(News from Nanowerk) Anyone with diabetes cannot live without them – test strips for measuring blood sugar. They contain enzymes that react with glucose in the blood.
“Once used, conventional enzyme-based photometric or electrochemical measurements no longer work and the test strip is discarded,” says Professor Yvonne Joseph of the TU Bergakademie Freiberg. “Enzymes are proteins that trigger biochemical reactions. As proteins, however, they are not temperature stable,” continues the professor of electronic materials and sensors.
She and her team set out to find another sensor material. She found what she was looking for in the laboratory of her colleague, Professor Hermann Ehrlich. The biomimetic expert has been developing new biosourced materials for several years. A bath sponge coated with the mineral atacamite was considered for glucose measurement.
“The unique structure of the microporous 3D sponge structure effectively promotes the activity of atacamite as an electrocatalyst. Therefore, glucose molecules can diffuse into the porous 3D network, which facilitates the transfer of electrons between glucose and atacamite and leads to powerful glucose sensor properties,” says research associate Dr Parvaneh Rahimi.
She crushed the sensor material from the sponge and added carbon as an electrical conductor as well as paraffin oil as a binder. Dr. Parvaneh Rahimi then applied the homogeneous paste to a Teflon backing which served as the electrode body. When the electrode was immersed in a glucose solution, the sugar molecules diffused into the porous coated sponge. They reacted on its surface, resulting in a measurable electric current.
The findings are published in Applied organic materials (“High performance three-dimensional spongin-atacamite biocomposite for the non-enzymatic electrochemical detection of glucose”).
Potential for Enzyme-Free and Reusable Test Strips for Diabetes Management
The researchers tested the new measuring method in two steps: with a solution containing glucose and with three different blood samples from anonymous donors in a doctor’s office in Freiberg. “Both tests revealed stable measurement results over a period of one month. As a sensor, the material would therefore be reusable,” explains Professor Yvonne Joseph. Before it can be used in test strips for diabetes management, the new sensor material would need to undergo further testing and clinical studies.
Background: sensor materials from cultured sponges
Researchers at the TU Bergakademie Freiberg developed the atacamite sponge material from a cultured sea sponge. When sponge fibers react with an ammonia solution containing copper, the mineral atacamite is formed. This mineral, very rare in nature, attaches itself so strongly to the fibers of the sponge that a robust material is formed.
No experiments were conducted on living organisms to research the new material made from sponges grown in Tunisia. All requirements of the Nagoya Protocol on access to genetic resources and fair and equitable sharing of benefits have been met in the breeding and purchase of the sponges used.