Wenxin Lin

Enhancement of nonlinear optical activity in new six-branched dendritic dipolar chromophore

A new six-branched chromophore GGQ1 is designed and synthesized via the incorporation of an FTC-type chromophore 1 with phenyl glycerol ester. The six-branched chromophore GGQ1 shows a large molecular weight of 3834 Daltons and can directly form thin films with quite high active chromophore loading density. For comparison, guest–host doped polymer films are fabricated by doping chromophore 1 and BF1 into poly(4-vinylphenol). All of these doped films show a saturated trend in second harmonic generation coefficient (d33) and a maximum d33 value between 50–70 pm V−1 around the doping concentration of 25 wt%, due to the strong interchromophore electrostatic interactions. In contrast, GGQ1 films display a d33 value of 192 pm V−1. The results indicate that the six-branched chromophore could efficiently reduce the interchromophore electrostatic interactions and enhance the macroscopic optical nonlinearity, showing promise for applications in nonlinear optical (NLO) materials.

A Large Capacity Cationic Metal–Organic Framework Nanocarrier for Physiological pH Responsive Drug Delivery

A nanoscale cationic porous drug carrier ZJU-101 (ZJU = Zhejiang University), synthesized by the solvothermal method to get the crystal size of ∼300 nm, was used to load diclofenac sodium, an anionic drug. This positively charged host materials showed a large loading capacity of diclofenac sodium (∼0.546 g/g) through ion exchange and penetration procedures. The drug delivery in the inflamed tissues (pH = 5.4) exhibited a more effective release in comparison with that in the normal tissues (pH = 7.4), demonstrating a physiological pH responsive drug release. This discriminating drug release process was controlled by anion exchange between anions in phosphate buttered saline (PBS) and coordinated/free diclofenac anions.

Six-branched chromophores with isolation groups: synthesis and enhanced optical nonlinearity

Three new six-branched chromophores with different isolation groups were designed and synthesized by incorporating azo chromophores onto phenyl glycerol ester via an esterification reaction. The chemical structures were confirmed by 1H NMR, 13C NMR, FT-IR spectroscopy, mass spectrometry, element analysis and UV-visible absorption spectra. The six-branched dendritic chromophores can form thin films directly without adding any polymer matrix and show a quite high chromophore loading density. After electric poling, the nonlinear optical coefficients (d33) of the dendrimer films were determined to be around 113, 142 and 136 pm V−1, which are almost 3 times the maximum d33 value of the azo-chromophore doped polymer films. The further improvement in optical nonlinearity was successfully realized by mixing the six-branched chromophores containing different isolation groups.

Pressure controlled drug release in a Zr-cluster-based MOF

A robust zirconium-cluster-based metal-organic framework (MOF) ZJU-800 with an excellent drug loading capacity (about 58.80 wt%) has been synthesized. The system shows an adjustable release time of the drug diclofenac sodium from 2 days to 8 days by controlling the degree of compaction between MOF and drug using pressure.

Thermal Stimuli-Triggered Drug Release from a Biocompatible Porous Metal-Organic Framework.

Drug delivery carriers with a high drug loading capacity and biocompatibility, especially for controlled drug release, are urgently needed due to the side effects and frequently dose in the traditional therapeutic method. In our work, a Zr-based metal-organic framework named ZJU-801, which is isoreticular with NU-801, has been designed and further demonstrated as an excellent drug delivery system (DDS) with a high drug loading of 41.7 %. Such a high drug loading capacity may be ascribed to the appropriate match of the size and the large pore volume of this kind of Zr MOF material. Compared with DS@NU-801, this DDS has successfully achieved on-command heating-activated drug release, which was probably attributed to the bulkier ligand, the better stability, and the intense π-π interaction between ZJU-801 and diclofenac sodium (DS) demonstrated comprehensively by SEM, powder X-ray diffraction (PXRD), FTIR and 13 C solid-state NMR spectroscopy as well as computer simulations. It is worth noting that premature drug release was avoided effectively without any complicated post-modifications. The low cytotoxicity and good biocompatibility of our DDS were certificated by the in vitro favorable results from an MTT assay, a WST-1 assay, and confocal microscopy imaging.