Self-assembly of morphology-tunable architectures from tetraarylmethane derivatives for targeted drug delivery.

Tetraarylmethane compounds consisting of two pyrogallol and two aniline units, namely, Ar2CAr'2 {Ar = 3,4,5-C6H2(OH)3 and Ar' = 3,5-R2-4-C6H2NH2 [R = Me (1), iPr (2)]} exhibit excellent self-assembly behavior. Compound 1 yields size-tunable hollow nanospheres (HNSs) with a narrow size distribution, and 2 yields various morphologies ranging from microtubules to microrods via self-assembly induced by hydrogen bonding and π-π stacking interactions. On the basis of the experimental results, a plausible mechanism for morphology tunability was proposed. As a means of utilizing the self-assembled HNSs for targeting controlled drug delivery, folic acid (FA) and rhodamine 6G (Rh6G) were grafted onto compound 1 to yield the FA-Rh6G-1 complex. The HNSs fabricated with FA-Rh6G-1 showed low cytotoxicity against human embryonic kidney 293T cells and CT26 colon carcinoma cells and good doxorubicin (DOX) loading capacity (9.6 wt %). The FA receptor-mediated endocytosis of FA-Rh6G-1 HNSs examined by using a confocal laser scanning microscope and a flow cytometer revealed that the uptake of FA-Rh6G-1 HNSs into CT26 cells was induced by FA receptor-mediated endocytosis. In vitro drug delivery tests showed that the DOX molecules were released from the resulting HNSs in a sustainable and pH-dependent manner, demonstrating a potential application for HNSs in targeted drug delivery for cancer therapy.

Polymer-Block-Polypeptides and Polymer-Conjugated Hybrid Materials as Stimuli-Responsive Nanocarriers for Biomedical Applications.

Stimuli-responsive nanocarriers are a class of soft materials that includes natural polymers, synthetic polymers, and polypeptides. Recently, modern synthesis tools such as atom transfer radical polymerization, reversible addition-fragmentation chain transfer polymerization, nitroxide-mediated radical polymerization, ring-opening polymerization of α-amino acid N-carboxyanhydrides, and various "click" chemistry strategies were simultaneously employed for the design and synthesis of nanosized drug delivery vehicles. Importantly, the research focused on the improvement of the nanocarrier targetability and the site-specific, triggered release of therapeutics with high drug loading efficiency and minimal drug leakage during the delivery to specific targets. In this context, nanocarriers responsive to common stimuli such as pH, temperature, redox potential, light, etc. have been widely used for the controlled delivery of therapeutics to pathological sites. Currently, different synthesis and self-assembly strategies improved the drug loading efficacy and targeted delivery of therapeutic agents to the desired site. In particular, polypeptide-containing hybrid materials have been developed for the controlled delivery of therapeutic agents. Therefore, stimuli-sensitive synthetic polypeptide-based materials have been extensively investigated in recent years. This review focuses on recent advances in the development of polymer-block-polypeptides and polymer-conjugated hybrid materials that have been designed and evaluated for various stimuli-responsive drug and gene delivery applications.

Palladium nanoparticles decorated mesoporous carbon spheres as catalyst for reduction of 4-nitrophenol.

Two kinds of polyaromatics with mesoporous have been synthesized from aromatic hydrocarbons using anhydrous zinc chloride as the Friedel-Crafts catalyst and chloromethyl methyl ether as a cross-linker, after the Pd nanoparticles (PdNPs) decorated on the mesoporous carbon spheres (Pd@CSs) have been prepared by simply mixing the as-prepared polyaromatics (polynaphthalene or polypyrene) with PdCl2, reducing the Pd2+ to Pd0 by using NaBH4, followed by thermal treatment at 600 degrees C for 5 h in nitrogen atmosphere. The synthesized PdNPs have a uniform size distribution with an average size smaller than 15 nm and they can be loaded on the highly mesoporous carbon microspheres. Structural of the resulting Pd@CSs were carried out using FE-SEM, HR-TEM, X-ray differaction, dispersive X-ray spectroscopy. The resulting Pd@CSs have been investigated as a catalyst for the reduction of 4-nitrophenol to 4-aminophenol, showing the Pd@CSs have high catalytic reactivity and recyclability.