scholarly journals Responsive Janus Structural Color Hydrogel Micromotors for Label-Free Multiplex Assays

Research ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Huan Wang ◽  
Lijun Cai ◽  
Dagan Zhang ◽  
Luoran Shang ◽  
Yuanjin Zhao
Keyword(s):  
Detection Efficiency ◽  
Multiplex Assay ◽  
Detection Sensitivity ◽  
Structural Color ◽  
Label Free ◽  
Structural Colors ◽  
Multiplex Assays ◽  
Highly Sensitive ◽  
Label Free Detection ◽  
Coding Capacity

Micromotors with self-propelling ability demonstrate great values in highly sensitive analysis. Developing novel micromotors to achieve label-free multiplex assay is particularly intriguing in terms of detection efficiency. Herein, structural color micromotors (SCMs) were developed and employed for this purpose. The SCMs were derived from phase separation of droplet templates and exhibited a Janus structure with two distinct sections, including one with structural colors and the other providing catalytic self-propelling functions. Besides, the SCMs were functionalized with ion-responsive aptamers, through which the interaction between the ions and aptamers resulted in the shift of the intrinsic color of the SCMs. It was demonstrated that the SCMs could realize multiplex label-free detection of ions based on their optical coding capacity and responsive behaviors. Moreover, the detection sensitivity was greatly improved benefiting from the autonomous motion of the SCMs which enhanced the ion-aptamer interactions. We anticipate that the SCMs can significantly promote the development of multiplex assay and biomedical fields.

Target-induced structure switching of DNA for label-free and ultrasensitive electrochemiluminescent detection of proteins

2014 ◽  
Vol 50 (24) ◽  
pp. 3211-3213 ◽  
Author(s):  
Mengli Yang ◽  
Ying Chen ◽  
Yun Xiang ◽  
Ruo Yuan ◽  
Yaqin Chai
Keyword(s):  
Dna Structure ◽  
Label Free ◽  
Switching Strategy ◽  
Highly Sensitive ◽  
Label Free Detection ◽  
Exo Iii ◽  
Recycling Amplification ◽  
Structure Switching ◽  
Induced Structure

Highly sensitive and label-free detection of thrombin is achieved via a target-induced DNA structure switching strategy and Exo III-assisted recycling amplification.

scholarly journals Stomatocyte structural color-barcode micromotors for multiplex assays

2019 ◽  
Vol 7 (3) ◽  
pp. 644-651 ◽  
Author(s):  
Lijun Cai ◽  
Huan Wang ◽  
Yunru Yu ◽  
Feika Bian ◽  
Yu Wang ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Colloidal Crystal ◽  
Structural Color ◽  
Multiplex Detection ◽  
Color Coding ◽  
Functional Elements ◽  
Structural Colors ◽  
Multiplex Assays ◽  
Magnetic Elements ◽  
Extracting Solvent

Abstract Artificial micromotors have a demonstrated value in the biomedical area. Attempts to develop this technology tend to impart micromotors with novel functions to improve the values. Herein, we present novel structural color-barcode micromotors for the multiplex assays. We found that, by rapidly extracting solvent and assembling monodispersed nanoparticles in droplets, it could form stomatocyte colloidal crystal clusters, which not only showed striking structural colors and characteristic reflection peaks due to their ordered nanoparticles arrangement, but also provided effective cavities for the integration of functional elements. Thus, the micromotors with catalysts or magnetic elements in their cavities, as well as with the corresponding structural color coding, could be achieved by using the platinum and ferric oxide dispersed pre-gel to fill and duplicate the stomatocyte colloidal crystal clusters. We have demonstrated that the self-movement of these structural color-barcode micromotors could efficiently accelerate the mixing speed of the detection sample and greatly increase the probe–target interactions towards faster and more sensitive single or multiplex detection, and the magnetism of these barcode micromotors enables the flexible collection of the micromotors, which could facilitate the detection processes. These features make the stomatocyte structural color-barcode micromotors ideal for biomedical applications.

scholarly journals Super-Nernstian ion sensitive field-effect transistor exploiting charge screening in WSe2/MoS2 heterostructure

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Sooraj Sanjay ◽  
Mainul Hossain ◽  
Ankit Rao ◽  
Navakanta Bhat
Keyword(s):  
Field Effect ◽  
Field Effect Transistors ◽  
Point Of Care ◽  
Low Cost ◽  
Ph Sensor ◽  
Detection Sensitivity ◽  
Label Free ◽  
Back Gate ◽  
Dielectric Thickness ◽  
Label Free Detection

AbstractIon-sensitive field-effect transistors (ISFETs) have gained a lot of attention in recent times as compact, low-cost biosensors with fast response time and label-free detection. Dual gate ISFETs have been shown to enhance detection sensitivity beyond the Nernst limit of 59 mV pH−1 when the back gate dielectric is much thicker than the top dielectric. However, the thicker back-dielectric limits its application for ultrascaled point-of-care devices. In this work, we introduce and demonstrate a pH sensor, with WSe2(top)/MoS2(bottom) heterostructure based double gated ISFET. The proposed device is capable of surpassing the Nernst detection limit and uses thin high-k hafnium oxide as the gate oxide. The 2D atomic layered structure, combined with nanometer-thick top and bottom oxides, offers excellent scalability and linear response with a maximum sensitivity of 362 mV pH−1. We have also used technology computer-aided (TCAD) simulations to elucidate the underlying physics, namely back gate electric field screening through channel and interface charges due to the heterointerface. The proposed mechanism is independent of the dielectric thickness that makes miniaturization of these devices easier. We also demonstrate super-Nernstian behavior with the flipped MoS2(top)/WSe2(bottom) heterostructure ISFET. The results open up a new pathway of 2D heterostructure engineering as an excellent option for enhancing ISFET sensitivity beyond the Nernst limit, for the next-generation of label-free biosensors for single-molecular detection and point-of-care diagnostics.

scholarly journals The Localized Enhancement of Surface Plasmon Standing Waves Interacting With Single Nanoparticles

2021 ◽  
Author(s):  
hongyao liu ◽  
Xuqing Sun ◽  
Xue Wang ◽  
Fei Wang ◽  
Chang Wang ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
Electric Dipole ◽  
Surrounding Medium ◽  
Standing Waves ◽  
High Sensitivity ◽  
Detection Sensitivity ◽  
Label Free ◽  
Vertical Electric Dipole ◽  
Lower Dielectric Constant ◽  
Label Free Detection

Abstract Real-time, high-sensitivity, and label-free detection to single nanoparticles has been achieved via visualizing the interaction between surface plasmon polaritons (SPPs) and nanoparticles, which is widely applied to chemistry and biology. In this work, aiming to enhance the detection sensitivity to nanoparticles, we explore the interaction of SPP standing waves with single nanoparticles. Compared with SPPs, the inhomogeneous fields of SPP standing waves modulate charge distributions around the particle and excite different electric dipole modes that tailor localized enhancements. For nanoparticles situating at electric antinodes of SPP standing waves, a vertical electric dipole is excited and high-density charges are stimulated around nanoparticle-film nanocavities, leading to further increased localized enhancement. The localized enhancement experiences more increase with smaller particle size, lower dielectric constant of surrounding medium, and lower particle refractive index. Via tailoring the localized enhancement by SPP standing waves, the sensitivity of SPP microscopy can be improved, which would broaden its applications on nanotechnology, biomedicine, and environmental monitoring.

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 Label-Free Detection of Zeptomol miRNA via Peptide Nucleic Acid Hybridization Using Novel Cyclic Voltammetry Method

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 836
Author(s):  
Shintaro Takase ◽  
Kouta Miyagawa ◽  
Hisafumi Ikeda
Keyword(s):  
Nucleic Acid ◽  
Peptide Nucleic Acid ◽  
Microelectrode Array ◽  
Pcr Amplification ◽  
Nucleic Acid Hybridization ◽  
Detection Sensitivity ◽  
Cyclic Voltammograms ◽  
Dna Duplexes ◽  
Label Free ◽  
Label Free Detection

To harness the applicability of microribonucleic acid (miRNA) as a cancer biomarker, the detection sensitivity of serum miRNA needs to be improved. This study evaluated the detection sensitivity of miRNA hybridization using cyclic voltammograms (CVs) and microelectrode array chips modified with peptide nucleic acid (PNA) probes and 6-hydroxy-1-hexanethiol. We investigated the PNA probe modification pattern on array chips using fluorescently labeled cDNA. The pattern was not uniformly spread over the working electrode (WE) and had a one-dimensional swirl-like pattern. Accordingly, we established a new ion-channel sensor model wherein the WE is negatively biased through the conductive π–π stacks of the PNA/DNA duplexes. This paper discusses the mechanism underlying the voltage shift in the CV curves based on the electric double-layer capacitance. Additionally, the novel hybridization evaluation parameter ΔE is introduced. Compared to conventional evaluation using oxidation current changes, ΔE was more sensitive. Using ΔE and a new hybridization system for ultrasmall amounts of aqueous solutions (as low as 35 pL), 140 zeptomol label-free miRNA were detected without polymerase chain reaction (PCR) amplification at an adequate sensitivity. Herein, the differences in the target molar amount and molar concentration are elucidated from the viewpoint of hybridization sensitivity.

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