What Triaxial Electrospray Emitters Are—and Why They Matter
Triaxial electrospray emitters are specialized microscopic nozzles that apply high voltage to three concentric liquid streams, creating uniform layered microdroplets that solidify into precisely structured microparticles for uses such as time‑release drug delivery, biosensing, and self‑healing materials manufacturing. In their new study, MIT researchers show how these emitters can be 3D printed instead of fabricated in costly semiconductor cleanrooms, turning a niche laboratory tool into a practical manufacturing technology. Electrospraying already underpins applications from mass spectrometry to space propulsion, thanks to its ability to atomize liquids into incredibly small droplets. But scaling arrays of miniaturized emitters has been difficult and expensive. By proving that complex triaxial geometries can be printed in a single step, the MIT team moves electrospray emitters closer to mainstream pharmaceutical technology and precision manufacturing, especially for drug delivery microparticles that demand tight control over particle size and structure.
3D Printed Nozzles Replace the Cleanroom
The core breakthrough is fabrication. Traditional multi-emitter electrospray arrays depend on semiconductor cleanrooms and complex microfabrication steps that can take months and still fail to produce the required geometries. MIT’s team instead used vat photopolymerization, a 3D resin-printing method, to build triaxial electrospray emitter arrays layer by 25-micrometer layer. Each array packs 16 nozzles into roughly one square centimeter, with an intricate three-dimensional network of microchannels feeding three immiscible liquids to every emitter. “We couldn’t make a device like this in a semiconductor cleanroom. This is only possible because they are 3D-printed,” said Luis Fernando Velásquez-García of MIT’s Microsystems Technology Laboratories. The process is a single print that finishes in a few hours, with no post‑assembly of internal flow paths. That speed enables rapid design iterations and opens the door to broader access beyond specialized microfabrication facilities.
Precise Control of Drug Delivery Microparticles
The triaxial design is tailored for pharmaceutical technology and advanced materials. Each 3D printed nozzle emits three non-mixing liquids at once, which merge into stable droplets containing three distinct layers. When these droplets solidify, they form compound microparticles with a core and two shells. That structure is ideal for time-release drug delivery microparticles: the outer layer can erode in the stomach, exposing a second layer that controls how a therapeutic core reaches and releases in a target region of the intestines. MIT’s tests show the 3D printed arrays generate uniform, three-layered droplets at scale, a key requirement for reliable dosing and predictable behavior in the body. The researchers also report that the viscosity of the middle liquid is a decisive parameter for droplet stability and layer consistency, giving formulators a clear handle on tuning performance for drugs, biosensors, or artificial cells used in tissue regeneration.
From Specialized Labs to Accessible Precision Manufacturing
Electrospray emitters have long been limited to specialized laboratories because of their cost and fabrication complexity. By shifting to 3D printed nozzles, MIT’s work changes the economics and accessibility of precision manufacturing for microstructured particles. Arrays of miniaturized triaxial emitters can now be produced in hours, not months, and without semiconductor-level cleanrooms that smaller companies and research groups often lack. Velásquez-García argues that “the particles these devices generate, whether they are used for a self-healing composite or to deliver medicine, can have a big impact in many applications. We want to democratize this technology so the benefits can touch many more people.” With scalable electrospray emitters, manufacturers could produce tailored drug delivery microparticles, embedded repair capsules for self-healing composites, or multipayload biosensing particles in compact, flexible production lines rather than monolithic, capital‑intensive facilities.
Future Applications in Pharmaceutical and Advanced Material Design
The immediate impact of 3D printed electrospray emitters lies in their ability to make complex particles practical at scale, but their future reach is wider. In pharmaceuticals, they could support personalized therapies, where different layers carry distinct drugs or release profiles in a single microparticle batch. In advanced materials, self-healing systems can be engineered so that embedded capsules contain separate reactive components in each layer, only mixing when damage occurs. The same architecture lends itself to biosensors that host multiple chemical markers, improving detection sensitivity or allowing multi-analyte readouts. Because the emitter arrays are defined digitally, manufacturers can adjust channel designs, nozzle spacing, and droplet size without overhauling an entire production line. As 3D printing resolutions improve and material options grow, triaxial electrospray emitters are likely to become a flexible platform for precision manufacturing, bridging pharmaceutical technology and high-performance functional materials.
