Refractive Index Sensor by Interrogation of Etched MgO Nanoparticle-Doped Optical Fiber Signature

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Fiber Optic Refractive Index Distributed Multi-Sensors by Scattering-Level Multiplexing With MgO Nanoparticle-Doped Fibers

© 2020 IEEE. Personal use of this material is permitted. Permissíon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisíng or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.[EN] In this work, we present the architecture of a multiplexed refractive index (RI) sensing system based on the interrogation of Rayleigh backscattering. The RI sensors are fabricated by fiber wet-etching of a high-scattering MgO nanoparticle-doped fiber, without the need for a reflector or plasmonic element. Interrogation is performed by means of optical backscatter reflectometry(OBR), which allows a detection with a millimeter-level spatial resolution. Multiplexing consists of a simultaneous scan of multiple fibers, achieved by means of scattering-level multiplexing (SLMux) concept, which uses the backscattered power level in each location as a diversity element. The sensors fabricated have sensitivity in the order of 0.473-0.568 nm/RIU (in one sensing point) and have been simultaneously detected together with a distributed temperature sensing element for multi-parameter measurement. An experimental setup has been prepared to demonstrate the capability of each sensing region to operate without cross-talk, while operating multi-fiber detection.This work was supported in part by the ORAU Programme at Nazarbayev University (LIFESTART and FOSTHER Grants), in part by the Agence Nationale de la Recherche (ANR) Project NanoSlim under Grant ANR-17-17-CE08-0002, in part by the National Natural Science Foundation for Excellent Youth Foundation of China under Grant 61722505, in part by the Key Program of Guangdong Natural Science Foundation under Grant 2018B030311006, and in part by The Spanish Ministry of Economy and Competitiveness under Grant DIMENSION TEC2017 88029-R. The associate editor coordinating the review of this article and approving it for publication was Prof. Marco Petrovich.Ayupova, T.; Shaimerdenova, M.; Korganbayev, S.; Sypabekova, M.; Bekmurzayeva, A.; Blanc, W.; Sales Maicas, S.... (2020). Fiber Optic Refractive Index Distributed Multi-Sensors by Scattering-Level Multiplexing With MgO Nanoparticle-Doped Fibers. IEEE Sensors Journal. 20(5):2504-2510. https://doi.org/10.1109/JSEN.2019.2953231S2504251020

Disruption of Bcl-2 and Bcl-xL by viral proteins as a possible cause of cancer

The Bcl proteins play a critical role in apoptosis, as mutations in family members interfere with normal programmed cell death. Such events can cause cell transformation, potentially leading to cancer. Recent discoveries indicate that some viral proteins interfere with Bcl proteins either directly or indirectly; however, these data have not been systematically described. Some viruses encode proteins that reprogramme host cellular signalling pathways controlling cell differentiation, proliferation, genomic integrity, cell death, and immune system recognition. This review analyses and summarises the existing data and discusses how viral proteins interfere with normal pro- and anti-apoptotic functions of Bcl-2 and Bcl-xL. Particularly, this article focuses on how viral proteins, such as Herpesviruses, HTLV-1, HPV and HCV, block apoptosis and how accumulation of such interference predisposes cancer development. Finally, we discuss possible ways to prevent and treat cancers using a combination of traditional therapies and antiviral preparations that are effective against these viruses

Spatial-Division Multiplexing Approach for Simultaneous Detection of Fiber-Optic Ball Resonator Sensors: Applications for Refractometers and Biosensors

Fiber-optic ball resonators are an attractive technology for refractive index (RI) sensing and optical biosensing, as they have good sensitivity and allow for a rapid and repeatable manufacturing process. An important feature for modern biosensing devices is the multiplexing capacity, which allows for interrogating multiple sensors (potentially, with different functionalization methods) simultaneously, by a single analyzer. In this work, we report a multiplexing method for ball resonators, which is based on a spatial-division multiplexing approach. The method is validated on four ball resonator devices, experimentally evaluating both the cross-talk and the spectral shape influence of one sensor on another. We show that the multiplexing approach is highly efficient and that a sensing network with an arbitrary number of ball resonators can be designed with reasonable penalties for the sensing capabilities. Furthermore, we validate this concept in a four-sensor multiplexing configuration, for the simultaneous detection of two different cancer biomarkers across a widespread range of concentrations

Morphometric characteristics of cancer cells grown in embryonic microenvironment and under antiviral treatment

We describe here that both embryonic microenvironment treatment and antiviral treatment have the potential to serve as effective factors in changing morphometric characteristics of two highly aggressive cancer cell lines, with proven capability to decrease viability of cancer cells, reduce amount of colonies formed after treatment, alter intracellular features of cell such as nucleus and cytoskeleton and diminish aldehyde dehydrogenase activity after treatmen

Morphometric characteristics of cancer cells grown in embryonic microenvironment and under antiviral treatment

We describe here that both embryonic microenvironment treatment and antiviral treatment have the potential to serve as effective factors in changing morphometric characteristics of two highly aggressive cancer cell lines, with proven capability to decrease viability of cancer cells, reduce amount of colonies formed after treatment, alter intracellular features of cell such as nucleus and cytoskeleton and diminish aldehyde dehydrogenase activity after treatmen

SHALLOW-TAPERED CHIRPED FIBER BRAGG GRATING SENSORS FOR DUAL REFRACTIVE INDEX AND TEMPERATURE SENSING

In this work, we present a gold-coated shallow-tapered chirped fiber Bragg grating (stCFBG) for dual refractive index (RI) and temperature sensing. The stCFBG has been fabricated on a 15-mm long chirped FBG, by tapering a 7.29-mm region with a waist of 39 µm. The spectral analysis shows two distinct regions: a pre-taper region, in which the stCFBG is RI-independent and can be used to detect thermal changes, and a post-taper region, in which the reflectivity increases significantly when the RI increments. We estimate the RI and thermal sensitivities as 382.83 dB/RIU and 9.893 pm/◦C, respectively. The cross-talk values are low (−1.54 × 10−3 dB/◦C and 568.1 pm/RIU), which allows an almost ideal separation between RI and thermal characteristics. The stCFBG is a compact probe, suitable for long-term and temperature-compensated biosensing and detection of chemical analytes

Biocompatible scaffolds based on natural polymers for regenerative medicine

The chitosan and gelatine are commonly used biopolymers for the tissue engineering applications. In the previous methods for the cryogels synthesis, multistep preparation methods using toxic cross-linking agents such as glutaraldehyde are reported. Here, we present a two-step preparation method of gelatin macroporous cryogels and one-step preparation method of chitosan or gelatin cryogels. The physico-chemical properties of obtained scaffolds were characterized using FTIR, zeta potential, SEM and laser confocal microscopy. Non-toxic and biodegradable cross-linking agents such as oxidized dextran and 1,1,3,3-tetramethoxypropane are utilized. The one-step chitosan cryogels had degradation degree ~2 times higher compared to the cryogels prepared with a two-step method i.e. reduced by borohydride. Scaffolds cross-linked by glutaraldehyde had about 40% viability, whereas nine various compositions of cryogels showed significantly higher viability (~80%) of fibroblast cells in vitro. The cryogels were obtained without using the harmful compounds and therefore can be used straightforward as biocompatible and biodegradable scaffolds for the cell culturing purposes and other biomedical applications

FIBER OPTIC REFRACTIVE INDEX SENSORS BASED ON A BALL RESONATOR AND OPTICAL BACKSCATTER INTERROGATION

In this work, we introduced fabrication and interrogation of simple and highly sensitive fiber-optic refractive index (RI) sensors based on ball resonators built on the tip of single-mode fibers. The probes have been fabricated through a CO2 fiber splicer, with a fast (~600 s) and repeatable method. The ball resonator acted as a weak interferometer with a return loss below −50 dB and was interrogated with an optical backscatter reflectometer measuring the reflection spectrum. The ball resonators behaved as weak interferometers with a shallow fringe and a spectrum that appeared close to a random signal, and RI sensitivity could be measured either through wavelength shift or amplitude change. In this work, we reported four samples having sensitivity ranges 48.9–403.3 nm/RIU and 256.0–566.2 dB/RIU (RIU = refractive index unit). Ball resonators appeared as a sensitive and robust platform for RI sensing in liquid and can be further functionalized for biosensing. View Full-Text Keywords: optical fiber sensors; optical resonators; refractive index sensors; optical backscatter reflectometry; ball resonato