scholarly journals A Nanoplasmonic-Based Biosensing Approach for Wide-Range and Highly Sensitive Detection of Chemicals

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1961
Author(s):  
Francesco Arcadio ◽  
Luigi Zeni ◽  
Aldo Minardo ◽  
Caterina Eramo ◽  
Stefania Di Di Ronza ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Limit Of Detection ◽  
Slab Waveguide ◽  
Grating Pattern ◽  
Transparent Substrate ◽  
Synthetic Receptor ◽  
Sensing Applications ◽  
Wide Range ◽  
Plastic Optical Fibers ◽  
Highly Sensitive Detection

In a specific biosensing application, a nanoplasmonic sensor chip has been tested by an experimental setup based on an aluminum holder and two plastic optical fibers used to illuminate and collect the transmitted light. The studied plasmonic probe is based on gold nanograting, realized on the top of a Poly(methyl methacrylate) (PMMA) chip. The PMMA substrate could be considered as a transparent substrate and, in such a way, it has been already used in previous work. Alternatively, here it is regarded as a slab waveguide. In particular, we have deposited upon the slab surface, covered with a nanograting, a synthetic receptor specific for bovine serum albumin (BSA), to test the proposed biosensing approach. Exploiting this different experimental configuration, we have determined how the orientation of the nanostripes forming the grating pattern, with respect to the direction of the input light (longitudinal or orthogonal), influences the biosensing performances. For example, the best limit of detection (LOD) in the BSA detection that has been obtained is equal to 23 pM. Specifically, the longitudinal configuration is characterized by two observable plasmonic phenomena, each sensitive to a different BSA concentration range, ranging from pM to µM. This aspect plays a key role in several biochemical sensing applications, where a wide working range is required.

scholarly journals Suspended-Core Microstructured Polymer Optical Fibers and Potential Applications in Sensing

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3449 ◽  
Author(s):  
Wanvisa Talataisong ◽  
Rand Ismaeel ◽  
Martynas Beresna ◽  
Gilberto Brambilla
Keyword(s):  
Optical Fibers ◽  
Material Selection ◽  
Biological Species ◽  
Single Step ◽  
3D Printer ◽  
Sensing Applications ◽  
Wide Range ◽  
Potential Applications ◽  
Pressure Chemical ◽  
Polymer Optical Fibers

The study of the fabrication, material selection, and properties of microstructured polymer optical fibers (MPOFs) has long attracted great interest. This ever-increasing interest is due to their wide range of applications, mainly in sensing, including temperature, pressure, chemical, and biological species. This manuscript reviews the manufacturing of MPOFs, including the most recent single-step process involving extrusion from a modified 3D printer. MPOFs sensing applications are then discussed, with a stress on the benefit of using polymers.

scholarly journals One-rod core microstructured optical fibers for evanescent sensing applications: an alternative approach

2021 ◽  
Author(s):  
Dinesh Kumar Sharma ◽  
Saurabh Mani Tripathi
Keyword(s):  
Optical Fibers ◽  
Structural Parameters ◽  
Sensitivity Coefficient ◽  
Confinement Loss ◽  
Microstructured Optical Fibers ◽  
Sensing Applications ◽  
Alternative Approach ◽  
Plastic Optical Fibers ◽  
Relative Errors ◽  
Mode Area

Abstract The advent of polymer (or plastic) optical fibers (POFs) with porous cross-section has contributed significantly to the sensing applications. We intend to explore the sensing attributes of polymer-based one-rod core microstructured optical fibers (P-MOFs) via utilizing an auxiliary approach. The sensitivity coefficient and the overlapping factor of P-MOF’s introduced design in air-filled and water-filled layouts against the structural parameters are exploited. We reported the overlapping factor of ~ 94% and ~ 82% for the said configurations of the fibers, respectively, at the wavelength of 0.633 µm. The confinement loss, mode-index, and effective mode-area are also evaluated for the anticipated structures. For assessing the confinement loss, an alternative approach based on double-clad fiber (DCF) approximation is employed. The validity of the simulated results is scrutinized with those as documented in the literature. Relative errors are also tabulated.

scholarly journals Highly Sensitive Electrochemical Biosensor Using Folic Acid-Modified Reduced Graphene Oxide for the Detection of Cancer Biomarker

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1272
Author(s):  
Renu Geetha Bai ◽  
Kasturi Muthoosamy ◽  
Rando Tuvikene ◽  
Huang Nay Ming ◽  
Sivakumar Manickam
Keyword(s):  
Graphene Oxide ◽  
Folic Acid ◽  
Reduced Graphene Oxide ◽  
Limit Of Detection ◽  
Differential Pulse ◽  
Great Promise ◽  
Sensing Applications ◽  
Reduced Graphene ◽  
Highly Sensitive ◽  
Highly Sensitive Detection

The detection of cancer biomarkers in the early stages could prevent cancer-related deaths significantly. Nanomaterials combined with biomolecules are extensively used in drug delivery, imaging, and sensing applications by targeting the overexpressed cancer proteins such as folate receptors (FRs) to control the disease by providing earlier treatments. In this investigation, biocompatible reduced graphene oxide (rGO) nanosheets combined with folic acid (FA)-a vitamin with high bioaffinity to FRs-is utilized to develop an electrochemical sensor for cancer detection. To mimic the cancer cell environment, FR-β protein is used to evaluate the response of the rGO-FA sensor. The formation of the rGO-FA nanocomposite was confirmed through various characterization techniques. A glassy carbon (GC) electrode was then modified with the obtained rGO-FA and analyzed via differential pulse voltammetry (DPV) for its specific detection towards FRs. Using the DPV technique, the rGO-FA-modified electrode exhibited a limit of detection (LOD) of 1.69 pM, determined in a linear concentration range from 6 to 100 pM. This excellent electrochemical performance towards FRs detection could provide a significant contribution towards future cancer diagnosis. Moreover, the rGO-FA sensing platform also showed excellent specificity and reliability when tested against similar interfering biomolecules. This rGO-FA sensor offers a great promise to the future medical industry through its highly sensitive detection towards FRs in a fast, reliable, and economical way.

Validated Stability Indicating HPTLC Method for the Estimation of Amoxapine in Different Stress Conditions

2019 ◽  
Vol 15 (3) ◽  
pp. 273-279
Author(s):  
Shweta G. Rangari ◽  
Nishikant A. Raut ◽  
Pradip W. Dhore
Keyword(s):  
High Performance ◽  
Limit Of Detection ◽  
Degradation Products ◽  
Analysis Data ◽  
Peak Height ◽  
Good Resolution ◽  
Stability Indicating ◽  
Limit Of Quantitation ◽  
Wide Range ◽  
Hptlc Method

Background:The unstable and/or toxic degradation products may form due to degradation of drug which results into loss of therapeutic activity and lead to life threatening condition. Hence, it is important to establish the stability characteristics of drug in various conditions such as in temperature, light, oxidising agent and susceptibility across a wide range of pH values.Introduction:The aim of the proposed study was to develop simple, sensitive and economic stability indicating high performance thin layer chromatography (HPTLC) method for the quantification of Amoxapine in the presence of degradation products.Methods:Amoxapine and its degraded products were separated on precoated silica gel 60F254 TLC plates by using mobile phase comprising of methanol: toluene: ammonium acetate (6:3:1, v/v/v). The densitometric evaluation was carried out at 320 nm in reflectance/absorbance mode. The degradation products obtained as per ICH guidelines under acidic, basic and oxidative conditions have different Rf values 0.12, 0.26 and 0.6 indicating good resolution from each other and pure drug with Rf: 0.47. Amoxapine was found to be stable under neutral, thermal and photo conditions.Results:The method was validated as per ICH Q2 (R1) guidelines in terms of accuracy, precision, ruggedness, robustness and linearity. A good linear relationship between concentration and response (peak area and peak height) over the range of 80 ng/spot to 720 ng/spot was observed from regression analysis data showing correlation coefficient 0.991 and 0.994 for area and height, respectively. The limit of detection (LOD) and limit of quantitation (LOQ) for area were found to be 1.176 ng/mL and 3.565 ng/mL, whereas for height, 50.063 ng/mL and 151.707 ng/mL respectively.Conclusion:The statistical analysis confirmed the accuracy, precision and selectivity of the proposed method which can be effectively used for the analysis of amoxapine in the presence of degradation products.

Signal Processing Enhanced Fiber Vibration Sensors

2013 ◽  
Vol 543 ◽  
pp. 302-305
Author(s):  
Daniele Tosi ◽  
Massimo Olivero ◽  
Alberto Vallan ◽  
Guido Perrone
Keyword(s):  
Signal Processing ◽  
Optical Fibers ◽  
Adaptive Filters ◽  
Spectral Estimation ◽  
Cost Effective ◽  
Fiber Sensors ◽  
High Frequencies ◽  
Vibration Sensors ◽  
Signal Processing Algorithms ◽  
Plastic Optical Fibers

The paper analyzes the feasibility of cost-effective fiber sensors for the measurement of small vibrations, from low to medium-high frequencies, in which the complexity of the measurement is moved from expensive optics to cheap electronics without losing too much performance thanks to signal processing algorithms. Two optical approaches are considered: Bragg gratings in standard telecom fibers, which represent the most common type of commercial fiber sensors, and specifically developed sensors made with plastic optical fibers. In both cases, to keep the overall cost low, vibrations are converted into variations of the light intensity, although this makes the received signal more sensitive to noise. Then, adaptive filters and advanced spectral estimation techniques are used to mitigate noise and improve the sensitivity. Preliminary results have demonstrated that the combined effect of these techniques can yield to a signal-to-noise improvement of about 30 dB, bringing the proposed approaches to the level of the most performing sensors for the measurement of vibrations.

scholarly journals Strain Sensor via Wood Anomalies in 2D Dielectric Array

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1022
Author(s):  
Rashid G. Bikbaev ◽  
Ivan V. Timofeev ◽  
Vasiliy F. Shabanov
Keyword(s):  
Higher Plants ◽  
Numerical Study ◽  
Reciprocal Lattice ◽  
Strain Sensing ◽  
Photonic Materials ◽  
Sensing Applications ◽  
Wide Range ◽  
Sensor Structure ◽  
Optical Behavior ◽  
Chlorophyll Absorption

Optical sensing is one of many promising applications for all-dielectric photonic materials. Herein, we present an analytical and numerical study on the strain-responsive spectral properties of a bioinspired sensor. The sensor structure contains a two-dimensional periodic array of dielectric nanodisks to mimic the optical behavior of grana lamellae inside chloroplasts. To accumulate a noticeable response, we exploit the collective optical mode in grana ensemble. In higher plants, such a mode appears as Wood’s anomaly near the chlorophyll absorption line to control the photosynthesis rate. The resonance is shown persistent against moderate biological disorder and deformation. Under the stretching or compression of a symmetric structure, the mode splits into a couple of polarized modes. The frequency difference is accurately detected. It depends on the stretch coefficient almost linearly providing easy calibration of the strain-sensing device. The sensitivity of the considered structure remains at 5 nm/% in a wide range of strain. The influence of the stretching coefficient on the length of the reciprocal lattice vectors, as well as on the angle between them, is taken into account. This adaptive phenomenon is suggested for sensing applications in biomimetic optical nanomaterials.

scholarly journals Melt-Spun Photoluminescent Polymer Optical Fibers for Color-Tunable Textile Illumination

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1740
Author(s):  
Konrad Jakubowski ◽  
Manfred Heuberger ◽  
Rudolf Hufenus
Keyword(s):  
Energy Transfer ◽  
Optical Fibers ◽  
Color Space ◽  
Emission Spectra ◽  
Wide Range ◽  
Color Tunable ◽  
Melt Spun ◽  
Polymer Optical Fibers ◽  
Collective Emission ◽  
Down Conversion

The increasing interest in luminescent waveguides, applied as light concentrators, sensing elements, or decorative illuminating systems, is fostering efforts to further expand their functionality. Yarns and textiles based on a combination of distinct melt-spun polymer optical fibers (POFs), doped with individual luminescent dyes, can be beneficial for such applications since they enable easy tuning of the color of emitted light. Based on the energy transfer occurring between differently dyed filaments within a yarn or textile, the collective emission properties of such assemblies are adjustable over a wide range. The presented study demonstrates this effect using multicolor, meltspun, and photoluminescent POFs to measure their superimposed photoluminescent emission spectra. By varying the concentration of luminophores in yarn and fabric composition, the overall color of the resulting photoluminescent textiles can be tailored by the recapturing of light escaping from individual POFs. The ensuing color space is a mean to address the needs of specific applications, such as decorative elements and textile illumination by UV down-conversion.

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