Zhiyong Zhao

Inhibition and Stabilization: Cucurbituril Induced Distinct Effects on the Schiff Base Reaction

The different effects of cucurbit[7]uril (CB[7]) on the Schiff base reactions in aqueous solution were explored by 1H NMR spectroscopy and single X-ray crystallography. With CB[7], the condensation reaction of aldehyde and primary amine is dramatically inhibited. In contrast, the presence of CB[7] does tremendously stabilize iminium cation in water through ion-dipole interactions. A single crystal structure of the complex of iminium ion 7 with CB[7] grown in water is reported.

Probing guest compounds enabling the facile isolation of cucurbit[10]uril

A large set of commercially available amino compounds were assessed toward binding with cucurbit[10]uril (CB[10] ), with the purpose of facilitating the isolation of pure CB[10]. We found that the addition of a specific guest into a relevant mixture of CB[n] allowed the displacement of CB[5] from CB[10]·CB[5]. Subsequent washing of the resulting precipitate-CB[10]·Gn (G=guest) with dimethyl sulfoxide (DMSO), enabled to get pure CB[10] in a facile and highly efficient way.

Self-assembly of DNA-based Nanomaterials and Potential Application in Drug Delivery

DNA can be self-assembled into programmable two-dimensional and three-dimensional nanoarchitectures with arbitrarily predetermined sizes and shapes. Because of the addressable arbitrary size and shape, great capacity of cargo loading, ability to be internalized by cells, the stability of structures under physiological conditions and excellent biocompatibility, the pristine DNA nanostructures are explored as drug vehicles in drug delivery. In addition, DNA block copolymer and DNADendron hybrid, as new building blocks, can be self-assembled into different kinds of ordered structures, e.g., nanofibers, spherical micelles, and vesicles, in aqueous solution. Recent studies have shown that some of these nanostructures could easily enter cells with excellent cell uptake efficiency. Herein, this review will mainly introduce the self-assembly behavior of pristine DNA and DNA hybrid materials including DNA block copolymers and DNA-Dendron hybrids, and their application in drug delivery.

A Highly Selective and Strong Anti-Interference Host-Guest Complex as Fluorescent Probe for Detection of Amantadine by Indicator Displacement Assay

Amantadine (AMA) and its derivatives are illicit veterinary drugs that are hard to detect at very low concentrations. Developing a fast, simple and highly sensitive method for the detection of AMA is highly in demand. Here, we designed an anthracyclic compound (ABAM) that binds to a cucurbit[7]uril (CB[7]) host with a high association constant of up to 8.7 × 108 M−1. The host-guest complex was then used as a fluorescent probe for the detection of AMA. Competition by AMA for occupying the cavity of CB[7] allows ABAM to release from the CB[7]-ABAM complex, causing significant fluorescence quenching of ABAM (indicator displacement assay, IDA). The linear range of the method is from 0.000188 to 0.375 μg/mL, and the detection limit can be as low as 6.5 × 10−5 μg/mL (0.35 nM). Most importantly, due to the high binding affinity between CB[7] and ABAM, this fluorescence host-guest system shows great anti-interference capacity. Thus, we are able to accurately determine the concentration of AMA in various samples, including pharmaceutical formulations.

Amphiphilic DNA Organic Hybrids: Functional Materials in Nanoscience and Potential Application in Biomedicine

Due to the addressability and programmability, DNA has been applied not merely in constructing static elegant nanostructures such as two dimensional and three dimensional DNA nanostructures but also in designing dynamic nanodevices. Moreover, DNA could combine with hydrophobic organic molecules to be a new amphiphilic building block and then self-assemble into nanomaterials. Of particular note, a recent state-of-the-art research has turned our attention to the amphiphilic DNA organic hybrids including small molecule modified DNA (lipid-DNA, fluorescent molecule-DNA, etc.), DNA block copolymers, and DNA-dendron hybrids. This review focuses mainly on the development of their self-assembly behavior and their potential application in nanomaterial and biomedicine. The potential challenges regarding of the amphiphilic DNA organic hybrids are also briefly discussed, aiming to advance their practical applications in nanoscience and biomedicine.

CCDC 1477092: Experimental Crystal Structure Determination

Related Article: Wanjun Gong, Jun Ma, Zhiyong Zhao, Fang Gao, Feng Liang, Haijun Zhang, Simin Liu|2017|J.Org.Chem.|82|3298|doi:10.1021/acs.joc.6b02971