Coaxial Nozzle Assembly to Fabricate Capsules and Provide Double Layers of Protection

Dispenses Liquid Materials and Encapsulates Them at the Same Time to Build Double-Layered Capsules

This encapsulation nozzle uses a coaxial configuration with three channels to fabricate materials into capsules with two layers of protective coatings. Encapsulation is a manufacturing procedure that aims to atomize, immobilize, protect, and control the release of materials by housing them within capsules. Researchers have used this procedure to create capsules of materials such as living cells, pharmaceutical compounds, chemicals, and flavors. Many agricultural, pharmaceutical, and chemical industries are interested in encapsulation mechanisms that can create material capsules with multiple layers to facilitate multiple distinct functions, rather than capsules with just a single layer. However, available multi-layered encapsulation procedures are not effective and are difficult to produce.

Researchers at the University of Florida have developed a proficient multi-layered capsule fabrication system by creating a nozzle device that utilizes a coaxial dispensing mechanism. The nozzle has multiple concentric channels around a common axis that simultaneously dispense the core material along with the different surrounding materials, enabling multi-layered capsule fabrication. The multiple layers of the capsules support additions to the material, such as reinforced surfaces to provide greater protection and stability.

Application

Encapsulation nozzle with three concentric dispensing channels that fabricates capsules with more than one shell layer

Advantages

• Provides control over flow rates of liquid material during capsule assembly, enabling users to control shell layer thickness
• Enables multi-layer capsule fabrication, improving various capsule-based applications in agriculture, biotechnology, and medicine
• Implements easily, manufacturing various single- and double-layered capsules from diverse liquid materials

Technology

This coaxial nozzle produces multi-layered capsules. The nozzle is made up of three channels (core flow, annular flow, and sheath flow) that have a common axis and together form the core, inner shell, and outer shell of the capsule, respectively. The different liquid materials exit through the channels of the coaxial nozzle to form a compound liquid flow that creates the multi-shelled, multi-layered capsules. The capsule formation process varies based on the velocity or flow rate of each liquid material and its particular properties. Syringe pumps deliver the liquid materials into the different channels, and an ultrasonic vibrator helps break up the flow of the fluid in the nozzle, allowing the multi-layered capsules to form more effectively.