The factors that govern the allosteric chemical sensing of polythiophene chemosensors: scope and limitation toward signal-amplification sensing

Abstract

The allosteric sensing of target guest molecules was drastically inhibited by introducing thiophene spacers in the polythiophene backbone, which is caused by the conformational relaxation.

Allosteric Signal-Amplification Sensing of Peptides with Cyclodextrin-Polymer Conjugates in Aqueous Media

“…To further generalize the present SASS induced by modifying the hydrophobic chromophores on the CDx portal, we used permethylated β-CDx-PT conjugate chemosensors, CDPT s (Figure a), both of which possess flexible PT backbones ( anti ↔ syn ) upon interacting with the guests. Previously reported PT-based chemosensors showed similar behavior. ,, After elucidating the optical properties of CDPT s as with CDPF s (Figure S19), peptide sensing was performed in 1:9 (v/v) CH 3 OH/33 mM PBS. As shown in in Figure S40, CDPT 1 did not show any complexation behavior due to its rigid and less flexible β-CDx branches (Figure a).…”

“…Previously reported PT-based chemosensors showed similar behavior. 44,45,49 After elucidating the optical properties of CDPTs as with CDPFs (Figure S19), peptide sensing was performed in 1:9 (v/v) CH 3 OH/33 mM PBS. As shown in in Figure S40, CDPT 1 did not show any complexation behavior due to its rigid and less flexible β-CDx branches (Figure 2a).…”

“…As shown in Figure b, the SASS approach contains three essential processes: (1) a target guest molecule binds to the recognition site of a chemosensor, (2) the allosteric propagation of the binding information to a signal-amplifying polymer occurs, and (3) an amplifying response originates from the polymer reporter. As shown in Figure c, we demonstrated the mechanism of the SASS approach using bisthiourea-binaphthyl-conjugated polythiophene (PT), which enabled the sensing of various phthalates at binding constants 15-times higher than those of its corresponding monomer. , The signal amplification process can be explained as follows: (i) First, a target guest molecule, which acts as an allosteric effector for allosterism, binds to the molecular clipping moiety. (ii) As a result of the first binding, the structural change in the clipping unit changes the dihedral angle of bithiophene (θ 1 = syn → more syn ) at the beginning of the allosteric propagation.…”

“…As shown in Figure 1c, we demonstrated the mechanism of the SASS approach using bisthiourea-binaphth- yl-conjugated polythiophene (PT), which enabled the sensing of various phthalates at binding constants 15-times higher than those of its corresponding monomer. 44,45 The signal amplification process can be explained as follows: (i) First, a target guest molecule, which acts as an allosteric effector for allosterism, binds to the molecular clipping moiety. (ii) As a result of the first binding, the structural change in the clipping unit changes the dihedral angle of bithiophene (θ 1 = syn → more syn) at the beginning of the allosteric propagation.…”