
Vol 13 (15) ◽  
pp. 1832-1838
Author(s):  
Jiaxi Cheng ◽  
Fenghua Jiang ◽  
Siqi Zhang
Keyword(s):  
Detection Limit ◽  
Water Samples ◽  
Recovery Rate ◽  
Label Free ◽  
Detection Range ◽  
Low Detection Limit ◽  
Sensing Platform ◽  
Label Free Detection ◽  
Nanofluidic Device

We develop a label-free, sensitive and selective nanochannel sensing platform for detection of TC. The nanosensor provided a low detection limit, a wide detection range and excellent recovery rate in different water samples.

Sign in / Sign up

Export Citation Format

Share Document