A team of US nephrologists is developing first-of-its kind implantable artificial kidney with microchip filters and living kidney cells that will be powered by a patient's own heart to help kidney patients.Dr William H. Fissell IV, nephrologist and associate professor of medicine from Tennessee-based Vanderbilt University, is making major progress on a first-of-its kind device to free kidney patients from dialysis.“We are creating a bio-hybrid device that can mimic a kidney to remove enough waste products, salt and water to keep a patient off dialysis," Fissell said.The goal is to make it small enough, roughly the size of a soda can, to be implanted inside a patient's body.
The key to the device is a microchip.“It's called silicon nanotechnology. It uses the same processes that were developed by the microelectronics industry for computers," Fissell explained.The chips are affordable, precise and make ideal filters.Fissell and his team are designing each pore in the filter one by one based on what they want that pore to do. Each device will hold roughly fifteen microchips layered on top of each other.But the microchips have another essential role beyond filtering."They're also the scaffold in which living kidney cells will rest," said Fissell.
Fissell and his team use live kidney cells that will grow on and around the microchip filters. The goal is for these cells to mimic the natural actions of the kidney.Because this bio-hybrid device sits out of reach from the body's immune response, it is protected from rejection."The issue is not one of immune compliance, of matching, like it is with an organ transplant," said Fissell.The device operates naturally with a patient's blood flow.“Our challenge is to take blood in a blood vessel and push it through the device. We must transform that unsteady pulsating blood flow in the arteries and move it through an artificial device without clotting or damage,” the authors noted.
Vanderbilt biomedical engineer Amanda Buck is using fluid dynamics to see if there are certain regions in the device that might cause clotting.She uses computer models to refine the shape of the channels for the smoothest blood flow.Then they rapidly prototype the new design using 3D printing and test it to make the blood flow as smoothly as possible.Fissell says he has a long list of dialysis patients eager to join a future human trial. Pilot studies of the silicon filters can start in patients by the end of 2017.