Low-cost planar waveguide-based optofluidic sensor for real-time refractive index sensing

Abstract

We report on the design, fabrication, and characterization of mass-producible, sensitive, intensity-detection-based planar waveguide sensors for rapid refractive index (RI) sensing; the sensors comprise suspended glass planar waveguides on glass substrates, and are integrated with microfluidic channels. They are facilely and cost-effectively constructed via vacuum-less processes. They yield a high throughput, enabling mass production. The sensors respond to solutions with different RIs via variations in the transmitted optical power due to coupling loss in the sensing region, facilitating real-time and simple RI detection. Experiments yield a good resolution of 5.65 × 10−4 RIU. This work has major implications for several RI-sensing-based applications.

A 3D-cascade-microlens optofluidic chip for refractometry with adjustable sensitivity

“…The LoD was calculated as 0.04% salinity according to three times of the standard deviation of baseline level and the regression equation, representing a significant improvement compared to the reported value 1% (w/w) using waveguidebased intensity modulation. 21 3.4.2 Urine specific gravity. Urine specific gravity is a central parameter indicating the hydration balance in the body and urinary health.…”

“…Additionally, although intensity modulation can function for interferometric methods as well, complexity and difficulty in structure fabrication may limit their scale-up productions. 21 For example, FBGs and PCFs have high requirements in micro and nanostructure precision while functionalization procedures e.g. mirror coating for Fabry-Pérot resonators and gold deposition for SPR sensors have to be precisely performed to achieve satisfactory reproducibility.…”

“…Due to the low fabrication complexity and the employment of a silicon photodiode as the detector, low cost and mass production was feasible. 21 An optofluidic prism represents another refractometric structure sensitive to RI. [23][24][25] For example, Chao et al used a prism chip to measure the refractive index ranging from 1.33 to 1.52, although the resolution was lower than 5 × 10 −3 RIU.…”

Polymer Optical Waveguide Grating-Based Biosensor to Detect Effective Drug Concentrations of Ginkgolide A for Inhibition of PMVEC Apoptosis

“…The liquid chromatography technique is a main detection method for analyzing drug monomers, but this technology also has some limitations, such as the long sample preparation time, multi-step operation, and high cost [4,5]. In comparison, optical waveguide sensors with high sensitivity, high integration, and high compatibility have been proposed to achieve highly precise biomedical detection, aimed at special selection of matter based on lab-on-chip application [6][7][8][9][10]. Some typical waveguide structures have been used to define sensors such as interferometers [11], resonators [12], and gratings [13].…”

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

“…Planar waveguide-based sensors have shown great potential in several application fields and represent an active research area. The development of these devices has mainly been boosted by the increasing need for rapid and automated devices to operate in several areas [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. In particular, these kinds of platforms can also be used to exploit Surface Plasmon Resonance (SPR) and Localized Surface Plasmon Resonance (LSPR) phenomena in order to achieve excellent performances in biosensing applications [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ].…”