Controlled assembly of mesoscale structures using DNA as molecular bridges

Area of Science:

• Materials Science
• Nanotechnology
• Biochemistry

Background:

• Self-assembly is a fundamental process in nature and materials science.
• DNA nanotechnology offers precise control over molecular assembly.
• Creating ordered mesoscale structures from colloidal particles is challenging.

Purpose of the Study:

• To develop a method for constructing precise mesoscale polyhedral structures.
• To utilize DNA as a specific molecular linker for colloidal assembly.
• To demonstrate the formation of defined polyhedral building blocks using binary microsphere mixtures.

Main Methods:

• Carboxy-modified polystyrene microspheres were functionalized with single-stranded DNA using carboxydiimide chemistry.
• Fluorescently labeled DNA was used to confirm hybridization via fluorescence resonance energy transfer (FRET) in confocal microscopy.
• Binary mixtures of microspheres with specific size ratios (0.818/0.211 µm and 0.818/0.364 µm) were combined to form polyhedral structures.
• Confocal microscopy in reflection mode and scanning electron microscopy (SEM) were used for structural characterization.

Main Results:

• Successful decoration of polystyrene beads with DNA was confirmed through FRET.
• Specific size ratios of DNA-functionalized beads self-assembled into defined polyhedral structures.
• Tetrahedral structures were formed using 0.818 µm and 0.211 µm beads.
• Octahedral structures were formed using 0.818 µm and 0.364 µm beads.
• Confocal and SEM data confirmed the formation of mesoscale polyhedral building blocks.

Conclusions:

• DNA-mediated assembly provides a robust method for creating ordered mesoscale polyhedral structures.
• The size ratio of the constituent microspheres is critical for directing the formation of specific polyhedral geometries.
• This approach offers a pathway for designing and fabricating novel mesoscale materials with potential applications in photonics, catalysis, and sensing.