High-sensitivity label-free optical fiber optrodes based on the excitation of Bloch surface waves

2016 ◽  
Author(s):  
M. Scaravilli ◽  
G. Castaldi ◽  
A. Cusano ◽  
V. Galdi
2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Médéric Loyez ◽  
Mathilde Wells ◽  
Stéphanie Hambÿe ◽  
François Hubinon ◽  
Bertrand Blankert ◽  
...  

Abstract Background Early malaria diagnosis and its profiling require the development of new sensing platforms enabling rapid and early analysis of parasites in blood or saliva, aside the widespread rapid diagnostic tests (RDTs). Methods This study shows the performance of a cost-effective optical fiber-based solution to target the presence of Plasmodium falciparum histidine-rich protein 2 (PfHRP2). Unclad multimode optical fiber probes are coated with a thin gold film to excite Surface Plasmon Resonance (SPR) yielding high sensitivity to bio-interactions between targets and bioreceptors grafted on the metal surface. Results Their performances are presented in laboratory conditions using PBS spiked with growing concentrations of purified target proteins and within in vitro cultures. Two probe configurations are studied through label-free detection and amplification using secondary antibodies to show the possibility to lower the intrisic limit of detection. Conclusions As malaria hits millions of people worldwide, the improvement and multiplexing of this optical fiber technique can be of great interest, especially for a future purpose of using multiple receptors on the fiber surface or several coated-nanoparticles as amplifiers.


2019 ◽  
Vol 9 ◽  
pp. 184798041983272 ◽  
Author(s):  
M Principe ◽  
M Consales ◽  
G Castaldi ◽  
V Galdi ◽  
A Cusano

Recently, within the emerging framework of “lab-on-fiber” technologies, we successfully demonstrated the integration of phase-gradient plasmonic metasurfaces on the tip of an optical fiber. The resulting optical-fiber “meta-tips” promise to empower the typical fiber-optics application scenarios (e.g. sensing, telecommunications, imaging, etc.) with the advanced light-manipulation capabilities endowed by metasurfaces. Here, we explore more in detail the possibility to exploit this platform in label-free biological or chemical sensing applications. Specifically, we carry out a parametric study of the surface sensitivity and show that phase-gradient metasurfaces generally outperform their gradient-free counterparts, without imposing additional fabrication complexity. Therefore, the phase gradient can be effectively exploited as an additional degree of freedom in the design of high-sensitivity devices.


Author(s):  
Antonia Perju ◽  
Nongnoot Wongkaew

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.


Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 826
Author(s):  
Yanting Liu ◽  
Xuming Zhang

This review aims to summarize the recent advances and progress of plasmonic biosensors based on patterned plasmonic nanostructure arrays that are integrated with microfluidic chips for various biomedical detection applications. The plasmonic biosensors have made rapid progress in miniaturization sensors with greatly enhanced performance through the continuous advances in plasmon resonance techniques such as surface plasmon resonance (SPR) and localized SPR (LSPR)-based refractive index sensing, SPR imaging (SPRi), and surface-enhanced Raman scattering (SERS). Meanwhile, microfluidic integration promotes multiplexing opportunities for the plasmonic biosensors in the simultaneous detection of multiple analytes. Particularly, different types of microfluidic-integrated plasmonic biosensor systems based on versatile patterned plasmonic nanostructured arrays were reviewed comprehensively, including their methods and relevant typical works. The microfluidics-based plasmonic biosensors provide a high-throughput platform for the biochemical molecular analysis with the advantages such as ultra-high sensitivity, label-free, and real time performance; thus, they continue to benefit the existing and emerging applications of biomedical studies, chemical analyses, and point-of-care diagnostics.


Optik ◽  
2015 ◽  
Vol 126 (21) ◽  
pp. 2930-2933 ◽  
Author(s):  
Nai-Fei Ren ◽  
Bing Sun ◽  
Ming-Yang Chen

2009 ◽  
Vol 1203 ◽  
Author(s):  
Matthias Bäcker ◽  
Arshak Poghossian ◽  
Maryam H. Abouzar ◽  
Sylvia Wenmackers ◽  
Stoffel D. Janssens ◽  
...  

AbstractCapacitive field-effect electrolyte-diamond-insulator-semiconductor (EDIS) structures with O-terminated nanocrystalline diamond (NCD) as sensitive gate material have been realized and investigated for the detection of pH, penicillin concentration, and layer-by-layer adsorption of polyelectrolytes. The surface oxidizing procedure of NCD thin films as well as the seeding and NCD growth process on a Si-SiO2 substrate have been improved to provide high pH-sensitive, non-porous thin films without damage of the underlying SiO2 layer and with a high coverage of O-terminated sites. The NCD surface topography, roughness, and coverage of the surface groups have been characterized by SEM, AFM and XPS methods. The EDIS sensors with O-terminated NCD film treated in oxidizing boiling mixture for 45 min show a pH sensitivity of about 50 mV/pH. The pH-sensitive properties of the NCD have been used to develop an EDIS-based penicillin biosensor with high sensitivity (65-70 mV/decade in the concentration range of 0.25-2.5 mM penicillin G) and low detection limit (5 μM). The results of label-free electrical detection of layer-by-layer adsorption of charged polyelectrolytes are presented, too.


2014 ◽  
Vol 105 (6) ◽  
pp. 063118 ◽  
Author(s):  
Daquan Yang ◽  
Shota Kita ◽  
Feng Liang ◽  
Cheng Wang ◽  
Huiping Tian ◽  
...  

2008 ◽  
Vol 18 (01) ◽  
pp. 187-194
Author(s):  
PEIJI ZHAO ◽  
DWIGHT WOOLARD ◽  
JORGE M. SEMINARIO ◽  
ROBERT TREW

There is considerable interest in electrical sensing of biomolecular binding since it has the potential to be label free, to work easily in aqueous environments native to the biomolecules, and to be integrated with small, fast, and inexpensive microelectronoics as detection instrumentation. Although electrochemical methods have been used successfully in detections of DNA molecules with Ag labels at very high sensitivity (~ p ml), detection of DNA molecules in terms of label free techniques has a lower sensitivity (~ μ ml). Here, the surface attachment chemistry is critical towards the detection of ultra-low concentration of biomolecules. In this article, based on density functional theory, we have calculated and analyzed the electrical characteristics of the contact between aromatic molecules and silicon (100) − 2×1 surfaces. Design principles for silicon based electrodes of electrochemically biomolecular sensing instruments for label-free sensing of single or a few biomolecular molecules have also been discussed.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1028
Author(s):  
Na Zhao ◽  
Qijing Lin ◽  
Kun Yao ◽  
Fuzheng Zhang ◽  
Bian Tian ◽  
...  

The optical fiber temperature and refractive index sensor combined with the hollow needle structure for medical treatment can promote the standardization of traditional acupuncture techniques and improve the accuracy of body fluid analysis. A double-parameter sensor based on fiber Bragg grating (FBG) is developed in this paper. The sensor materials are selected through X-ray diffraction (XRD) analysis, and the sensor sensing principle is theoretically analyzed and simulated. Through femtosecond laser writing pure silica fiber, a high temperature resistant wavelength type FBG temperature sensor is obtained, and the FBG is corroded by hydrofluoric acid (HF) to realize a high-sensitivity intensity-type refractive index sensor. Because the light has dual characteristics of energy and wavelength, the sensor can realize simultaneous dual-parameter sensing. The light from the lead-in optical fiber is transmitted to the sensor and affected by temperature and refractive-index; then, the reflection peak is reflected back to the lead-out fiber by the FBG. The high temperature response and the refractive index response of the sensor were measured in the laboratory, and the high temperature characteristics of the sensor were verified in the accredited institute. It is demonstrated that the proposed sensor can achieve temperature sensing up to 1150 °C with the sensitivity of 0.0134 nm/°C, and refractive sensing over a refractive range of 1.333 to 1.4027 with the sensitivity of −49.044 dBm/RIU. The sensor features the advantages of two-parameter measurement, compact structure, and wide temperature range, and it exhibits great potential in acupuncture treatment.


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