A facile low-cost paper-based SERS substrate for label-free molecular detection

2019 ◽  
Vol 291 ◽  
pp. 369-377 ◽  
Author(s):  
Vo Thi Nhat Linh ◽  
Jungil Moon ◽  
ChaeWon Mun ◽  
Vasanthan Devaraj ◽  
Jin-Woo Oh ◽  
...  
Keyword(s):  
Molecular Detection ◽  
Low Cost ◽  
Sers Substrate ◽  
Label Free

scholarly journals Label-free highly sensitive probe detection with novel hierarchical SERS substrates fabricated by nanoindentation and chemical reaction methods

2019 ◽  
Vol 10 ◽  
pp. 2483-2496
Author(s):  
Jingran Zhang ◽  
Tianqi Jia ◽  
Yongda Yan ◽  
Li Wang ◽  
Peng Miao ◽  
...  
Keyword(s):  
Ag Nanoparticles ◽  
Enhancement Factor ◽  
Low Cost ◽  
Hierarchical Structures ◽  
Production Method ◽  
Copper Surface ◽  
Sers Substrate ◽  
Label Free ◽  
Sers Substrates ◽  
Highly Sensitive

Nanostructures have been widely employed in surface-enhanced Raman scattering (SERS) substrates. Recently, in order to obtain a higher enhancement factor at a lower detection limit, hierarchical structures, including nanostructures and nanoparticles, appear to be viable SERS substrate candidates. Here we describe a novel method integrating the nanoindentation process and chemical redox reaction to machine a hierarchical SERS substrate. The micro/nanostructures are first formed on a Cu(110) plane and then Ag nanoparticles are generated on the structured copper surface. The effect of the indentation process parameters and the corrosion time in the AgNO3 solution on the Raman intensities of the SERS substrate with hierarchical structures are experimentally studied. The intensity and distribution of the electric field of single and multiple Ag nanoparticles on the surface of a plane and with multiple micro/nanostructures are studied with COMSOL software. The feasibility of the hierarchical SERS substrate is verified using R6G molecules. Finally, the enhancement factor using malachite green molecules was found to reach 5.089 × 109, which demonstrates that the production method is a simple, reproducible and low-cost method for machining a highly sensitive, hierarchical SERS substrate.

scholarly journals Label‐free molecular detection of antibiotic susceptibility for Mycobacterium smegmatis using a low cost electrode format

2020 ◽  
Author(s):  
Fatma Doğan Güzel ◽  
Hamed Ghorbanpoor ◽  
Araz Norouz Dizaji ◽  
Iremnur Akcakoca ◽  
Yasin Ozturk ◽  
...  
Keyword(s):  
Mycobacterium Smegmatis ◽  
Antibiotic Susceptibility ◽  
Molecular Detection ◽  
Low Cost ◽  
Label Free

scholarly journals Demonstration of a Label-Free and Low-Cost Optical Cavity-Based Biosensor Using Streptavidin and C-Reactive Protein

Biosensors ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 4
Author(s):  
Donggee Rho ◽  
Seunghyun Kim
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Optical Cavity ◽  
Sample Volume ◽  
Small Sample ◽  
Label Free ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
Cavity Structure

An optical cavity-based biosensor (OCB) has been developed for point-of-care (POC) applications. This label-free biosensor employs low-cost components and simple fabrication processes to lower the overall cost while achieving high sensitivity using a differential detection method. To experimentally demonstrate its limit of detection (LOD), we conducted biosensing experiments with streptavidin and C-reactive protein (CRP). The optical cavity structure was optimized further for better sensitivity and easier fluid control. We utilized the polymer swelling property to fine-tune the optical cavity width, which significantly improved the success rate to produce measurable samples. Four different concentrations of streptavidin were tested in triplicate, and the LOD of the OCB was determined to be 1.35 nM. The OCB also successfully detected three different concentrations of human CRP using biotinylated CRP antibody. The LOD for CRP detection was 377 pM. All measurements were done using a small sample volume of 15 µL within 30 min. By reducing the sensing area, improving the functionalization and passivation processes, and increasing the sample volume, the LOD of the OCB are estimated to be reduced further to the femto-molar range. Overall, the demonstrated capability of the OCB in the present work shows great potential to be used as a promising POC biosensor.

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.

Low-cost flexible plasmonic nanobump metasurfaces for label-free sensing of serum tumor marker

2020 ◽  
Vol 150 ◽  
pp. 111905 ◽  
Author(s):  
Jinfeng Zhu ◽  
Zhengying Wang ◽  
Shaowei Lin ◽  
Shan Jiang ◽  
Xueying Liu ◽  
...  
Keyword(s):  
Tumor Marker ◽  
Low Cost ◽  
Label Free ◽  
Serum Tumor Marker

Development of Bioimpedance Sensors and Measurement System for Biomedical In-Vitro Applications

2021 ◽  
Vol 7 (2) ◽  
pp. 496-499
Author(s):  
Stadler B. Eng. Sebastian ◽  
Herbert Plischke ◽  
Christian Hanshans
Keyword(s):  
Measurement System ◽  
Low Cost ◽  
Measurement Data ◽  
Impedance Measurement ◽  
Microtiter Plate ◽  
Label Free ◽  
Single Chip ◽  
Do It Yourself ◽  
Store And Forward

Abstract Bioimpedance analysis is a label-free and easy approach to obtain information on cellular barrier integrity and cell viability more broadly. In this work, we introduce a small, low-cost, portable in vitro impedance measurement system for studies where a shadow-free exposure of the cells is a requirement. It can be controlled by a user-friendly web interface and can perform measurements automated and autonomously at short intervals. The system can be integrated into an existing IoT network for remote monitoring and indepth analyses. A single-board computer (SBC) serves as the central unit, to control, analyze, store and forward the measurement data from the single-chip impedance analyzer. Various materials and manufacturing methods were used to produce a purpose-built lid on top of a modified 24-well microtiter plate in a “do it yourself” fashion. Furthermore, three different sensor designs were developed utilizing anodic aluminum oxide (AAO) membranes and gold-plated electrodes. Preliminary tests with potassium chloride (KCl) showed first promising results.

scholarly journals Rapid Antibody Selection Using Surface Plasmon Resonance for High-Speed and Sensitive Hazelnut Lateral Flow Prototypes

Biosensors ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 130 ◽  
Author(s):  
Georgina Ross ◽  
Maria Bremer ◽  
Jan Wichers ◽  
Aart van Amerongen ◽  
Michel Nielen
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
High Speed ◽  
Selection Process ◽  
Low Cost ◽  
Real Life ◽  
Cross Reactivity ◽  
Lateral Flow ◽  
Label Free

Lateral Flow Immunoassays (LFIAs) allow for rapid, low-cost, screening of many biomolecules such as food allergens. Despite being classified as rapid tests, many LFIAs take 10–20 min to complete. For a really high-speed LFIA, it is necessary to assess antibody association kinetics. By using a label-free optical technique such as Surface Plasmon Resonance (SPR), it is possible to screen crude monoclonal antibody (mAb) preparations for their association rates against a target. Herein, we describe an SPR-based method for screening and selecting crude anti-hazelnut antibodies based on their relative association rates, cross reactivity and sandwich pairing capabilities, for subsequent application in a rapid ligand binding assay. Thanks to the SPR selection process, only the fast mAb (F-50-6B12) and the slow (S-50-5H9) mAb needed purification for labelling with carbon nanoparticles to exploit high-speed LFIA prototypes. The kinetics observed in SPR were reflected in LFIA, with the test line appearing within 30 s, almost two times faster when F-50-6B12 was used, compared with S-50-5H9. Additionally, the LFIAs have demonstrated their future applicability to real life samples by detecting hazelnut in the sub-ppm range in a cookie matrix. Finally, these LFIAs not only provide a qualitative result when read visually, but also generate semi-quantitative data when exploiting freely downloadable smartphone apps.

scholarly journals MALDIViz: A Comprehensive Informatics Tool for MALDI-MS Data Visualization and Analysis

2017 ◽  
Vol 22 (10) ◽  
pp. 1246-1252 ◽  
Author(s):  
Kishore Kumar Jagadeesan ◽  
Simon Ekström
Keyword(s):  
Mass Spectrometry ◽  
High Throughput ◽  
High Throughput Screening ◽  
Web Application ◽  
Low Cost ◽  
Maldi Ms ◽  
Ionization Mass ◽  
Label Free ◽  
Label Free Detection ◽  
R Shiny

Recently, mass spectrometry (MS) has emerged as an important tool for high-throughput screening (HTS) providing a direct and label-free detection method, complementing traditional fluorescent and colorimetric methodologies. Among the various MS techniques used for HTS, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) provides many of the characteristics required for high-throughput analyses, such as low cost, speed, and automation. However, visualization and analysis of the large datasets generated by HTS MALDI-MS can pose significant challenges, especially for multiparametric experiments. The datasets can be generated fast, and the complexity of the experimental data (e.g., screening many different sorbent phases, the sorbent mass, and the load, wash, and elution conditions) makes manual data analysis difficult. To address these challenges, a comprehensive informatics tool called MALDIViz was developed. This tool is an R-Shiny-based web application, accessible independently of the operating system and without the need to install any program locally. It has been designed to facilitate easy analysis and visualization of MALDI-MS datasets, comparison of multiplex experiments, and export of the analysis results to high-quality images.

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