Effects of Chain-Chain Associations on Hybridization in DNA Brushes

DNA brushes are commonly used in biosensing and materials science due to their ability to bind complementary nucleic acids. Brush chains are typically designed to be long enough to ensure sequence-specific binding. However, at these lengths, unintended base pairing between chains may occur. These associations could interfere with the intended hybridization to target sequences. Prior research has shown that DNA brushes can form intra- or interchain base pairs. Yet, the extent to which these associations affect hybridization activity remains unclear. No prior work had resolved the role of adhesive region placement along the chain. This gap motivated an investigation into how chain-chain associations influence DNA brush hybridization. Understanding this could improve the design of DNA-based sensors and diagnostic tools. The study aimed to clarify the thermodynamic consequences of such associations. These findings could inform the optimization of DNA brush systems for practical applications.

The goal of this work was to assess how chain-chain associations influence the hybridization of DNA brushes to complementary nucleic acids. Researchers focused on adhesive regions within the brush chains that could lead to unintended base pairing. The study aimed to determine whether these associations suppress hybridization activity. The adhesive region's position along the chain was also examined as a variable. The researchers sought to quantify the thermodynamic impact of these associations. They compared DNA brush behavior to commercial SNP microarrays for context. The study aimed to provide insights into how chain associations affect hybridization efficiency. These insights could guide the design of more effective DNA brush systems.

DNA brushes were synthesized using 20-mer chains with four-nucleotide adhesive regions. These regions allowed for potential base pairing between chains. The adhesive regions were positioned at different locations along the chain backbone. The affinity of these regions was also modified to assess its impact. The brushes were exposed to complementary solution nucleic acids. Melting transitions were measured to estimate hybridization free energies. This approach allowed comparison of hybridization activity with and without chain associations. The results were compared to commercial Affymetrix SNP microarray data for validation.

Higher-affinity adhesive regions suppressed DNA brush hybridization more than lower-affinity ones. This suppression was measured relative to hybridization in solution. Chain associations near the middle of the brush were more detrimental than those at the ends. Associations at the immobilized or free end had less impact on hybridization activity. Changes in brush density did not significantly affect hybridization thermodynamics. This was observed within the tested coverage window. The results were consistent with data from commercial SNP microarrays. These findings suggest that chain associations can significantly influence hybridization behavior.

The study found that chain associations suppress DNA brush hybridization activity. This effect was most pronounced when associations occurred near the chain's center. The adhesive region's affinity played a key role in determining the extent of suppression. Brush density had minimal impact on hybridization thermodynamics within the tested range. These findings align with observations from commercial SNP microarrays. The results suggest that chain associations can significantly influence hybridization efficiency. The placement and affinity of adhesive regions are critical design factors. These insights could help improve the performance of DNA brush systems in practical applications.