Figure 5.

Multiplexed Biosensing

(A) Photograph of three sensor devices attached conformally to a polydimethylsiloxane brain mimic. Scale bar is 1 cm.

(B) Changes in resistance with respect to temperature in artificial cerebrospinal fluid (aCSF). Error bars are standard deviations for N = 5 devices. For linear regression (y = ax + b), resistance = (3.9×temperature) + 700, where temperature is in degrees Celsius; R² = 0.99.

(C) Real-time pH sensing at unfunctionalized In₂O₃ nanoribbons in three different devices exposed to buffer solutions with pH values from 10 to 4.

(D) Simultaneous sensing of temperature, pH, serotonin, and dopamine in aCSF (pH = 7.4). Two adjacent devices were simultaneously exposed to solutions of 1 pM serotonin, 1 pM dopamine, 1 nM serotonin, and 1 nM dopamine, sequentially. Only transistors functionalized with the respective target-specific aptamers responded to the corresponding targets. All sensors responded to a pH change in aCSF (7.4–7.3). The devices were operated at V_DS = 0.2 V and V_GS = 0.25 V.