scholarly journals All-Opto Plasmonic-Controlled Bulk and Surface Sensitivity Analysis of a Paired Nano-Structured Antenna with a Label-Free Detection Approach

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6166
Author(s):  
Sneha Verma ◽  
Souvik Ghosh ◽  
B.M.A. Rahman
Keyword(s):  
Refractive Index ◽  
Surface Layer ◽  
Major Axis ◽  
Spectral Shift ◽  
Label Free ◽  
Detection Approach ◽  
Label Free Detection ◽  
Surface Sensing ◽  
A Minor ◽  
Nanostructured Sensors

Gold nanoantennas have been used in a variety of biomedical applications due to their attractive electronic and optical properties, which are shape- and size-dependent. Here, a periodic paired gold nanostructure exploiting surface plasmon resonance is proposed, which shows promising results for Refractive Index (RI) detection due to its high electric field confinement and diffraction limit. Here, single and paired gold nanostructured sensors were designed for real-time RI detection. The Full-Width at Half-Maximum (FWHM) and Figure-Of-Merit (FOM) were also calculated, which relate the sensitivity to the sharpness of the peak. The effect of different possible structural shapes and dimensions were studied to optimise the sensitivity response of nanosensing structures and identify an optimised elliptical nanoantenna with the major axis a, minor axis b, gap between the pair g, and heights h being 100 nm, 10 nm, 10 nm, and 40 nm, respectively. In this work, we investigated the bulk sensitivity, which is the spectral shift per refractive index unit due to the change in the surrounding material, and this value was calculated as 526–530 nm/RIU, while the FWHM was calculated around 110 nm with a FOM of 8.1. On the other hand, the surface sensing was related to the spectral shift due to the refractive index variation of the surface layer near the paired nanoantenna surface, and this value for the same antenna pair was calculated as 250 nm/RIU for a surface layer thickness of 4.5 nm.

scholarly journals Comparison of DNAzyme activity for the development of an immobilized heme sensor

MRS Advances ◽  
2018 ◽  
Vol 3 (26) ◽  
pp. 1491-1496
Author(s):  
Natalie Hughes ◽  
Nancy Nguyen ◽  
Deanna-Kaye Daley ◽  
Justin Grennell ◽  
Amira Gee ◽  
...  
Keyword(s):  
Self Assembly ◽  
Point Of Care ◽  
Label Free ◽  
Detection Range ◽  
Chemical Complexity ◽  
Detection Strategy ◽  
Detection Approach ◽  
Label Free Detection ◽  
G Quadruplex ◽  
Care Systems

ABSTRACTPoint-of-care systems require highly sensitive, quantitative and selective detection platforms for the real-time multiplexed monitoring of target analytes. To ensure facile development of a sensor, it is preferable for the detection assay to have minimal chemical complexity, contain no wash steps and provide a wide and easily adaptable detection range for multiple targets. Current studies involve label-free detection strategy for relevant clinical molecules such as heme using G-quadruplex based self-assembly. We have explored the measurement of binding and kinetic parameters of various G-quadruplex/heme complexes which are able to self-associate to form a DNAzyme with peroxidase mimicking capabilities and are critical to nucleic acid research. The detection strategy includes immobilizing the G-quadruplex sequences within a polymer matrix to provide a self-assembly based detection approach for heme that could be translated towards other clinically relevant targets.

Label free detection of DNA hybridization by refractive index tapered fiber biosensor

2010 ◽  
Author(s):  
M. I. Zibaii ◽  
H. Latifi ◽  
E. Ghanati ◽  
M. Gholami ◽  
S. M. Hosseini
Keyword(s):  
Refractive Index ◽  
Dna Hybridization ◽  
Label Free ◽  
Tapered Fiber ◽  
Label Free Detection

Integration of digital microfluidics with whispering-gallery mode sensors for label-free detection of biomolecules

Lab on a Chip ◽  
2017 ◽  
Vol 17 (10) ◽  
pp. 1740-1748 ◽  
Author(s):  
Sentayehu F. Wondimu ◽  
Sebastian von der Ecken ◽  
Ralf Ahrens ◽  
Wolfgang Freude ◽  
Andreas E. Guber ◽  
...  
Keyword(s):  
Refractive Index ◽  
Digital Microfluidics ◽  
Whispering Gallery Mode ◽  
Label Free ◽  
Biosensor Arrays ◽  
Whispering Gallery ◽  
Label Free Detection ◽  
Detection Of Biomolecules

WGM biosensor arrays are integrated with a DMF system. The viability of the system is demonstrated by refractive-index and biosensing experiments.

scholarly journals Chiral Plasmonic Biosensors

Biosensors ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 120 ◽  
Author(s):  
Vladimir Bochenkov ◽  
Tatyana Shabatina
Keyword(s):  
Refractive Index ◽  
Surface Plasmon Resonance ◽  
Plasmonic Nanostructures ◽  
Label Free ◽  
Highly Sensitive ◽  
Label Free Detection ◽  
Recent Developments ◽  
Detection Of Biomolecules ◽  
Local Refractive Index ◽  
Unique Capability

Biosensing requires fast, selective, and highly sensitive real-time detection of biomolecules using efficient simple-to-use techniques. Due to a unique capability to focus light at nanoscale, plasmonic nanostructures provide an excellent platform for label-free detection of molecular adsorption by sensing tiny changes in the local refractive index or by enhancing the light-induced processes in adjacent biomolecules. This review discusses the opportunities provided by surface plasmon resonance in probing the chirality of biomolecules as well as their conformations and orientations. Various types of chiral plasmonic nanostructures and the most recent developments in the field of chiral plasmonics related to biosensing are considered.

scholarly journals Silicon Photonic Micro-Ring Resonators for Chemical and Biological Sensing: A Tutorial

2021 ◽  
Author(s):  
Patrick Steglich ◽  
Dominik G. Rabus ◽  
Cinzia Sada ◽  
Martin Paul ◽  
Michael G. Weller ◽  
...  
Keyword(s):  
Free Surface ◽  
Limit Of Detection ◽  
Design Guidelines ◽  
Ring Resonators ◽  
Biological Sensing ◽  
Label Free ◽  
Sensing Applications ◽  
Silicon Photonic ◽  
Label Free Detection ◽  
Surface Sensing

Silicon photonic micro-ring resonators (MRR) developed on the silicon-on-insulator (SOI) platform, owing to their high sensitivity and small footprint, show great potential for many chemical and biological sensing applications such as label-free detection in environmental monitoring, biomedical engineering, and food analysis. In this tutorial, we provide the theoretical background and give design guidelines for SOI-based MRR as well as examples of surface functionalization procedures for label-free detection of molecules. <br>After introducing the advantages and perspectives of MRR, fundamentals of MRR are described in detail, followed by an introduction to the fabrication methods, which are based on a complementary metal-oxide semiconductor (CMOS) technology. Optimization of MRR for chemical and biological sensing is provided, with special emphasis on the optimization of waveguide geometry. At this point, the difference between chemical bulk sensing and label-free surface sensing is explained, and definitions like waveguide sensitivity, ring sensitivity, overall sensitivity as well as the limit of detection (LoD) of MRR are introduced. Further, we show and explain chemical bulk sensing of sodium chloride (NaCl) in water and provide a recipe for label-free surface sensing.

Direct Label Free Detection of Orchid Virus Using a Micro/Nano Hybrid Structured Biosensor

2019 ◽  
Author(s):  
Wei-Jhen Wang ◽  
Chia-Hwa Lee ◽  
Chin-Wen Li ◽  
Stephen Liao ◽  
Fuh-Jyh Jan ◽  
...  
Keyword(s):  
Label Free ◽  
Self Assembled Monolayer ◽  
Detection Range ◽  
Elisa Kit ◽  
Detection Approach ◽  
Linear Detection ◽  
Label Free Detection ◽  
Semiconductor Fabrication ◽  
Direct Label ◽  
Higher Sensitivity

Abstract In this study, a label-free detection approach for effective detection of the odontoglossum ringspot virus (ORSV) infected orchids has been developed. We used semiconductor fabrication process to fabricate 1,810 micro/nano hybrid structured sensing electrodes on a 8 inch reclaimed wafer. The self-assembled monolayer (SAM) process was then employed to sequentially modify the electrode surface with 11-mercaptoundecanoic acid (11-MUA), 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/ N-hydroxysuccinimide (NHS), anti-ORSV, and ORSV. EIS was conducted for the ORSV concentration detection. Experimental results demonstrated that the ORSV concentration in a virus infected orchid leaf could be effectively detected. When compared with the ELISA kit, our device possesses a wider linear detection range (0.5–50,000 ng/mL) and a higher sensitivity. The specificity of our device on ORSV detection was also confirmed. Our sensing device retains advantages, such as label-free, lower amounts of the antibody and target sample required, low detection time, and a wider linear detection range. Those results imply the feasibility of our sensing device in field applications.

scholarly journals Chiral Hybrid Nanosystems and Their Biosensing Applications

2020 ◽  
Author(s):  
Vladimir E. Bochenkov ◽  
Tatyana I. Shabatina
Keyword(s):  
Refractive Index ◽  
Electric Fields ◽  
Metal Nanostructures ◽  
Order Structure ◽  
Molecular Adsorption ◽  
Label Free ◽  
Label Free Detection ◽  
Hybrid Nanosystems ◽  
Local Refractive Index

The presented chapter is devoted to chiral biosensing using various metal nanostructures and their hybrid nanosystems with optically active bio- and organic molecules. Plasmonic nanosystems and nanostructures provide an excellent platform for label-free detection of molecular adsorption by detecting tiny changes in the local refractive index or amplification of light-induced processes in biomolecules. Based on recent theoretical and experimental developments in plasmon-enhanced local electric fields, we consider the main types of molecular-plasmonic hybrid systems capable of generating an amplified chiroptical signal for such applications as detecting the presence of certain biomolecules and (in some cases) determination of their orientation and higher-order structure.

scholarly journals Rayleigh anomaly-enabled mode hybridization in gold nanohole arrays by scalable colloidal lithography for highly-sensitive biosensing

Nanophotonics ◽  
2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Zhiliang Zhang ◽  
Feng Zhao ◽  
Renxian Gao ◽  
Chih-Yu Jao ◽  
Churong Ma ◽  
...  
Keyword(s):  
Refractive Index ◽  
Plasmonic Nanostructures ◽  
Label Free ◽  
Colloidal Lithography ◽  
Large Area ◽  
Nanohole Array ◽  
Highly Sensitive ◽  
Label Free Detection ◽  
Nanohole Arrays ◽  
Rayleigh Anomaly

Abstract Plasmonic sensors exhibit tremendous potential to accomplish real-time, label-free, and high-sensitivity biosensing. Gold nanohole array (GNA) is one of the classic plasmonic nanostructures that can be readily fabricated and integrated into microfluidic platforms for a variety of applications. Even though GNA has been widely studied, new phenomena and applications are still emerging continuously expanding its capabilities. In this article, we demonstrated narrow-band high-order resonances enabled by Rayleigh anomaly in the nanohole arrays that are fabricated by scalable colloidal lithography. We fabricated large-area GNAs with different hole diameters, and investigated their transmission characteristics both numerically and experimentally. We showed that mode hybridization between the plasmon mode of the nanoholes and Rayleigh anomaly of the array could give rise to high-quality decapole resonance with a unique nearfield profile. We experimentally achieved a refractive index sensitivity, i.e., RIS up to 407 nm/RIU. More importantly, we introduced a spectrometer-free refractive index sensing based on lens-free smartphone imaging of GNAs with (intensity) sensitivity up to 137%/RIU. Using this platform, we realized the label-free detection of BSA molecules with concentration as low as 10−8 M. We believe our work could pave the way for highly sensitive and compact point-of-care devices with cost-effective and high-throughput plasmonic chips.

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