Bioelectronics Laboratory
  • Preclinical

Implant packaging for small animals

Light polymer enclosures, coatings and feedthroughs that keep implant electronics working through chronic studies in mice.

Encapsulated implant with a polyester suture mesh and a lead running to a Micro-Leads cuff electrode, with a 5 mm scale bar
Encapsulated implant with polyester suture mesh and a Micro-Leads cuff electrode.

The problem

Biology is a wet world; electronics come from a dry one. An implant's package has to keep its electronics dry in the body while staying small and light enough for a mouse to carry.

Our approach

Polymer-based encapsulation sized for mice, using epoxy and additive manufacturing, tested in accelerated saline soaks and in chronic implantation.

Metal and ceramic packaging is too costly and heavy for preclinical devices

Clinical implants are sealed in metal cans with ceramic feedthroughs. For devices implanted in mice, that approach is too expensive and too heavy, so we use polymer-based encapsulation instead, including epoxy and additive manufacturing. Our 2022 system already used a two-part 3D-printed shell with a polyester suture mesh.

Microscope images of laser-welded feedthrough wires entering a polymer-encapsulated circuit board
Laser-welded feedthroughs and a polymer-encapsulated circuit board under the microscope.

How the package is built

In the design described in our patent application, two housing segments close around the circuit boards and battery, and a feedthrough in one segment carries leads out through the wall. A conformal parylene-C coating is added during encapsulation, silicone relieves strain where the leads exit, and a polyester mesh on the housing gives the surgeon a suture anchor.

Patent drawing of the implant with the two halves of its housing pulled apart, exposing the stacked circuit boards and battery; one housing segment has a small feedthrough port at its end
The two halves of the housing separated to expose the circuit boards and battery; one segment (106) carries the feedthrough (107) for the leads. Adapted from WO 2024/108110, FIG. 2. Full size
CAD rendering of a green circuit board and battery inside a clear, rounded polymer enclosure with a lead exit at the top
CAD rendering of the version 3 implant inside its enclosure.

Next: 3D-printed enclosures that report on themselves

We are developing 3D-printed implant enclosures with built-in wireless monitoring of moisture inside the package.