NC State finds new nanomaterial could be breakthrough for implantable medical devices

Roger Narayan, Associate Professor, Primary Core Faculty. Joint Department of Biomedical Engineering. NC State University and UNC Chapel Hill

A team of researchers led by North Carolina State University has made a breakthrough that could lead to new dialysis devices and a host of other revolutionary medical implants. The researchers have found that the unique properties of a new material can be used to create new devices that can be implanted into the human body – including blood glucose sensors for diabetics and artificial hemo-dialysis membranes that can scrub impurities from the blood. Researchers have long sought to develop medical devices that could be implanted into patients for a variety of purposes, such as monitoring glucose levels in diabetic patients. However, existing materials present significant problems.

For example, devices need to be made of a material that prevents the body's proteins from building up on sensors and preventing them from working properly. And any implanted device also needs to avoid provoking an inflammatory response from the body that would result in the body's walling off the device or rejecting it completely.

Now a new study finds that nanoporous ceramic membranes may be used to resolve these issues. Dr. Roger Narayan – an associate professor in the joint biomedical engineering department of NC State and the University of North Carolina at Chapel Hill – led the research and says the nanoporous membranes could be used to "create an interface between human tissues and medical devices that is free of protein buildup."

The new research, published in a special issue of Biomedical Materials, is the first in-depth study of the biological and physical properties of the membranes. The study suggests that the human body will not reject the nanoporous ceramic membrane. Narayan adds that this could be a major advance for the development of kidney dialysis membranes and other medical devices whose development has been stalled by poor compatibility with human tissues. Narayan was also the lead researcher on the team that first developed these new materials. ###

Narayan's co-authors on the paper include NC State materials science engineering doctoral students Ravi Aggarwal and Wei Wei; NC State postdoctoral research associate Dr. Chunming Jin; Dr. Nancy Monteiro-Riviere, professor of investigative dermatology and toxicology at NC State's College of Veterinary Medicine and the Center for Chemical Toxicology Research and Pharmacokinetics; and Rene Crombez and Dr. Weidian Shen of Eastern Michigan University.

Note to editors: The study abstract follows.

"Mechanical and biological properties of nanoporous carbon membranes"

Authors: Dr. Roger J. Narayan, Ravi Aggarwal, Wei Wei, Dr. Chunming Jin, Dr. Nancy A. Monteiro-Riviere, North Carolina State University; Rene Crombez, Dr. Weidian Shen, Eastern Michigan University

Published: Aug. 8, 2008, in Biomedical Materials

Abstract: Implantable blood glucose sensors have inadequate membrane–tissue interfaces for long term use. Biofouling and inflammation processes restrict biosensor membrane stability. An ideal biosensor membrane material must prevent protein adsorption and exhibit cell compatibility. In addition, a membrane must exhibit high porosity and low thickness in order to allow the biosensor to respond to analyte fluctuations.

In this study, the structural, mechanical and biological properties of nanoporous alumina membranes coated with diamond-like carbon thin films were examined using scanning probe microscopy, nanoindentation and MTT viability assay. We anticipate that this novel membrane material could find use in immunoisolation devices, kidney dialysis membranes and other medical devices encountering biocompatibility issues that limit in vivo function.

Contact: Matt Shipman matt_shipman@ncsu.edu 919-515-6386 North Carolina State University