A biodegradable implantable micropump for biomedical applications, focusing on peripheral nerve repair

Abstract

Fully biodegradable microsystems enable therapies for temporary medical conditions that could not be addressed before. We present the first entirely biodegradable, wireless, implantable micropump for biomedical applications, with potential uses ranging from internal negative pressure wound therapy and drug delivery to soft robotics for temporary incontinence. As a proof-of-concept, the micropump was designed for peripheral nerve repair. It is magnetically actuated, featuring a nozzle/diffuser configuration, with a membrane of POMaC elastomer bonded to a magnetic POMaC/CIP composite. POMaC/CIP 20 wt% is selected for its mechanical and magnetic properties (Young’s modulus: 45 kPa, magnetic relative permeability: 1.14). A magnetic disc (6 mm x 0.5 mm) maximizes displacement and is actuated via a motor-driven magnetic setup at 4-8 Hz. An equivalent circuit model predicts under-pressure generation trends, confirmed experimentally through continuous/alternate pumping, repeatability assessments, and 240,000-cycle stability tests. In vitro and ex-vivo tests demonstrate consistent under-pressure (~2.3 kPa), meeting nerve regeneration requirements. Accelerated degradation tests show 31% mass loss after seven weeks, supporting short-term use. This platform is adaptable to diverse biomedical contexts, enabling novel therapies previously unachievable.