Preparation and Multivalently Enhanced Guest-Binding Affinity of Water-Soluble Cyclophane Heptadecamers

2008 ◽  
Vol 73 (8) ◽  
pp. 3205-3211 ◽  
Author(s):  
Osamu Hayashida ◽  
Daisuke Sato
Keyword(s):  
Binding Affinity ◽  
Water Soluble ◽  
Guest Binding

scholarly journals Synthesis and Guest-Binding Properties of pH/Reduction Dual-Responsive Cyclophane Dimer

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3097
Author(s):  
Osamu Hayashida ◽  
Yudai Tanaka ◽  
Takaaki Miyazaki
Keyword(s):  
Electrostatic Interaction ◽  
Disulfide Bonds ◽  
Water Soluble ◽  
Guest Molecules ◽  
Binding Behavior ◽  
Dual Responsive ◽  
Guest Binding ◽  
Basic Solutions ◽  
Ph Conditions ◽  
Almost All

A water-soluble cyclophane dimer having two disulfide groups as a reduction-responsive cleavable bond as well as several acidic and basic functional groups as a pH-responsive ionizable group 1 was successfully synthesized. It was found that 1 showed pH-dependent guest-binding behavior. That is, 1 strongly bound an anionic guest, 6-p-toluidinonaphthalene-2-sulfonate (TNS) with binding constant (K/M−1) for 1:1 host-guest complexes of 9.6 × 104 M−1 at pH 3.8, which was larger than those at pH 7.4 and 10.7 (6.0 × 104 and 2.4 × 104 M−1, respectively), indicating a favorable electrostatic interaction between anionic guest and net cationic 1. What is more, release of the entrapped guest molecules by 1 was easily controlled by pH stimulus. Large favorable enthalpies (ΔH) for formation of host-guest complexes were obtained under the pH conditions employed, suggesting that electrostatic interaction between anionic TNS and 1 was the most important driving force for host-guest complexation. Such contributions of ΔH for formation of host-guest complexes decreased along with increased pH values from acidic to basic solutions. Upon addition of dithiothreitol (DTT) as a reducing reagent to an aqueous PBS buffer (pH 7.4) containing 1 and TNS, the fluorescence intensity originating from the bound guest molecules decreased gradually. A treatment of 1 with DTT gave 2, having less guest-binding affinity by the cleavage of disulfide bonds of 1. Consequently, almost all entrapped guest molecules by 1 were released from the host. Moreover, such reduction-responsive cleavage of 1 and release of bound guest molecules was performed more rapidly in aqueous buffer at pH 10.7.

The effects of hexafluoroisopropanol on guest binding by water-soluble capsule and cavitand hosts

2015 ◽  
Vol 51 (99) ◽  
pp. 17604-17606 ◽  
Author(s):  
Jesse V. Gavette ◽  
Ioannis D. Petsalakis ◽  
Giannoula Theodorakopoulos ◽  
Kang-Da Zhang ◽  
Yang Yu ◽  
...  
Keyword(s):  
Water Soluble ◽  
Guest Binding

scholarly journals A water-soluble boronic acid sensor for caffeic acid based on double sites recognition

RSC Advances ◽  
2020 ◽  
Vol 10 (47) ◽  
pp. 28148-28156
Author(s):  
Zhancun Bian ◽  
Guiqian Fang ◽  
Ran Wang ◽  
Dongxue Zhan ◽  
Qingqiang Yao ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Caffeic Acid ◽  
Binding Affinity ◽  
Boronic Acid ◽  
Water Soluble ◽  
Specific Recognition ◽  
Recognition Sites

Herein, the specific recognition of caffeic acid by the double sites boronic acid sensor 5c is reported. The synergistic effect of the two recognition sites greatly improves the binding affinity and selectivity of the sensor.

Computational Design of Thiourea-based Cyclophane Sensors for Small Anions

2012 ◽  
Vol 65 (3) ◽  
pp. 303 ◽  
Author(s):  
Huifang Xie ◽  
Ming Wah Wong
Keyword(s):  
Molecular Dynamics ◽  
Binding Affinity ◽  
Density Functional ◽  
Computational Design ◽  
Binding Pocket ◽  
Solvent Medium ◽  
Guest Binding ◽  
Molecular Dynamics Calculations ◽  
Anion Complexes ◽  
Dynamics Simulations

The host–guest binding properties of a tri-thiourea cyclophane receptor (1) with several common anions have been investigated using density functional theory (DFT) and molecular dynamics calculations. Receptor 1 is predicted to be an effective receptor for binding small halogen and Y-shaped (NO3– and AcO–) anions in the gas phase, cyclohexane and chloroform. The calculated order of anion binding affinity for the receptor 1 in chloroform is F– > Cl– > AcO– > NO3– >Br– > H2PO4– > HSO4–. The binding free energies are strongly influenced by a dielectric solvent medium. The structures of the receptor–anion complexes are characterized by multiple (typically 6) hydrogen bonds in all cases. The overall binding affinity of various anions is determined by the basicity of anion, size and shape of the binding site, and solvent medium. Explicit chloroform solvent molecular dynamics simulations of selected receptor–anion complexes reveal that the anions are strongly bound within the binding pocket via hydrogen-bonding interactions to all the receptor protons throughout the simulation. A sulfur analogue of receptor 1 (2), with a larger central cavity, is shown to be a more effective sensor than 1 for small anions. Two different approaches to develop the thiourea-based cyclophane receptor into a chromogenic sensor were examined.

scholarly journals Correlation between Conformational Equilibria of Free Host and Guest Binding Affinity in Non-preorganized Receptors

2013 ◽  
Vol 78 (16) ◽  
pp. 7785-7795 ◽  
Author(s):  
Romen Carrillo ◽  
Ezequiel Q. Morales ◽  
Víctor S. Martín ◽  
Tomás Martín
Keyword(s):  
Binding Affinity ◽  
Guest Binding ◽  
Conformational Equilibria

scholarly journals Cyclodextrin Complex Formation with Water-Soluble Drugs: Conclusions from Isothermal Titration Calorimetry and Molecular Modeling

2021 ◽  
Vol 22 (7) ◽  
Author(s):  
Karim S. Shalaby ◽  
Muhammad I. Ismail ◽  
Alf Lamprecht
Keyword(s):  
Molecular Modeling ◽  
Complex Formation ◽  
Drug Release ◽  
Binding Affinity ◽  
Isothermal Titration Calorimetry ◽  
Water Soluble ◽  
Titration Calorimetry ◽  
Cyclodextrin Complex ◽  
Water Soluble Drugs

AbstractCyclodextrin (CD) complexes are frequently used for enhancing the solubility or absorption of poorly water-soluble drugs. On the contrary, little is known about their complex formation with water-soluble drugs. Here, we have studied the interaction between 2-hydroxypropyl β-CD (HPβCD) and three water-soluble drugs, namely naloxone (NX), oxycodone (OC), and tramadol (TR), by isothermal titration calorimetry (ITC) combined with molecular modeling in view of the potential impact on drug release. The results showed that the complex formation of HPβCD with all three drugs occurs spontaneously. The complexes formed with NX and OC were found to be 2NX:1HPβCD and 3OC:2HPβCD, respectively. TR was found to form 2 complexes with HPβCD; of 1:2 and 1:1 complexation ratios. The binding of HPβCD to NX was greater than to OC due to the higher hydrophobicity of the structure of the former. Moreover, the binding affinity of HPβCD to TR was higher than to OC, which indicated the effect of the higher flexibility of the guest in increasing the binding affinity. In vitro drug release experiments from the various complexes revealed a significant impact of the stoichiometry of the complex on the release profiles. Accordingly, the co-administration of cyclodextrins with water-soluble drugs should be closely monitored, as it may result in unintentional complex formation that can potentially impact the drugs’ gastrointestinal absorption.

Synthesis, Guest-Binding, and Reduction-Responsive Degradation Properties of Water-Soluble Cyclophanes Having Disulfide Moieties

2013 ◽  
Vol 78 (11) ◽  
pp. 5463-5469 ◽  
Author(s):  
Osamu Hayashida ◽  
Kazuaki Ichimura ◽  
Daisuke Sato ◽  
Terutaka Yasunaga
Keyword(s):  
Water Soluble ◽  
Guest Binding ◽  
Degradation Properties
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