Harvard Chip Synthesizes 64 DNA Sequences in Parallel Using Water-Based Enzymes

A Harvard-led team has published a method for writing DNA on a silicon chip using electricity and water-based enzymes rather than the organic solvents that dominate the synthetic DNA industry today. The work appeared this month in Nature Electronics, and the underlying platform turns out to have been borrowed from neuroscience, not genomics.

According to a release from the Harvard John A. Paulson School of Engineering and Applied Sciences, the chip synthesized 64 distinct DNA sequences on its surface simultaneously. That number matters because, as reporting from Phys.org notes, enzymatic DNA synthesis approaches had previously been limited to roughly a dozen sequences at a time. The conventional alternative, phosphoramidite chemistry, handles larger arrays but requires hazardous organic solvents and generates substantial chemical waste.

The architecture that makes parallel synthesis possible here is electrochemical. As described in the Harvard SEAS release, each of the chip's 64 synthesis sites contains two concentric ring electrodes surrounding anchored DNA strands at the center. When the chip activates a site, the inner ring generates protons to drop the local pH, which triggers enzymatic elongation of the DNA strand. Simultaneously, the outer ring pulls those protons back before they can drift to neighboring sites. Cycle by cycle, the chip builds 64 independent sequences without crosstalk between sites.

The platform wasn't designed for DNA synthesis at all. According to Interesting Engineering's coverage of the paper, the semiconductor architecture was originally developed by Jeffrey Abbott, a former PhD student in the lab of senior author Donhee Ham, for recording electrical activity from large populations of neurons. After redesigning the surface electrodes, the team found that the same precision current-injection approach could control the chemical microenvironment needed for DNA synthesis.

As a proof-of-concept demonstration, the team used the chip to encode a 169-byte text string into DNA, illustrating potential data-storage applications, per Phys.org's coverage of the Nature Electronics paper.

A few caveats are worth sitting with. The sequences demonstrated ran up to 39 nucleotides in length. Current synthesis is also limited by diffusing deprotection intermediates between cycles, a bottleneck the authors acknowledge rather than solve. Sixty-four sites on a single chip is a benchmark relative to prior enzymatic work, not a competitive number for commercial DNA synthesis platforms that operate across far larger arrays using chemistry that, for all its environmental cost, remains fast and cheap per nucleotide. DNA synthesis currently runs roughly $0.05 to $0.10 per nucleotide through commercial providers, according to Medical Daily's analysis, meaning cost-competitiveness at scale is an open question this paper doesn't answer.

What the paper does establish is proof that spatial pH patterning via electrochemistry can drive parallel enzymatic DNA synthesis on a semiconductor substrate, and that doing so is feasible with water as the solvent. Whether the approach can scale from 64 sites to the thousands needed for synthetic biology applications is the next engineering question. The authors themselves frame this as a platform, not a product. That's the right framing.

Sources cited:
- Nature Electronics (via Harvard SEAS release) (https://seas.harvard.edu/news/making-dna-semiconductor-chip)
- Phys.org, Semiconductor chip writes 64 DNA sequences in water (https://phys.org/news/2026-06-semiconductor-chip-dna-sequences-enzymatic.html)
- Interesting Engineering, Silicon chip creates 64 DNA sequences using electric currents (https://interestingengineering.com/innovation/silicon-chip-w64-dna-sequences-electric-currents)
- Medical Daily, Harvard Built a Silicon Chip That Writes DNA (https://www.medicaldaily.com/harvard-silicon-chip-dna-synthesis-gene-therapy-2026-476033)
- Mirage News, Harvard Scientists Transform Chip Into DNA Writing Tool (https://www.miragenews.com/harvard-scientists-transform-chip-into-dna-1707323/)