A Fast and Sensitive Quantitative Lateral Flow Immunoassay for Cry1Ab Based on a Novel Signal Ampliﬁcation Conjugate

Chunxiang Chen,Jian Wu

doi:10.3390/s120911684

Abstract

A novel lateral flow immunoassay (LFIA) signal amplification strategy for the detection of Cry1Ab based on amplification via a polylysine (PL) chain and biotin-streptavidin system (BSAS) is described. In this system, multiple fluorescence dyes (FL) were directly coated on the surface of PL and conjugated with antibody via the BSAS for construction of novel signal amplification (FLPL-BSAS-mAb1) conjugates, in which FL, PL and BSAS were employed to improve the sensitivity of LFIA. Compared with conventional LFIA, the sensitivity of FLPL-BSAS-mAb1-based LFIA was increased by approximately 100-fold. Quantified linearity was achieved in the value range of 0–1,000 pg/mL. The limit of detection (LOD) was reached 10 pg/mL after optimization of reaction conditions. To our knowledge, this represents one of the most sensitive LFIA for Cry1Ab yet reported. Furthermore, the detection time for this method was about 10 min. Therefore, it should be an attractive alternative compared to conventional immunoassays in routine control for Cry1Ab.

Highlights

Modified organisms (GMOs) have been mainly developed for mass production of agricultural plants
The Cry1Ab were captured by the pAb2 on the test line (T line), while FLPL-biotin-streptavidin system (BSAS)-monoclonal antibody against Cry1Ab (mAb1) conjugate were captured by Cry1Ab
The fluorescence dyes (FL) intensity at the T line was proportional to the concentration of Cry1Ab protein and scanned by a portable fluorescence strip reader

Summary

Introduction

Modified organisms (GMOs) have been mainly developed for mass production of agricultural plants. The Cry toxins are insecticidal proteins, which are considered to be harmless and Sensors 2012, 12 non-toxic to human being and animals. For the detection of Cry1Ab, the most commonly used formats are enzyme-linked immunosorbent assay (ELISA) [1,2,3,4] and lateral flow immunoassay (LFIA) [5], while various innovative analytical techniques have been developed for quantitative or qualitative detection of Cry1Ab protein [6,7,8,9,10,11,12,13,14]. The main drawback of ELISA is the relatively long assay time required, large-scale instruments and professional operating techniques. It is of crucial importance to establish a rapid testing methodology for monitoring Cry toxins

Methods

Results

Conclusion