Self-Expanding Anchors for Stabilizing Percutaneously Implanted Microdevices in Biological Tissues

Area of Science:

• Biomedical Engineering
• Materials Science
• Minimally Invasive Devices

Background:

• Percutaneously implanted miniaturized devices are crucial for disease diagnosis and treatment.
• Ensuring the stability of these microdevices is critical to prevent functional loss and clinical complications due to tissue migration.

Purpose of the Study:

• To develop and evaluate novel anchoring methods for percutaneously implanted microdevices.
• To assess the efficacy of biocompatible anchors in preventing microdevice dislodgement across various tissue types.

Main Methods:

• Two anchoring methods were developed: a self-expanding nitinol mesh and self-expanding hydrogel particles in netting.
• These anchors were integrated into drug-screening microdevices and tested for dislodgement forces in liver, kidney, fat, and muscle tissues.
• Dislodgement forces were compared between anchored and non-anchored microdevices.

Main Results:

• Nitinol-anchored microdevices showed dislodgement forces ranging from 520 ± 28 to 738 ± 37 mN.
• Hydrogel-anchored microdevices exhibited dislodgement forces from 457 ± 47 to 735 ± 98 mN.
• Anchored microdevices demonstrated a 30-50 fold increase in resistance to dislodgement compared to non-anchored devices (13 ± 2 to 15 ± 3 mN).

Conclusions:

• Both nitinol mesh and hydrogel particle anchors significantly enhance the stability of microdevices in biological tissues.
• These anchoring methods are compatible with percutaneous implantation and removal without increasing needle gauge requirements.
• The developed anchors show promise in reducing the risk of microdevice migration and improving therapeutic outcomes.