Significance Testing and Multivariate Analysis of Datasets from Surface Plasmon Resonance and Surface Acoustic Wave Biosensors: Prediction and Assay Validation for Surface Binding of Large Analytes.

Mihaela Puiu,Lucian-Gabriel Zamfir,Valentin Buiculescu,Cristina Mitrea,Camelia Bala,Angela Baracu

doi:10.3390/s18103541

Abstract

In this study, we performed uni- and multivariate data analysis on the extended binding curves of several affinity pairs: immobilized acetylcholinesterase (AChE)/bioconjugates of aflatoxin B1(AFB1) and immobilized anti-AFB1 monoclonal antibody/AFB1-protein carriers. The binding curves were recorded on three mass sensitive cells operating in batch configurations: one commercial surface plasmon resonance (SPR) sensor and two custom-made Love wave surface-acoustic wave (LW-SAW) sensors. We obtained 3D plots depicting the time-evolution of the sensor response as a function of analyte concentration using real-time SPR binding sensograms. These “calibration” surfaces exploited the transient periods of the extended kinetic curves, prior to equilibrium, creating a “fingerprint” for each analyte, in considerably shortened time frames compared to the conventional 2D calibration plots. The custom-made SAW sensors operating in different experimental conditions allowed the detection of AFB1-protein carrier in the nanomolar range. Subsequent statistical significance tests were performed on unpaired data sets to validate the custom-made LW-SAW sensors.

Highlights

Affinity sensors using gold/thiol chemistry for immobilization of biomolecules onto surfaces are probably the most versatile platforms for real time monitoring of biomolecular events through molecular recognition [1]
AChE/AFB1 -horseradish peroxidase (HRP) and AChE/AFB1 -Bovine serum albumin (BSA) were chosen as model systems for the binding kinetics/affinity of high molecular weight (HMW) analytes to univalent ligands
It was previously reported that AChE /AFB1 -HRP binding follows a Langmuir-like pattern characteristic for univalent ligand/univalent analyte interaction [10]

Summary

Introduction

Affinity sensors using gold/thiol chemistry for immobilization of biomolecules onto surfaces are probably the most versatile platforms for real time monitoring of biomolecular events through molecular recognition [1]. Due to their inherent properties, thin gold films are perfectly suited to detect a broad range of analytes using surface plasmon resonance and surface acoustic wave sensors, supporting both functionalization with organic self-assembled layers and interfacing of electrochemical, optical or piezoelectric transducers [2]. In a typical LW-SAW approach an electrical signal is converted at interdigital transducers (IDT’s) into polarized transversal waves propagating parallel to the sensing surface, due to the piezoelectric properties of the substrate material [8]. The wave is converted back at another IDT into an electrical signal

Methods

Results

Conclusion