Cucurbit[7]uril Host-Guest Complexes with Biguanidinium Cations in Aqueous Solution

Supramolecularly assisted chlorhexidine-bacterial membrane interaction with enhanced antibacterial activity and reduced side effects

Bacterial infection has emerged as a grievous threat to public health, and lots of antibacterial agents were developed to solve this issue. However, enhancing the antibacterial activity of antibacterial agents while reducing their side effects remains a challenge. Herein, a supramolecular antibacterial agent based on the host-guest interaction between cucurbit[7]uril (CB[7]) and chlorhexidine (CHX) was designed. CHX can be encapsulated in the cavity of CB[7] to form a 1:3 host-guest complex (CHX-3CB[7]). It was amazingly found that this supramolecular complex could display higher antibacterial activity than CHX alone. Electrospray mass spectrometry and UV-vis spectra revealed that the introduction of CB[7] promoted the protonation of N-atoms on CHX, resulting in stronger ion interaction with phospholipids and thus enhancing the destruction of the bacterial membrane. Scanning electron microscopy (SEM), surface ζ-potentials and outer/inner membrane integrity assays also reveal that the introduction of CB[7] aggravates the rupture of membrane. What is more, the cytotoxicity and irritation of CHX were decreased by forming the host-guest complex with CB[7]. This work provides a paradigm for enhancing antibacterial activity and reducing side effects of drugs through supramolecular chemistry.

Contrasting interactions of DNA-intercalating dye acridine orange with hydroxypropyl derivatives of β-cyclodextrin and γ-cyclodextrin hosts

The present study demonstrates contrasting binding interactions of acridine orange dye with HPβCD and HPγCD hosts, always illustrating fluoresence “turn on” in the case of HPβCD and showing an interesting fluorescence “off/on switching” in the case of the HPγCD host.

Photodeamination to quinone methides in cucurbit[n]urils: potential application in drug delivery

A prodrug is encapsulated in CB[7] and is photochemically transformed into an active drug inside this supramolecular complex.

A naphthalimide derived fluorescent sensor for solid-phase screening of cucurbit[7]uril-guest interactions

A naphthalimide based fluorescent sensor displaying a significant increase in emission upon binding CB[7] with notable pH stability was developed and utilized in a surface-bound displacement assay for the rapid detection of CB[7] encapsulation of therapeutically relevant drug classes. Previously unknown binders with moderate to strong affinities were discovered.