Fabrication of Precise Asymmetric Nanoshells Array with Nanogaps for a Label-Free Immunoassay Based on NIR-Light Responsive LSPR

2012 ◽  
Vol 523-524 ◽  
pp. 680-685
Author(s):  
Shuhei Uchida ◽  
Kazuya Yamamura ◽  
Nobuyuki Zettsu
Keyword(s):  
Near Infrared ◽  
Atmospheric Pressure Plasma ◽  
High Sensitivity ◽  
Medical Diagnostics ◽  
Localized Surface Plasmon ◽  
Label Free ◽  
Fabrication Technique ◽  
Alternative Structures ◽  
Wide Range ◽  
Surrounding Refractive Index

Localized surface plasmon resonance (LSPR) based sensors are a well established technology utilized for label-free biochemical sensing in immunoassay, medical diagnostics and environmental monitoring. The understanding of asymmetric metal nanoparticles, new object for complex, coupled plasmon systems providing localized significantly enhanced E-field, is central to a wide range of novel applications and processes in science of higher sensitive sensing systems. However, few methods are available for actual characterization of such nanostructures at the single particle level. Here we propose a precise and large sized scale fabrication technique for asymmetric nanoshells array with nanogaps of several tens of nanometers for LSPR sensor through atmospheric pressure plasma etching processes. A nanoshell was simply constructed by laminating thin Au films on periodic isolated polymer nanoparticles template. This nanoshells array was expected to exhibit specific near-infrared plasmonic properties. When measuring the sensitivity, nanoshells array exhibited a high sensitivity to changes of surrounding refractive index and showed a higher sensor figure of merit than the alternative structures. This indicated that the enhanced plasmon E-field in the asymmetric nanostructures improved sensor performance. Our fabrication technique and the optical properties of the arrays will provide useful information for developing new plasmonic applications.

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

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 126 ◽  
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.

scholarly journals Perfect Dual-Band Absorber Based on Plasmonic Effect with the Cross-Hair/Nanorod Combination

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 493 ◽  
Author(s):  
Yuan-Fong Chou Chau ◽  
Chung-Ting Chou Chao ◽  
Hung Ji Huang ◽  
Muhammad Raziq Rahimi Kooh ◽  
N. T. R. N. Kumara ◽  
...  
Keyword(s):  
Figure Of Merit ◽  
Near Infrared ◽  
High Sensitivity ◽  
Dual Band ◽  
Localized Surface Plasmon ◽  
Perfect Absorber ◽  
Plasmonic Effect ◽  
Plasmonic Sensor ◽  
Nanophotonic Devices ◽  
The Cross

Plasmonic effect using a cross-hair can convey strongly localized surface plasmon modes among the separated composite nanostructures. Compared to its counterpart without the cross-hair, this characteristic has the remarkable merit of enhancing absorptance at resonance and can make the structure carry out a dual-band plasmonic perfect absorber (PPA). In this paper, we propose and design a novel dual-band PPA with a gathering of four metal-shell nanorods using a cross-hair operating at visible and near-infrared regions. Two absorptance peaks at 1050 nm and 750 nm with maximal absorptance of 99.59% and 99.89% for modes 1 and 2, respectively, are detected. High sensitivity of 1200 nm refractive unit (1/RIU), figure of merit of 26.67 and Q factor of 23.33 are acquired, which are very remarkable compared with the other PPAs. In addition, the absorptance in mode 1 is about nine times compared to its counterpart without the cross-hair. The proposed structure gives a novel inspiration for the design of a tunable dual-band PPA, which can be exploited for plasmonic sensor and other nanophotonic devices.

scholarly journals Wide Range Refractive Index Sensor Using a Birefringent Optical Fiber

2021 ◽  
Author(s):  
Moutusi De ◽  
Vinod Kumar Singh
Keyword(s):  
Refractive Index ◽  
Near Infrared ◽  
High Sensitivity ◽  
Infrared Region ◽  
Device Fabrication ◽  
Refractive Index Sensor ◽  
Potential Candidate ◽  
Wide Range ◽  
Analyte Detection ◽  
Birefringent Optical Fiber

Abstract In this article, an efficient high birefringent D-shaped photonic crystal fiber (HB-D-PCF) plasmonic refractive index sensor is reported. It is able to work over a long low refractive index (RI) analyte range from 1.29 to 1.36. This modified simple structured hexagonal PCF has high birefringence in the near-infrared region. A thin gold film protected by a titanium dioxide (TiO2) layer is deposited on the D-surface of the PCF which acts as surface plasmon active layer. The sensor consists of an analyte channel on the top of the fiber. The performance of the HB-D-PCF is analyzed based on finite element method (FEM). Both wavelength and amplitude interrogation techniques are applied to study the sensing performance of the optimized sensor. Numerical results show wavelength and amplitude sensitivity of 9245nm/RIU and 1312 RIU-1 respectively with high resolution. Owing to the high sensitivity, long range sensing ability as well as spectral stability the designed HB-D-PCF SPR sensor is a potential candidate for water pollution control, glucose concentration testing, biochemical analyte detection as well as portable device fabrication.

scholarly journals Colorimetric Sensing with Gold Nanoparticles on Electrowetting-Based Digital Microfluidics

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1423
Author(s):  
Zhen Gu ◽  
Jing-Jing Luo ◽  
Le-Wei Ding ◽  
Bing-Yong Yan ◽  
Jia-Le Zhou ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Low Cost ◽  
Digital Microfluidics ◽  
High Sensitivity ◽  
Bulk Solution ◽  
Label Free ◽  
Colorimetric Sensing ◽  
Wide Range ◽  
The Stability ◽  
Digital Microfluidic

Digital microfluidic (DMF) has been a unique tool for manipulating micro-droplets with high flexibility and accuracy. To extend the application of DMF for automatic and in-site detection, it is promising to introduce colorimetric sensing based on gold nanoparticles (AuNPs), which have advantages including high sensitivity, label-free, biocompatibility, and easy surface modification. However, there is still a lack of studies for investigating the movement and stability of AuNPs for in-site detection on the electrowetting-based digital microfluidics. Herein, to demonstrate the ability of DMF for colorimetric sensing with AuNPs, we investigated the electrowetting property of the AuNPs droplets on the hydrophobic interface of the DMF chip and examined the stability of the AuNPs on DMF as well as the influence of evaporation to the colorimetric sensing. As a result, we found that the electrowetting of AuNPs fits to a modified Young–Lippmann equation, which suggests that a higher voltage is required to actuate AuNPs droplets compared with actuating water droplets. Moreover, the stability of AuNPs was maintained during the processing of electrowetting. We also proved that the evaporation of droplets has a limited influence on the detections that last several minutes. Finally, a model experiment for the detection of Hg2+ was carried out with similar results to the detections in bulk solution. The proposed method can be further extended to a wide range of AuNPs-based detection for label-free, automatic, and low-cost detection of small molecules, biomarkers, and metal ions.

scholarly journals Historical Evolution and Food Control Achievements of Near Infrared Spectroscopy, Electronic Nose, and Electronic Tongue—Critical Overview

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5479
Author(s):  
Balkis Aouadi ◽  
John-Lewis Zinia Zaukuu ◽  
Flora Vitális ◽  
Zsanett Bodor ◽  
Orsolya Fehér ◽  
...  
Keyword(s):  
Electronic Nose ◽  
Fruits And Vegetables ◽  
Near Infrared ◽  
Electronic Tongue ◽  
Nir Spectroscopy ◽  
High Sensitivity ◽  
Food Control ◽  
Time Data ◽  
Production Chain ◽  
Wide Range

Amid today’s stringent regulations and rising consumer awareness, failing to meet quality standards often results in health and financial compromises. In the lookout for solutions, the food industry has seen a surge in high-performing systems all along the production chain. By virtue of their wide-range designs, speed, and real-time data processing, the electronic tongue (E-tongue), electronic nose (E-nose), and near infrared (NIR) spectroscopy have been at the forefront of quality control technologies. The instruments have been used to fingerprint food properties and to control food production from farm-to-fork. Coupled with advanced chemometric tools, these high-throughput yet cost-effective tools have shifted the focus away from lengthy and laborious conventional methods. This special issue paper focuses on the historical overview of the instruments and their role in food quality measurements based on defined food matrices from the Codex General Standards. The instruments have been used to detect, classify, and predict adulteration of dairy products, sweeteners, beverages, fruits and vegetables, meat, and fish products. Multiple physico-chemical and sensory parameters of these foods have also been predicted with the instruments in combination with chemometrics. Their inherent potential for speedy, affordable, and reliable measurements makes them a perfect choice for food control. The high sensitivity of the instruments can sometimes be generally challenging due to the influence of environmental conditions, but mathematical correction techniques exist to combat these challenges.

scholarly journals Recent Insights and Multifactorial Applications of Carbon Nanotubes

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1502
Author(s):  
Muthu Thiruvengadam ◽  
Govindasamy Rajakumar ◽  
Venkata Swetha ◽  
Mohammad Azam Ansari ◽  
Saad Alghamdi ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Drug Delivery ◽  
Near Infrared ◽  
Medical Diagnostics ◽  
Cortical Atrophy ◽  
Silicon Chips ◽  
Therapeutic Modalities ◽  
Wide Range ◽  
High Flexibility ◽  
Carbon Based Nanomaterials

Nanotechnology has undergone significant development in recent years, particularly in the fabrication of sensors with a wide range of applications. The backbone of nanotechnology is nanostructures, which are determined on a nanoscale. Nanoparticles are abundant throughout the universe and are thought to be essential building components in the process of planet creation. Nanotechnology is generally concerned with structures that are between 1 and 100 nm in at least one dimension and involves the production of materials or electronics that are that small. Carbon nanotubes (CNTs) are carbon-based nanomaterials that have the structure of tubes. Carbon nanotubes are often referred to as the kings of nanomaterials. The diameter of carbon is determined in nanometers. They are formed from graphite sheets and are available in a variety of colors. Carbon nanotubes have a number of characteristics, including high flexibility, good thermal conductivity, low density, and chemical stability. Carbon nanotubes have played an important part in nanotechnology, semiconductors, optical and other branches of materials engineering owing to their remarkable features. Several of the applications addressed in this review have already been developed and used to benefit people worldwide. CNTs have been discussed in several domains, including industry, construction, adsorption, sensors, silicon chips, water purifiers, and biomedical uses, to show many treatments such as injecting CNTs into kidney cancers in rats, drug delivery, and directing a near-infrared laser at the cancers. With the orderly development of research in this field, additional therapeutic modalities will be identified, mainly for dispersion and densification techniques and targeted drug delivery systems for managing and curing posterior cortical atrophy. This review discusses the characteristics of carbon nanotubes as well as therapeutic applications such as medical diagnostics and drug delivery.

scholarly journals Photonic Crystal Surfaces as a General Purpose Platform for Label-Free and Fluorescent Assays

2010 ◽  
Vol 15 (2) ◽  
pp. 120-135 ◽  
Author(s):  
Brian T. Cunningham
Keyword(s):  
Photonic Crystal ◽  
High Throughput Screening ◽  
High Sensitivity ◽  
Surface Enhanced Raman Spectroscopy ◽  
General Purpose ◽  
Detection Sensitivity ◽  
Microfluidic Channels ◽  
Label Free ◽  
Surface Areas ◽  
Wide Range

Photonic crystal (PC) surfaces can be designed to provide a wide range of functions that are used to perform biochemical and cell-based assays. Detection of the optical resonant reflections from PC surfaces enables high sensitivity label-free biosensing, whereas the enhanced electromagnetic (EM) fields that occur at resonant wavelengths can be used to enhance the detection sensitivity of any surface-based fluorescence assay. Fabrication of PCs from inexpensive plastic materials over large surface areas enables them to be incorporated into standard formats that include microplates, microarrays, and microfluidic channels. This report reviews the design of PC biosensors, their associated detection instrumentation, and biological applications. Applications including high-throughput screening of small molecules, cell membrane integrin activation, gene expression analysis, and protein biomarker detection are highlighted. Recent results in which PC surfaces are used for enhancing the detection of surface-enhanced Raman spectroscopy, and the development of high-resolution PC-based laser biosensors are also described.

scholarly journals Integrált optikai szenzor biológiai minták gyors analíziséhez

2015 ◽  
Vol 156 (52) ◽  
pp. 2116-2119
Author(s):  
Anna Mathesz ◽  
Sándor Valkai ◽  
Orsolya Sipos ◽  
Balázs Stercz ◽  
Béla Kocsis ◽  
...  
Keyword(s):  
Medical Diagnostics ◽  
Microfluidic System ◽  
Enzyme Linked Immunosorbent Assay ◽  
Label Free ◽  
Microbial Forensics ◽  
Wide Range ◽  
Label Free Detection ◽  
Integrated Optical ◽  
Measuring Techniques ◽  
Escherichia Coli Bacteria

Introduction: In the medical diagnostics of bacteria, the rapid detection of pathogenic microorganisms from body fluids is one of the most important tasks. The majority of the modern measuring techniques are based on specific labels bound to the bacteria. However, this strategy usually assumes a rather time-consuming procedure involving several steps (e.g., the widely used enzyme-linked immunosorbent assay normally consists of 5 consecutive steps). Hence, there is an urgent need for the elaboration of rapid, “label-free” techniques, that are often based on Lab-on-a-chip devices. Aim: In this paper, the authors report on the development of a biosensor based on a miniature, integrated optical Mach–Zehnder interferometer. Method: Functionalization of the measuring arm of the sensor by antibodies, made the rapid and specific label-free detection of pathogens feasible. Results: Using the combination of the interferometer with a microfluidic system, the device was able to detect Escherichia coli bacteria at concentrations as low as 106 colony forming unit/ml within minutes. Conclusions: This makes the newly developed biosensor a promising device for a wide range of applications, not only in medical microbiology, but microbial forensics, criminal investigations, bio-terrorism threats and in environmental studies as well. Orv. Hetil., 2015, 156(52), 2116–2119.

scholarly journals Label-Free Assays on the BIND System

2004 ◽  
Vol 9 (6) ◽  
pp. 481-490 ◽  
Author(s):  
Brian T. Cunningham ◽  
Peter Li ◽  
Stephen Schulz ◽  
Bo Lin ◽  
Cheryl Baird ◽  
...  
Keyword(s):  
Fluorescent Dyes ◽  
Dynamic Range ◽  
Low Cost ◽  
High Sensitivity ◽  
Receptor Expression ◽  
Label Free ◽  
Protein Protein Interaction ◽  
Small Molecule Screening ◽  
Guided Mode ◽  
Wide Range

Screening of biochemical interactions becomes simpler, less expensive, and more accurate when labels, such as fluorescent dyes, radioactive markers, and colorimetric reactions, are not required to quantify detected material. SRU Biosystems has developed a biosensor technology that is manufactured on continuous sheets of plastic film and incorporated into standard microplates and microarray slides to enable label-free assays to be performed with high throughput, high sensitivity, and low cost per assay. The biosensor incorporates a narrow band guided-mode resonance reflectance filter, in which the reflected color is modulated by the attachment/detachment of biochemical material to the surface. The technology offers 4 orders of linear dynamic range and uniformity within a plate, with a coefficient of variation of 2.5%. Using conventional biochemical immobilization surface chemistries, a wide range of assay applications are enabled. Small molecule screening, cell proliferation/cytotoxicity, enzyme activity screening, protein-protein interaction, and cell membrane receptor expression are among the applications demonstrated.

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