Under acidic conditions, reduced graphene oxide (rGO) was functionalized with p-aminobenzoic acid, which formed the diazonium ions through the diazotization with a wet-chemical method. Surfactants or stabilizers were not applied during the diazotization. After the functionalized rGO was treated through mild sonication in aqueous solution, these functionalized rGO sheets were less than two layers, which was determined by atomic force microscopy (AFM) imaging. The water solubility of functionalized rGO after the introduction of polyethyleneimine (PEI) was improved significantly; it was followed by covalent binding of folic acid (FA) molecules to the functionalized rGO to allow us to specifically target CBRH7919 cancer cells by using FA as a receptor. The loading and release behaviors of elsinochrome A (EA) and doxorubicin (DOX) on the functionalized rGO sheets were investigated. The EA loading ratio onto rGO-C(6)H(4)-CO-NH-PEI-NH-CO-FA (abbreviated rGO-PEI-FA, the weight ratio of drug loaded onto rGO-PEI-FA) was approximately 45.56 %, and that of DOX was approximately 28.62 %. It was interesting that the drug release from rGO-PEI-FA was pH- and salt-dependent. The results of cytotoxicity (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry (FCM) assays, as well as cell morphology observations) clearly showed that the concentration of rGO-PEI-FA as the drug-delivery composite should be less than 12.5 mg L(-1). The conjugation of DOX and rGO-PEI-FA can enhance the cancer-cell apoptosis effectively and can also push the cancer cells to the vulnerable G2 phase of the cell cycle, which is most sensitive and susceptible to damage by drugs or radiation.

Hydrogels with ultrahigh water content, ∼99 wt %, and highly excellent mechanical strength were prepared by 4'-para-phenylcarboxyl-2,2':6',2″-terpyridine (PPCT) in KOH aqueous solution. The self-assembled structure, rheological properties, and the gel-sol transformation temperature (Tgel-sol) of PPCT/KOH hydrogels that depend on PPCT and KOH concentrations were studied, indicating easily controllable conditions for producing hydrogels in PPCT and KOH mixtures. An important finding was that the hydration radius (Rh) of cations (M(+) = Li(+), Na(+), K(+), Cs(+), NH4(+), (CH3)4N(+), (CH3CH2)4N(+), (CH3CH2CH2)4N(+), (CH3CH2CH2CH2)4N(+)) plays a vital role in gelation of PPCT/MOH systems. To produce hydrogels in PPCT/MOH systems, the Rh of M(+) must be in a suitable region of 3.29 to 3.58 Å, e.g., K(+), Na(+), Cs(+), and the capability of M(+) for inducing PPCT to form hydrogels is K(+) > Na(+) > Li(+), which is followed by the Hofmeister series. The hydrogels of PPCT and KOH mixtures are responsive to external stimuli including temperature and shearing force, and present gelation-induced enhanced fluorescence emission property. The states of being sensitive to the stimuli can readily recover to the original hydrogels, which are envisaged to be an attracting candidate to produce self-healing materials. A typical function of the hydrogels of PPCT and KOH mixtures is that formaldehyde (HCHO) can speedily be adsorbed via electrostatic interaction and converted into nontoxic salts (HCOOK and CH3OK), making it a promising candidate material for HCHO removal in home furnishings to reduce indoor environmental pollutants.

Targeting delivery is a promising technique for the therapy of cancers. A molecule FA-EEYSV-NH 2 , which consists of target recognition site folic acid (FA), dipeptide linker, and peptide drug, was designed as a novel anticancer prodrug. The molecules could self-assemble into nanoparticles at pH 7.0 and nanofibers at pH 5.0. By the aid of pH-responsiveness, the self-assemblies were used purposefully as targeted vehicles of self-delivery prodrugs. The results of cell toxicity and internalization assays have proved that the self-assemblies have good cancer cell selectivity. The selection was mainly attributed to the pH-responsive structure transition of self-assemblies and the FA active-targeting effect. We hope that our work could provide a useful strategy for finely tuning the properties and activities of peptide-based supramolecular nanomaterials, thus optimizing nanomedicines with enhanced performance.

We report a new, simple strategy to apply honeycomb films for the patterning of colloidal particles. By combination of a "bottom-up" breath figure method and the electrochemical properties of the honeycomb films of ferrocenyl-based oligomers, highly ordered hybrid membranes coated with ring-like patterning of 0D- and 1D-Ag nanoparticles (NPs) have been fabricated. One interesting phenomenon is that the nucleation and adsorption of Ag dots occurred preferentially at the edges of the micropores. The hybrid membranes exhibited richly electrochemical activities towards reduction of iodate and enhanced effectively catalytic reduction of organic dyes. We believe that this method can be used to decorate and/or assemble functional metal NPs such as Au, Pd, and Cu on honeycomb-patterned materials for the further applications of photonics, sensors, and catalysis.