Oligonucleotide-Oligocation Conjugate Specificity
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Solution Overview
Problem
Existing nucleic acid hybridization methods face challenges in achieving specific detection of unique sequences in complex biological samples due to non-specific binding of cationic oligonucleotide-oligocation conjugates to genomic DNA, leading to decreased specificity and affinity.
Innovation Solution
Specific selection of oligonucleotide-oligocation conjugates with defined structures and linkers, comprising oligonucleotides and organic oligocation moieties, which enhance affinity and specificity for target sequences, allowing for improved hybridization methods, including PCR and detection techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oligonucleotide-oligocation conjugates are used to target specific sequences, then affinity for target nucleic acid is improved, but specificity decreases due to non-specific binding to genomic DNA
Solution Approach 1:
The patent applies local quality by modifying only specific positions of the oligonucleotide chain with cationic groups rather than uniformly modifying all positions. This localized modification approach (at specific nucleotide positions) provides sufficient electrostatic neutralization for target binding while minimizing non-specific interactions with genomic DNA, thus resolving the contradiction between affinity and specificity.
Solution Approach 2:
The patent changes the chemical parameter of the oligonucleotide by introducing cationic groups with specific charge densities and distributions. By controlling the number, position, and type of cationic modifications, the patent optimizes the balance between electrostatic attraction to the target (improving affinity) and reduction of non-specific binding (maintaining specificity).
2Stability of the object's composition
If polyamines are used to decrease electrostatic repulsion between negatively charged acid nucleic strands, then hybridization stability is improved, but non-specific binding to genomic DNA increases
Solution Approach 1:
The patent segments the cationic modification into discrete, localized units along the oligonucleotide chain rather than using continuous polyamine structures. This segmentation allows controlled electrostatic neutralization at the hybridization interface while reducing the overall non-specific binding capacity, thereby improving hybridization stability without excessive non-specific binding.
3Reliability
If cationic groups are grafted to oligonucleotides to stabilize hybridization, then affinity for target sequence is improved, but tolerance to mismatches increases resulting in decreased specificity
Solution Approach 1:
The patent places cationic groups at specific local positions along the oligonucleotide chain, particularly at positions that contact the major groove or specific regions of the target. This localized placement provides electrostatic stabilization for perfect matches while maintaining stringency for mismatched bases, as the cationic groups do not uniformly stabilize all binding configurations.
Data Source
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AI summary
The invention relates to a method for manipulating, isolating, detecting or amplifying a target nucleic acid in a sample by hybridization with an oligonucleotide-oligocation conjugate, comprising allowing said nucleic acid to react with an oligonucleotide- oligocation conjugate comprising at least A1 and Bj linked together directly or via a linker, wherein. A, is an i-mer oligonucleotides, with i = 3 to 50, where Ai is an oligomer with naturally or non naturally occurring nucleobases and/or pentafuranosyl groups and/or native phosphodiester bonds, optionally comprising a marker group. Bj is a j-mer organic oligocation moiety, with j = 1 to 50, where B is - HPO3-R1-(NH-R2)n-NH-R3-O-, where R1, R2 and R3 are lower alkylene, identical or different, NH-R2 moieties being identical or different when n is >1; HPO3-R1-CH(X)-R3-O-, where Ri and R3, identical or different, are lower alkylene and X is putrescine, spermidine or spermine residue.