Silver Nanoparticles and DNA Origami Advances Streamline DNA Assembly and Nanomanufacturing

New research is advancing the assembly and manufacturing of DNA structures, with scientists in Japan developing a silver nanoparticle-based method for cutting and joining DNA and researchers in Texas uncovering design principles that make DNA origami fold more reliably. The Japanese technique improves DNA assembly efficiency by two to five times and has been shown to work in live cells, while the DNA origami findings could make nanoscale materials faster and easier to produce.

The silver nanoparticle splicing method was developed by researchers at Nagoya University and Gifu University and published in Nucleic Acids Research. Traditional DNA splicing relies on restriction enzymes and sticky ends, but these enzymes often lack precision and produce joins that are not optimal. The Japanese team instead used chemical reactions with silver nanoparticles, drawing on research from the 1990s that used silver ions to cut 3′-thiol-modified DNA but achieved only a 14% recovery rate due to nonspecific binding. By substituting nanoparticles for ions, the researchers could remove the silver by centrifugation, greatly improving recovery.

Initial attempts faced another hurdle: achieving high cleaving efficiency required temperatures and durations that damaged the DNA. At 70°C, the DNA achieved only 50% efficiency, and it took two hours at 95°C to approach 100% efficiency. Coating the silver nanoparticles with polyethylene glycol (PEG) increased efficiency from 36% to 92% at 37°C over two hours. After optimization, the team achieved cleaving efficiency above 91% at 50°C within one to two hours. The new technique improves DNA assembly efficiency by two to five times. The researchers successfully introduced a DNA fragment into live cells, confirming expression of a green fluorescent protein gene. Their next goals include verifying reproducibility across a wide range of sequences, scaling up to longer DNA, developing kit-format protocols, and extending the technique to genome-scale DNA assembly, mRNA libraries, and long-chain DNA encoding therapeutic proteins.

In a separate study published in Small, researchers at The University of Texas at Austin systematically analyzed how design choices affect the folding of DNA origami, a technique that uses DNA strands to self-assemble into programmable shapes. Using real-time fluorescence measurements, electron microscopy, and theoretical modeling, they identified energetic forces that determine whether a structure assembles correctly. Folding depends on a balance between favorable DNA binding interactions and unfavorable energy costs associated with forming loops. The team also found that "cooperativity" — how different parts of the structure influence one another during assembly — plays a central role. Reducing the number of inter-helical connections in the design increases cooperative behavior and improves folding yields, whereas simply strengthening binding between strands is less effective because it introduces entropic penalties.

As part of the work, the researchers created what they believe is the smallest Longhorn logo ever made: a structure entirely made of DNA, measuring about 100 nanometers across and 2 nanometers thick. It is thousands of times smaller than the thickness of a human hair, and approximately 10 million tiny Longhorns would fit in the volume of a grain of sand. The team also demonstrated a practical improvement: by using a shorter, more focused heating-and-cooling process lasting one to two hours instead of a traditional multiple-day process, they boosted assembly yields by up to 17% and fabricated millions of copies in less than two hours. The findings provide a clearer framework for designing DNA nanostructures with higher efficiency and reliability, which could accelerate applications in medicine, electronics, and materials science.