What Triaxial Electrospray Emitters Are and Why They Matter
Triaxial electrospray emitters are specialized electronic nozzles that use high voltage to eject three immiscible liquids through concentric microchannels, forming stable, multilayered microdroplets that can solidify into precisely structured microparticles suited for controlled drug delivery, biosensing, or self-healing materials. In drug delivery manufacturing, these 3D printed nozzles can build nanoparticles with a core of active medicine wrapped in multiple protective and time-release shells, allowing drugs to survive harsh environments such as the stomach and release later in the intestines. This multilayer capability is vital for complex pharmaceutical production, but conventional microfabrication methods demand access to semiconductor cleanrooms and intricate, slow workflows. By shifting to 3D printing, MIT’s approach aims to make high-precision electrospray emitters accessible to smaller labs and companies that need advanced drug-delivery manufacturing tools without the infrastructure burden.
3D Printed Nozzles Replace Cleanroom-Based Microfabrication
MIT researchers have designed arrays of triaxial electrospray emitters that are manufactured in a single 3D-printing step, avoiding traditional cleanroom processes. The team used vat photopolymerization to solidify thin layers of liquid resin into complex internal geometries, printing layers only 25 micrometers tall—far thinner than a human hair. The result is a compact array, slightly larger than a coin, that packs 16 nozzles into about one square centimeter. These 3D printed nozzles incorporate intricate three-dimensional microchannels which would be extremely hard to realise with standard semiconductor fabrication. As Luis Fernando Velásquez-García notes, “We couldn’t make a device like this in a semiconductor cleanroom. This is only possible because they are 3D-printed.” For drug delivery manufacturing, that means precision electrospray tools can now be produced in hours instead of through lengthy, specialized fabrication runs.
From Time-Release Drug Capsules to Self-Healing Materials
The new electrospray emitters can produce three-layer microdroplets at scale, enabling compound microparticles with carefully designed shells and cores. In a pharmaceutical production scenario, the outer shell might erode in gastric fluid, exposing a second layer that regulates the release of a drug-loaded core further along the digestive tract. The same architecture can support biosensors with three different chemical markers in separate layers or self-healing materials where one layer carries a reactive agent and another carries a catalyst. Because electrospray emitters generate smaller microdroplets much faster than many competing techniques, they are attractive for high-throughput manufacturing. MIT’s printed arrays produced uniform, three-layer droplets across all 16 nozzles, which is essential for consistent dosing and predictable performance in drug-delivery manufacturing and in functional materials where particle-to-particle variation can undermine reliability.
Engineering Uniform Microdroplets Without Cross-Talk
Achieving uniformity across many emitters is a central engineering challenge. In these 3D printed devices, a network of coiled, helical microchannels distributes each of the three liquids evenly to all nozzles, keeping the footprint compact while preventing emitters from interfering with one another. Velásquez-García explains that, thanks to this layout, the emitters “never learn they have company,” which helps maintain a stable, consistent spray from each nozzle. The research team iterated through multiple architectures and operating conditions, testing different flow rates and voltages to stabilize the layered microdroplets. They found that the viscosity of the middle liquid is especially important for droplet stability, since it preserves layer thickness as droplets form. These findings show that both fluid formulation and device geometry must be tuned together to meet the strict demands of advanced drug delivery manufacturing and other electrospray-based processes.
Democratizing Precision Drug-Delivery Manufacturing
Because these triaxial electrospray emitters are 3D printed in a single step within a few hours, they remove a major barrier to entry: the need for expensive cleanroom facilities and specialized microfabrication expertise. Smaller research institutions and emerging pharmaceutical companies can, in principle, print their own arrays for drug delivery manufacturing, biosensor production, or experimental self-healing materials, speeding up innovation cycles. Design iteration is far easier as well; researchers can modify microchannel geometry or nozzle arrangements digitally and print updated prototypes without retooling a fabrication line. According to MIT’s Microsystems Technology Laboratories, this makes it possible to “aggressively optimize” designs for specific pharmaceutical production needs. By combining low-cost, rapid fabrication with the fine control required for multilayer drug particles, 3D printed electrospray emitters signal a shift toward more accessible, distributed biomedical manufacturing ecosystems.
