Innovative Fabrication of Hollow Microneedle Arrays Enabling Blood Sampling with a Self-Powered Microfluidic Patch

Area of Science:

• Biomedical Engineering
• Microfluidics
• Materials Science

Background:

• Microneedles offer a less invasive alternative to traditional blood sampling methods like venous puncture.
• Existing methods like finger-pricking face challenges in manual handling and sample volume.
• Hollow microneedle arrays (HMNAs) are promising for integrated sample-to-answer systems, but fabricating long, sharp needles is difficult.

Purpose of the Study:

• To develop a novel fabrication protocol for high aspect ratio hollow microneedle arrays (HMNAs).
• To integrate HMNAs into a self-powered microfluidic sampling patch for efficient biofluid collection.
• To validate the performance of the microneedle sampling patch for potential point-of-care applications.

Main Methods:

• A two-step fabrication process involving percussion laser drilling and micro-milling was used to create stainless steel HMNAs.
• HMNAs were integrated into a microfluidic patch with a capillary pump.
• The capillary pump was optimized to generate negative pressure up to 40.9 ± 1.8 kPa for sample aspiration.

Main Results:

• Successful fabrication of sharp-tipped HMNAs with a high aspect ratio was achieved.
• The integrated sampling patch demonstrated the feasibility of collecting 40 μL of liquid in vitro.
• The optimized capillary pump provided sufficient negative pressure for effective sample aspiration.

Conclusions:

• The novel fabrication method enables the production of HMNAs suitable for deep skin penetration and capillary blood sampling.
• The developed self-powered microfluidic sampling patch represents a significant advancement in biofluid collection technology.
• This proof-of-concept system lays the foundation for future all-in-one biofluid sampling and point-of-care testing devices.