In conclusion, this study successfully optimized the inkjet printing process to fabricate rGO-based lactate biosensors with high sensitivity and selectivity. By optimizing the printing layers, density of Anti-L, and incubation time for lactate samples, the sensor achieved linear responses with a high sensitivity of about 0.5 per 100 µM lactate and a low detection limit at 23 µM. The use of ethyl cellulose in the ink also reduced the coffee ring effect and produced a uniform film of rGO. Overall, this study demonstrates the potential of inkjet printing technology for the fabrication of highly sensitive and reliable biosensors, with potential applications in various fields, such as healthcare and environmental monitoring.