An Implanted Magnetic Microfluidic Pump for In Vivo Bone Remodeling Applications.

Area of Science:

• Biomedical Engineering
• Regenerative Medicine
• Biomaterials

Background:

• Fluid flow modulation in bone intramedullary cavities stimulates cellular activity and bone growth.
• Previous studies were limited by external pumps and transcutaneous tubing.
• A need exists for minimally invasive methods to study in vivo fluid dynamics in bone.

Purpose of the Study:

• To develop and characterize an implantable magnetic microfluidic pump for in vivo bone studies.
• To assess the wireless actuation and pressure delivery capabilities of the device.
• To evaluate the pump's efficacy in modulating fluid pressure within a rodent's femoral intramedullary cavity.

Main Methods:

• Fabrication of a compact polydimethylsiloxane (PDMS) microfluidic pump with NdFeB magnets.
• Utilized an external actuator with a larger magnet for wireless pump operation.
• Characterized static and dynamic pressures of the pump.
• Implanted the pump into Fischer-344 rats and connected it to the femur's intramedullary cavity.

Main Results:

• Successfully fabricated a compact (22 mm diameter, 5 mm thickness) implantable magnetic microfluidic pump.
• Demonstrated wireless, on-demand actuation of the pump using an external magnetic actuator.
• Achieved fluid pressure modulation up to 38 mmHg within the rat's femoral intramedullary cavity.

Conclusions:

• The developed implantable magnetic microfluidic pump offers a novel, minimally invasive tool for in vivo bone fluid flow modulation.
• This technology facilitates the study of bone mechanobiology and growth stimulation in a more natural physiological environment.
• The wireless actuation and controlled pressure delivery open new avenues for therapeutic interventions targeting bone regeneration.