Flexible sensors and electronic devices constitute one of the great frontiers of research in the third millennium. The advantages of these technologies are obvious: the possibility to wrap or fold the devices (with space saving benefits), the opportunity to manufacture wearable accessories and the weight reduction of the final product [1]. Many vital sectors of the modern manufacturing industry are interested by the general evolution towards flexible electronics: displays, solar cells, batteries and sensors.

In the case of biosensors in particular the development of flexible devices is particularly attractive due to their ability to adapt to human body, making possible the realization of wearable medical equipment. Example of biosensors include devices for the detection of glucose, organophosphates, proteins, antibiotics and many others. Their working principle may vary, but one of the most promising is the electrochemical one. Most of the electrochemical sensors are based on an enzyme mediated catalysis that produces or uses electrons. The resulting flux of current can be quantified and used for the sensing of the target specie.

These sensors, called enzymatic, present however some disadvantages. Firstly, the enzyme loses activity over time. Moreover, the enzyme is typically not completely stable when immobilized on a substrate. For these reasons, a primary goal of modern research on biosensing is the development of non-enzymatic sensors.

In the present work, a flexible non-enzymatic electrochemical glucose biosensor is presented. The functioning of the device is based on CuO, a common p-type semiconductor already used for the manufacturing of non-enzymatic glucose sensors [2, 3]. CuO nanoparticles are synthesized via a hydrothermal reaction and inkjet printed on a flexible substrate. Such flexible substrate is obtained by electroless plating with NiP a polymer sheet and by subsequently applying a platinum layer via electrolytic deposition. Sensitivity and selectivity of the obtained devices are finally tested with electrochemical techniques and their operative range is determined.

The obtained single use bendable sensors may result of great interest for the control of patients affected by diabetes mellitus, a pathology that constitute one of the primary health risks in the world.

[1] M. A. Alam, and S. Kumar; ed. B. Bhushan; “Flexible Electronics" chapter in Encyclopedia of Nanotechnology, Springer Netherlands, Dordrecht (2012) 860-865

[2] R. Ahmad, N. Tripathy, Y. B. Hahn, A. Umar, A. A. Ibrahim and S. H. Kim, Dalt. Trans. 44 (2015) 12488-12492

[3] R. Ahmad, M. Vaseem, N. Tripathy and Y. B. Hahn, Anal. Chem. 85 (2013) 10448-10454