ELECTROPHORETIC IMPLANTS FOR PROGRAMMABLE, FLOW FREE INTRACEREBRAL PHARMACOLOGY

Intracerebral pharmacology still relies heavily on pressure injection, cannulas, and osmotic pumps. These pressure based methods can introduce convection, reflux along the implantation tract, and local tissue displacement. As a result, concentration gradients at the target site can be uncertain and strongly dependent on tissue properties and surgical details. These failure modes are well documented in convection enhanced delivery work, where reflux and leakage depend on catheter geometry and flow rate and can cause off target spread and sub therapeutic exposure.
Here we present an flow-free implantable delivery technology based on electrophoretic transport through a polyelectrolyte hydrogel interface. The device functions as an electrophoretic micro pump: an applied current in the nA - µA range drives selective transport from an reservoir into tissue while suppressing bulk fluid flow. We characterize quantitative control metrics relevant for preclinical use, including delivered dose versus charge, delivery efficiency, and the effective transport number for the delivered species (efficiency ≈ 90%, delivery rate up to 180 pmol/min). Example use cases include local chemotherapy for brain tumors and localized delivery of neurotransmitters for circuit modulation experiments. By making dosing more quantitative and interpretable, electrophoretic implants provide a complementary tool for intracerebral pharmacology and methods development.