Fig. 5: Sensing performances of FEOS as probes.
From: Towards explicit regulating-ion-transport: nanochannels with only function-elements at outer-surface
a A scheme showing the working mechanism of the sensor using FEOS as probes. b Capture process of multi-scale targets through designed single-stand DNA. c Sensitivity and selectivity of the DNA@OS (DNA is a designed sequence specifically bonding with targets) for the recognition of ions (Hg2+), small molecules (ATP), protein (Lysozyme) and cells (MCF7). The selective detection of multiscale targets using FEOS was realized based on the change of frec signal output induced by the surface charge at outer surface. LoD is defined as the limitation of detection for the targets. d Formation of “supersandwich” DNA structure (ssw-DNA) with long concatamers through the successive hybridization of alternating DNA unit. And gradual disassembly of ssw-DNA based on interaction between ATP and the repeat DNA units through increasing ATP concentration. e Agarose gel electrophoresis characterizing of the ssw-DNA: 1) DNA marker; 2) p1; 3) p2 (ATP ampter); 4) p1 + p2; 5) target+p1 + p2. f Depth distribution of the “supersandwich” DNA in nanochannel-system using ToF-SIMS. g Laser scanning confocal microscopy of the OS after the assembly (top) and the disassembly of ssw-DNA (bottom). The scale bar is 20 μm. h The LoD of ATP using ssw-DNA as probe based on nanochannel method and electrochemical method (Fig. S30). i Specificity of ssw-DNA@OS for ATP, in contrast with other NTPs. For the sensing performances part, five sensors using FE@OS were established to obtain each error bar of sensitivity and specificity.
