A Miniaturized Wireless, Battery-free Implant for In Vivo Musculoskeletal Stimulation

Area of Science:

• Biomedical Engineering
• Neuroprosthetics
• Implantable Devices

Background:

• Current muscle stimulation methods often require invasive procedures or bulky equipment.
• There is a need for minimally invasive, adaptable solutions for therapeutic muscle stimulation.
• Wireless, battery-free technologies offer advantages in long-term implantable applications.

Purpose of the Study:

• To develop and evaluate a miniaturized, wireless, and battery-free implant for musculoskeletal stimulation.
• To demonstrate the implant's capability for generating therapeutic electrical stimulation.
• To assess the in vivo efficacy of the implant in triggering muscle-induced movement.

Main Methods:

• Design and fabrication of an 8 × 8 mm² implantable device.
• Utilized a 2.4 GHz wireless protocol for external control and power transfer.
• Benchtop testing for voltage output and in vivo testing on rodent gastrocnemius muscle.

Main Results:

• The implant generated a monophasic voltage of up to 11.9 V in benchtop tests.
• Successfully triggered synchronized limb movement in rodents, with a 15 mm limb deflection.
• Demonstrated the ability to deliver customizable stimulation protocols wirelessly.

Conclusions:

• The developed implant is a viable, miniaturized solution for wireless, battery-free musculoskeletal stimulation.
• The technology shows promise for applications in muscle rehabilitation and potentially cardiac pacing.
• External adjustability of stimulation parameters enhances its versatility for diverse therapeutic needs.