Dynamic behavior of a spring-powered micronozzle needle-free injector

Area of Science:

• Biomedical Engineering
• Drug Delivery Systems
• Medical Devices

Background:

• Conventional needle injections for macromolecular therapeutics face challenges with patient compliance due to pain and needle phobia.
• Needle-free drug delivery strategies are being researched to overcome the skin barrier.
• Jet injection, an established needle-free method, has underexplored potential for therapeutic delivery.

Purpose of the Study:

• To design, engineer, and evaluate the dynamic behavior of a novel spring-powered micronozzle needle-free injector.
• To investigate the fluid mechanics and jet evolution of the injector using simulation and ex vivo models.
• To assess the potential of this new device for subcutaneous and dermal drug delivery.

Main Methods:

• Fluid mechanics simulations were performed in air to determine jet force, speed, and duration.
• Polyacrylamide gel was used to simulate soft tissue and study jet evolution with varying injected volumes.
• Ex vivo characterization was conducted on pig skin to evaluate device performance in a biological context.

Main Results:

• Jet force, velocity, and duration were found to be directly dependent on the injection volume.
• Simulations in gel allowed for the identification of jet penetration stages and mechanistic explanations.
• Distinct jet behavior was observed in pig skin, offering insights for subcutaneous and dermal delivery applications.

Conclusions:

• The novel spring-powered micronozzle injector demonstrates tunable performance based on injection volume.
• The device exhibits unique characteristics compared to existing jet injectors.
• This needle-free injector holds significant potential for future clinical applications in drug delivery.