Silk microneedles could vaccinate farmed fish underwater
Science & technology · 2 November 2026
Infectious disease causes major losses in aquaculture. Metal-needle vaccination is effective, but each fish must be sedated and removed from the water; the fast, repetitive work also creates risks of accidental needlesticks and cross-contamination. Baths and medicated feed are simpler, but they do not ensure that every animal receives the required dose.
Researchers at MIT and the US Department of Agriculture have developed microneedles made from food-grade silk fibroin. A thin shellac coating stops them dissolving immediately, allowing them to pierce wet skin, stay attached while the fish swims, and release bacterial or DNA vaccines at a controlled rate. The team tuned versions to release their cargo over periods ranging from minutes to 24 hours.
In rainbow trout, the device could be applied to fish weighing only one or two grams, far below the roughly 30-gram threshold for conventional injection. The study demonstrates delivery and material stability, not yet population-scale protection against outbreaks. Automation and commercial-farm trials will be needed to establish efficacy, safety, and cost.
Source: Zach Winn · MIT News.