File Name : figure s2.tif

Caption : fig. s2: illustrated diagram showing the construction of the proposed 3d-gr@al2o3 sensor, including the insertion of the conductive cable into the printed support, the composition of the composite material, and its immobilization within the support.

File Name : figure s3.tif

Caption : fig. s3: edx analysis of sensors with (a) 0% e (b) 5% (m/m) of al2o3 in your composition. analysis condition: acquisition time 10 s, accelerating voltage 15 kv, process time 5 s. 

File Name : figure s4.tif

Caption : fig. s4: (a) cv voltammograms and (b) nyquist diagrams of 3d-gr@al2o3 (red line) and gce (black line) in 2.5 mmol l-1 potassium ferricyanide/ferrocyanide in kcl medium 100 mmol l-1. cv scan rate 0.1 v. eis conditions: applied potential of 0.224 v, 10 mv of amplitude, and the frequency region ranging from 10,000 to 0.1 hz.