Prestress as an optimal biomechanical parameter for needle penetration

Area of Science:

• Biomedical Engineering
• Dermatology
• Materials Science

Background:

• Precise intradermal and subcutaneous injections are crucial for effective drug delivery.
• Skin properties significantly influence injection depth due to variable deflection.
• Factors like age, disease, and ethnicity affect skin mechanics and injection outcomes.

Purpose of the Study:

• To investigate factors influencing skin deflection during needle penetration.
• To evaluate the efficacy of applying prestress to the skin surface for injection.
• To optimize needle parameters for accurate drug delivery.

Main Methods:

• Utilized an ex vivo skin model to simulate injection conditions.
• Varied parameters including surface prestress, needle gauge, velocity, and actuation depth.
• Measured skin deflection and force required for needle penetration.

Main Results:

• Prestress application significantly minimized skin deflection during needle insertion.
• Minimized variability in achieving targeted penetration depths.
• Injection force increased with prestress and decreased with larger needle gauges.

Conclusions:

• Surface prestress is essential for reducing skin variability and enhancing injection precision.
• Optimizing prestress and needle gauge can improve the accuracy of intradermal and subcutaneous drug delivery.
• This approach offers a method for more reliable administration of therapeutic formulations.