scholarly journals State-of-the-Art Optical Devices for Biomedical Sensing Applications—A Review

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 973
Author(s):  
N. L. Kazanskiy ◽  
S. N. Khonina ◽  
M. A. Butt ◽  
A. Kaźmierczak ◽  
R. Piramidowicz

Optical sensors for biomedical applications have gained prominence in recent decades due to their compact size, high sensitivity, reliability, portability, and low cost. In this review, we summarized and discussed a few selected techniques and corresponding technological platforms enabling the manufacturing of optical biomedical sensors of different types. We discussed integrated optical biosensors, vertical grating couplers, plasmonic sensors, surface plasmon resonance optical fiber biosensors, and metasurface biosensors, Photonic crystal-based biosensors, thin metal films biosensors, and fiber Bragg grating biosensors as the most representative cases. All of these might enable the identification of symptoms of deadly illnesses in their early stages; thus, potentially saving a patient’s life. The aim of this paper was not to render a definitive judgment in favor of one sensor technology over another. We presented the pros and cons of all the major sensor systems enabling the readers to choose the solution tailored to their needs and demands.


2021 ◽  
Vol 9 ◽  
Author(s):  
Xiao-Guang Gao ◽  
Ling-Xiao Cheng ◽  
Wen-Shuai Jiang ◽  
Xiao-Kuan Li ◽  
Fei Xing

Being the first successfully prepared two-dimensional material, graphene has attracted extensive attention from researchers due to its excellent properties and extremely wide range of applications. In particular, graphene and its derivatives have displayed several ideal properties, including broadband light absorption, ability to quench fluorescence, excellent biocompatibility, and strong polarization-dependent effects, thus emerging as one of the most popular platforms for optical sensors. Graphene and its derivatives-based optical sensors have numerous advantages, such as high sensitivity, low-cost, fast response time, and small dimensions. In this review, recent developments in graphene and its derivatives-based optical sensors are summarized, covering aspects related to fluorescence, graphene-based substrates for surface-enhanced Raman scattering (SERS), optical fiber biological sensors, and other kinds of graphene-based optical sensors. Various sensing applications, such as single-cell detection, cancer diagnosis, protein, and DNA sensing, are introduced and discussed systematically. Finally, a summary and roadmap of current and future trends are presented in order to provide a prospect for the development of graphene and its derivatives-based optical sensors.



Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 125
Author(s):  
Shubin Yan ◽  
Haoran Shi ◽  
Xiaoyu Yang ◽  
Jing Guo ◽  
Wenchang Wu ◽  
...  

Due to their compact size and high sensitivity, plasmonic sensors have become a hot topic in the sensing field. A nanosensor structure, comprising the metal–insulator–metal (MIM) waveguide with a stub and a horizontal B-Type cavity, is designed as a refractive index sensor. The spectral characteristics of proposed structure are analyzed via the finite element method (FEM). The results show that there is a sharp Fano resonance profile, which is excited by a coupling between the MIM waveguide and the horizontal B-Type cavity. The normalized HZ field is affected by the difference value between the outer radii R1 and R2 of the semi-circle of the horizontal B-Type cavity greatly. The influence of every element of the whole system on sensing properties is discussed in depth. The sensitivity of the proposed structure can obtain 1548 nm/RIU (refractive index unit) with a figure of merit of 59. The proposed structure has potential in nanophotonic sensing applications.



2021 ◽  
Vol 2075 (1) ◽  
pp. 012010
Author(s):  
Nurul Athirah Mohamad Abdul Ghafar ◽  
Arni Munira Markom ◽  
Marni Azira Markom ◽  
Ahmad Razif Muhammad

Abstract Heavy metal contaminations such as mercury, lead, arsenic, cadmium, and zinc are becoming more serious and have become a hazard to human health. Due to their non-biodegradable nature, they can easily accumulate in the environment and cause toxicity even at low concentrations. Therefore, detecting the presence of these metal ions requires a highly sensitive sensing method. Traditional detection methods, such as electrochemical analysis, require complicated sample preparation, are costly, and typically require a lengthy measurement period. These days, optical fiber sensors have been acknowledged due to their unique characteristics such as compact size, high sensitivity, low cost, high flexibility, and immunity to electromagnetic interference. An overview of an optical fiber sensor technology for heavy chemical measurement is discussed in this paper. The sensing mechanisms are summarized, as well as the chemical water quality parameters and sensitivities.



Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 583 ◽  
Author(s):  
Chun Lin ◽  
Chyuan Kao ◽  
Chan Lin ◽  
Kuan Chen ◽  
Yun Lin

This study compared the sensing characteristics of ZnO (ZO) treated with ammonia (NH3) plasma for 1 min, 3 min, and 6 min, under the EIS structure. The measurement results revealed that, after 3 min of NH3 plasma treatment, the Mg-doped ZnO (MZO) sensing film had a high hydrogen ion sensitivity, linearity, hysteresis, and drift rate of 53.82 mV/pH, 99.04%, 2.52 mV, and 1.75 mV/h, respectively. The sensing film was used with sodium and potassium ion solutions, and it performed satisfactorily in sensing hydrogen ions. Additionally, we investigated the biomedical sensing properties of Mg-doped ZnO (MZO) sensing film with regard to urea, creatinine, and glucose solutions and found that the Mg-doped ZnO (MZO) sensing film treated with NH3 plasma for 3 min had the best properties for sensing urea, creatinine, and glucose. Specifically, with glucose, the sensing film achieved the best linearity and sensitivity and of 97.87% and 10.73 mV/mM, respectively. The results revealed that the sensing characteristics varied with the processing environment and are useful in the developing biomedical sensing applications with different sensing elements.



Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5196 ◽  
Author(s):  
Young-Geun Han

Recent research and development progress of relative humidity sensors using microfiber knot resonators (MKRs) are reviewed by considering the physical parameters of the MKR and coating materials sensitive to improve the relative humidity sensitivity. The fabrication method of the MKR based on silica or polymer is briefly described. The many advantages of the MKR such as strong evanescent field, a high Q-factor, compact size, and high sensitivity can provide a great diversity of sensing applications. The relative humidity sensitivity of the MKR is enhanced by concerning the physical parameters of the MKR, including the waist or knot diameter, sensitive materials, and Vernier effect. Many techniques for depositing the sensitive materials on the MKR surface are discussed. The adsorption effects of water vapor molecules on variations in the resonant wavelength and the transmission output of the MKR are described regarding the materials sensitive to relative humidity. The sensing performance of the MKR-based relative humidity sensors is discussed, including sensitivity, resolution, and response time.



2016 ◽  
Vol 1812 ◽  
pp. 77-82
Author(s):  
J. Márquez ◽  
M. De la Cruz-Guzmán ◽  
L.F. Cházaro ◽  
G. Palestino

ABSTRACTPorous silicon (PSi) combines the potential of miniaturization with a very large surface area. The PSi surface can be chemically modified resulting in a high sensitivity (low detection threshold) device for chemical and biomolecular sensing. In previous work, we have shown that redox proteins and fluorescent ligands can be infiltrated into PSi (PSiMc) structures. The hybrid devices have shown interesting new properties produced by the coupling of the individual properties of PSi nanostructures and the modifiers. In this work, we have obtained a PSiMc/redox protein bioelectrode, which presents a quasi-reversible electrochemical response. This effect was attributed to the semiconducting nature of the PSi substrate and to the functional groups of the crosslinking molecules (MPTS), which together produce a capacitive effect on the device. On the other hand, the chemical modification of PSiMc with fluorescent ligands allowed us to fabricate fluorescent PSi hybrid nanostructures, which were tested for the detection of environmental pollutants such as heavy metals (specifically Hg2+). We found that the selectivity of this optical device depends on the selected recognizing molecule. The captured metal induces the formation of a metallic complex that shows higher fluorescence compared with the sensor device. These results demonstrate the viability of using porous silicon as optical sensors and electrochemical biosensors. The infiltration of fluorescent recognizing molecules and proteins into the PSi matrix were evaluated by specular reflectance, FTIR spectroscopy, fluorescence spectroscopy and cyclic voltammetry.



2018 ◽  
Vol 7 (3.12) ◽  
pp. 648 ◽  
Author(s):  
Miranji Katta ◽  
Sandanalakshmi R

From past few years, there is a revolutionary progress in biomedical sensing applications as a result of incredible growth in technological advancements. The biomedical sensors play a key role in the global market and it is estimated to reach 15.01 Billion US$ by 2022. As a worldwide research focus, there is especially a strong interest in the use of micro and Nanosystems in health monitoring. Most of the researchers applying innovative techniques to noninvasive patient monitoring and diagnostics developed with micro and nanofabricated technologies like MEMS/NEMS. Which provides more compact, inexpensive, accurate, and reliable detection tools to identify more life-threatening diseases in early times. This review paper will focus on various tropical disease detection methods and scope of the BioMEMS towards the detection of more prevalent tropical diseases.    



Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3308 ◽  
Author(s):  
Zhihua Wei ◽  
Jie Huang ◽  
Jing Li ◽  
Junshan Li ◽  
Xuyang Liu ◽  
...  

In this study, an ultra-compact humidity sensor based on a double-folded substrate integrated waveguide (SIW) re-entrant cavity was proposed and analyzed. By folding a circular re-entrant cavity twice along its two orthogonally symmetric planes, the designed structure achieved a remarkable size reduction (up to 85.9%) in comparison with a conventional TM010-mode circular SIW cavity. The operating principle of the humidity sensor is based on the resonant method, in other words, it utilizes the resonant properties of the sensor as signatures to detect the humidity condition of the ambient environment. To this end, a mathematical model quantitatively relating the resonant frequency of the sensor and the relative humidity (RH) level was established according to the cavity perturbation theory. The sensing performance of the sensor was experimentally validated in a RH range of 30%–80% by using a humidity chamber. The measured absolute sensitivity of the sensor was calculated to be 135.6 kHz/%RH, and the corresponding normalized sensitivity was 0.00627%/%RH. It was demonstrated that our proposed sensor not only has the merits of compact size and high sensitivity, but also benefits from a high Q-factor and ease of fabrication and integration. These advantages make it an excellent candidate for humidity sensing applications in various fields such as the agricultural, pharmaceutical, and food industries.



Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 300 ◽  
Author(s):  
Siqi Hu ◽  
Guofeng Yan ◽  
Chunzhou Wu ◽  
Sailing He

An ethanol vapor sensor based on a microfiber with a quantum-dot (QD) gel coating is proposed and demonstrated. The QD gel was made from UV glue as the gel matrix and CdSe/ZnS QDs with a concentration of 1 mg/mL. The drawing and coating processes were conducted by using a simple and low-cost system developed for this study. Bending, ethanol sensing, temperature response, and time response tests were carried out, respectively. The experimental results showed that the fabricated sensor had a high sensitivity of −3.3%/ppm, a very low temperature cross-sensitivity of 0.17 ppm/°C, and a fast response time of 1.1 s. The easily fabricated robust structure and the excellent sensing performance render the sensor a promising platform for real ethanol sensing applications.



2018 ◽  
Vol 96 (4) ◽  
pp. 359-365
Author(s):  
Yanping Xu ◽  
Xiaoyi Bao

Micro-structured fibers are important devices that have drawn intensive attentions and proved to be powerful platforms for various applications over the past decades due to their remarkable merits and advantages, such as small footprint, immunity to electromagnetic interferences, light weight, high physical flexibility, and low cost. Modifications in optical fibers can be used as light-steering elements to excite and couple back different core and cladding modes and form various in-fiber structures, including in-line fiber interferometer, fiber micro-cantilever, fiber random gratings, and so on. These micro-structures, when applied as fiber-optic sensors in the presence of external disturbances, show high sensitivity in terms of the significant changes in the guided light features. Novel micro-structured bend-insensitive fiber-based in-line fiber interferometer and micro-cantilever have been proposed to realize both static and dynamic parameter measurements, including temperature, axial strain, surrounding refractive index, and vibration. We have also developed a novel fiber random grating along with a spectral correlation algorithm for simultaneous measurement of three static measurands. To move a step forward, random fiber lasers based on fiber random grating are achieved for either improving the laser performances or sensing applications of temperature, strain, and ultrasound measurements with high sensitivity.



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