Optimal voice coil actuators for needle-free jet injection

Area of Science:

• Biomedical Engineering
• Mechanical Engineering
• Electromagnetics

Background:

• Needle-free jet injectors offer advantages over traditional needles for drug delivery.
• Scaling existing designs for different volumes presents engineering challenges.
• Optimizing motor performance is crucial for efficient and effective jet injection.

Purpose of the Study:

• To establish a scaling model for electrically-actuated needle-free jet injectors.
• To derive an optimal motor design based on electromagnetic principles.
• To demonstrate the model's utility by designing a compact motor for 300 μL ampoules.

Main Methods:

• Developed an analytical electromagnetic model for the actuator motor.
• Analyzed the relationship between injection volume and required motor size.
• Derived a scale-invariant optimal motor design.
• Designed and experimentally verified a motor for 300 μL disposable injection ampoules.

Main Results:

• The scaling model establishes a clear relationship between injection volume and motor size.
• The derived optimal motor design is approximately scale-invariant.
• A lightweight motor and support structure (300 g) was designed for 300 μL ampoules.
• Experimental results showed excellent agreement with model predictions, achieving 1000 N/kg peak force and a 150 m/s water jet.

Conclusions:

• The presented scaling model is a valuable tool for designing efficient, compact needle-free jet injectors.
• The scale-invariant optimal motor design facilitates adaptation across various injection volumes.
• The successful design and verification demonstrate the practical applicability of the model for medical device development.