Jian-Feng Ge

A Small-Molecule-Based Ternary Data-Storage Device

High-density data storage (HDDS) is urgently required to address ongoing rapid increases in amounts of information. Here we present a prototype sandwich device that has ternary data-storage performance. Three characteristic currents can be read out using a certain constant voltage after removal of the applied voltage. Two electron pull groups and one electron push group are identified as the species responsible for electron flow. We believe that our observation will offer an interesting and useful theoretical approach for a huge increase in the memory density of potential future devices.

Modification of magnetic silica/iron oxide nanocomposites with fluorescent polymethacrylic acid for cancer targeting and drug delivery

Biocompatible and water-soluble magnetic nanoparticles with mesoporous core-shell structure were prepared and successfully modified with a fluorescent polymer chain as a labelling segment and folic acid as the cancer targeting moiety and loaded with a drug for directional release. The porous silica oxide structure and long molecular chains of polymethacrylic acid embedded the drug efficiently in the nanocomposites and did not affect the magnetic properties of the carrier. Sustained release of the loaded drug was observed over 100 h under in vitro conditions. Furthermore, the drug carrier is able to drill into the cell membranes and obtain a sustained release of the anticancer drug into the cytoplasm. The in vitro cellular uptake of the drug demonstrated that the drug-loaded nanocomposites could effectively target the tumor cells. Our model experiments indicated that this multifunctional mesoporous core-shell magnetic nanoparticle can be exploited as an anticancer drug delivery vehicle for targeting and therapy applications.

Benzo[a]phenoxazinium-Based Red-Emitting Chemosensor for Zinc Ions in Biological Media

A benzo[a]phenoxazinium-based chemosensor bearing an N,N-di(2-picolyl)ethylenediamine unit was successfully synthesized. It is a long-wave emission and fully water-soluble fluorescent sensor with good membrane permeability for the selective detection of Zn(2+).

Reversible Near-Infrared pH Probes Based on Benzo[a]phenoxazine

Several benzo[a]phenoxazine derivatives containing substituted N-aromatic groups are evaluated for their pH-dependent absorption and emission properties. Among the compounds exhibiting optical responses under near-neutral and subacid pH conditions, benzo[a]phenoxazine derivatives with an electron-withdrawing aromatic group attached to nitrogen of the imino group show potential application as near-infrared pH sensors. Three water-soluble pH probes based on benzo[a]phenoxazine with different pyridinium structures are designed and synthesized. Their reversible pH-dependent emissions in buffer solution containing 0.1% dimethyl sulfoxide (DMSO) locate in 625-850 nm with the fluorescent enhancement of 8.2-40.1 times, and their calculated pKa values are 2.7, 5.8, and 7.1, respectively. A composite probe containing the three benzo[a]phenoxazines shows a linear pH-emission relationship in the range of pH 1.9-8.0. Real-time detection of intracellular pH using an in vitro assay with HeLa cells is also reported.

Facile preparation of coating fluorescent hollow mesoporous silica nanoparticles with pH-sensitive amphiphilic diblock copolymer for controlled drug release and cell imaging

A smart fluorescent drug carrier based on hollow mesoporous silica (HMS) nanoparticles was prepared step by step. First, HMS nanoparticles were doped with lanthanide rare-earth nanocrystals (YVO4:Eu3+). Then the surface of HMS@YVO4:Eu3+ was modified by octadecyltrimethoxysilane (C18). Afterwards, it was coated by designed pH-sensitive amphiphilic diblock copolymer (poly(MPEG-b-DBAM), PMD) through hydrophobic van der Waals interactions. The results of characterization such as transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR) reveal that the material shows excellent monodisperse spherical morphology and narrow size distribution (180 nm) with hollow-core@mesoporous-silica-shell@thin-polymer-film structure. The multifunctional system HMS@YVO4:Eu3+@C18@PMD was utilized to deliver the model drug ibuprofen (IBU), and the drug loading content of the system is as high as 834 mg/g (drug/carrier). Due to the coated pH-sensitive polymer film, the loaded drug is selectively released in mildly acidic environment. The time of release of about 80% drug was however prolonged from 50 to 150 h (at pH = 5.0) by the effect of modified C18, which has thus achieved longer-term release. Besides, the prepared material is easily imported into human mouth epidermal carcinoma (KB) cells and showed good and stable red fluorescence, which is suitable for cell imaging.

Initiator-lightened polymers: preparation of end-functionalized polymers by ATRP and their intramolecular charge transfer and aggregation-induced emission

A simple strategy to prepare AIE polymers is invented using an AIE initiator for atom transfer radical polymerization. The dual photoresponse by intramolecular charge-transfer and luminogen aggregation of the initiator is well-realized and even enlarged after polymerization, due to the linkage of polymer chains.

Discovery of Novel Benzo[a]phenoxazine SSJ-183 as a Drug Candidate for Malaria

Malaria is a serious infectious disease caused by protozoan parasites in tropical and subtropical regions. Even inhabitants of temperate zones are exposed to the danger of malaria infection because of travel and global warming. Novel, effective, safe, and inexpensive drugs are required to treat malaria and contribute to the global goal of eradication. A search for new antimalarial agents has been performed by the synthesis of new benzo[a]phenoxazines, followed by biological evaluations. The derivative SSJ-183 (5), having a 4-aminopyridine group, showed an IC50 value against Plasmodium falciparum of 7.6 nM and a selectivity index of >7300. Cure was achieved by three oral doses of 5 at 100 mg/kg to mice infected with the Plasmodium berghei ANKA strain. The safety of 5 was supported by acute toxicity testing in mice with single doses up to 2000 mg/kg po, chromosome aberration test, in vitro as well as in vivo micronucleus tests, and phototoxicity studies in mice. Thus, 5 is a promising candidate as a new antimalarial agent.

N-Pyridineium-2-yl Darrow Red analogue: unique near-infrared lysosome-biomarker for the detection of cancer cells.

The lysosome-targetable OFF-ON type pH sensor that does not emit at pH = 4.0 is adopted for the selective detection of cancer cells, and the acidity difference of lysosomes in cancer and normal cells is verified. Three pH probes based on Darrow Red derivatives were designed and prepared that were demonstrated to be lysosome-specific biomarkers with inducible emission at 580-850 nm by the comparable in cellular imaging assays using HeLa, KB, and V79 cells. Of these, a pyridineium-2-yl Darrow Red analogue with a pKa of 2.4 was found to be a lysosome tracker for cancer cells, it is a unique pH sensor for the optical identification and distinction of cancer cells from normal cells and has potential application as a fluorescent biomaker of cancer cells in in vitro assays.

Fluorinated rhodacyanine (SJL-01) possessing high efficacy for visceral leishmaniasis (VL)

Anti-Leishmania in vitro and in vivo activities of various rhodacyanine derivatives have been examined. Among them, the fluorinatied variant SJL-01 (8) showed IC(50) of 0.011 microM against Leishmania donovani strain MHOM/ET/67/L82 (selective index of >15000) and 95-97% inhibition against L. donovani strain MHOM/ET/67/HU in female BALB/c mice by 1.3-12.5 mg/kg x 5 iv administrations. Negative results on chromosomal aberration test and in vitro micronucleus test suggest that compound 8 is a hopeful candidate for visceral leishmaniasis (VL).

Ultrafast broadband optical limiting in simple pyrene-based molecules with high transmittance from visible to infrared regions

Pyrene is considered as one of the most promising nonlinear functional building blocks. The nonlinear optical properties of materials can be improved by modifying the main nonlinear group possession ratio occupied in frontier molecular orbitals. Accordingly, we designed and synthesized two isomeric molecules based on pyrene for ultrafast broadband optical limiters. Different pyrene possession ratios occupied in frontier molecular orbitals were calculated through quantum chemical methods between two molecules. The higher average pyrene possession ratio occupied in frontier molecular orbitals exhibited better nonlinear properties in such structures, which was consistent with the experimental data. Excellent optical limiting behaviors were observed under femtosecond laser excitations at multiple wavelengths (range from 515 to 900 nm), which resulted from two-photon absorption (TPA) and TPA induced excited-state absorption (ESA). Moreover, the sample exhibited extremely high transmittance (>91%) from visible to infrared regions (500 to 900 nm). Our results show that pyrene-based derivatives can be considered as promising candidates for broadband ultrafast optical limiters.