Considerations on Circuit Design and Data Acquisition of a Portable Surface Plasmon Resonance Biosensing System.

Keke Chang,Baiqiong Cao,Xiaohui Sun,Hao Liang,Ruipeng Chen,Min Jiang,Xinran Hu,Jianwei Li,Shun Wang,Liuzheng Ma,Jiandong Hu,Juanhua Zhu

doi:10.3390/s150820511

Abstract

The aim of this study was to develop a circuit for an inexpensive portable biosensing system based on surface plasmon resonance spectroscopy. This portable biosensing system designed for field use is characterized by a special structure which consists of a microfluidic cell incorporating a right angle prism functionalized with a biomolecular identification membrane, a laser line generator and a data acquisition circuit board. The data structure, data memory capacity and a line charge-coupled device (CCD) array with a driving circuit for collecting the photoelectric signals are intensively focused on and the high performance analog-to-digital (A/D) converter is comprehensively evaluated. The interface circuit and the photoelectric signal amplifier circuit are first studied to obtain the weak signals from the line CCD array in this experiment. Quantitative measurements for validating the sensitivity of the biosensing system were implemented using ethanol solutions of various concentrations indicated by volume fractions of 5%, 8%, 15%, 20%, 25%, and 30%, respectively, without a biomembrane immobilized on the surface of the SPR sensor. The experiments demonstrated that it is possible to detect a change in the refractive index of an ethanol solution with a sensitivity of 4.99838 × 105 ΔRU/RI in terms of the changes in delta response unit with refractive index using this SPR biosensing system, whereby the theoretical limit of detection of 3.3537 × 10−5 refractive index unit (RIU) and a high linearity at the correlation coefficient of 0.98065. The results obtained from a series of tests confirmed the practicality of this cost-effective portable SPR biosensing system.

Highlights

In the last two decades there has been a great effort towards the development of portable surface plasmon resonance (SPR) bioanalyzers to meet the need for fast and non-destructive detection in numerous important areas including food safety, environmental monitoring and agriculture [1,2,3].Optical SPR bioanalyzers designed to measure refractive index changes and quantify biomolecular interactions caused by the binding of interacting molecules are typically based on surface plasmons propagating along the metal-dielectric interface where the interaction between an evanescent wave and dielectric occurs [4,5,6]
The circuit and signal conditioning approaches designed for an inexpensive portable SPR biosensing system constructed using a laser line generator and a linear UPD3575D charge-coupled device (CCD) module have been thoroughly considered
The circuit for collecting the signals from the linear CCD array and transferring the measurement results to the computer is mainly composed of a PIC24FJ128GA008 microcontroller, a driver circuit for running the laser line generator, and an extension memory for storing the initialized parameters and measurement results

Summary

Introduction

In the last two decades there has been a great effort towards the development of portable surface plasmon resonance (SPR) bioanalyzers to meet the need for fast and non-destructive detection in numerous important areas including food safety, environmental monitoring and agriculture [1,2,3].Optical SPR bioanalyzers designed to measure refractive index changes and quantify biomolecular interactions caused by the binding of interacting molecules are typically based on surface plasmons propagating along the metal-dielectric interface where the interaction between an evanescent wave and dielectric occurs [4,5,6]. In the last two decades there has been a great effort towards the development of portable surface plasmon resonance (SPR) bioanalyzers to meet the need for fast and non-destructive detection in numerous important areas including food safety, environmental monitoring and agriculture [1,2,3]. The price of these bioanalyzers when designed by using a common surface plasmon resonance biosensor is extremely high due to the complicated configurations of the optics and electronics. Portable and cost-effective surface plasmon resonance instruments are urgently needed and have potential in many practical applications, including medical diagnostics, drug screening and basic scientific research.

Objectives

Methods

Results

Conclusion