Self-assemblies of amphiphilic homopolymers: synthesis, morphology studies and biomedical applications

The need for a simplified access to supramolecular assemblies with enhanced tenability has led to the development of amphiphilic homopolymers (APHPs). This review highlights recent advances and future trends in APHP design, self-assembly, and biomedical applications.

An amphiphilic squarylium indocyanine dye for long-term tracking of lysosomes

A novel amphiphilic squarylium indocyanine (LysoCy) is reported for remarkable lysosome tracking in live cells.

"On-off-on" switchable sensor: a fluorescent spiropyran responds to extreme pH conditions and its bioimaging applications

A novel spiropyran that responds to both extreme acid and extreme alkali and has an "on-off-on" switch is reported. Benzoic acid at the indole N-position and carboxyl group at the indole 6-position contribute to the extreme acid response. The ionizations of carboxyl and phenolic hydroxyl groups cause the extreme alkali response. Moreover, the fluorescent imaging in bacterial cells under extreme pH conditions supports the mechanism of pH response.

A unique perylene-based DNA intercalator: localization in cell nuclei and inhibition of cancer cells and tumors

To date, perylene derivatives have not been explored as DNA intercalator to inhibit cancer cells by intercalating into the base pairs of DNA. Herein, a water-soluble perylene bisimide (PBDI) that efficiently intercalates into the base pairs of DNA is synthesized. Excitingly, PBDI is superior to the commercial DNA intercalator, amonafide, for specific nuclear accumulation and effective suppression of cancer cells and tumors.

Perylene-cored star-shaped polycations for fluorescent gene vectors and bioimaging

Two star polycations, poly(2-aminoethyl methacrylate) (PAEMA, P1) and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA, P2), have been synthesized with perylene diimide (PDI) as the central fluorophore. (1)H NMR and (13)C NMR are used to confirm the successful synthesis of a macromolecular initiator. Using ATRP strategy, P1 and P2 are obtained with narrow molecular weight distribution. The star polymers have good fluorescence properties in aqueous solution, which provides fluorescent tracing and imaging during gene delivery. Both P1 and P2 can efficiently condense DNA into stable nanoparticles. Transfection studies demonstrate that P1 and P2 deliver DNA into live cells with higher efficiency and lower cytotoxicity than polyethylenimine (PEI, 25 kDa). P2 shows higher capacity for gene delivery than P1 due to its better buffering and faster rate of cellular internalization.

Systemic gene silencing in plants triggered by fluorescent nanoparticle-delivered double-stranded RNA

A cationic fluorescence nanoparticle efficiently enters plants with high transfection efficacy. Applying a mixture of G2/dsRNA to the model plant, Arabidopsis root, leads to significant reduction in the expression of important developmental genes and results in apparent phenotypes. This study reports a non-viral gene nanocarrier which triggers gene silencing in plants and leads to systemic phenotypes.

A fluorescent perylene-assembled polyvinylpyrrolidone film: synthesis, morphology and nanostructure

A fluorescent polyvinylpyrrolidone (PVP) film with assembled nanostructures is successfully prepared in one pot by using perylene-3,4,9,10-tetracarboxylic acid dianhydride (PDA) as the fluorophore. The reactive anhydride groups in PDA play an important role in the covalent bonding of fluorescent molecules in the fluorescent PVP film, which has been demonstrated by a small-molecule model reaction. Interestingly, rod-like structures are found on the surface of the fluorescent film, which is attributed to the π-π interaction of PDA that occurred in the crosslinked PVP film. Further polarized optical microscopy (POM), X-ray diffraction (XRD) and optical analyses demonstrate the stable existence of π-conjugated nanostructures in the fluorescent PDA-based PVP film. The reactive anhydrides and the π-π interaction of perylene molecules are essential for the fabrication of the fluorescent perylene-assembled PVP film. This method could be extended to the preparation of the fluorescent PVP film with self-assembled nanostructures.

A difunctional squarylium indocyanine dye distinguishes dead cells through diverse staining of the cell nuclei/membranes

Functionalized fluorescent dyes have attracted great interest for the specific staining of subcellular organelles in multicellular organisms. A novel nanometer-sized water-soluble multi-functional squarylium indocyanine dye (D1) that contains four primary amines is synthesized. The dye exhibits good photostability, non-toxicity and biocompatibility. Isothermal titration calorimetry demonstrates that an affinity between D1 and DNA is higher than that between D1 and analogue of phospholipids. Analysis of circular dichroism spectra indicates that D1 targets to the DNA minor groove and aggregates to a helix. Because of the distinct affinity between the dye and subcellular organelles, the dye exhibits difunctional abilities to label the cell nuclei in fixed cells/tissue and the cell membranes in live cells/tissue. By combination of the two staining capabilities, the dye is further explored as a specific marker to distinguish apoptotic cells in live cells/tissue. The research opens a new way to design novel multifunctional dyes for life science applications.

Selective killing of lung cancer cells by miRNA-506 molecule through inhibiting NF-κB p65 to evoke reactive oxygen species generation and p53 activation

The tumor suppressor p53, nuclear factor-κB (NF-κB) and reactive oxygen species (ROS) have crucial roles in tumorigenesis, although the mechanisms of cross talk between these factors remain largely unknown. Here we report that miR-506 upregulation occurs in 83% of lung cancer patients (156 cases), and its expression highly correlates with ROS. Ectopic expression of miR-506 inhibits NF-κB p65 expression, induces ROS accumulation and then activates p53 to suppress lung cancer cell viability, but not in normal cells. Interestingly, p53 promotes miR-506 expression level, indicating that miR-506 mediates cross talk between p53, NF-κB p65 and ROS. Furthermore, we demonstrated that miR-506 mimics inhibited tumorigenesis in vivo, implicating that miR-506 might be a potential therapeutic molecule for selective killing of lung cancer cells.

Systemically interfering with immune response by a fluorescent cationic dendrimer delivered gene suppression

A water-soluble, fluorescent, cationic dendrimer systemically delivers dsRNA into insect cells and tissues, resulting in the suppression of the immune gene.

pH-responsive self-assembly of fluorophore-ended homopolymers

pH-responsive perylene-ended amphiphilic homopolymers can self-assemble into flower-like structures by the pH-adjustment.

A multifunctional perylenediimide derivative (DTPDI) can be used as a recyclable specific Hg2+ ion sensor and an efficient DNA delivery carrier

A multifunctional perylenediimide derivative (DTPDI) can be used as a recyclable specific Hg²⁺ ion sensor and an efficient DNA delivery carrier.

pH-sensitive unimolecular fluorescent polymeric micelles: from volume phase transition to optical response

A schematic representation of volume phase transition and fluorescence response of unimolecular micelles.

Highly water-soluble perylenediimide-cored poly(amido amine) vector for efficient gene transfection

A highly water-soluble perylenediimide-core poly(amido amine) (PDI-PAmAm) with peripheral amine groups has been synthesized. PDI-PAmAm can be rapidly internalized into live cells with high efficacy of gene delivery and low cytotoxicity.

UV-irradiation-induced templated/in-situ formation of ultrafine silver/polymer hybrid nanoparticles as antibacterial

Two types of facile approaches toward ultrafine Ag/polymer hybrid nanoparticles (NPs) within 10 nm are introduced. Template and in-situ formation method are developed by photoreduction based on inverse microemulsion (IME) polymerization of N,N-dimethylacrylamide (DMAA). The template method refers to the usage of size-varied polymeric PDMAA NPs as templates for the preparation of Ag/PDMAA hybrids with desired morphology and optical property. To avoid the self-seeding nucleation of free Ag(+) in the solution, in-situ formation method is developed by introducing AgNO3 during IME polymerization, in which product hybrids could be obtained via autoprecipitation in large scale. Additionally, the produced Ag/PDMAA hybrids show high antibacterial performance.

Effects of artesunate and ursolic acid on hyperlipidemia and its complications in rabbit

OBJECTIVE

To find the novel hypolipidemic agents, the effects of ursolic acid and artesunate on hyperlipidemia and its complications were determined in rabbit fed with Western-type diet.

METHODS AND RESULTS

New Zealand rabbits fed a Western-type diet developed a hyperlipidemia. Rabbits received ursolic acid (25mg/kg) or artesunate (25mg/kg) alone, or in combination (12.5+12.5mg/kg), to prevent hyperlipidemia. Ursolic acid or artesunate alone significantly decreased the plasma cholesterol and triglyceride in rabbits. Furthermore, they both attenuated liver steatosis and reduced the area of aortic root lesions. The combination of ursolic acid and artesunate was more potent than either agent alone, which indicates a strong synergistic effect.

CONCLUSION

The hypolipidemic effect of artesunate is firstly reported. Its combination with ursolic acid might have the potential to further develop for the treatment of atherosclerosis.

[A new method of isolating and culturing rabbit osteoblasts in vitro]

To establish an experimental model of osteoblasts to easily cause calcification of bone matrix in vitro, we took cranium of a newborn rabbit out under an aseptic condition, removed the connective tissue of the bony suture, and cut the cranium freely into the fragments of not more than 1 mm2. The we isolated and cultured the osteoblasts using tissue explant method. We observed growth status of primary osteoblasts and subcultured osteoblasts using inverted microscope. Then we conducted enzyme staining and alizarin red staining for the third generation of osteoblasts to detect the alkaline phosphatase (ALP) expression and calcified nodules. The result showed that there were calcified nodules or calcification formed after the primary osteoblasts climbing out from the bone for 1 week, and each generation of osteoblasts had the similar calcification with the primary osteoblasts, and there was an increase in calcified nodules after the continuous culture. There was a strong expression of ALP in the plasma membrane of osteoblasts. The calcified nodules were red with alizarin red staining. It is well concluded that osteoblasts isolated with this method easily cause calcification, and can be used as a new experimental model.

Fluorescent nanoparticle delivered dsRNA toward genetic control of insect pests

A fluorescent cationic core-shell nanoparticle efficiently enters into cells with high transfection efficacy. A FNP/CHT10-dsRNA complex is orally fed to insect pests and knocks down a midgut-specific chitinase gene of the Asian corn borer, which leads to death. This is the first report on the genetic control of insect pests through a non-viral gene delivery system to knock down key developmental gene expression.