Surface Plasmon Resonance Biosensor Based on Smart Phone Platforms.

Yun Liu,Fang Cheng,Hanqi Wang,Wei Peng,Shimeng Chen,Qiang Liu

doi:10.1038/srep12864

Yun Liu, Fang Cheng + Show 4 more

Open Access

https://doi.org/10.1038/srep12864

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Abstract

We demonstrate a fiber optic surface plasmon resonance (SPR) biosensor based on smart phone platforms. The light-weight optical components and sensing element are connected by optical fibers on a phone case. This SPR adaptor can be conveniently installed or removed from smart phones. The measurement, control and reference channels are illuminated by the light entering the lead-in fibers from the phone’s LED flash, while the light from the end faces of the lead-out fibers is detected by the phone’s camera. The SPR-sensing element is fabricated by a light-guiding silica capillary that is stripped off its cladding and coated with 50-nm gold film. Utilizing a smart application to extract the light intensity information from the camera images, the light intensities of each channel are recorded every 0.5 s with refractive index (RI) changes. The performance of the smart phone-based SPR platform for accurate and repeatable measurements was evaluated by detecting different concentrations of antibody binding to a functionalized sensing element, and the experiment results were validated through contrast experiments with a commercial SPR instrument. This cost-effective and portable SPR biosensor based on smart phones has many applications, such as medicine, health and environmental monitoring.

Highlights

Some analytical methods intended for smart phones demand light sources with high intensities or monochromatic lights that cannot be achieved by a phone flash
The measurement channel (MC), control channel (CC) and reference channel (RC) are illuminated by the light entering into the lead-in fibers from the phone light-emitting diodes (LED) flash, whereas the light from the end faces of the lead-out fibers is detected by the phone camera
Because all components are fixed to the phone case, the touch-screen interface and display are not affected during the detection process

Summary

Introduction

Some analytical methods intended for smart phones demand light sources with high intensities or monochromatic lights that cannot be achieved by a phone flash. We demonstrate a portable fiber-optic surface plasmon resonance (SPR) biosensor using a smart phone as a sensing platform. This SPR sensor employs surface electromagnetic evanescent waves at the metal dielectric interface and is highly sensitive to changes in the small refractive index (RI)[15]. All optical components and the sensing element are connected by optical fibers and fixed on a phone case, which is designed to have a simple, light-weight, small structure adapted to smart phones and simple installation or removal. When the sample is injected into the flow cell, the light interacting with the sensing region is absorbed because of the SPR resonance, and the phone camera measures a corresponding intensity change of the light coming out of the lead-out fiber.

Methods

Results

Conclusion