Figure 4.

pH insensitive sensing lipid for detection Fe³⁺ ions (a) A schematic of the hydroxyl γ-pyrone derivatives lipid engineered by Nguyen et al. group. (b-i) and (b-ii) comparison between commercial DCPC lipid (blue) and Nguyen’s modified lipid (red) behavior in pH solutions. Reprinted from [92], Copyright 2013, with permission from Elsevier. SiNR-FET sensor functionalized with Gly–Gly–His (GGH) for detection Cu²⁺ (c) GGH tethered on gold structure and (d-i–iv) sensor response at pH 4,5,6 and 7, respectively. Reproduced with permission from [104]. Copyright 2019 MDPI.