Co3O4 nanoparticles embedded in laser-induced graphene for a flexible and highly sensitive enzyme-free glucose biosensor

Developing flexible and wearable enzyme-free biosensors for detecting glucose is indispensable for preliminary diabetes diagnosis and human healthcare monitoring. Herein, an innovative flexible Co3O4 nanoparticles uniformly embedded in 3D porous laser-induced graphene (Co3O4 NPs-LIG) electrode is fabricated by a new one-step laser direct writing carbonization technique. The hybrid electrode featuring the remarkable synergistic effect on account of the excellently conductive LIG and multiple high activation sites of Co3O4 NPs can enhance charge transfer, thereby boosting glucose sensing performance. Benefit from the dramatic properties, the proposed flexible non-enzymatic glucose biosensor exhibits a prominent glucose sensitivity of 214 μA mM–1 cm–2, an extremely low limit of detection of 0.41 μM, a wide linear detection of 1 μM to −9 mM, and a fast response time within 0.49 s. Additionally, impressive repeatability, favorable stability, and great selectivity are achieved in the detection of glucose concentration. Finally, a possible sensing mechanism of the glucose biosensor is also discussed based on the First principles. This study provides a novel and facile strategy for constructing heterostructure of transition metal oxide NPs embedded in LIG, which serves to develop flexible and wearable highly sensitive enzyme-free biosensors for detecting glucose in the near future. [Display omitted] •An innovative electrode was composed of Co3O4 nanoparticles uniformly embedded in 3D porous laser-induced graphene.•The sensitivity of the flexible non-enzymatic glucose sensor was 214 μA mM–1 cm–2 with a low detection limit of 0.41 μM.•The synergy between Co3O4 and laser-induced graphene is beneficial to the electrocatalytic reaction of glucose.•The sensor had impressive repeatability, superior stability and showed prominent selectivity towards glucose.