Anti human tnf α antibody

Figure S1 in the supporting information illustrates the protocol for functionalizing the HfO₂ effective layer of a MoS2 transistor sensor with anti-human TNF-α antibody receptors for detecting TNF-α molecules. First, an as-fabricated transistor biosensor is immersed in 5% (3-Aminopropyl) triethoxysilane (APTES, purchased from Sigma-Aldrich Co. LLC.) in ethanol for 1 hour. After the incubation, the sensor is rinsed with phosphate buffered saline (PBS) and blown dry by nitrogen gas. After this step, the HfO₂ effective layer is silanized with an APTES monolayer. The device is subsequently immersed in 5% gluteraldehyde (GA) (purchased from Sigma-Aldrich Co. LLC.) in PBS for 2 hours followed by rinsing with PBS. Afterwards, anti-human TNF-α antibody (from eBioscience, Inc.) of 50 ug/ml concentration in DI water is dropped on the sensor and incubated for 1 hour. For studying the equilibrium-state sensor responses, the as-functionalized sensor is incubated with TNF-α solutions with incremental concentrations (i.e., n = 60 fM, 300 fM, 600 fM, 3 pM, and 6 pM; the incubation time for each of the concentrations: ~2 hours). The incubation is performed using the setup illustrated in Fig. 1(d). After each incubation process, the transfer characteristics of the transistor sensor are measured.