Hongye Huang

Stimulus responsive cross-linked AIE-active polymeric nanoprobes: fabrication and biological imaging application

The combination of functional polymers and hydrophobic AIE dyes to prepare luminescent organic nanoparticles (LONs) with strong fluorescence, great water dispersibility and desirable biocompatibility has received a lot of attention for potential applications in cell imaging and theranostics. Although great effort has been devoted to preparing AIE dye based LONs through both covalent and noncovalent strategies, the fabrication of cross-linked AIE dye based LONs with stimulus responsive behavior has not been reported previously. In this work, the AIE dye based LONs were constructed via cross-linking aldehyde-containing polymers and AIE dye (2,2′-diaminotetraphenyl ethylene) with two amino groups through formation of a Schiff base, which is a well-known dynamic bond with pH responsiveness. After successful incorporation of the hydrophobic AIE dye into the copolymers, cross-linked core–shell luminescent nanoparticles can be formed. The obtained AIE dye based LONs exhibited strong fluorescence and high water dispersibility because the AIE dye aggregated in the core and the hydrophilic polymers were covered on the shell. Biological evaluation results demonstrated that the AIE dye based LONs exhibited excellent biocompatibility and biological imaging properties. More importantly, these AIE dye based LONs exhibited desirable pH responsiveness, implying that these polymeric LONs can be potentially utilized for pH sensors and controlled drug delivery. With the combination of dynamic crosslinking and pH responsiveness, the obtained AIE dye based LONs should be of great significance for biomedical applications.

A rather facile strategy for the fabrication of PEGylated AIE nanoprobes

Fluorescent organic nanoparticles (FNPs) have attracted great research interest for biological sensors, biological imaging and disease treatment. However, the preparation of ultrabright FNPs using conventional organic dyes is still a challenge for their aggregation caused quenching effect. In this work, we reported for the first time that polyethylene glycol (PEG) and an aggregation induced emission (AIE) dye, 2,2′-diaminotetraphenyl ethylene (DATPE), can be facilely conjugated by trimellitic anhydride chloride. Taking advantage of the different reaction activities of anhydride and chloride, anhydride-terminated PEG (ADPEG) was first synthesized through the reaction between hydroxyl groups and benzoyl chloride. Then ADPEG could further react with the amino groups of DATPE. Because of the AIE properties of DATPE, these amphiphilic triblock copolymers can self-assemble into FNPs (PEG-TPE FNPs) and emit strong blue-green fluorescence in aqueous solution. Cell uptake behavior and cytotoxicity evaluation suggested that PEG-TPE FNPs possessed excellent cytocompatibility and could be facilely taken up by cells, implying that PEG-TPE FNPs are promising for biomedical applications. More importantly, the method described in this work is rather simple and effective and, more importantly, can be extended to fabricate many other multifunctional FNPs on a large scale for various biomedical applications.

Towards development of a versatile and efficient strategy for fabrication of GO based polymer nanocomposites

Surface modification of graphene oxide (GO) with polymers is of particular importance for its applications. Although much progress has been made in the surface modification of GO, the surface modification of GO with synthetic polymers in aqueous solution has demonstrated to be problematic. In the present work, we report for the first time a versatile and effective method for the surface modification of GO with synthetic polymers in aqueous solution taking advantage of mussel inspired chemistry. Poly(ethylene glycol) methyl ether methacrylate and itaconic anhydride (IA) monomers were chosen to prepare hydrophilic polymers (poly(IA-co-PEGMA)) via free radical living polymerization. These hydrophilic polymers were further reacted with dopamine through ring-opening reaction between IA and dopamine, which could be highly efficiently attached to the GO surface via mussel inspired chemistry using dopamine as the adhesion component. The successful modification of GO with polymers was confirmed by using a series of characterization techniques. The resulting GO–polymer nanocomposites displayed great dispersibility in aqueous and organic solutions, making them promising for various applications. Compared with previous methods, the biomimic strategy described in this work could facilely and effectively immobilize synthetic polymers on GO in aqueous solution at room temperature and under an air atmosphere. More importantly, this strategy could also be utilized for the fabrication of almost any polymer nanocomposite because of the designability and applicability of living polymerization, and the versatility and strong adhesion of dopamine.

Fabrication and biological imaging application of AIE-active luminescent starch based nanoprobes.

Fabrication of water dispersible, biocompatible and ultrabright luminescent polymeric nanoprobes (LPNs) has been the subject of great research interest. Although a number of LPNs have been fabricated previously through different strategies, the preparation of luminescent carbohydrate polymers with aggregation-induced emission (AIE) characterstic has received only limited attention. In this work, we reported for the first time that AIE-active luminescent starch can be facilely fabricated via mixing the aldehyde-contained AIE dye 4-(1,2,2-triphenylvinyl) benzaldehyde (TPE-CHO) with carboxyl methyl starch sodium (CMS) and amino phenylboronic acid in a one-pot procedure, in which aminophenylboronic acid can serve as the linkage for conjugation of TPE-CHO and CMS. The final products (TPE-CMS LPNs) were characterized by a number of characterization techniques such as (1)H nuclear magnetic resonance spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and fluorescence Spectroscopy in detail. To examine their biomedical application potential, the biocompatibility as well as cell uptake behavior of TPE-CMS LPNs were further determined. We demonstrated that TPE-CMS LPNs showed high water dispersibility and strong fluorescence, well biocompatibility and efficient cell internalization behavior, making them promising candidates for various biomedical applications.

Facile fabrication of luminescent polymeric nanoparticles containing dynamic linkages via a one-pot multicomponent reaction: Synthesis, aggregation-induced emission and biological imaging

Luminescent polymeric nanoparticles (LPNs) with aggregation-induced emission (AIE) feature have emerged as the most promising candidates for biological imaging owing to their unique AIE feature, great water dispersity, strong fluorescence, low cytotoxicity and biocompatibility. Although numerous successful strategies for construction of AIE-active LPNs have been developed, the preparation of dynamic linkages containing AIE-active LPNs based on multicomponent reactions has been rarely reported. In this work, we report a facile method for the formation of AIE-active LPNs via a one-pot conjugation of PEG-B(OH)2, 1-thioglycerol and AIE-active dye PhE-alc in short time under rather mild reaction conditions (e.g. ambient temperature, air atmosphere, absent of metal catalysts and in the present of water). The successful formation of AIE-active mPEG-PhE LPNs was confirmed by different characterization techniques in details. The great optical and biological properties certified their applicable for biological imaging application. More importantly, the novel method for the formation of AIE-active LPNs is rather simple, high efficiency and atom economy, which greatly enriched their practical biomedical applications.

Fabrication and biomedical applications of AIE active nanotheranostics through the combination of a ring-opening reaction and formation of dynamic hydrazones

Aggregation-induced emission (AIE) dyes based on fluorescent organic nanoparticles (FONs) have attracted increasing interest over the past few years. However, the biomedical applications of AIE dyes based on FONs for simultaneous biological imaging and therapeutic applications have rarely been reported thus far. In this study, an amino group terminated phenothiazine (named as ATPHE) with AIE features and red fluorescence was synthesized and utilized for the fabrication of AIE active FONs via a facile one-pot strategy, which relied on the ring-opening reaction between ATPHE and an anhydride containing compound. Then, the keto group of the AIE active polymeric intermediate was subsequently conjugated with hydrazide terminated polyethylene glycol (HTPEG) through the formation of hydrazone bonds. These amphiphilic AIE active copolymers are readily self-assembled into nanoscale particles in an aqueous solution, which resulted in strong luminescence and good water dispersibility of the final HTPEG@ATPHE-co-BTDA FONs. The excellent physicochemical and biological properties of HTPEG@ATPHE-co-BTDA FONs give them high potential for biological imaging and controlled drug delivery applications. Taken together, we developed a simple strategy for the fabrication of AIE active nanoparticles, which are promising for biological imaging and controlled drug delivery.

Microwave-assisted multicomponent reactions for rapid synthesis of AIE-active fluorescent polymeric nanoparticles by post-polymerization method

The development of simple and effective methods for synthesis of fluorescent polymeric nanoparticles (FPNs) with aggregation-induced emission (AIE) plays an important role for the biomedical applications of AIE-active FPNs. In present work, we developed a facile strategy for the fabrication of AIE-active FPNs by a post-polymerization method based on the microwave-assisted Kabachnik-Fields (KF) reaction, which can conjugate with poly(PEGMA-NH2), AIE-active dye (TPE-CHO) and diethyl phosphate (DP) under microwave irradiation within 5min. The characterization results confirm that PEGMA-TPE FPNs are successfully prepared through the microwave-assisted KF reaction. The resultant AIE-active FPNs show high water dispersity, intensive fluorescence and low cytotoxicity. These features make these AIE-active FPNs great potential for biomedical applications. Moreover, the microwave-assisted KF reaction is simple, fast, atom economy that should be a general strategy for the fabrication of various multifunctional AIE-active FPNs. We believe this work will open up a new avenue for the preparation of AIE-active functional materials with great potential for different applications.

Carbon nanotube based polymer nanocomposites: biomimic preparation and organic dye adsorption applications

The development of highly efficient adsorbents for the removal of organic dyes from wastewater has attracted much attention recently. Surface modification of adsorbents with polymers is a general strategy for enhancement of their adsorption capability. In this work, a novel strategy of a combination of mussel inspired chemistry and SET-LRP has been developed for the fabrication of highly efficient adsorbents, poly(sodium-p-styrene sulfonate) modified multi-walled carbon nanotubes (CNTs), for the first time. The adsorption applications of these CNT based polymer nanocomposites for the removal of a cationic dye (methylene blue, MB) from a water solution were also examined. The successful preparation of these CNT based polymer nanocomposites was confirmed by a series of characterization techniques. Furthermore, the influence of adsorption parameters including contact time, concentration of MB, adsorption temperature and time has been investigated. According to the experimental data, the adsorption capacity of MB was directly proportional to the contact time, while inversely proportional to the temperature. The maximum adsorption capacity of MB for CNT-PDA-PSPSH was 160 mg g−1, demonstrating the excellent adsorptive property of functional CNTs for MB. The method described in this work for the preparation of CNT based polymer nanocomposites is simple, effective and general, and could be a universal strategy for preparation of highly efficient adsorbents for environmental applications.

A facile one-pot Mannich reaction for the construction of fluorescent polymeric nanoparticles with aggregation-induced emission feature and their biological imaging

Multicomponent reactions (MCRs) have recently attracted great attention as one of the most important tools for the construction of various organic compounds in modern organic chemistry. In this work, we introduced an efficient one-pot strategy to successfully fabricate the fluorescent polymeric nanoparticles (FPNs) with aggregation-induced emission (AIE) characteristic via the conjugation of hyperbranched polyamino compound polyethyleneimine (PEI), AIE dye (named as PhE-OH) and paraformaldehyde (PF) through a Mannich reaction. The final amphiphilies (PEI-PF-PhE) can self-assemble into micelles in aqueous solution. We demonstrated PEI-PF-PhE FPNs showed high water dispersity, intense orange-yellow fluorescence, excellent photostability, low toxicity and high cell imaging performance. As compared with other construction strategies, the one-pot Mannich reaction possesses a number of advantages, such as simplicity, atom economy, high-efficiency and multifunctional potential. Combined with the remarkable properties of the AIE-active FPNs and the one-pot Mannich reaction, we could expect that the strategy developed in this work should be a useful tool for construction of various AIE-active functional materials for biomedical applications.

Preparation of AIE-active fluorescent polymeric nanoparticles through a catalyst-free thiol-yne click reaction for bioimaging applications

Fluorescent polymeric nanoparticles (FPNs) with aggregation-induced emission (AIE) characteristics have attracted much attention for biomedical applications due to their remarkable AIE feature, high water dispersity and desirable biocompatibility. The development of facile and effective strategies for fabrication of these AIE-active FPNs therefore should be of great importance for their biomedical applications. In this work, we reported that a catalyst-free thiol-yne click reaction can be utilized for fabrication of AIE-active FPNs in short reaction time and even without protection of inert gas. The results indicated that the obtained AIE-active amphiphilic copolymers (PEGMA-PhE) can readily self-assemble into luminescent nanoparticles (PEGMA-PhE FPNs) with high water dispersity, uniform size and morphology, red fluorescence. Cell viability examination and cell uptake behavior of PEGMA-PhE FPNs confirmed that these AIE-active FPNs possess low toxicity towards cells and can be easily internalized by cells through non-specific route. Therefore the remarkable properties of PEGMA-PhE FPNs such as high water dispersity, AIE-active fluorescence and nanoscale size as well as excellent biocompatibility make them promising for biomedical applications.