Multiple dye-doped silica cross-linked micellar nanoparticles for colour-tuneable sensing of cysteine in an aqueous media and living cells.

This work demonstrated the design and synthesis of multiple dye-doped silica cross-linked micellar nanoparticles (MD-SCMNPs) by encapsulating three organic dyes (fluorescein derivative (FCD), coumarin derivative (HCE) and Rhodamine b (RhB)) in SCMNPs cores for colour-tuneable sensing of cysteine (Cys) in aqueous media and in living cells. In the presence of Cys, HCE exhibited blue emission, and RhB exhibited purple emission, while FCD reacted with Cys and exhibited green fluorescence "turn-on" in the core of MD-SCMNPs. This green-light-emitting sensing product may cause "step by step" fluorescent resonance energy transfer (FRET) from HCE to the sensing product and then to RhB. Based on the FRET process in the core, MD-SCMNPs can quantitatively detect Cys by a colour change with a low limit of detection (LOD) of 0.3 µM in living cells. Furthermore, MD-SCMNPs exhibited ultrasmall size (∼12 nm) and excellent dispersity and biocompatibility, which could potentially be used as a visualized Cys sensor for health monitoring and disease prediction in the human body.

Hydrogen bond-induced bright enhancement of fluorescent silica cross-linked micellar nanoparticles.

This work demonstrated the synthesis and design of ultra-bright and ultra-small fluorescent nanoparticles, which were prepared by encapsulating 4-(diphenylamino)benzaldehyde (DPB) in silica cross-linked micellar nanoparticles (SCMNPs). The DPB-doped SCMNPs (DPB-SCMNPs) exhibited ultra-bright fluorescence in an aqueous medium that was 22 times brighter than that of free DPB molecules in an organic solvent. For the first time, density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations were used to confirm that the enhanced brightness of the DPB-SCMNPs was due to a hydrogen bond-induced mechanism. In addition, the 3D fluorescence spectra and the Commission Internationale de L'Eclairage (CIE) diagram were employed to determine the optical properties and emission colour of the DPB-SCMNPs. Moreover, the DPB-SCMNPs were water-soluble, monodisperse and ultra-small (∼12 nm) and should be robust and stable in aqueous media and biological systems.

Novel Schiff base (DBDDP) selective detection of Fe (III): Dispersed in aqueous solution and encapsulated in silica cross-linked micellar nanoparticles in living cell.

This work demonstrated the synthesis of (4E)-4-(4-(diphenylamino)benzylideneamino)-1,2-dihydro-1,5- dimethyl-2-phenylpyrazol-3-one (DBDDP) for Fe (III) detection in aqueous media and in the core of silica cross-linked micellar nanoparticles in living cells. The free DBDDP performed fluorescence enhancement due to Fe (III)-promoted hydrolysis in a mixed aqueous solution, while the DBDDP-doped silica cross-linked micellar nanoparticles (DBDDP-SCMNPs) performed an electron-transfer based fluorescence quenching of Fe (III) in living cells. The quenching fluorescence of DBDDP-SCMNPs and the concentration of Fe (III) exhibited a linear correlation, which was in accordance with the Stern-Volmer equation. Moreover, DBDDP-SCMNPs showed a low limit of detection (LOD) of 0.1 ppm and an excellent selectivity against other metal ions. Due to the good solubility and biocompatibility, DBDDP-SCMNPs could be applied as fluorescence quenching nanosensors in living cells.

Mixed anionic surfactant-templated mesoporous silica nanoparticles for fluorescence detection of Fe(3.).

This work demonstrates a novel method for the synthesis of large pore mesoporous silica nanoparticles (MSNs) with a pore diameter of 10.3 nm and a particle diameter of ∼50 nm based on the incorporation of mixed anionic surfactants sodium dodecyl benzene sulfonate (SDBS) and sodium dodecyl sulphate (SDS) as the template in the synthesis process. The dispersity, morphology, pore structure and size of mesoporous nanoparticles were adjusted by changing the molar ratio of two anionic surfactants, the concentration of the co-structure-directing agent (3-aminopropyltrimethoxysilane) and the reaction temperature. The results of synthesis experiments suggested that the formation of large pore MSNs involved a nucleation and growth process. MSNs were post-grafted with a Schiff base moiety for fluorescence sensing of Fe(3+) in water. The applicability of functionalized MSNs was demonstrated by selective fluorescence detection of Fe(3+) in aqueous media.

Optically Tunable Chiral Plasmonic Guest-Host Cellulose Films Weaved with Long-range Ordered Silver Nanowires.

Plasmonic materials with large chiroptical activity at visible wavelength have attracted considerable attention due to their potential applications in metamaterials. Here we demonstrate a novel guest-host chiral nematic liquid crystal film composed of bulk self-co-assembly of the dispersed plasmonic silver nanowires (AgNWs) and cellulose nanocrystals (CNCs). The AgNWs-CNCs composite films show strong plasmonic optical activities, that are dependent on the chiral photonic properties of the CNCs host medium and orientation of the guest AgNWs. Tunable chiral distribution of the aligned anisotropic AgNWs with long-range order is obtained through the CNCs liquid crystal mediated realignment. The chiral plasmonic optical activity of the AgNWs-CNCs composite films can be tuned by changing the interparticle electrostatic repulsion between the CNCs nanorods and AgNWs. We also observe an electromagnetic energy transfer phenomena among the plasmonic bands of AgNWs, due to the modulation of the photonic band gap of the CNCs host matrix. This facile approach for fabricating chiral macrostructured plasmonic materials with optically tunable property is of interest for a variety of advanced optics applications.

Silica cross-linked nanoparticles encapsulating a phenothiazine-derived Schiff base for selective detection of Fe(iii) in aqueous media.

This work demonstrates a luminescent chemosensor based on silica cross-linked micellar nanoparticles (SCMNPs) designed by encapsulating a phenothiazine-derived Schiff base, (4E)-4-((10-dodecyl-10H-phenothiazin-7-yl)methyleneamino)-1,2-dihydro-1,5-dimethyl-2-phenylpyrazol-3-one (EDDP), for the selective detection of Fe3+. The encapsulation of EDDP inside SCMNPs (EDDP-SCMNPs) can avoid the metal (Fe3+/Fe2+)-promoted hydrolysis of EDDP and, thus, exhibit highly selective determination of Fe3+. The electron transfer (ET) from EDDP in the core to Fe3+ adsorbed on the shell of EDDP-SCMNPs was verified using UV-vis absorption, fluorescent emission and 3D fluorescence spectra. Moreover, EDDP-SCMNPs showed no sensing ability of Fe2+ due to the weak electron-accepting ability of Fe2+. Significantly, because of their ultrasmall size, nontoxicity, good water solubility and biocompatibility, EDDP-SCMNPs have potential applications in biological systems.

Silica cross-linked nanoparticles encapsulating fluorescent conjugated dyes for energy transfer-based white light emission and porphyrin sensing.

This work demonstrated that water-soluble fluorescent hybrid materials can be successfully synthesized by use of silica cross-linked micellar nanoparticles (SCMNPs) as scaffolds to encapsulate fluorescent conjugated dyes for pH sensing, porphyrin sensing and tunable colour emission. Three dyes were separately encapsulated inside SCMNPs (short to dye-SCMNPs). Each of the dye-SCMNPs indicated longer lifetime in water than that of free dye dissolved in organic solvent. The 7-(hexadecyloxy) coumarin-3-ethylformate (HCE) encapsulated inside SCMNPs (HCE-SCMNPs) exhibited fluorescence quenching by pH change in aqueous media. Furthermore, it was confirmed that the radiative and nonradiative energy transfer processes both occurred between HCE-SCMNPs and tetraphenyl-porphyrin (TPP), which were used to synthesize the water-soluble TPP sensor. Significantly, HCE-SCMNPs doped with 5,12-dicotyl-quinacridone (8CQA) and TPP showed water-soluble white light emission (CIE (0.29, 0.34)) upon singlet excitation of 376 nm due to colour adjustment of 8CQA and energy transfer from HCE (donor) to TPP (acceptor).

Ionic self-assembly of surface functionalized metal-organic polyhedra nanocages and their ordered honeycomb architecture at the air/water interface.

Metal-organic polyhedra (MOP) nanocages were successfully surface functionalized via ionic self-assembly and the ordered honeycomb architecture of the encapsulated MOP nanocages was also fabricated at the air/water surface. The results provide a novel synthetic method and membrane processing technique of amphiphilic MOP nanocages for various applications.

Rigid dendritic gelators based on oligocarbazoles.

The first rigid dendritic gel with strong emission based on oligocarbazole was reported. It is interesting that the second generation of dendron exhibited gelation ability under ultrasound, and two-component gel could be formed from the first generation of dendron assisted by 1,6-diaminohexane.