Researchers make progress in developing an implantable device.

Most patients with end-stage renal disease (ESRD) depend on hemodialysis and suffer excessive mortality and morbidity. Kidney failure is becoming an epidemic in the United States, fueled by diabetes, obesity and, paradoxically, improved cardiac care. Patients with hypertension and diabetes now live long enough to develop kidney failure.

Recent research has shown improved control of BP, nutrition, and cardiac disease with prolonged daily dialysis, but nationwide implementation of this strategy would overwhelm existing resources. Consequently, innovative efforts in tissue and biomedical engineering strive to create alternatives to transplant and in-center dialysis.

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An ideal alternative would be a wearable or implantable device integrated with state-of-the-art electronics. Such a device would have to mimic the kidney’s processes for filtering blood, reabsorbing salt and water, and excreting toxins. Making a device small enough to be implanted requires tight control over pore size, geometry, and chemistry, which can improve hydraulic permeability and molecular selectivity of dialysis membranes.

Using a unique technology called microelectromechanical systems (MEMS), my colleagues and I have designed and tested novel thin membranes with highly uniform slit-shaped pores using microfabrication techniques developed for the semiconductor industry. These membranes could be used to miniaturize dialysis equipment.

To reproduce the metabolic activity of the kidney, human kidney cells were harvested from donated organs not suitable for transplant and grown on these novel membranes. The cultured cells covered the membranes and appear to retain features of adult kidney cells. So far, tests in our laboratory suggest that the theoretical advantages of these new membranes can be realized in practice. 

Development of this technology is being funded with a $3.2 million NIH grant received by Shuvo Roy, PhD, adjunct staff in the department of biomedical engineering.