Highly sensitive reduced graphene oxide impedance sensor harnessing π-stacking interaction mediated direct deposition of protein probes.

Graphene-based electrochemical impedance sensors have recently received much attention due to their outstanding sensing capability and economic viability. In this study, we present a novel means of constructing an impedance sensing platform via harnessing intrinsic π-stacking interactions between probe protein molecules and reduced graphene oxide (RGO) substrate, obviating the need for introducing external chemical groups often required for covalent anchoring of the probes. To achieve this goal, protein molecules used as a probe were denatured to render their hydrophobic residues exposed in order to facilitate their direct π-stacking interactions with the surface of RGO nanosheets.

The interplay of peptide sequence and local structure in TiO2 biomineralization.

Using cyclic constrained TiO(2) binding peptides STB1 (CHKKPSKSC), RSTB1 (CHRRPSRSC) and linear peptide LSTB1 (AHKKPSKSA), it was shown that while affinity of the peptide to TiO(2) is essential to enable TiO(2) biomineralization, other factors such as biomineralization kinetics and peptide local structure need to be considered to predict biomineralization efficacy. Cyclic and linear TiO(2) binding peptides show significantly different biomineralization activities. Cyclic STB1 and RSTB1 could induce TiO(2) precipitation in the presence of titanium(IV)-bis-ammonium-lactato-dihydroxide (TiBALDH) precursor in water or tris buffer at pH 8.