Segregated PCR Primer Pairs for FFPE DNA Amplification
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for detecting drug-resistant Helicobacter pylori in formalin-fixed paraffin-embedded (FFPE) biopsy samples are inefficient due to DNA cross-linking, which hampers PCR amplification of trace bacterial DNA sequences, and there is a lack of robust and cost-effective methods for determining antibiotic resistance profiles.
Innovation Solution
The use of segregated PCR primer pairs targeting overlapping regions of drug-resistant genes, minimizing the risk of primer-dimer formation and cross-hybridization, allows for efficient amplification of diagnostic amplicons from FFPE samples, enabling the characterization of drug-resistant H. pylori strains by pooling primers and performing separate PCR reactions to produce specific amplicons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PCR amplification is performed on DNA from FFPE samples, then bacterial DNA sequences can be detected, but DNA cross-linking from formalin fixation reduces amplification efficiency and accuracy
Solution Approach 1:
The patent divides the amplification process into multiple separate PCR reactions, each targeting specific gene regions with dedicated primer pairs. This segmentation allows optimization of each reaction to overcome cross-linking barriers at different DNA locations, improving overall detection reliability despite formalin-induced damage
Solution Approach 2:
The patent modifies PCR parameters including using multiple primer pairs with different binding sites, adjusting annealing temperatures, and optimizing cycle conditions to enable successful amplification of cross-linked DNA from FFPE samples, thereby maintaining detection accuracy
2Adaptability or versatility
If multiple primer pairs are used to detect multiple drug resistance genes, then comprehensive resistance profiling is achieved, but primer-dimer formation and cross-hybridization increase false results
Solution Approach 1:
The patent segments the detection of multiple drug resistance genes into separate PCR reactions, each with its own optimized primer pair. This prevents primer-dimer formation and cross-hybridization between primers targeting different genes, while still enabling comprehensive resistance profiling through multiple targeted reactions
Solution Approach 2:
The patent uses specific control elements and optimized primer designs that act as intermediaries to prevent non-specific binding and primer-dimer formation, allowing multiple primer pairs to be used effectively without compromising amplification accuracy
3Measurement precision
If trace bacterial DNA is amplified from FFPE samples, then drug-resistant H. pylori can be characterized, but the low copy number of bacterial DNA limits successful amplification
Solution Approach 1:
The patent performs preliminary optimization of PCR conditions and selection of highly specific primer pairs before amplification to maximize the efficiency of detecting low copy number bacterial DNA from FFPE samples, thereby improving detection sensitivity despite limited starting material
Solution Approach 2:
The patent optimizes PCR parameters including cycle number, annealing temperature, and primer concentration to enhance amplification efficiency of trace bacterial DNA, enabling successful characterization of drug-resistant H. pylori even from low copy number samples
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the simultaneous detection of multiple drug-resistant mutations in H. pylori from FFPE samples with high accuracy, using Next Generation Sequencing (NGS) and Sanger sequencing, thereby improving the efficiency and practicality of determining antibiotic resistance profiles in clinical settings.
Implementation Method 1
The described methods and compositions are generally relevant to the use of polymerase chain reaction (PCR) amplification of trace DNA sequences from formalin-fixed paraffin-embedded (FFPE) biopsy samples
Implementation Method 2
The DNA-dependent DNA polymerases used for PCR amplification can neither traverse nor accurately replicate DNA sequences that are chemically cross-linked or contain many modified nitrogenous bases
Implementation Method 3
formalin fixation, which allows immobilization of cellular matter (primarily by cross-linking nitrogenous groups in macromolecules), reduces the efficacy of many nucleic acid methods such as polymerase chain reaction (PCR) amplification
Data Source
Figure 1
Figure 2
Figure 2
AI summary
The invention provides methods and compositions generally useful to the use of polymerase chain reaction (PCR) amplification of trace DNA sequences from formalin-fixed paraffin-embedded (FFPE) biopsy samples and specifically relevant to the identification of multi-drug resistant H. pylori in such biopsy samples.