Italian research team creates hybrid device that can “learn”
Most of us know pectin as a key ingredient for making delicious jellies and jams, not as a component for a complex hybrid device that links biological and electronic systems. But a team of Italian scientists have built on previous work in this field using pectin with a high degree of methylation as the medium to create a new architecture of hybrid device with a double-layered polyelectrolyte that alone drives memristive behavior.
A memristive device can be thought of as a synapse analogue, a device that has a memory. Simply stated, its behavior in a certain moment depends on its previous activity, similar to the way information in the human brain is transmitted from one neuron to another.
In an article published this week in AIP Advances, from AIP Publishing, the team explains the creation of the hybrid device. “In this research, we applied materials generally used in the pharmaceutical and food industries in our electrochemical devices,” said Angelica Cifarelli, a doctoral candidate at the University of Parma in Italy. “The idea of using the ‘buffering’ capability of these biocompatible materials as solid polyelectrolyte is completely innovative and our work is the first time that these bio-polymers have been used in devices based on organic polymers and in a memristive device.”
Memristors can provide a bridge for interfacing electronic circuits with nervous systems, moving us closer to realization of a double-layer perceptron, an element that can perform classification functions after an appropriate learning procedure. The main difficulty the research team faced was understanding the complex electrochemical interplay that is the basis for the memristive behavior, which would give them the means to control it. The team addressed this challenge by using commercial polymers, and modifying their electrochemical properties at the macroscopic level. The most surprising result was that it was possible to check the electrochemical response of the device by changing the formulation of gels acting as polyelectrolytes, allowing study of the ionic exchanges relating to the biological object, which activates the electrochemical response of the conductive polymer.
“Our developments open the way to make compatible polyaniline based devices with an interface that should be naturally, biologically and electrochemically compatible and functional,” said Cifarelli. The next steps are interfacing the memristor network with other living beings, for example, plants and ultimately the realization of hybrid systems that can “learn” and perform logic/classification functions.
The University of Parma (Italian: Università degli Studi di Parma, UNIPR) is one of the oldest universities in the world, founded in the 12th century.
It is organised in eighteen departments. As of November 2013 the University of Parma has about 32,000 students.
The school was founded in 1117 A.D as a center for study of the general liberal arts curriculum of the medieval period. The faculties of law and medicine were added in the 13th century. Pope John XXII closed the school in 1322, and during the next hundred years it was often reopened and closed. It became a university in 1502, and after 1545 under the patronage of the ducal House of Farnese. The Farnese Duke Ranuccio I founded and endowed the university College of Nobles with a distinguished faculty, but between 1731 and 1748 the university was again neglected.
Things improved in 1762 under Duke Ferdinand I de Bourbon, when he founded a great state university at Parma and endowed it with possessions confiscated from the Jesuits. Future Jesuit Father General Luigi Fortis was invited to head the College of Nobles. New studies were added. The university experienced a rapid growth phase and established an astronomical observatory, a botanical garden and laboratories of anatomy, chemistry and experimental physics. In 1811 the French government deemed the university an Academy of the Empire, but it lost this status a mere three years later. The university was closed to foreign students in 1831 and fell into decay. It was revived in 1854 by the duchess regent and is now a state administration with administrative autonomy.