Demonstration of a Low-Cost and Portable Optical Cavity-Based Sensor through Refractive Index Measurements.

Donggee Rho,Seunghyun Kim,Caitlyn Breaux

doi:10.3390/s19092193

Abstract

An optical cavity-based sensor using a differential detection method has been proposed for point-of-care diagnostics. We developed a low-cost and portable optical cavity-based sensor system using a 3D printer and off-the-shelf optical components. In this paper, we demonstrate the sensing capability of the portable system through refractive index measurements. Fabricated optical cavity samples were tested using the portable system and compared to simulation results. A referencing technique and digital low pass filtering were applied to reduce the noise of the portable system. The measurement results match the simulation results well and show the improved linearity and sensitivity by employing the differential detection method. The limit of detection achieved was 1.73 × 10−5 Refractive Index Unit (RIU), which is comparable to other methods for refractive index sensing.

Highlights

For several leading causes of death worldwide, such as cancers, diabetes, respiratory diseases, and infectious diseases, early detection significantly increases survival rates by allowing timely initiation of treatment for patients [1]
The refractive index measurements using the portable system were performed on a table with wheels toThe demonstrate the sensitivity of the portable system in typical settings
Refractive index measurements using the portable system were user performed on aThe tablefluidic with wheels to demonstrate the sensitivity of the portable system in typical user settings

Summary

Introduction

For several leading causes of death worldwide, such as cancers, diabetes, respiratory diseases, and infectious diseases, early detection significantly increases survival rates by allowing timely initiation of treatment for patients [1]. Current diagnostic technologies are mostly expensive and time consuming as they require centralized laboratories equipped with costly instruments operated by trained personnel [2]. Enzyme-linked immunosorbent assay (ELISA) is the gold standard diagnostic tool for detecting protein biomarkers with high sensitivity, but it requires lengthy and complicated procedures performed in a laboratory including multiple incubation, labeling, and washing steps [1,2]. With these issues, laboratory-based assays including ELISA are not appropriate for early diagnosis of diseases [3].

Methods

Results

Conclusion