A fluorescence-based pH sensor with microfluidic mixing and fiber optic detection for wide range pH measurements

Moradi, Vahid; Akbari, Mohsen; Wild, Peter

doi:10.1016/j.sna.2019.07.031

Cited by 31 publications

(18 citation statements)

References 60 publications

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“…In detail, we combined optical waveguides, realized by the thermal diffusion of titanium thin stripes on LN, with a microfluidic channel mechanically engraved onto the same substrates by means of a self-polishing saw. This microfabrication strategy allows achieving a perfect alignment across the microchannel of the input and the output waveguides, overcoming the typical limitations typically occurring in the optical fiber embedding process [ 8 , 9 , 10 , 11 , 12 , 55 ]. Then, the coupling between the optical and fluidic components of the device has been demonstrated to efficiently work for different channel sizes—i.e., 50 and 200 µm.…”

Section: Discussionmentioning

confidence: 99%

“…Nevertheless, the integration of complex protocols could provide some issues in the miniaturization of multiple stages in these materials—for instance, the integration of optical probes. In fact, in this case, they are typically implemented in such devices by either the embedding of optical fibers [ 8 , 9 , 10 , 11 , 12 ] or by the realization of optical waveguides [ 13 , 14 , 15 , 16 , 17 ], using the polymer itself. However, the first solution shows the problem of reproducibility related to the alignment of the fibers with the other LOC components, leading each device to have different performances; meanwhile, the second still shows high light losses compared to the standard photonics materials due to their poor optical properties.…”

Section: Introductionmentioning

confidence: 99%

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Opto-Microfluidic System for Absorbance Measurements in Lithium Niobate Device Applied to pH Measurements

Zamboni

Zaltron

Izzo

et al. 2020

Sensors

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The aim of Lab-on-a-chip systems is the downscaling of analytical protocols into microfluidic devices, including optical measurements. In this context, the growing interest of the scientific community in opto-microfluidic devices has fueled the development of new materials. Recently, lithium niobate has been presented as a promising material for this scope, thanks to its remarkable optical and physicochemical properties. Here, we present a novel microfluidic device realized starting from a lithium niobate crystal, combining engraved microfluidic channels with integrated and self-aligned optical waveguides. Notably, the proposed microfabrication strategy does not compromise the optical coupling between the waveguides and the microchannel, allowing one to measure the transmitted light through the liquid flowing in the channel. In addition, the device shows a high versatility in terms of the optical properties of the light source, such as wavelength and polarization. Finally, the developed opto-microfluidic system is successfully validated as a probe for real-time pH monitoring of the liquid flowing inside the microchannel, showing a high integrability and fast response.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Opto-Microfluidic System for Absorbance Measurements in Lithium Niobate Device Applied to pH Measurements

Zamboni

Zaltron

Izzo

et al. 2020

Sensors

View full text Add to dashboard Cite

show abstract

“…Besides the analysis of sweat, based on the changes of fluorescence intensity, these devices can incorporate modules of light sources, polymer optical fibers and photodetectors to detect pH concentrations. In one study, a type of fluorescence-based optical devices implemented on a microfluidic chip was designed to measure pH concentrations [ 79 ]. The fluorescence dye named 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS) is biocompatible and photostable.…”

Section: Integrated Wearable Optical Devicesmentioning

confidence: 99%

“…The fluorescence intensity is highly sensitive to pH that is correlated to resulting voltage at PD. Notably, a laser cutting method has been used in fabricating the microfluidic channels of PMMA-based chip [ 79 ].…”

Section: Integrated Wearable Optical Devicesmentioning

confidence: 99%

Optical Waveguides and Integrated Optical Devices for Medical Diagnosis, Health Monitoring and Light Therapies

Wang

Dong

2020

Sensors

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Optical waveguides and integrated optical devices are promising solutions for many applications, such as medical diagnosis, health monitoring and light therapies. Despite the many existing reviews focusing on the materials that these devices are made from, a systematic review that relates these devices to the various materials, fabrication processes, sensing methods and medical applications is still seldom seen. This work is intended to link these multidisciplinary fields, and to provide a comprehensive review of the recent advances of these devices. Firstly, the optical and mechanical properties of optical waveguides based on glass, polymers and heterogeneous materials and fabricated via various processes are thoroughly discussed, together with their applications for medical purposes. Then, the fabrication processes and medical implementations of integrated passive and active optical devices with sensing modules are introduced, which can be used in many medical fields such as drug delivery and cardiovascular healthcare. Thirdly, wearable optical sensing devices based on light sensing methods such as colorimetry, fluorescence and luminescence are discussed. Additionally, the wearable optical devices for light therapies are introduced. The review concludes with a comprehensive summary of these optical devices, in terms of their forms, materials, light sources and applications.

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“…A more accessible approach is manufacturing PMMA microfluidic systems. Moradi et al recently used this technique for development of a pH sensor [12]. They used a double sided tape for bonding consecutive layers.…”

Section: Introductionmentioning

confidence: 99%

3D-Printed Microfluidic Sensor for Fluorescence Measurements

Nawrot

Gzubicka

Malecha

2020

Period. Polytech. Elec. Eng. Comp. Sci.

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In this work a fluorescent microfluidic sensor is developed, manufactured and characterized through additive manufacturing technique, using transparent photopolymer. A technology widely known as 3D printing is very suitable for tailor-made microfluidic chips, as it allows for rapid manufacturing. Optical structures can be developed using transparent materials, and this work describes a technique for increasing light transmission through such structure. A complete, inexpensive electronic device is described, containing microfluidic chip, light source, photodetector, microcontroller, communication interface and a multifunctional package with embedded connectors. Performed analyses show that performed surface modification significantly improves light transmission through structure, the material does not show autofluorescence, and whole device is suitable for fluorescence measurements.

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A fluorescence-based pH sensor with microfluidic mixing and fiber optic detection for wide range pH measurements

Cited by 31 publications

References 60 publications

Opto-Microfluidic System for Absorbance Measurements in Lithium Niobate Device Applied to pH Measurements

Opto-Microfluidic System for Absorbance Measurements in Lithium Niobate Device Applied to pH Measurements

Optical Waveguides and Integrated Optical Devices for Medical Diagnosis, Health Monitoring and Light Therapies

3D-Printed Microfluidic Sensor for Fluorescence Measurements

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