초록 |
The host-guest (H-G) interaction has been widely used to the biomedical areas such as hydrogel, bio-glue, and drug delivery. Especially, the H-G complex of cyclodextrin (CD) with adamantane (Ad) are emerging due to their compatibility in biological system. Despite the considerable interests, the relation of forces to thermodynamic energy of H-G complexes still remain ambiguous. Herein, we directly measured the interaction between CD and ditopic Ad (di-Ad) molecule in aqueous solution using a surface forces apparatus (SFA) depending on the cavity size of CD and the concentration of di-Ad. The adhesion forces were measured only between the β-CD in presence of di-Ad, which showed a drastic increase with increasing the concentration of di-Ad and gradually decreased after reaching complete H-G complex. Furthermore, a quartz crystal microbalance with dissipation (QCM-D) monitoring was used to convert the adhesion force to a single molecular interaction energy of β-CD with di-Ad (~10 kBT), which was comparable to previous experimental and theoretical studies. This findings demonstrate the direct correlation between the adhesive force and thermodynamic energy of H-G complexes. |