Chinese Journal of Chemistry

Cytosolic protein delivery techniques are of great importance for cell biology, biotechnology and protein drug development. The design of carriers with robust efficiency in cytosolic protein delivery is challenging. This account provides a progress report of polymeric carriers for this purpose in our group. During the past years, we have developed several types of functionalized polymers for cytosolic protein and peptide delivery by engineering polymers with ligands such as guanidinium, boronate, coordination ligands and fluoroalkyls. The designed polymers showed improved protein/peptide binding affinities, and successfully delivered various cargo proteins into the cytosol of living cells, while maintaining their bioactivity. In addition, the polymers showed potent efficiencies in the delivery of tumor antigens, therapeutic peptides, toxins and antioxidant proteins in vivo. We hope these polymers could be translated for protein delivery in the treatment of various diseases in the future.

What is the most favorite and original chemistry developed in your research group?

Fluorinated polymers for cytosolic biomolecule delivery.

How do you get into this specific field? Could you please share some experiences with our readers?

I get into this field by unexpected discoveries when designing polymeric gene delivery systems. Usually, modification of polymers with hydrophobic ligands yields more efficient gene carriers. Fluoroalkyl ligands were

proposed as one type of hydrophobic candidates in our experiments. Interestingly, the fluorous ligand modified polymers showed unprecedented efficiency in gene delivery. More importantly, the polymers exhibited excellent serum resistance and could achieve high efficiency at extremely low polymer dose. These unexpected discoveries motivated us to investigate the fluorine effect of fluorinated materials in gene, protein and peptide delivery.

A novel aromatic diamine monomer bearing tertbutyl and 4‐tertbutylphenyl groups, 3,3′‐ditertbutyl‐4,4′‐diaminodiphenyl‐4′′‐tertbutylphenylmethane (TADBP), was prepared and characterized. A series of non‐coplanar polyimides (PIs) were synthesized via a conventional one‐step polycondensation from TADBP and various aromatic dianhydrides including pyromellitic dianhydride (PMDA), 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA), 4,4′‐oxydiphthalic anhydride (OPDA), 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride (BTDA) and 4,4′‐(hexafluoroisopropylidene)dipthalic anhydride (6FDA). All PIs exhibit excellent solubility in common organic solvents such as N,N‐dimethylformamide (DMF), N,N‐dimethylacetamide (DMAc), N‐methyl‐2‐pyrrolidone (NMP), dimethyl sulfoxide (DMSO), chloroform (CHCl₃), tetrahydrofuran (THF), and so on. Furthermore, the obtained transparent, strong and flexible polyimide films present good thermal stability and outstanding optical properties. Their glass transition temperatures (T_gs) are in the range of 298 to 347°C, and 10% weight loss temperatures are in excess of 490°C with more than 53% char yield at 800°C in nitrogen. All the polyimides can be cast into transparent and flexible films with tensile strength of 80.5–101 MPa, elongation at break of 8.4%–10.5%, and Young's modulus of 2.3–2.8 GPa. Meanwhile, the PIs show the cutoff wavelengths of 302–356 nm, as well as low moisture absorption (0.30% –0.55%) and low dielectric constant (2.78–3.12 at 1 MHz).

A series of 4‐aryl‐5,10‐dihydro‐4H‐benzo[g]chromene‐5,10‐dione derivatives were synthesized by a three‐component reaction with aromatic aldehyde, 2‐hydroxy‐1,4‐dihydronaphthalene‐1,4‐dione, and malononitrile catalyzed by triethylbenzylammonium chloride under solvent‐free conditions. The novel efficient method has the advantages of environmental friendliness, high yield, simple work‐up and ease of operation.

Silicon is very promising negative electrode materials for improving the energy density of lithium‐ion batteries (LIBs) because of its high specific capacity, moderate potential, environmental friendliness, and low cost. However, the volume variation of Si negative electrodes is huge during lithiation/delithiation processes which results in pulverization, low cycling efficiency, and permanent capacity loss. In order to overcome this problem, tremendous efforts have been attempted. Among them the most successful strategy is to incorporate other components into silicon to form composite, especially the carbon medium. In this mini review, the recent progress on Si/C materials used as negative electrode of LIBs is summarized such as Si/amorphous carbon composite, Si/graphene composites, Si/carbon nanotubes or fibers composites. The fabrication, structure, electrochemical performances of different Si/C composites are discussed. In addition, some future directions are pointed out.

To find new antiviral agents, novel chalcone derivatives containing a purine moiety were designed and synthesized by combining bioactive substructures. The antiviral activities of the derivatives against tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV) were evaluated. Results showed that most of the derivatives showed antiviral activities. Compounds 3n and 3p exhibited excellent curative, protective and inactivation activities against TMV, with the EC₅₀ values of 452.4, 416.2, 241.2 and 438.7, 418.6, 261.7 µg•mL⁻¹, respectively, which were better than those of ribavirin (585.8, 436.0 and 268.7 µg•mL⁻¹). Compounds 3n and 3p showed remarkable curative and protective activities against CMV. Compound 3n showed a moderate affinity to TMV coat protein, with binding constant K_a and K_d values of 1.5 × 10⁴ L•mol⁻¹ and 79.8 µmol•L⁻¹, respectively. These findings provided an important structural insight for further designs of highly active chalcone derivatives and a basis for further study on their mechanism of action.

A simple and efficient one‐pot method has been developed for the synthesis of α‐aminonitriles from aldehydes, amines and tributyltin cyanide in the presence of a catalytic amount of iodine with high yields. The reactions proceeded smoothly at room temperature via very simple procedure.

Chemical oxidation is used to cut and unzip multi‐walled carbon nanotubes in the transverse direction and the axial direction to form graphene oxide nanoribbon (GONR). Ruthenium oxide/reduced graphene oxide nanoribbon composite (RuO₂/rGONR) with a 72.5 wt% RuO₂ loading is synthesized through an aqueous‐phase reaction, in which GONR is served as starting material, followed by mild thermal treatment in ambient air. The resulting RuO₂/rGONR composite achieves specific capacitance up to 677 F·g⁻¹ at the current density of 1 A·g⁻¹ in three‐electrode system using 1 mol·L⁻¹ H₂SO₄ as electrolyte. The resultant electrode exhibits an excellent rate capability (91.8% retention rate at 20 A·g⁻¹). Especially, the symmetric supercapacitor assembled on the basis of RuO₂/rGONR electrode delivers high energy density (16.2 Wh·kg⁻¹) even at the power density of 9885 W·kg⁻¹, which is very essential for supercapacitors.

A new sequiterpenoid compound 8aα‐hydroxy‐1‐isopropyl‐4,7‐dimethyl‐1,2,3,4,6,8a‐hexahydro‐naphthalene‐2,6‐dione (1), together with seven known compounds anti‐HH‐dimer‐coumarin (2), (−)‐5‐exo‐hydroxy‐borneol (3), O‐hydroxyl cinnamic acid (4), 9β‐hydroxy‐ageraphorone (5), 10Hα‐9‐oxo‐ageraphorone (6), 10Hβ‐9‐oxo‐ageraphorone (7) and 9‐oxo‐10,11‐dehydroageraphorone 8, was isolated from the leaves of Eupatorium adenophorum Spreng. The structures were elucidated by IR, ¹H and ¹³C NMR, EIMS, HMBC and single‐crystal X‐ray spectral data.

In this study, we report a novel and facile autoclave strategy for synthesis of near‐infrared (NIR) CuInS₂ QDs by employing glutathione (GSH) as capping ligand and stabilizer in aqueous media under 100°C. Various experimental parameters including the ratio of precursors, reaction time, reaction temperature, pH effect and stability have been systematically studied. The QDs were characterized by X‐ray diffraction (XRD), transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FT‐IR). The as‐synthesized NIR QDs exhibited low cytotoxicity and maintained excellent cell viability even up to 100 µg/mL. After bioconjugation with Arg‐Gly‐Asp (RGD) peptide, the obtained CuInS₂‐RGD QDs have demonstrated high targeting ability with good fluorescence cell imaging performance.

The molecular weight and the proposed structure of the Angelica sinensis polysaccharide‐iron complex (APIC) were studied. Fourier transform infrared spectroscopy, X‐ray powder diffraction, differential scanning calorimetry, transmission electron microscopy, electron paramagnetic resonance, thermogravimetric analysis, atomic force microscopy, and gel filtration chromatography were used to characterize APIC, which is a macromolecule complex composed of Angelica sinensis polysaccharide (ASP) and iron. The structure of APIC was proposed to be a polynuclear ferrihydrite core chelated firmly by an encircling framework of ASP chains, forming a core molecule, which is surrounded by a removable outer protective sheath of colloidal ASP. And the molecular formula of APIC was proposed to be {[(Fe₂O₃·2.2H₂O)₁₀₄₃(ASP)₃₂](ASP)₁₂}, with MW=270000 Da.