Qiao Lin

Monitoring Glucose Without Pinpricks

More than a million people with type 1 diabetes—an autoimmune disease that is life-threatening unless treated with frequent doses of insulin—will soon be able to check their blood sugar levels without the daily drawing of their own blood.

A team of researchers, led by Qiao Lin, has invented a microfabricated, miniature sensor that can eventually be implanted in a patient’s body for long-term, continuous glucose monitoring. It will be part of a closed-loop system that will automatically deliver insulin to diabetic patients based on blood sugar levels.

There are 17.9 million people in the United States of America diagnosed with diabetes, according to the American Diabetes Association.

Lin’s glucose sensor consists of a microscopic diaphragm, which vibrates under remote magnetic excitation in a microchamber filled with a glucose-sensitive polymer solution.

When glucose enters the chamber through a semipermeable membrane, it binds reversibly with the polymer, changing the viscosity of the solution. As the viscous damping on the diaphragm vibration directly depends on the viscosity, the glucose concentration can be determined by wireless vibration measurements. Depending on the result, insulin can be injected to maintain a normal glucose level.

The reversible binding of glucose to the polymer is key. “It is a physical process and so the glucose is not consumed,” said Lin. This is a key difference between his device and current, less reliable, sensors that use an irreversible electrochemical reaction of glucose with an enzyme.

The project has been carried out by an interdisciplinary team including Lin and his mechanical engineering PhD student Xian Huang at Columbia, biopolymer chemists Qian Wang and his Ph.D. student Siqi Li at the University of South Carolina, and Jerome Schultz at University of California, Riverside, an expert in biosensors.

Lin also directs the Columbia BioMEMS Laboratory, which conducts research in microelectromechanical systems (MEMS) as applied to biological sensing and manipulation, with an emphasis on controlling, sensing and characterizing biomolecules and cells by integrating MEMS transducers with microfluidics. The goal of these systems is primarily to facilitate understanding of fundamental biophysical phenomena and to enable practical biomedical applications.

Lin was a postdoctoral scholar in Caltech’s electrical engineering department and an assistant professor of mechanical engineering at Carnegie Mellon University prior to joining the Columbia Engineering faculty.

BS, Tsinghua University (Beijing), 1985; MS, Tsinghua University, 1988; PhD, California Institute of Technology, 1998.