Surmounting a PCR challenge using a Contradictory matrix from the Theory of Inventive Problem Solving (TRIZ).

Jiří Drábek

doi:10.1186/s40064-015-1577-3

Abstract

In this paper I tested whether Contradictory Matrix with 40 Inventive Principles, the simplest instrument from the Theory of Inventive Problem Solving (TRIZ), is a useful approach to a real-life PCR scenario. The PCR challenge consisted of standardization of fluorescence melting curve measurements in Competitive Amplification of Differentially Melting Amplicons (CADMA) PCR for multiple targets. Here I describe my way of using the TRIZ Matrix to generate seven alternative solutions from which I can choose the successful solution, consisting of repeated cycles of amplification and melting in a single PCR run.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-015-1577-3) contains supplementary material, which is available to authorized users.

Highlights

Competitive Amplification of Differentially Melting Amplicons (CADMA) is a modified form of PCR based on competition between two partially overlapping forward primers for a DNA template (Kristensen et al 2012a; Borgbo et al 2014; Kristensen et al 2012b), one of which binds to both wildtype and mutated templates while the other is mutation-specific
This paper describes a protocol of the simplest TRIZ method, a 39 × Contradiction Matrix with Inventive Principles, applied to the problem of optimization of reactions for multiple targets in CADMA (Competitive Amplification of Differentially Melting Amplicons) PCR
Step 2: suggestion of abstract solution To address this combination of conflicting properties, the TRIZ matrix (Additional file 2) gives the following hints: Cushion in advance (11), Change the colour (32), and Invert an object, system or process (13)

Summary

Introduction

CADMA is a modified form of PCR based on competition between two partially overlapping forward primers for a DNA template (Kristensen et al 2012a; Borgbo et al 2014; Kristensen et al 2012b), one of which binds to both wildtype and mutated templates while the other is mutation-specific. The reverse primer binds to both wildtype and mutated templates. CADMA PCR with a heterozygous (wildtype plus mutant) DNA template amplifies two sequences, while wildtype homozygous templates provide only one amplicon. The melting temperature of the heterozygote is distinguishable from that of the homozygote by its upward or downward shift of a melting temperature (Tm) peak, or by the presence of a second Tm peak. When a second Tm is present, calculation of the mutant to wildtype ratio is possible (data not shown, to be published elsewhere). My colleagues and I have encountered a difficulty in simultaneous CADMA analyses of several targets using multiple DNA samples in a single thermocycler

Methods

Results

Discussion

Conclusion