Different mechanism of capacitance change for gas detection using semiconducting and metallic single-walled carbon nanotubes

Semiconducting single-walled carbon nanotubes (s-SWCNTs) with lower absorption energy of NO₂ gas exhibited higher sensitivity than metallic SWCNTs. The result originated from quantum capacitance of s-SWCNTs, which was readily affected by charge transfer, whereas that of m-SWCNTs showed no change with even more transferred charges. However, m-SWCNT that were aligned polarize adsorbed gases on the surface by a local field that contributed the capacitance changes of m-SWCNT networks. This is a newly introduced detection mechanism of gas sensing using m-SWCNTs.     

Stability and orientation of cecropin P1 on maleimide self-assembled monolayer (SAM) surfaces and suggested functional mutations

One of the main challenges of biosensor design is to understand the protein or peptide stability on the chip in high resolution structural detail.Since conventional experimental methods are limited by the resolution for their applications on surface tethered peptides/proteins,a recently developed coarse grained simulation method is employed to explore the peptide/surface interaction in residue-level resolution.This work shows how the coarse grained model successfully describes peptide–surface interactions by evaluating thermal stability of the peptide cecropin P1 in bulk solution and on surfaces by physical adsorption and chemical tethering.The simulation also reproduces observations of peptide orientations on the self-assembled monolayer surface from earlier experimental work.Additionally,using knowledge obtained from the simulations,specific mutations are suggested and the desired structure and pose on the surface is obtained.In summary,this work sheds a light on the reasonable biosensor design that is guided by simulations.