Aggregation-Induced Emission Nanoparticles Encapsulated with PEGylated Nano Graphene Oxide and Their Applications in Two-Photon Fluorescence Bioimaging and Photodynamic Therapy in Vitro and in Vivo.

Aggregation-induced emission (AIE) nanoparticles have been shown promise for fluorescence bioimaging and photodynamic therapy due to the good combination of nanoparticles and organic dyes or photosensitizers. Among several kinds of AIE nanoparticles, those that are capsulated with nanographene oxides (NGO) are easy to make, size-tunable, and have proven to be very stable in deionized water. However, the stability in saline solution still needs improvement for further applications in chemical or biomedical fields, and the efficacy of photodynamic therapy using NGO-capsulate AIE photosensitizers has not been evaluated yet. Herein, we modified NGO with polyethylene glycol (PEG) to improve the stability of NGO-capsulated AIE nanoparticles in phosphate buffer saline. Furthermore, by combining this modification method with a dual-functional molecule which has both typical AIE property and photosensitizing ability, we performed both two-photon fluorescence bioimaging and photodynamic therapy in vitro and in vivo. Our work shows that AIE nanoparticles capsulated with PEGylated nanographene oxide can be a powerful tool for future bioimaging and photodynamic therapy applications.

Kinetics of Polymer Desorption from Colloids Probed by Aggregation-Induced Emission Fluorophore.

Polymer adsorption and desorption are fundamental in many industrial and biomedical applications. Here, we introduce a new method to monitor the polymer desorption kinetics in situ based on the behavior of aggregation-induced emission. Poly(ethylene oxide) and colloidal silica (SiO2) were used as a model system. It was found that the aggregation-induced emission method could be successfully used to determine the polymer desorption kinetics, and the polymer desorption followed the first-order kinetics. It was also found that the polymer desorption rate constant decreased with the increasing molecular weight, which could be described by a power law function kd ≈ M-0.28, close to that of the adsorption rate constant.

Protonation tuning of quantum interference in azulene-type single-molecule junctions.

The protonation of azulene derivatives with quantum interference effects is studied by the conductance measurements of single-molecule junctions. Three azulene derivatives with different connectivities are synthesized and reacted with trifluoroacetic acid to form the protonated states. It is found that the protonated azulene molecular junctions produce more than one order of magnitude higher conductance than the neutral states, while the molecules with destructive interference show more significant changes. These experimental observations are supported by our recently-developed parameter free theory of connectivity, which suggests that the largest conductance change occurs when destructive interference near the Fermi energy in the neutral state is alleviated by protonation.

AIE-doped poly(ionic liquid) photonic spheres: a single sphere-based customizable sensing platform for the discrimination of multi-analytes.

By simultaneously exploiting the unique properties of ionic liquids and aggregation-induced emission (AIE) luminogens, as well as photonic structures, a novel customizable sensing system for multi-analytes was developed based on a single AIE-doped poly(ionic liquid) photonic sphere. It was found that due to the extraordinary multiple intermolecular interactions involved in the ionic liquid units, one single sphere could differentially interact with broader classes of analytes, thus generating response patterns with remarkable diversity. Moreover, the optical properties of both the AIE luminogen and photonic structure integrated in the poly(ionic liquid) sphere provide multidimensional signal channels for transducing the involved recognition process in a complementary manner and the acquisition of abundant and sufficient sensing information could be easily achieved on only one sphere sensor element. More importantly, the sensing performance of our poly(ionic liquid) photonic sphere is designable and customizable through a simple ion-exchange reaction and target-oriented multi-analyte sensing can be conveniently realized using a selective receptor species, such as counterions, showing great flexibility and extendibility. The power of our single sphere-based customizable sensing system was exemplified by the successful on-demand detection and discrimination of four multi-analyte challenge systems: all 20 natural amino acids, nine important phosphate derivatives, ten metal ions and three pairs of enantiomers. To further demonstrate the potential of our spheres for real-life application, 20 amino acids in human urine and their 26 unprecedented complex mixtures were also discriminated between by the single sphere-based array.

A highly selective fluorescence turn-on detection of ClO- with 1-methyl-1,2-dihydropyridine-2-thione unit modified tetraphenylethylene.

A new selective and sensitive fluorescence turn-on detection of ClO- is reported by taking advantage of the specific reaction between a 1-methyl-1,2-dihydropyridine-2-thione unit and ClO- and the aggregation induced-emission (AIE) behavior of the tetraphenylethylene unit.

A selective and light-up fluorescent probe for ß-galactosidase activity detection and imaging in living cells based on an AIE tetraphenylethylene derivative.

An aggregation induced emission (AIE) based bioimaging probe, TPE-Gal, was designed for light-up imaging of ß-galactosidase in living cells. The applicability of TPE-Gal in imaging endogenous ß-galactosidase activity was confirmed in OVCAR-3 cells.

Characterizing the Adsorption of Poly(vinyl alcohol) on Colloidal Silica with Aggregation-Induced Emission Fluorophore.

The adsorption of polymer on colloidal particle has significant influence on colloid structure and dynamics. Here we introduce a new method to monitor the adsorption in situ, based on the different emission behavior of aggregation-induced emission (AIE) luminogen in different micro environments. Poly(vinyl alcohol) (PVA) and colloidal silica (CS) were used as a model system. It was found that AIE molecules exhibited extremely low fluorescence intensity in water and PVA solution, while their emission efficiency was enhanced when adsorbed on CS, and became significantly boosted when PVA was adsorbed on CS at the same time. The fluorescence intensity increases with the amount of added PVA and reaches a saturation point, which is earlier than that obtained by the well-established solvent relaxation NMR method, due to their different sensitivities for adsorption segments in specific conformation. This new method is advantageous in quick response, where the measurement can be finished within 2 min, while others usually take hours. Therefore, it is expected that this new method may be used to monitor the dynamical adsorption process of polymer on colloidal particles.

A fluorescent turn-on low dose detection of gamma-radiation based on aggregation-induced emission.

A new sensitive fluorescence turn-on detection of gamma-radiation is reported by taking advantage of aggregation induced-emission (AIE) behaviour of the tetraphenylethylene unit and the cascade radiochemical and protonation reactions.