Low-Cost Label-Free Bio-Detection System Using Double-Sided Grating Waveguide Couplers

Author(s):  
Yi-Fan Ku ◽  
Hsun-Yuan Li ◽  
Yu-Chung Lin ◽  
Wen-Hsin Hsieh ◽  
Guo-En Chang

Low-cost label-free bio-sensing systems have long been desired to enable rapid, sensitive, quantitative, and high-throughput biosensing for bio-medical and chemical applications. Here we present an optical bio-detection system consists of injection-molded biosensors based on double-sided grating waveguide couplers and an optical intensity-based detection platform for low-cost, real-time, and label-free biosensing. The biosensors were fabricated combining injection-molding and sputtering techniques, providing unique advantages of low-cost and reduced production time. A simple and cost-effective optical intensity-based detection system employing a low-cost light emitting diode and a simple photodetector is also developed to perform label-free biosensing. We demonstrate that a high refractive index resolution of 6.43 × 10−5 RIU is achieved with this compact bio-sensing system, showing great promises for low-cost, real-time, label-free detection in bio-medical and chemical applications.

Author(s):  
Pamela Martinez-Vega ◽  
Araceli Lopez-Badillo ◽  
J. Luis Luviano-Ortiz ◽  
Abel Hernandez-Guerrero ◽  
Jaime G. Cervantes

Abstract The modern world progressively demands more energy; according to forecasts energy consumption will grow at an average annual rate of 3 percent. Therefore, it is necessary to purchase products or devices that are efficient and environmentally friendly. Technology in LED (Light Emitting Diode) lighting is presented as an alternative to energy saving, since LEDs have proven to be extremely efficient, have a long service life and their cost-effective ratio is very good. However, the heat emitted by the LED chip must be dissipated effectively, since the overheating of the chip reduces the efficiency and lifetime of the lamp. Therefore, heat sinks that are reliable, efficient and inexpensive should be designed and built. The present work proposes new designs for heat sinks in LED lamps, some of the models in the design of the fins refer to the Fibonacci series. The models proposed in the present work that have a significant advantage are the Type 1E Model (5.2% mass savings and better thermal efficiency of 8.33%), GR Type 1 Model (3.12% lighter and 3.33% more efficient) and the GRL Type Model (4. 51% mass savings and 5.55% thermally more efficient) compared to the Type 2 Reference Model proposed by Jang et al. [12].


Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4861 ◽  
Author(s):  
Sumit Agrawal ◽  
Christopher Fadden ◽  
Ajay Dangi ◽  
Xinyi Yang ◽  
Hussain Albahrani ◽  
...  

Photoacoustic computed tomography (PACT) has been widely explored for non-ionizing functional and molecular imaging of humans and small animals. In order for light to penetrate deep inside tissue, a bulky and high-cost tunable laser is typically used. Light-emitting diodes (LEDs) have recently emerged as cost-effective and portable alternative illumination sources for photoacoustic imaging. In this study, we have developed a portable, low-cost, five-dimensional (x, y, z, t, λ ) PACT system using multi-wavelength LED excitation to enable similar functional and molecular imaging capabilities as standard tunable lasers. Four LED arrays and a linear ultrasound transducer detector array are housed in a hollow cylindrical geometry that rotates 360 degrees to allow multiple projections through the subject of interest placed inside the cylinder. The structural, functional, and molecular imaging capabilities of the LED–PACT system are validated using various tissue-mimicking phantom studies. The axial, lateral, and elevational resolutions of the system at 2.3 cm depth are estimated as 0.12 mm, 0.3 mm, and 2.1 mm, respectively. Spectrally unmixed photoacoustic contrasts from tubes filled with oxy- and deoxy-hemoglobin, indocyanine green, methylene blue, and melanin molecules demonstrate the multispectral molecular imaging capabilities of the system. Human-finger-mimicking phantoms made of a bone and blood tubes show structural and functional oxygen saturation imaging capabilities. Together, these results demonstrate the potential of the proposed LED-based, low-cost, portable PACT system for pre-clinical and clinical applications.


Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2951 ◽  
Author(s):  
Daniel Carreres-Prieto ◽  
Juan T. García ◽  
Fernando Cerdán-Cartagena ◽  
Juan Suardiaz-Muro

Local administrations demand real-time and continuous pollution monitoring in sewer networks. Spectroscopy is a non-destructive technique that can be used to continuously monitor quality in sewers. Covering a wide range of wavelengths can be useful for improving pollution characterization in wastewater. Cost-effective and in-sewer spectrophotometers would contribute to accomplishing discharge requirements. Nevertheless, most available spectrometers are based on incandescent lamps, which makes it unfeasible to place them in a sewerage network for real-time monitoring. This research work shows an innovative calibration procedure that allows (Light-Emitting Diode) LED technology to be used as a replacement for traditional incandescent lamps in the development of spectrophotometry equipment. This involves firstly obtaining transmittance values similar to those provided by incandescent lamps, without using any optical components. Secondly, this calibration process enables an increase in the range of wavelengths available (working range) through a better use of the LED’s spectral width, resulting in a significant reduction in the number of LEDs required. Thirdly, this method allows important reductions in costs, dimensions and consumptions to be achieved, making its implementation in a wide variety of environments possible.


2021 ◽  
Author(s):  
Mario Moisés Alvarez ◽  
Sergio Bravo-González ◽  
Everardo González-González ◽  
Grissel Trujillo-de Santiago

Loop-mediated isothermal amplification (LAMP) has been recently studied as an alternative method for cost-effective diagnostics in the context of the current COVID-19 pandemic. Recent reports document that LAMP-based diagnostic methods have a comparable sensitivity and specificity to that of RT-qPCR. We report the use of a portable Arduino-based LAMP-based amplification system assisted by pH microelectrodes for the accurate and reliable diagnosis of SARS-CoV-2 during the first 3 minutes of the amplification reaction. We show that this simple system enables a straightforward discrimination between samples containing or not containing artificial SARS-CoV-2 genetic material in the range of 10 to 10,000 copies per 50 μL of reaction mix. We also spiked saliva samples with SARS-CoV-2 synthetic material and corroborated that the LAMP reaction can be successfully monitored in real time using microelectrodes in saliva samples as well. These results may have profound implications for the design of real-time and portable quantitative systems for the reliable detection of viral pathogens including SARS-CoV-2.


2021 ◽  
pp. 155335062199776
Author(s):  
Deven K. Gupta ◽  
Lily Chen ◽  
Andrew E. Heidari ◽  
Steven Chau ◽  
Brandyn Dunn ◽  
...  

Need. Battery-powered Light Emitting Diode (LED) surgical headlights are necessary for improved intraoperative illumination but may be costly. Technical Solution. The objective of this study was to develop a low-cost surgical headlight using a consumer-grade LED headlight and 3D-printed mount. Proof of Concept. Eighteen surgical residents performed simulation exercises that mimicked suturing in the oral cavity using both a custom prototype headlight and a commercial surgical headlight. The time required to complete the task with each headlight was recorded along with an exit survey. A second device was created based on the critiques of the first device and was tested by ten additional surgical trainees. Surgical residents completed the simulation task in 27 ± 8.6 seconds and 21 ± 5.6 seconds with the commercially available headlight and first prototype, respectively. In the second experiment, the simulation task was completed in 23 ± 11.1 and 23 ± 12.2 seconds with the commercially available headlight and second device, respectively. Survey results showed an overall positive consensus, with critiques about headband security, suggestions for smaller LED chassis, and a more robust mounting bracket. Some preferred the prototype headlight due to the wider field of illumination compared to the commercially available unit (ie, beam spread/beam angle). Next Steps. Future adjustments are required to optimize the location of the headlight and the battery to modify the weight distribution of the device. Conclusion. These findings demonstrate that our prototype models are viable alternatives to conventional surgical headlights and warrant continued optimization for broader adoption by surgeons and trainees for whom higher-cost alternatives are not an option.


2018 ◽  
Vol 106 ◽  
pp. 105-110 ◽  
Author(s):  
Juan Gomez-Cruz ◽  
Srijit Nair ◽  
Angel Manjarrez-Hernandez ◽  
Sandra Gavilanes-Parra ◽  
Gabriel Ascanio ◽  
...  

2020 ◽  
pp. 095400832094538
Author(s):  
Deepika C Hasija ◽  
Vaijayanti D Ghase ◽  
Meenakshi M Rananaware ◽  
Vishwanath R Patil

A set of anthracene containing polyfluorenes (PFs) having 9,10-diphenylanthracene with alkyl substituents and aniline containing fluorenes were prepared. Commonly, light-emitting polymers were synthesized using expensive palladium-like catalysts. In the present work, palladium was replaced by copper as a cost-effective PF synthesis catalyst, which is also suitable for large-scale polymer synthesis. Synthesized PFs emit light in the blue region with a bandgap of 2.87–2.90 eV. Thermally stable PFs had a decomposition temperature of more than 305°C and a glass transition temperature of 125–138°C. PFs were soluble in organic solvents and had a molecular weight of around 21,700–25,500. The electrochemical study of these PFs showed low level of highest occupied molecular orbital (HOMO) energy of −5.16 to −5.26 eV, which was significantly higher than that of PF (5.7 eV). These findings suggested that the resulting PFs could be used as a component of the light-emitting diode.


2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Altamash Fakki ◽  
Salahaldein Ahmed ◽  
Jongwon Park ◽  
Chang-Soo Kim

There is an ever increasing need for simple, low-cost instruments for ubiquitous medical and environmental measurements in conjunction with networks and Internet-of-things. This work demonstrates that the optical mouse, one of the most common optoelectronic computer peripherals, can be used for chemical quantification. Particularly, we explore the feasibility of using the preassembled optical platform of mouse for oxygen and pH quantification. The image sensor and the light-emitting diode (LED) serve as photodetector and excitation/illumination light source, respectively, while the preinstalled microoptics (e.g., lens and waveguide) provide a fixed optical arrangement convenient for sample analysis. This novel, cost-effective approach demonstrates the potential application of optical mouse for bioanalytical devices in conjunction with commercial sensor strips or simple microfluidic elements. This is one viable option for seamless integration of bioanalytical capability into existing personal computers and associate networks without significant additional hardware.


Biosensors ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 386
Author(s):  
Mario Moisés Alvarez ◽  
Sergio Bravo-González ◽  
Everardo González-González ◽  
Grissel Trujillo-de Santiago

Loop-mediated isothermal amplification (LAMP) has been recently studied as an alternative method for cost-effective diagnostics in the context of the current COVID-19 pandemic. Recent reports document that LAMP-based diagnostic methods have a comparable sensitivity and specificity to that of RT-qPCR. We report the use of a portable Arduino-based LAMP-based amplification system assisted by pH microelectrodes for the accurate and reliable diagnosis of SARS-CoV-2 during the first 3 min of the amplification reaction. We show that this simple system enables a straightforward discrimination between samples containing or not containing artificial SARS-CoV-2 genetic material in the range of 10 to 10,000 copies per 50 µL of reaction mix. We also spiked saliva samples with SARS-CoV-2 synthetic material and corroborated that the LAMP reaction can be successfully monitored in real time using microelectrodes in saliva samples as well. These results may have profound implications for the design of real-time and portable quantitative systems for the reliable detection of viral pathogens including SARS-CoV-2.


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