2.2. Manufacturing of glucose biosensors
The glucose biosensor was fabricated by coating the printed conductive
PLA with GOx solution. Nafion and GOx were purchased from Sigma (USA),
and GOx was stored at −20°C until used. Nafion 117 (5% (w/w) in mixed
alcohols) was obtained from Sigma (USA). The GOx solution was prepared
by dissolving 1X phosphate buffer saline (PBS) at a concentration of 7.2
mg/mL. Nafion/MWCNT solution was prepared by adding 1% (w/v) MWCNT to
the Nafion solution. For complete dispersion of MWCNT in the solution,
ultrasonication was performed for 30 min, followed by high-speed
stirring (800 rpm) at 40°C for 24 h. The produced GOx solution and the
Nafion/MWCNT solution were mixed in a 1:1 ratio to prepare the
Nafion/MWCNT/GOx solution. To coat the WE, approximately 10 μL of the
Nafion/MWCNT/GOx solution was casted on the part that touches the
solution of the printed conductive PLA and incubated at room temperature
until the casted solution dried completely.