Figure 2

Salivary collection and analysis protocol. Salivary conductivity is measured using a printed-circuit board. (A) Collect saliva smoothly with a cotton swab. (B) Place salivary sample in an Eppendorf tube after collection. (C) Centrifuge the salivary sample at 3500 rpm for 5 min. (D) Dilute the salivary sample fivefold with ultrapure water after centrifugation. (E) Analyze salivary conductivity using a developed portable bio-device equipped with a disposable printed-circuit board electrode. (F) Record real-time data of salivary conductivity immediately.