Biomimetic Recognition of Organic Drug Molecules in Water by Amide Naphthotubes

Abstract

Molecular recognition in water is the basis of numerous biological functions. The key for efficient and selective recognition of an organic drug molecule is to bind both its polar and nonpolar groups. This is achieved by bioreceptors for which specific noncovalent interactions are efficiently used in a hydrophobic pocket. In contrast, most synthetic receptors cannot efficiently bind the neutral, polar groups of drug molecules and, thus, often exhibit poor binding selectivity and affinity. In this research, we report a systematic study on the binding behaviors of three types of macrocyclic hosts (amide naphthotubes, cucurbit[7]uril, and β-cyclodextrin) to 18 model compounds and 13 drug molecules. Our results show that the high desolvation penalty of polar groups of guests is the reason for the relatively low binding affinity of cucurbit[7]uril and β-cyclodextrin. However, amide naphthotubes with a biomimetic cavity bind efficiently and selectively to organic guests through hydrophobic effects and hydrogen bonding. Drug molecules with multiple polar groups can be better accommodated by these naphthotubes. The anti-configured naphthotube show good biocompatibility according to preliminary cell experiments and is capable of enhancing the water solubility of two poorly soluble drug molecules. Therefore, they may have practical applications in pharmaceutical sciences.

A new cotton functionalized with iron(III) trimer-like metal framework as an effective strategy for the adsorption of triarylmethane dye: An insight into the dye adsorption processes

“…The results described above suggest that the adsorption mechanisms of dye onto the Cotton@Fe-BTC composite imply intense electrostatic interactions such as those between oppositely charged species. As these species are solvated in the aqueous media, desolvation is needed to favor the interaction between the Cotton@Fe-BTC surface and the dye [44,45,46]. The ease of desolvation may affect the nature of binding and, hence, solvation/desolvation penalty has an essential effect on the dye adsorption process.…”

“…It is noteworthy that short alkyl group chains bound to nitrogen will favors the solvation effect more than long alkyl group chains. The cationic portion of the dye contains iminium ion with a pendant methyl or ethyl group, which makes the surface hydrophobic [44,45,46]. Thus, the mechanisms involved in the adsorption dye onto Cotton@Fe-BTC composite may be mainly due to the more intense electrostatic interactions between the oppositely charged species or dipoles.…”

A hypoxia-responsive supramolecular formulation for imaging-guided photothermal therapy

“…Significant modulations in the photophysical and photochemical properties of PTAs can be achieved via the formation of supramolecular complex with macrocyclic hosts 12 , 13 . These modulations involve p K a shifts 14 , improved solubility 14 - 16 , fluorescence quenching or enhancement 12 , 17 , hypsochromic or bathochromic shift of wavelengths 18 , 19 , enhanced photochemical stability 19 , 20 , etc. The formed supramolecular dyes are now widely utilized for applications in, but by no means limited to sensing 21 , 22 , bioimaging 23 - 25 , supramolecular dye lasers 26 , 27 , organic luminescent materials 28 - 30 , phototherapies 31 - 44 .…”

An Activatable Host–Guest Conjugate as a Nanocarrier for Effective Drug Release through Self-Inclusion

“…Supramolecular chemotherapy is of great interest owing to the dynamic nature of noncovalent interactions that contributes to the protection of drugs and controlled release at target tissues. − Among noncovalent interactions, host–guest interactions have been widely used to carry drugs that benefited from their tunable binding ability and a well-defined host–guest structure with an accurate binding ratio. ,,− For supramolecular chemotherapy systems based on host–guest interactions, the strong binding affinity of the host to drugs is essential for efficient protection of drugs from a harsh physiological environment. − However, a drug encapsulated in a stable binary host–guest complex is hard to be released by competitive guests, especially considering the low concentrations of competitive guests at target tissues. To date, some important advances have taken place to achieve controlled release of stably encapsulated drugs, ,,− but it still remains a challenge to construct a supramolecular chemotherapy system equipped with both sufficient protection and highly effective release of drugs simultaneously.…”