Figure 4.
Tyrosinase-sensing performance of nanostructured WVFY peptides-modified flexible Al2O3/In2O3 bio-FETs
(A) Schematic illustration of the flexible Al2O3/In2O3 bio-FETs functionalized with WVFY peptides in response to tyrosinase and sensing mechanism. In the presence of tyrosinase, the phenolic hydroxyl group in WVFY will be oxidized to catechol and finally transferred to benzoquinone with the consumption of protons. This could be detected potentiometrically by measuring the channel conductivity.
(B) Family of typical transfer curves of WVFY-modified bio-FETs measured in 0.1× PBS solution with various concentrations of tyrosinase: baseline (black), 10−14M (red), 10−13M (deep blue), 10−12M (green), 10−11M (purple), 10−10M (ginger), and 10−9M (sky blue). The Vth shifted positively with increased tyrosinase concentration (CTYR).
(C) A family of transfer curves of Al2O3/In2O3 bio-FETs without WVFY peptides when exposed to different CTYR, illustrating minor response.
(D) Linear relationships between the ΔVth and CTYR in logarithmic scale. Error bars indicate the standard deviations of three repeated tests with p < 0.05.
(E) Output characteristics of flexible WVFY-modified bio-FETs configured by varying CTYR. The Ids decreased with the improvement of CTYR, which was in line with the transfer performance. The applied gate bias was 0.3 V.
(F) Real-time sensing response of flexible WVFY-modified bio-FETs with tyrosinase. The drain and gate voltage (Vds and Vgs) were 0.1 and 0.2 V, respectively.
(G) Relationships between the sensing response (1 - I/I0) and CTYR.