A novel three-dimensional DNA nanostructure used for thrombin detection

2017 ◽  
Vol 9 (35) ◽  
pp. 5115-5120 ◽  
Author(s):  
Huawei Shu ◽  
He Mei ◽  
Jinxin Gu ◽  
Yongbin Yang ◽  
Baoguang Chen ◽  
...  
Keyword(s):  
Three Dimensional ◽  
High Sensitivity ◽  
Label Free ◽  
Electrochemical Aptasensor ◽  
Dna Nanostructure

In this paper, a label-free electrochemical aptasensor for the detection of thrombin with high sensitivity is proposed.

scholarly journals Fabrication of AuNPs/MWCNTS/Chitosan Nanocomposite for the Electrochemical Aptasensing of Cadmium in Water

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 105
Author(s):  
Selma Rabai ◽  
Ahlem Teniou ◽  
Gaëlle Catanante ◽  
Messaoud Benounis ◽  
Jean-Louis Marty ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Electrochemical Biosensor ◽  
Electrochemical Impedance ◽  
High Sensitivity ◽  
Label Free ◽  
Electrochemical Aptasensor ◽  
Applied Potential ◽  
Toxic Heavy Metals ◽  
Cadmium Detection ◽  
Interfering Ions

Cadmium (Cd2+) is one of the most toxic heavy metals causing serious health problems; thus, designing accurate analytical methods for monitoring such pollutants is highly urgent. Herein, we report a label-free electrochemical aptasensor for cadmium detection in water. For this, a nanocomposite combining the advantages of gold nanoparticles (AuNPs), carbon nanotubes (CNTs) and chitosan (Cs) was constructed and used as immobilization support for the cadmium aptamer. First, the surface of a glassy carbon electrode (GCE) was modified with CNTs-CS. Then, AuNPs were deposited on CNTs-CS/GCE using chrono-amperometry. Finally, the immobilization of the amino-modified Cd-aptamer was achieved via glutaraldehyde cross-linking. The different synthesis steps of the AuNPs/CNTs/CS nano assembly were characterized by cyclic voltammetry (CV). Electrochemical impedance spectroscopy (EIS) was employed for cadmium determination. The proposed biosensor exhibited excellent performances for cadmium detection at a low applied potential (−0.5 V) with a high sensitivity (1.2 KΩ·M−1), a detection limit of 0.02 pM and a wide linear range (10−13–10−4 M). Moreover, the aptasensor showed a good selectivity against the interfering ions: Pb2+; Hg2+ and Zn2+. Our electrochemical biosensor provides a simple and sensitive approach for Cd2+ detection in aqueous solutions, with promising applications in the monitoring of trace amounts of heavy metals in real samples.

scholarly journals Label-Free Biomedical Imaging with High Sensitivity by Stimulated Raman Scattering Microscopy

Science ◽  
2008 ◽  
Vol 322 (5909) ◽  
pp. 1857-1861 ◽  
Author(s):  
Christian W. Freudiger ◽  
Wei Min ◽  
Brian G. Saar ◽  
Sijia Lu ◽  
Gary R. Holtom ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Biomedical Imaging ◽  
Stimulated Raman Scattering ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Raman Microscopy ◽  
Label Free ◽  
Omega 3 ◽  
Low Sensitivity ◽  
Stimulated Raman

Label-free chemical contrast is highly desirable in biomedical imaging. Spontaneous Raman microscopy provides specific vibrational signatures of chemical bonds, but is often hindered by low sensitivity. Here we report a three-dimensional multiphoton vibrational imaging technique based on stimulated Raman scattering (SRS). The sensitivity of SRS imaging is significantly greater than that of spontaneous Raman microscopy, which is achieved by implementing high-frequency (megahertz) phase-sensitive detection. SRS microscopy has a major advantage over previous coherent Raman techniques in that it offers background-free and readily interpretable chemical contrast. We show a variety of biomedical applications, such as differentiating distributions of omega-3 fatty acids and saturated lipids in living cells, imaging of brain and skin tissues based on intrinsic lipid contrast, and monitoring drug delivery through the epidermis.

scholarly journals Highly Sensitive Electrochemical Aptasensor for Detecting the VEGF165 Tumor Marker with PANI/CNT Nanocomposites

Biosensors ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 114
Author(s):  
Yunjeong Park ◽  
Min-Sung Hong ◽  
Woo-Hyuk Lee ◽  
Jung-Gu Kim ◽  
Kyunghoon Kim
Keyword(s):  
Tumor Marker ◽  
Limit Of Detection ◽  
Biological Fluid ◽  
Low Cost ◽  
High Sensitivity ◽  
Label Free ◽  
Electrochemical Aptasensor ◽  
Promising Tool ◽  
Highly Sensitive ◽  
Endothelial Growth Factor

Sensing targeted tumor markers with high sensitivity provides vital information for the fast diagnosis and treatment of cancer patients. A vascular endothelial growth factor (VEGF165) have recently emerged as a promising biomarker of tumor cells. The electrochemical aptasensor is a promising tool for detecting VEGF165 because of its advantages such as a low cost and quantitative analysis. To produce a sensitive and stable sensor electrode, nanocomposites based on polyaniline (PANI) and carbon nanotube (CNT) have potential, as they provide for easy fabrication, simple synthesis, have a large surface area, and are suitable in biological environments. Here, a label-free electrochemical aptasensor based on nanocomposites of CNT and PANI was prepared for detecting VEGF165 as a tumor marker. The nanocomposite was assembled with immobilized VEGF165 aptamer as a highly sensitive VEGF165 sensor. It exhibited stable and wide linear detection ranges from 0.5 pg/mL to 1 μg/mL, with a limit of detection of 0.4 pg/mL because of the complementary effect of PANI/CNT. The fabricated aptasensor also exhibited good stability in biological conditions, selectivity, and reproducibility after several measurement times after the dissociation process. Thus, it could be applied for the non-invasive determination of VEGF, in biological fluid diagnosis kits, or in an aptamer-based biosensor platform in the near future.

scholarly journals Pronounced Linewidth Narrowing of Vertical Metallic Split-Ring Resonators via Strong Coupling with Metal Surface

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2194
Author(s):  
Wei Du ◽  
Youcheng Zhu ◽  
Zhendong Yan ◽  
Xiulian Xu ◽  
Xiaoyong Xu ◽  
...  
Keyword(s):  
Strong Coupling ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Ring Resonators ◽  
Label Free ◽  
Split Ring ◽  
Split Ring Resonators ◽  
Dielectric Substrates ◽  
Biomedical Sensing ◽  
Plasmon Polaritons

We theoretically study the plasmonic coupling between magnetic plasmon resonances (MPRs) and propagating surface plasmon polaritons (SPPs) in a three-dimensional (3D) metamaterial consisting of vertical Au split-ring resonators (VSRRs) array on Au substrate. By placing the VSRRs directly onto the Au substrate to remove the dielectric substrates effect, the interaction between MPRs of VSRRs and the SPP mode on the Au substrate can generate an ultranarrow-band hybrid mode with full width at half maximum (FWHM) of 2.2 nm and significantly enhanced magnetic fields, compared to that of VSRRs on dielectric substrates. Owing to the strong coupling, an anti-crossing effect similar to Rabi splitting in atomic physics is also obtained. Our proposed 3D metamaterial on a metal substrate shows high sensitivity (S = 830 nm/RIU) and figure of merit (FOM = 377), which could pave way for the label-free biomedical sensing.

scholarly journals Acoustohydrodynamic tweezers via spatial arrangement of streaming vortices

2021 ◽  
Vol 7 (2) ◽  
pp. eabc7885
Author(s):  
Haodong Zhu ◽  
Peiran Zhang ◽  
Zhanwei Zhong ◽  
Jianping Xia ◽  
Joseph Rich ◽  
...  
Keyword(s):  
Acoustic Radiation ◽  
Acoustic Streaming ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Spatial Arrangement ◽  
Label Free ◽  
Droplet Transport ◽  
Dimensional Boundary ◽  
Acoustic Tweezers ◽  
Contact Free

Acoustics-based tweezers provide a unique toolset for contactless, label-free, and precise manipulation of bioparticles and bioanalytes. Most acoustic tweezers rely on acoustic radiation forces; however, the accompanying acoustic streaming often generates unpredictable effects due to its nonlinear nature and high sensitivity to the three-dimensional boundary conditions. Here, we demonstrate acoustohydrodynamic tweezers, which generate stable, symmetric pairs of vortices to create hydrodynamic traps for object manipulation. These stable vortices enable predictable control of a flow field, which translates into controlled motion of droplets or particles on the operating surface. We built a programmable droplet-handling platform to demonstrate the basic functions of planar-omnidirectional droplet transport, merging droplets, and in situ mixing via a sequential cascade of biochemical reactions. Our acoustohydrodynamic tweezers enables improved control of acoustic streaming and demonstrates a previously unidentified method for contact-free manipulation of bioanalytes and digitalized liquid handling based on a compact and scalable functional unit.

Fabrication of electro-active nano-trans surfaces to design label free electrochemical aptasensor for ochratoxin A detection

2021 ◽  
Vol 379 ◽  
pp. 138172
Author(s):  
Maham Liaqat ◽  
Sara Riaz ◽  
Mian Hasnain Nawaz ◽  
Mihaela Badea ◽  
Akhtar Hayat ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Label Free ◽  
Electrochemical Aptasensor

Efficient chemosensors for toxic pollutants based on photoluminescent Zn(II) and Cd(II) metal-organic networks

2021 ◽  
Author(s):  
Luis David Rosales-Vazquez ◽  
Alejandro Dorazco-González ◽  
Victor Sanchez-Mendieta
Keyword(s):  
Optical Sensors ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Environmental Research ◽  
Toxic Pollutants ◽  
Sensitivity And Selectivity ◽  
Metal Organic ◽  
Analytical Tools ◽  
Organic Networks

Optical sensors with high sensitivity and selectivity, as important analytical tools for chemical and environmental research, can be accomplished by straightforward synthesis of luminescent one-, two- and three-dimensional Zn(II) and...

scholarly journals Integrating high-performing electrochemical transducers in lateral flow assay

2021 ◽  
Author(s):  
Antonia Perju ◽  
Nongnoot Wongkaew
Keyword(s):  
High Performance ◽  
Point Of Care ◽  
Low Cost ◽  
High Sensitivity ◽  
Lateral Flow ◽  
Analytical Performance ◽  
Label Free ◽  
High Performing ◽  
Lateral Flow Assays ◽  
Electrochemical Transducers

AbstractLateral flow assays (LFAs) are the best-performing and best-known point-of-care tests worldwide. Over the last decade, they have experienced an increasing interest by researchers towards improving their analytical performance while maintaining their robust assay platform. Commercially, visual and optical detection strategies dominate, but it is especially the research on integrating electrochemical (EC) approaches that may have a chance to significantly improve an LFA’s performance that is needed in order to detect analytes reliably at lower concentrations than currently possible. In fact, EC-LFAs offer advantages in terms of quantitative determination, low-cost, high sensitivity, and even simple, label-free strategies. Here, the various configurations of EC-LFAs published are summarized and critically evaluated. In short, most of them rely on applying conventional transducers, e.g., screen-printed electrode, to ensure reliability of the assay, and additional advances are afforded by the beneficial features of nanomaterials. It is predicted that these will be further implemented in EC-LFAs as high-performance transducers. Considering the low cost of point-of-care devices, it becomes even more important to also identify strategies that efficiently integrate nanomaterials into EC-LFAs in a high-throughput manner while maintaining their favorable analytical performance.

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