Silk Microneedles Offer Underwater Fish Vaccination
MIT and USDA researchers coated food-grade silk microneedles in shellac to vaccinate fish while they swim.
Updated on Nov. 6, 2026 in Pet Health
Researchers at MIT and the USDA developed food-grade silk microneedles coated in shellac that penetrate and stay attached to fish skin underwater. The system can deliver bacterial and DNA vaccines and was published in ACS Nano.
Why it matters
Current needle-based fish vaccination is labor intensive, costly, stressful for fish, and dangerous for workers, and it only works once fish reach about 30 grams. A method that works on much smaller fish could make disease prevention practical across aquaculture.
The trials tested rainbow trout, with the microneedles delivering vaccines to fish as small as 1 to 2 grams, far below the roughly 30 grams needed for metal-needle vaccination. Half of the DNA plasmid structure was preserved after four weeks of dry storage, but the device has not yet been tested at commercial scale.
The players
MIT
The Massachusetts Institute of Technology is a private research university in Cambridge, Massachusetts, known for its engineering and materials science programs.
USDA
The United States Department of Agriculture is the federal agency overseeing agricultural research, food safety, and animal health, including aquaculture work through its research centers.
The details
The microneedles are made of food-grade silk coated in shellac, which forms a moisture barrier that keeps them water-resistant until injection. They are single-use and designed to pierce wet skin and remain attached while fish swim, and the system can store a range of vaccines.
Timeline
Farmed aquatic animals first exceeded wild-caught animals in global food production by weight in 2021.
Li began the fish vaccine project in Marelli's lab in 2022.
Li received a USDA fellowship funding the project in 2024.
The microneedle research article was published on November 6, 2026.
Big Picture
Metal-needle injection after sedation remains the most effective current method for vaccinating farmed fish, and the microneedle system offers an alternative that avoids sedation. Farmed aquatic animals now exceed wild-caught animals in global food production, raising the stakes for reliable disease prevention in aquaculture.
For fish farmers, the microneedle approach could reduce the labor, cost, and handling stress of vaccination, especially for small fish. The method is not yet ready for commercial use, so current vaccination practices remain in place for now.
The takeaway
Vaccinating fish earlier and with less handling could reduce disease outbreaks as aquaculture grows to meet rising global demand. Farm operators should watch for further development of this approach before changing their own vaccination routines.
Further reading
For related coverage, explore more on Pet Health.
Source note: This article includes information reported by Ocean News & Technology.
