Analysis of Surface Plasmon Resonance Curves with a Novel Sigmoid-Asymmetric Fitting Algorithm

Sensors

Daeho Jang²  Geunhyoung Chae¹  Sehyun Shin² 

[1] College of Information and Communication Engineering, Sungkyunkwan University, Suwon 440-476, Korea; E-Mail:;School of Mechanical Engineering, Korea University, Seoul 136-701, Korea; E-Mail:

关键词: surface plasmon resonance;    fitting algorithm;    sigmoid-asymmetric;    critical angle;    resonance angle;   

DOI  :  10.3390/s151025385

来源: mdpi

【 摘 要 】

The present study introduces a novel curve-fitting algorithm for surface plasmon resonance (SPR) curves using a self-constructed, wedge-shaped beam type angular interrogation SPR spectroscopy technique. Previous fitting approaches such as asymmetric and polynomial equations are still unsatisfactory for analyzing full SPR curves and their use is limited to determining the resonance angle. In the present study, we developed a sigmoid-asymmetric equation that provides excellent curve-fitting for the whole SPR curve over a range of incident angles, including regions of the critical angle and resonance angle. Regardless of the bulk fluid type (i.e., water and air), the present sigmoid-asymmetric fitting exhibited nearly perfect matching with a full SPR curve, whereas the asymmetric and polynomial curve fitting methods did not. Because the present curve-fitting sigmoid-asymmetric equation can determine the critical angle as well as the resonance angle, the undesired effect caused by the bulk fluid refractive index was excluded by subtracting the critical angle from the resonance angle in real time. In conclusion, the proposed sigmoid-asymmetric curve-fitting algorithm for SPR curves is widely applicable to various SPR measurements, while excluding the effect of bulk fluids on the sensing layer.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.