Shape Memory Alloy Capsule Micropump for Drug Delivery Applications.

Area of Science:

• Biomedical Engineering
• Materials Science

Background:

• Micropumps are essential for precise drug delivery.
• Existing shape memory alloy (SMA) micropumps have limitations in terms of size, cost, and contamination risk.

Purpose of the Study:

• To develop and optimize a novel SMA-actuated micropump for drug delivery applications.
• To create a compact, self-contained, and reusable drug delivery system.

Main Methods:

• Designed a micropump integrating a replaceable drug reservoir.
• Utilized NiTi-alloy SMA wires actuated by joule heating for longitudinal actuation.
• Developed a model to optimize geometrical parameters and enclosure material.
• Integrated bicuspid-inspired polymeric check-valves for flow regulation.

Main Results:

• Achieved large strokes (5.6 mm) and high actuation speed (11 mm/s).
• Generated static head pressures up to 14 kPa (105 mmHg) with high throughput (>2524 μL/min).
• Optimized design for maximum deflection at low power using low-stiffness materials and thinner SMA wires.
• Demonstrated consistent performance for drug delivery applications.

Conclusions:

• The novel SMA micropump design is compact, cost-effective, and minimizes contamination.
• The design's longitudinal actuation and integrated features enable efficient and precise drug delivery.
• The reusable and replaceable reservoir enhances its practicality for diverse drug types and repeated use.