Self-assembly of DNA arrays into multilayer stacks

Area of Science:

• Nanotechnology
• Biomolecular Engineering
• Materials Science

Background:

• DNA self-assembly is a key technique for creating nanoscale structures.
• Controlling the architecture of DNA assemblies is crucial for advanced applications.

Purpose of the Study:

• To investigate the self-assembly of multilayer hexagonal DNA arrays.
• To understand the influence of magnesium ion (Mg2+) concentration on DNA array formation and structure.

Main Methods:

• Utilizing a mixture of three single-stranded DNA sequences.
• Employing slow cooling protocols with varying Mg2+ concentrations.
• Analyzing self-assembled aggregates using atomic force microscopy (AFM).
• Identifying structural phases and domains via Moiré pattern analysis.

Main Results:

• Self-assembly yields diverse multilayer DNA architectures dependent on Mg2+ concentration.
• Optimal conditions for defined bilayers/multilayers (700 nm) found at 2-5 mM Mg2+.
• Larger arrays (up to 20 microm) observed at 10-15 mM Mg2+, with 20-60% multilayer content.
• Identified specific interlayer packing: translations (17.5 nm), rotations (20°, 30°), and cubic close packing.

Conclusions:

• Mg2+ concentration is a critical factor in directing the self-assembly and structural complexity of hexagonal DNA arrays.
• Precise control over multilayer DNA architectures is achievable, enabling the design of complex nanostructures.