Determination of the Detection Limit of the Detection of GMO in Food Using the Isothermal Solid-Phase Recombinase Polymerase Amplification on Microfluidic DVDs

Noor Azlina Masdor

doi:10.54987/ajpb.v3i2.637

Abstract

A major drawback of the current literature on bioassay development is that these tests are not made using statistically robust methods for establishing the limit of detection. As an alternative, researchers often make use of simple detection-limit methods that are only roughly indicative of the actual detection limit. We can only assume that this is due to a practical need for simplified processes, in addition to the notion that the limit of detection theory has already been lowered to practice for bioassays. A DNA sensor based on light intensity of the scanning laser on a DVD drive with microfluidic layer etched onto the polycarbonate surface of an ordinary DVD has been previously developed for fast screening of genetically modified organisms (GMOs). The resultant calibration curve showed a sigmoidal calibration curve but was not modelled according to any of the sigmoidal models available. The objective of this study is the remodel the data using the standard 4-PL model and to determine the Limits of Detection (LOD) based on the standard method. The LOD value obtained through the 4PL modelling exercise based on a pooled standard deviation method yielded an LOD value of 62 mg/g (95% confidence interval of 17 to 158), which was quite similar to the classical three standard deviation of the blank method but was lower than the rough estimation employed in the original publication.

Highlights

Biochemical diagnostic procedures, such as protein binding, rely on biomolecular interactions as its diagnostic modality, and as a consequence, their calibration curves are more complex
Researchers often use basic techniques that give an approximate estimate of the detection limit, sometimes without any indication of confidence in the estimate
This absence of robust techniques is possibly owing to a practical desire for easy and simple procedures, as well as a lack of such approaches that have diminished the ideas of limit of detection theory to practise for bioassays

Summary

INTRODUCTION

Biochemical diagnostic procedures, such as protein binding, rely on biomolecular interactions as its diagnostic modality, and as a consequence, their calibration curves are more complex. Where y signifies the response signal (optical density), x signifies the DNA log concentration, a and d signify the maximum and minimum signal response of the calibration curve, correspondingly, b is the Hill coefficient which represents the slope-like parameter and c represents the DNA log concentration producing a 50% signal response (EC50) value. Both the classical three times the standard deviation of the blank and another statistically robust technique for estimating the analytical LOD of a classic sigmoidal correlation based on the pooled standard deviation of datapoints will be utilized [11]. The four-parameter logistics model and nonlinear regression analysis software will be used in tandem to calculate the LOD and execute regression analysis (PRISM, v 5.1) from www.graphpad.com

AND DISCUSSION

Findings

Rohatgi