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Transition-metal carbides, nitrides or carbonitrides (named as MXenes) are a novel type of two-dimensional (2D) materials with the features of traditional 2D materials but more variable chemical compositions. MXenes and related materials have raised more and more research attention and been extensively explored for different applications. In this work, we developed a novel method to synthesize magnetic MXene composites (Ti3C2-MNPs) for the first time through a one-pot route, which relied on the incorporation of Fe3O4 nanoparticles into Ti3C2 nanosheets via thermal treatment. The potential utilization of these Ti3C2-MNPs for catalytic degradation of organic dyes through advanced oxidation processes (AOPs) were also evaluated in details. We demonstrated that Fe3O4 nanoparticles with size about 5 nm could be anchored onto Ti3C2 with well dispersed state. The catalytic degradation results demonstrated that Ti3C2-MNPs possess extremely high degradation efficiency towards different organic dyes under optimal conditions. The electron spin resonance (ESR) spectra identified that both hydroperoxyl radicals (•OH) and superoxide radicals (•O2-) radicals were involved in the degradation process. This work reported a novel one-step method for fabrication MXenes based multifunctional composites, which show extremely high efficiency for AOPs. This method could also be extended for fabrication of many other multifunctional composites for various applications.

Herein a simple and novel approach has been developed for surface modification of delaminate MXene with nano-mixed silver oxide which combined with mussel-inspired chemistry. Surface modification with dopamine as a secondary reaction platform for loading nano-silver compounds for removal of iodine was achieved. The internal structure and morphology were characterized by SEM and TEM. The element content and distribution analysis of EDS and XPS proved that nano silver compounds were successfully supported and uniformly dispersed on the surface of MXene. Then the adsorption batch experiment was carried out, adsorption time, pH and other factors on the adsorption performance of the adsorbents were studied in details. By calculating the enthalpy change, Gibbs free energy and thermodynamic parameters, the adsorption reaction was found to be an exothermic process. The adsorption kinetics measured the maximum adsorption capacity of 80 mg/g and the removal efficiency is as high as 80% and the adsorption equilibrium time has also been improved. The adsorption kinetics were well fitted by pseudo first-order and second-order models. All the above results demonstrated that the composite from mussel-inspired chemistry has excellent adsorption properties towards iodine ions. This study not only deepens the research on the adsorption behavior of iodine adsorption, but also provides new research directions and experimental methods for pseudo-iodine adsorption.

Fluorescence imaging and magnetic resonance imaging have been research hotspots for adjuvant therapy and diagnosis. However, traditional fluorescent probes or contrast agents possess insurmountable weaknesses. In this work, we reported the preparation of dual-mode probes based on mesoporous silica nanomaterials (MSNs), which were doped with an aggregation-induced emission (AIE) dye and Gd3+ through a direct sol-gel method. In this system, the obtained materials emitted strong red fluorescence, in which the maximum emission wavelength was located at 669 nm, and could be applied as effective fluorescence probes for fluorescence microscopy imaging. Furthermore, the introduction of Gd3+ made the nanoparticles effective contrast agents when applied in contrast-enhanced magnetic resonance (MR) imaging because they could improve the contrast of MR imaging. The excellent biocompatibility of these nanoparticles, as demonstrated via a typical CCK-8 assay, and their performance in fluorescence cell imaging and MR imaging shows their potential for applications in biomedical imaging.

Cellulose nanocrystals (CNCs) are one of the most promising natural derived nanomaterials that possess a number of advantages such as nanoscale size, rich of surface functional groups, biodegradabi...

In recent years, cellulose nanocrystal (CNC) based materials have attracted great research attention for different applications owing to their unique properties and facile modification chemistry. In this work, CNC based thermo-responsive fluorescent composites were successfully prepared via the metal-free surface-initiated atom transfer radical polymerization (ATRP) of NIPAAm and a Schiff base containing dye (HDPAP). Results demonstrated CNC-poly (NIPAAm–HDPAP) composites display sensitive temperature-responsive coil-to-globule transition behavior at the temperature of lower critical solution temperature. The bright fluorescence offered by the Schiff base dye (HDPAP) was also confirmed by fluorescence spectra. Moreover, the preparation method of light meditated ATRP was proved to become the promising way in fabrication of multifunctional nanomaterials for its incomparable advantages, including low energy consumption, high efficiency, good monomer adaptation, free of transition metal ions.

Since the first discovery by Tang in 2001, aggregation-induced emission (AIE) phenomenon has attracted considerable research interest in various fields. In this contribution, AIE-active composites (named as An-HPG-β-CD) have been fabricated via conjugation of AIE-active compound An-B(OH)2 and hyperbranched polyglycerol functionalized β cyclodextrin (HPG-β-CD) based on dynamic phenyl borate for the first time. The potential biomedical applications of these AIE-active composites for biological imaging and drug delivery applications were further explored. The successful preparation of An-HPG-β-CD composites was confirmed through a series of characterization techniques. The An-HPG-β-CD composites possess great water dispersibility, low cytotoxicity, excellent fluorescence properties and uniform size and morphology, which make them promising for cell imaging. Furthermore, the cavities of An-HPG-β-CD composites could be utilized for loading with doxorubicin for drug delivery applications. In conclusion, we have developed a novel method for fabrication of AIE-active An-HPG-β-CD composites through formation of dynamic phenylboronic borate between β cyclodextrin containing hyperbranched polyglycerol and phenylboronic containing AIE dye. These AIE-active composites are of great potential in biological imaging and drug delivery applications.

This paper aims to reveal the formation process of pitchblende by analyzing its microstructural features on the nanoscale and atomic scale. Herein, we selected pitchblende samples from drilling cores from the Miaoershan area, southern China, as the research objects. The microstructural features of pitchblende particle cores were analyzed using high-resolution transmission electron microscopy (HRTEM), electron diffraction, energy spectrum (EDS) and electron microprobe analysis (EMPA), combined with density functional theory calculations. The results of this study reveal that the pitchblende grain boundaries are not clear, as they exhibit a cloudy distribution and some preferred orientations under HRTEM. The selected area electron diffraction (SAED) analyses show discontinuous ring patterns that are coherent with the presence of a preferred orientation. The HRTEM results reveal that pitchblende is a complex aggregate composed of nanocrystals with a diameter of 3–7 nm and unit cell parameters of a0 = 0.556 nm. The elements in the pitchblende are characterized by an irregular and scattered distribution of Ca, As, S, Fe, Mn, and Si. We assume that the formation of pitchblende is related to hard-base fluid in a reduced environment containing As and S. We used density functional theory calculations to obtain the pitchblende crystal structure model and simulated the positions of the U and O atoms to provide a reference for further analysis of the pitchblende crystal structure. We conjecture that uranium ions of U4+, U5+ and U6+ may coexist in pitchblende (stoichiometry U3O7).

The preparation of multifunctional composites that combine magnetic nanoparticles and supported nanomaterials has attracted great attention for various applications. In this work, a facile method was developed for the preparation of carbon nanotube (CNT)-based magnetic composites through a one-pot oxidation method using K2FeO4 as the oxidant, which was subsequently used as the reagent to generate the Fe3O4 nanoparticles and fabricate the magnetic CNT composites. This strategy could be performed at room temperature, so it is very mild and straightforward. The properties and structure of the as-fabricated CNT-Fe3O4 composites were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and vibrating sample magnetometry. The results suggested that this approach not only generated Fe3O4 magnetic nanoparticles on the surface of the CNTs but also produced a series of functional groups. In addition, the dried CNT-Fe3O4 composites were highly dispersible in water or organic solutions, and they also had a magnetic response that could satisfy the demand for magnetic separation. Finally, we adsorbed copper ions (Cu2+) and methylene blue (MB) using the CNT-Fe3O4 composites as adsorbents. The results indicated that the obtained composites could adsorb both Cu2+ and MB effectively. Taken together, we report a novel strategy for the fabrication of magnetic carbon nanotube composites through a facile oxidation and subsequent deposition procedure. These magnetic composites show great potential for the removal of environmental pollutants.

Because of its unique optical properties, the aggregation-induced emission (AIE) dye has attracted extensive attention for various applications. Especially, the utilization of AIE-active dyes for fabrication of fluorescent organic nanoparticles (FONs) has attracted the most research interest for biomedical applications. Therefore, the development of novel and effective strategies to design and prepare AIE-active FONs should be of great importance for the biomedical applications of AIE-active FONs. In this report, we reported an ultrafast strategy that based on the one-pot microwave-assisted Biginelli reaction for fabrication of AIE-active poly(AA-AEMA-TPE) copolymers, which use the 2-(methacryloyoxy) ethylacet, acrylic acid (AA) and 4′,4‴-(1,2-diphenylethene-1,2-diyl) bis([1,1′-biphenyl]-4-carbaldehyde) (TPE-CHO) as the substrates. The microwave-assisted Biginelli reaction is simple, efficient and atom-economical and can be accomplished within 3 min. Owing to their amphiphilicity, poly(AA-AEMA-TPE) copolymers will self-assemble into FONs with small size and high water dispersibility. The proton nuclear magnetic resonance (1H NMR) spectroscopy, UV-Vis spectrum and fluorescence spectrometer were used to characterize the resultant copolymers. We demonstrated that poly(AA-AEMA-TPE) FONs possess many excellent properties, such as high water dispersibility, intense fluorescence, obvious AIE feature and favorable biocompatibility. The above results suggest that poly(AA-AEMA-TPE) FONs are of great potential for fluorescent imaging. Moreover, the microwave-assisted Biginelli reaction can occur under a rather benign environment with high efficiency and good substrate adaptability. Therefore, we believe that the method developed in this work could greatly advance the applications of AIE-active functional materials.

Fluorescent nanodiamonds (FNDs) have attracted wide research interest due to their excellent optical properties and outstanding biocompatibility. Nevertheless, the complex preparation methods and high costs of FNDs still perplex their further biomedical applications. In this contribution, we developed an efficient one-step method for the preparation of water dispersible FNDs through a thiol-ene click reaction for the first time. Furthermore, a mass of carboxylic groups are introduced on the surface of FNDs, and this mass could lead to the dispersibility of FNDs in aqueous solutions. More importantly, the carboxylic groups on the surface of FNDs could further conjugate with various drug molecules and macromolecules. Therefore, the facile strategy for the preparation of FNDs with unique characteristics via the one-step thiol-ene reaction is expected to have high potential for various biomedical applications.

Fluorescent organic nanoparticles (FONs) with aggregation-induced emission (AIE) characteristics have emerged as ideal probes in fluorescent imaging for visualization of complex biological processes by taking advantages of excellent optical properties, designability and biocompatibility. Significant progresses in the syntheses of AIE-active FONs open up new possibilities in biological applications, whereas, only limited attention was focused on the fabrication of biodegradable FONs through the ring-opening polymerization (ROP) of AIE-active N-carboxyanhydrides (NCA) monomers. In this work, l -Cysteine (Cys) is functionalized with an AIE dye in the side chain, and then transformed into polymerizable NCA monomer with AIE feature. In the next step, amino-terminated poly(ethylene glycol) (PEG) was directly used to initiate the ROP of AIE-active NCA. The prepared amphiphilic copolymers contain hydrophilic PEG and hydrophobic AIE dye have a tendency to self-assemble into core-shell nanostructure. Results confirmed mPEG5000 Cys-Phe FONs owned high water dispersibility and excellent optical properties. Besides, biological evaluation results demonstrated that these AIE-active FONs possess good biocompatibility and fluorescent imaging performance. More importantly, the strategy also be extend for the preparation other polypeptides based fluorescent probes with desired structure and functions.

Fluorescent organic nanoparticles (FONs) with aggregation induced emission (AIE) properties have recently emerged as one of the most promising luminescent nanomaterials for biomedical applications due to their unique AIE feature. In this study, we reported the preparation of AIE active FONs through mixing AIE dye (TPE-CHO), 3-aminobenzeneboronic acids (ABBA) and glucan in one-pot. ABBA acted as a molecular “bridge” to conjugate TPE-CHO with glucan via formation of a Schiff base and phenyl borate. The resultant products (Glu–TPE FONs) showed amphiphilic properties and could self-assemble into nanoparticles in an aqueous solution. Glu–TPE FONs showed strong luminescence intensity and high water dispersibility because of the AIE properties of TPE-CHO and hydrophilic nature of glucan. To examine the biomedical application potential of glucan–AIE FONs, the responsiveness, biocompatibility and cell uptake behavior of Glu–TPE FONs were subsequently examined. We demonstrated that Glu–TPE FONs possess good biocompatibility and can be potentially used for biological imaging applications. More importantly, it is well known that the Schiff base and phenyl borate can respond to pH and glucose. Therefore, Glu–TPE FONs can be used for the fabrication of multifunctional biomaterials with stimuli responsiveness.

Tb3+-doped layered double hydroxides (LDHs) exhibit excellent optical characteristics, uniform size and uniform morphologies when synthesized through a hydrothermal method. However, due to their lack of functional groups and poor dispersibility, applications of these fluorescent Tb3+-doped LDHs have been largely impeded especially in the biomedical fields. In this work, a novel strategy was developed for the surface modification of these fluorescent Tb3+-doped LDHs using photoinduced surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization with hydrophilic poly(ethylene glycol) methacrylate (PEGMA) as the monomer. The final products were obtained via the metal free surface-initiated RAFT polymerization with light irradiation. Successful preparation of these fluorescent LDHs polymer composites (LDH-PEG) was confirmed by a number of analytical technologies, such as transmission electron microscopy, Fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis. In addition, laser scanning confocal microscope was employed to examine the cell uptake behavior of the LDH-PEG composites and evaluate their potential for biomedical applications. We demonstrated that the hydrophilic monomer PEGMA could be facilely grafted on the surface of Tb3+-doped LDHs through metal free photoinduced surface-initiated RAFT polymerization. The resultant LDH-PEG composites displayed high water dispersibility, strong fluorescence, low cytotoxicity and a desirable cell uptake performance. These features of the LDH-PEG composites indicated their great potential for biomedical applications. More importantly, photoinduced RAFT polymerization has the advantages of a conventional controlled living radical polymerization, which could overcome drawbacks such as toxicity, the fluorescence quenching effects of metal catalysts and the complex synthesis of chain transfer agents. Therefore, this method could be an alternative tool for the surface modification of materials and fabrication of multifunctional fluorescent nanomaterials based polymer composites.

Silica quantum dots (SiQDs) and their luminescent composites have displayed great potential for biomedical applications owing to their chemical inert and low cost. In this work, we report a facile, cost-effective and ultrafast strategy to prepare a stable luminescent SiQDs using N-[3-(trimethoxysilyl)propyl]ethylenediamine (EDAS) and salicylaldehyde as precursors for the first time. These luminescent SiQDs were further utilized for fabrication of luminescent mesoporous silica nanoparticles (MSNs) through direct encapsulation of SiQDs by MSNs. The novel synthetic and modified SiQDs uses commercial raw materials and the entire reaction can be completed within 30 s. The successful preparation of SiQDs and SiQDs@MSNs were characterized by various characterization equipments. The cell viability as well as cell uptake behavior of SiQDs@MSNs were also examined to evaluate their potential for biomedical applications. We demonstrated that these SiQDs@MSNs are low toxicity and of great potential for biological imaging. Based on the above results, we believe that these SiQDs@MSNs should be novel and promising candidates for biomedical applications owing to their intense fluorescence, biocompatibility and high specific surface areas.

Since their first discovery, the carbon nanotubes (CNTs) have attracted great research attention owing to their great mechanical properties, high chemical stability, unique electronic properties and diameter ratio. The CNTs have been extensively applied as adsorbents to remove various environmental pollutants for their large surface areas. Nevertheless, the performance of pristine CNTs for removal of cationic dye methylene blue (MB) is largely limited for their poor dispersibility and lack of functional groups. In this work, the functionalized CNTs have been synthetized through the self-polymerization of tannins under alkaline solution. The obtained samples, including pristine CNTs and CNT-TA composites, were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The effects of adsorption factors, including contact time, initial MB concentration, solution pH and temperature, were scientifically investigated. Results indicate that the adsorption capacity of functionalized CNTs at room temperature could reach up to 105 mg/g, which is much higher than that of pristine CNTs in the same experimental condition. According to the results of adsorption kinetics, isotherms and thermodynamics, the adsorption of MB onto CNT-TA follows the pseudo-first-order model and Freundlich isotherm model, and the MB adsorption process is exothermic and spontaneous. These results indicate the functionalized CNTs could be applied as high-performance adsorbents with great potential of adsorbing the cationic dye pollutants from aqueous solution.

Two dimensional nanomaterials have attracted great interest for diverse applications due to their unique structure feature, small size and high specific surface areas. Among them, the two-dimensional metal dichalcogenides have recently emerged as the outstanding ones for various applications ranged from biosensing, energy conversion and storage, and cancer photothermal treatment. In this work, a fast, facile and environmentally benign microwave irradiation method was developed to fabricate MoS2-PDA-Ag nanocomposites. To obtain MoS2-PDA-Ag nanocomposites, MoS2 nanosheets were first coated with polydopamine (PDA) films via self-polymerization of dopamine in alkaline aqueous solution. Then Ag nanoparticles were facilely deposed onto the surface of MoS2-PDA via in situ reduction by using microwave irradiation. Here, the PDA thin films were as the ad-layers for reduction and stabilizing the Ag nanoparticles simultaneously. The successful preparation of MoS2-PDA-Ag nanocomposites was characterized by means of transmission electron microscope, thermogravimetry analysis and X-ray photoelectron spectroscopy. We demonstrated that MoS2-PDA-Ag nanocomposites can be facilely fabricated via combination of mussel inspired chemistry and microwave irradiation. The resultant composites exhibited high catalytic activity towards 4-nitrophenol reduction and great antibacterial activity compared with pure MoS2 and MoS2-PDA.

In recent years, florescent polymeric nanoparticles (FPNs) containing aggregation-induced emission (AIE) fluorogens have received great intention for their potential applications in biological imaging and theranostic nanomedicine. Herein, we have developed AIE-active FPNs through a combination of reversible addition-fragmentation chain transfer (RAFT) polymerization and post-polymerization modification strategies. The salicylaldehyde (SA) containing zwitterionic copolymers are fabricated via RAFT polymerization and further modified by benzophenone hydrazone (BPH) via Schiff base reaction. The obtained AIE-active amphiphilic copolymers BPH-poly(FHMA-co-MPC) can self-assemble in aqueous solution with the hydrophobic fluorogens aggregating together to form the core and the hydrophilic chains to form the protective shell. BPH-poly(FHMA-co-MPC) and the resulting FPNs are characterized by 1H nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy and fluorescence spectroscopy. Results demonstrate that BPH-poly(FHMA-co-MPC) are successfully synthesized and as-prepared BPH-poly(FHMA-co-MPC) FPNs exhibit desirable morphology and size, good dispersibility, high brightness, remarkable photostability and large Stokes shifts. More importantly, through cytotoxicity test and cell uptake behavior, these BPH-poly(FHMA-co-MPC) FPNs show low toxicity and excellent cell dyeing behavior. Taken together, we have developed a facile and effective method for the fabrication of AIE-active FPNs, which display great potential for biomedical applications.

A novel and facile strategy that combination of surface ligand exchange and photo-initiated atom transfer radical polymerization (ATRP) has been developed for the preparation of fluorescent hydroxyapatite (HAp) based polymer composites, which were utilized for biological imaging applications. In particular, the photo-initiated ATRP not only inherited advantages of traditional ATRP but also overcome its deficiencies such as high energy consumption, transition metal contamination and long reaction time. In this method, a hydrophilic and biocompatible PEGMA was introduced to enhance the hydrophilic and biocompatibility of HAp nanocomposites. Simultaneously, the HAp-poly(PEGMA-co-AcFl) composites are endowed with bright green fluorescence by grafting with AcFl on the surface via copolymerization. The physicochemical properties of HAp-poly(PEGMA-co-AcFl) composites were characterized by a series of methods in detail. Results confirmed that HAp-poly(PEGMA-co-AcFl) composites possess controlled size and morphology, high water dispersibility and strong fluorescence. The cell viability and cell uptake behavior demonstrated that HAp-poly(PEGMA-co-AcFl) composites present low toxicity and can be potentially used for biological imaging. Taken together, we have developed a facile and efficient method for the fabrication of fluorescent HAp composites with desirable physicochemical and biological properties.

Aggregation-induced emission (AIE) is an abnormal phenomenon, which has been extensively explored for various applications. Taken advantage of the unique AIE feature, a number of luminescent nanoprobes with strong fluorescence intensity could thus be fabricated through different strategies; however, the fabrication of AIE-active carbohydrate polymers is still challenge owing to the poor solubility of carbohydrate polymers in most of organic solvents. In this work, a rather facile strategy has been developed for fabricating AIE-active sodium hyaluronate (Sh) through the formation of dynamic phenyl borate between the phenylboronic acid groups of AIE dye (An-B(OH)2)) and Sh in a “one-pot” route. This reaction could occur under low temperature, air atmosphere and in the present water. The physicochemical properties, biocompatibility, biological imaging and drug delivery performance of the final An-Sh fluorescent organic nanoparticles (FNPs) were confirmed by different characterization techniques. Results suggested that An-Sh FNPs possess high water dispersibility, strong fluorescence, and good biocompatibility. These excellent properties make An-Sh FNPs great potential for biological imaging and controlled drug delivery applications. In conclusion, we have developed a facile one-pot strategy for the preparation of AIE-active FNPs through the formation of dynamic bonds in rather mild experimental conditions. The outstanding properties and performance of An-Sh FNPs make them promising candidates for biological imaging and controlled drug delivery applications.

Mesoporous silicon nanoparticles (MSNs) have gradually developed into the multi-functional platforms in biomedical fields for their properties of high specific surface areas, regular mesoporous structure, low toxicity, chemical inert and facile functionalization. MSNs based fluorescent nanoprobes have been extensively investigated previously and many effective methods have been devoted to simplify the fabrication process. In this work, the MSNs based fluorescent polymer composites were prepared by a facile and effective reversible addition−fragmentation chain-transfer (RAFT) polymerization with the assistance by visible light irradiation, which could conduct in the presence of oxygen without complicated deoxygenation steps. A series of characterization techniques were employed to determine the successful synthesis of our preconceived MSNs-co-poly(MPC–AcFl) composites. Besides, the bright green fluorescence was observed in live L929 cells through CLSM, and cell viability evaluation was revealed that these as prepared composites were nearly no damage to cells. Combined with all the above results, the as prepared MSNs-co-poly(MPC–AcFl) composites should promising fluorescent nanoprobes for biomedical applications. Owing to the good monomer adoptability, the photoinduced oxygen tolerance RAFT polymerization could also be expanded for surface modification and construction of multifunctional composites.

Rare-earth ions doped hydroxyapatite nanoparticles (HAp:Ln NPs) have demonstrated to be very promising candidates for biological imaging applications owing to their small size and chemical compositions similar to bone. However, these HAp:Ln NPs with controllable size and morphology should be prepared under hydrothermal treatment with hydrophobic molecules as the protective layers. The hydrophobic nature of these luminescent HAp:Ln NPs largely impeded their applications in biomedical fields. In this study, a novel and effective strategy has been developed for the surface modification of HAp:Ln nanorods through the combination of surface ligand exchange reaction and reversible-addition fragmentation chain transfer (RAFT) polymerization using 2-methacryloyloxyethyl phosphorylcholine (MPC) and itaconic acid (IA) as the monomers. Herein, a small molecule adenosine 5'-monophosphate disodium salt (AMP) that contains a phosphate group and two hydroxyl groups was used to displace the hydrophobic oleic acid on pristine HAp NPs through surface ligand exchange reaction owing to its stronger interaction with HAp NPs. On the other hand, the MPC and IA were introduced on HAp NPs through RAFT polymerization after the chain transfer agent was immobilized on the HAp NPs through the esterification reaction. The poly(IA-MPC) could not only endow the high water dispersibility but also be used for loading anticancer agent cisplatin (CDDP) through coordination interaction. To evaluate their potential biomedical applications, the cell uptake behavior, drug loading capacity and release behavior as well as cell viability of HAp:Ln-AMP-poly(IA-MPC) polymeric composites were examined. We demonstrated that the method developed in this work is very effective for introduction of functional polymers onto HAp:Ln nanorods. The HAp:Ln-AMP-poly(IA-MPC) composites are promising for cell imaging and controlled delivery of CDDP.

Lanthanide-doped nanoprobes have received significant attentions for utilization in biological sensing and imaging due to their unique optical properties. However, only few works were focused on fabrication of europium complexes based fluorescence polymeric nanoparticles (FPNs) with excellent biocompatibility and biodegradability. In this study, we fabricated the FPNs (named as Eu(TTA)3Phen-GluEG FPNs) with encapsulated europium complexes which show low cytotoxicity, high sensitivity and deep penetration. Free amine group present on europium complexes initiated the ring-opening polymerization (ROP) of side-chain modified glutamic acid NCAs, offering a simple and effective method to prepare europium core FPNs with a uniform size distribution. Europium (III) chelates were furnished with a functional polyamino acid shell to fabricate biocompatible and biodegradable FPNs. Biological evaluation results demonstrate that such fabricated FPNs process excellent biocompatibility and dyeing performance. Therefore, we can expect that the fabrication approach will attract much research interest and effort on the preparation of biodegradable probes for various biological applications.

Fluorescent probes have long been regarded as tools for imaging living organisms with advantages such as high sensitivity, good designability and multifunctional potential. Many fluorescent probes, especially the probes based on aggregation-induced emission (AIE) dyes, have received increasing attention since the AIE phenomenon was discovered. These AIE dye-based fluorescent probes could elegantly overcome the notorious quenching effect caused by aggregation of conventional organic dyes. However, it is still difficult to directly apply these AIE-active dyes for biomedical applications owing to their hydrophobic nature. Therefore, the development of novel and facile strategies to endow them with water dispersibility is of critical importance. In this work, we exploit an efficient and simple strategy to fabricate an AIE dye-based fluorescent copolymer through the combination of reversible addition-fragmentation chain transfer and the Biginelli reaction. Moreover, the copolymer can self-assemble to fluorescent polymeric nanoparticles (FPNs) in water solution. Hydrophilic poly(PEGMA-co-AEMA) was reacted with the AIE-active dye 4′,4‴-(1,2-diphenylethene-1,2-diyl)bis([1,1′-biphenyl]-4-carbaldehyde (CHO-TPE-CHO) to form amphiphilic luminescent polymers using urea as the connection bridge. The successful synthesis of the final products (poly(PEGMA-co-AEMA-TPE) FPNs) was confirmed by various instruments. Furthermore, Transmission electron microscopy (TEM) images manifest that poly(PEGMA-co-AEMA-TPE) copolymers will self-assemble into spherical nanoparticles in aqueous environments with sizes between 100 nm and 200 nm. The cell uptake and bioimaging experiment confirm that poly(PEGMA-co-AEMA-TPE) FPNs have excellent biocompatibility and emit strong green fluorescence in a cellular environment. Thus, poly(PEGMA-co-AEMA-TPE) FPNs are excellent candidates for biomedical applications.

Over the past decades, graphene oxide (GO) and its composites with organic and inorganic components have gradually become one of the most popular carbon nanomaterials, on account of multitudinous advantages, including great conductivity, excellent thermal stability and large specific surface area. In particular, the magnetic GO based composites have been extensively investigated for various applications owing to their combined advantages from both GO and magnetic nanoparticles. Although many strategies have been developed for preparation of magnetic GO based composites, a facile and efficient strategy is still rarely reported. In this work, we developed a direct, ultrafast, green and non-toxic strategy for scalable production of GO–Fe3O4 hybrids for the first time. Compared with conventional preparation methods, this strategy only requires a simple one-step reaction and would produce no pollutants in the whole reaction process. Furthermore, it could convincingly demonstrate the successful preparation of GO–Fe3O4 hybrids with outstanding properties through a series of characterization techniques. Finally, the outstanding performance of GO–Fe3O4 hybrids in adsorption experiments has been also demonstrated. Results indicated that these GO–Fe3O4 composites are potentially used for environmental adsorption.

Nanodiamond (ND) is one of the most fascinating carbon materials that have been extensively investigated for biomedical applications owing to its small size, high specific surface areas, chemical inert and desirable biocompatibility. It has been reported that surface modification of ND with polymers could not only improve the dispersibility of final ND based composites but also endow them novel functions to fulfill the requirement for biomedical applications. Although some strategies have been developed previously, surface modification of ND with poly(amino acid)s has not been reported previously. In this work, poly(amino acid)s functionalized ND composites were fabricated through a ring-opening polymerization of α-amino acid N-carboxyanhydrides (NCAs), which was synthesized by conjugation of hydrophilic ethylene glycol with glutamic acid. The successful preparation of ND-GluEG composites was confirmed by a series of characterization techniques. The results suggest that the water dispersibility of final ND-GluEG composites is obviously improved. Moreover, ND-GluEG composites show low toxicity and are of great potential for biomedical applications.

Aggregation-induced emission (AIE) is a unique fluorescence phenomenon that has attracted great interest for various applications especially for the fabrication of AIE-active polymeric nanoparticles. The AIE-active fluorescent polymeric nanoparticles (FPNs) showed attractive optical properties, which could elegantly overcome the lousy aggregation-caused quenching (ACQ) effect of FPNs based on conventional organic fluorogens. Although great advances and progress have been achieved for the fabrication of AIE-active FPNs, the preparation of AIE-active carbohydrate polymers is still challengeable for the poor solubility of carbohydrate polymers in organic solvents. In this work, we reported the sodium alginate-based fluorescent biopolymers (OSA-PA-PhE) with AIE characteristic could be facilely fabricated via an ultrafast one-pot multicomponent reaction (named as Dobner reaction) with the assistance of microwave irradiation. Among the Dobner reaction system, the oxidized sodium alginate (OSA) and AIE-active dye (named as PhE-NH2) were conjugated using pyruvic acid (PA) as the molecular “bridge”. A number of characterization techniques, such as proton nuclear magnetic resonance (1H NMR), fourier transform infrared (FT-IR) spectroscopy, UV–Vis absorption spectroscopy, fluorescent spectroscopy and transmission electron microscopy (TEM), have been utilized to confirm the successful preparation of OSA-PA-PhE biopolymers. The biological evaluation results confirmed that the OSA-PA-PhE FPNs possessed ultrahigh biocompatibility and desirable imaging properties. Moreover, compared with the previous work about FPNs, this work had at least two obvious advantages, one was the original materials of sodium alginate are resourceful, cheaper, and compatible for human tissue and cells, and another was the novel Dobner reaction is a facile conjugation reaction under mild experimental conditions (e.g. catalyst-free, air atmosphere and in the presence of water). Considered the features of microwave-assisted Dobner reaction and OSA, the OSA-PA-PhE FPNs should be of great potential for different biomedical applications.

Poly(NIPAM-AcFl)/SiO2 nanomaterials were successfully prepared through a convenient oxygen tolerance light-induced RAFT polymerization. The successful preparation of the resulting Poly(NIPAM-AcFl)/SiO2 nanocomposites have been confirmed based on various characterization data. These Poly(NIPAM-AcFl)/SiO2 nanocomposites showed temperature responsive coil-to-globule transition behavior in aqueous solution, because of the hydrophilic and hydrophobic transformation of the H-bond when the temperature was greater than the lower critical solution temperature (LCST). More importantly, this facile RAFT polymerization based on photocatalysis would pave the way for the fabrication of other polymer/inorganic nanomaterials with great application potential in different fields. Compared with the traditional surface-initiated radical polymerization, our method possesses the advantages of no metal contamination, room temperature reaction condition and the oxygen tolerance properties could be the promising facile way for preparation of various nanocomposites.

Carbon-based fluorescent nanoparticles are considered to be new promising nontoxic fluorescence probes which suitable for various bioimaging and biomedical applications. However, the synthesis and production of such high-quality fluorescent carbon-based nanoparticles is still challenging, and its most application potential is unexplored. In this work, we introduce a facile light-induced surface-initiated atomic transfer radical polymerization (SI-ATRP) method to fabricate the nanodiamonds (NDs) based fluorescence probes in the absence of transition metal ligands. In this sample way, the Fluorescein was employed and played the role as the fluorescent signal and photocatalyst simultaneously for its photochemical property. Besides, the poor dispersibility of pristine NDs was also obviously improved by modifying with PEGMA, and the modified NDs (FNDs-polyPEGMA) display good dispersion and biocompatibility via characterization methods. A series of characterization techniques were also carried out to confirm the successful fabrication of fluorescent NDs after polymerization. Through our investigation, the as prepared FNDs-polyPEGMA nanoparticles with high dispersibility and stable green fluorescence could be the potentially used fluorescent probes in biomedical application.

(Zn/Al) layered double hydroxide (LDH) based fluorescence probes have been facilely fabricated via photo-induced surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization, which demonstrated green fluorescence, good biocompatibility and excellent dispersion performance in aqueous solution. The as prepared (Zn/Al)LDH polymeric composites were modified with 2-methacryloyloxyethyl phosphorylcholine (MPC), acrylic acid (AA) and diacroloyl-fluorescein (Ac-Fl). Among them, the comonomers MPC and AA were used to endow their water dispersibility, biocompatibility and potential drug carriers, while the Ac-Fl was served both as the fluorescence signal and photocatalyst for RAFT polymerization. A series of characterization methods, including 1H nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, transmission electronic microscopy, thermogravimetric analyses, X-ray photoelectron spectroscopy were employed to conform the successful of surface modification of LDH through photo-induced surface-initiated RAFT polymerization. Besides, UV-vis absorption spectra and fluorescence spectra were adopted to evaluate the optical characteristics of as prepared (Zn/Al)LDH-co-Poly(MPC-AA-Fl) composites, which exhibited high intense green fluorescence. Furthermore, the endocytosis behavior indicates that (Zn/Al)LDH-co-Poly(MPC-AA-Fl) composites could be potentially used in cell imaging and even drug delivery application for their excellent biocompatibility and all advantages described above.

Over the past years, fluorescent carbon nanoparticles have got growing interest for biological imaging. Fluorescent nanodiamonds (FNDs) are novel fluorescent carbon nanoparticles with multitudinous useful properties, including remarkable fluorescence properties, extremely low toxicity and high refractive index. However, facile preparation of FNDs with designable properties and functions from non-fluorescent detonation nanodiamonds (DNDs) has demonstrated to be challengeable. In this work, we reported for the first time that preparation of Polyethylene glycol (PEG) functionalized FNDs through a one-step thiol-ene click reaction using thiol containing PEG (PEG-SH) as the coating agent. Based on the characterization results, we demonstrated that PEG-SH could be efficiently introduced on DNDs to obtain FNDs through the thiol-ene click chemistry. The resultant FND-PEG composites showed high water dispersibility, strong fluorescence and low cytotoxicity. Moreover, FND-PEG composites could be internalized by cells and displayed good cell dyeing performance. All of these features implied that FND-PEG composites are of great potential for biological imaging. Taken together, a facile one-step strategy based on the one-step thiol-ene click reaction has been developed for efficient preparation of FND-PEG composites from non-fluorescent DNDs. The strategy should be also useful for fabrication of many other functional FNDs via using different thiol containing compounds for the universality of thiol-ene click reaction.

Recently, fullerene (C60) and its derivatives have attracted tremendous research interest in diverse fields owing to their excellent fluorescence and biological properties. In this work, the carboxyl groups containing fluorescent C60 COOH nanoparticles have been prepared via a one-step thiol-ene click reaction for the first time. Then, we would further demonstrate that C60 COOH nanoparticles possess excellent water dispersibility, low cytotoxicity, outstanding fluorescence properties and uniform minuscule based on various characterization techniques. On account of these advantages, we further evaluate their performance in cell imaging. Furthermore, the carboxyl groups on the surface of C60 COOH nanoparticles could not only improve their water dispersibility, but also be potentially used to conjugate with various biomolecules and drug molecules. Based on these carboxyl groups, we loaded the anticancer agent cisplatin on C60 COOH nanoparticles and further explore their potential for controlled drug release. Taken together, we have developed a novel thiol-ene click reaction for preparation of carboxyl groups functionalized fluorescent C60 based nanoparticles, which showed great potential for biological imaging and potential for intracellular controlled drug delivery. More importantly, this strategy developed in this work should also be expanded for fabrication of other fluorescent C60 based nanoparticles through utilizing different thiol-containing compounds and other fluorescent carbon nanoparticles. Therefore, this work will provide some novel ideas for the preparation of various fluorescent carbon nanoparticles for theranostic applications.

Recently, fullerene (C60) and its derivatives have been widely explored for many applications owing to their enriched physical and chemical properties. Specifically, the synthesis and biomedical applications of fluorescent C60 have been extensively investigated previously. However, the preparation of polymer-functionalized fluorescent C60 has not been reported thus far. In this study, water-dispersible fluorescent C60 polymer composites were successfully synthesized through the combination of the thiol-ene click reaction and subsequent ring-opening polymerization. First, 2-aminoethanethiol was introduced on the surface of C60 by the thiol-ene click reaction. The surface of amino group-functionalized C60 (C60-NH2) was further modified with poly(amino acid)s via ring-open polymerization of GluEG N-carboxyanhydrides (NCAs). The morphology, functional groups, optical properties and biocompatibility were examined by a number of characterization equipment and assays in detail. We demonstrated that the resultant fluorescent C60 poly(amino acid) (C60-GluEG) composites have a small size (about 5 nm), high water dispersibility, intense fluorescence and high photostability. Cell viability results implied that the C60-GluEG composites possess low cytotoxicity. Moreover, these C60-GluEG composites can easily penetrate into live cells, indicating their great potential for biological imaging applications.

Fluorescent polymeric nanoparticles (FPNs) as novel probes have attracted more and more attention for biomedical applications owing to their optical properties and multifunctional potential. However, most of FPNs based on conventional organic fluorogens encounter serious aggregation-caused quenching (ACQ) effect. In this work, to overcome these problems, amphiphilic fluorescent copolymers [Poly(PEGY-PhE)] containing aggregation-induced emission (AIE) fluorogens (AIEgens) have been prepared via a facile amino-yne click polymerization under rather mild experimental conditions (catalyst-free and room temperature). The Poly(PEGY-PhE) copolymers can self-assemble into FPNs and be well dispersed in aqueous solution. Fluorescence spectra demonstrate that Poly(PEGY-PhE) FPNs possess strong red fluorescence, excellent photostability and low critical micelle concentration. The biological assays confirm that these AIE-active Poly(PEGY-PhE) FPNs possess low cytotoxicity towards L929 cells and cell dyeing performance. More importantly, this amino-yne click polymerization provides a simple strategy to prepare robust biocompatible fluorescent nanoparticles for biological imaging because of their high efficiency, mild reaction conditions and simple experimental operation procedure.

Nanodiamond (ND)-based fluorescent probes have been extensively researched in cell imaging applications. Several outstanding properties of fluorescent NDs (FNDs), such as their excellent biocompatibility, intensive fluorescence and chemical stability in organisms, have made them the most promising carbon materials in biomedicine. However, the production of FNDs with nitrogen-vacancy defect centers was rather complicated and costly, which limited their wide application in the biomedical field. Moreover, the particle size of these types of FNDs was much larger than that of NDs produced by the detonation method; thus, it is difficult for them to penetrate the cell membrane. In this present work, a facile and ultrafast photo-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization was introduced for the fabrication of FND-based polymer composites. The photo-initiated RAFT polymerization is time saving, environmentally friendly and highly efficient. To prepare these FNDs, fluorescein was converted into diacryloyl fluorescein (AcFl), which was used not only as the photocatalyst but also a fluorescent comonomer. The functional monomer 2-methacryloyloxyethyl phosphorylcholine (MPC) was introduced to improve the water dispersibility of the FNDs. The successful fabrication of FNDs-polyMPC composites was proven by a series of characterization methods. These FNDs-polyMPC composites show high water dispersibility, strong fluorescence and low toxicity. The cell uptake behavior suggested that FNDs-polyMPC composites can be facilely internalized by cells. Taken together, FNDs-polyMPC composites can be fabricated by a photo-initiated RAFT polymerization. These FNDs-polyMPC composites possess excellent physicochemical and biological properties and are promising candidates for cell imaging applications.

Mesoporous silica nanoparticles (MSNs) should be one of the most important materials for biomedical application owing to their high specific surface area, regular porous structure, adjustable pore size and chemical inert. However, the biomedical applications of unmodified MSNs are largely impeded for their poor hydrophilicity and lack of functional groups. In this work, a novel photo-initiated atom transfer radical polymerization (ATRP) strategy has been reported for modified mesoporous silica nanoparticles (MSNs) with hydrophilicility copolymers using FeBr3 as the novel photocatalyst and itaconic acid (IA) and 2-methacryloyloxyethyl phosphorylcholine (MPC) as monomers. Because of the hydrophilicity and anticancer agent cis-dichlorodiamineplatinum(II) (CDDP) loading capacity of poly(MPC-co-IA), the controlled drug delivery applications MSNs-NH2-poly(MPC-co-IA) composites toward CDDP were further investigated. A series of characterization results demonstrated that MSNs-NH2-poly(MPC-co-IA) composites can be successfully fabricated through the novel photo-initiated ATRP. MSNs-NH2-poly(MPC-co-IA) composites showed obvious enhancement of water dispersibility, desirable biocompatibility, high drug loading capability, making them great potential for controlled drug delivery of CDDP. Moreover, as compared with the traditional ATRP, that using the transition metal ions and organic ligands as the catalysis systems in elevated temperature, our method provides a more facile, benign and cost-effective route for fabrication of multifunctional MSNs with great potential for biomedical applications. Finally, this FeBr3 based photoATRP strategy should be further extended for the fabrication of many other polymeric composites owing to its good monomer adoptability.

The fluorescent polymeric nanoparticles (FPNs) with encapsulated europium complexes have recently emerged as one of the most promising luminescent probes for biomedical applications owing to their unique optical properties, biocompatibility and structure designability. Significant progresses have been made for the preparation of biocompatible trivalent lanthanide ions (Ln3+) fluorescent nanoparticles, whereas, only limited attention was focused on the fabrication of europium ion containing FPNs with biodegradability, high sensitivity and deep penetration. In this work, a facile and simple method was developed to construct biodegradable and biocompatible luminescent polyurethanes (PUs) through a two-step polymerization. In this construction system, diisocyanate-terminating polyethylene glycol (NCO-PEG-NCO) was first synthesized and subsequently conjugated with dihydroxyl modified europium (III) chelates (Eu(TTA)3Phen-OH) to obtain these luminescent PUs. These PUs show amphipathic property and can assemble into core-shell FPNs in aqueous solution and exhibit high water dispersibility. Biological evaluation results suggest that Eu(TTA)3Phen-PEG2000 FPNs possess desirable biocompatibility and great potential for biological imaging applications. Therefore, we expect that the fabrication approach will inspire much research enthusiasm and effort for the preparation of biodegradable luminescent probes.

Hydroxyapatite (HAp), as an important biomaterial for the regeneration and reconstruction of bone tissue, has attracted more and more attention of researchers and scientists due to its unique structure and compositions. However, the preparation of fluorescent HAp with controllable morphology has achieved only limited success. In this work, we reported a novel strategy to construct the water dispersible fluorescent HAp nanorods via the combination of ligand exchange and metal-free atom transfer radical polymerization (ATRP). The Br-containing fluorescent HAp nanorods with controllable size and morphology were first prepared through hydrothermal treatment. A multifunctional organic molecule (named as PTH-Br) with aggregation-induced emission feature was immobilized on the surface of hydrophobic HAp nanorods through ligand exchange reaction. The PTH-Br could be used as the initiator and catalyst for surface-initiated metal-free ATRP using poly(ethylene glycol) methacrylate as monomer to obtain hydrophilic fluorescent HAp polymer nanoparticles. This strategy successfully endowed HAp nanorods excellent fluorescence properties and favorable water dispersibility but well preserved their regular morphology. Biological assays demonstrated that the HAp-PTH-poly(PEGMA) nanoparticles exhibited good biocompatibility and efficient cell uptake performance. Taken together, we have developed a rather facile strategy based on the surface ligand exchange reaction and metal-free photoATRP to fabricate fluorescent HAp with controllable size and morphology, high water dispersibility and biological properties. These HAp-PTH-poly(PEGMA) nanoparticles should be novel and promising candidates for biomedical applications.

The fluorescent organic nanoparticles (FONs) with aggregation-induced emission (AIE) feature have recently attracted the most research interest owing to their well designability, outstanding optical properties and great potential for biomedical applications. Therefore, the development of novel strategies that could facilely fabricate AIE-active functional materials with high efficiency should be of great importance for their biomedical applications. In this work, a novel strategy that based on the microwave-assisted multicomponent tandem polymerization (MCP) has been developed to fabricate the biodegradable FONs with AIE feature. The AIE-active dye (NH2-PhE-NH2) with two amino groups, hydrophilic dialdehyde-terminating copolymer (PEG-PCL-CHO) and diethyl phosphite were successfully conjugated via a “one-pot” microwave-assisted Kabachnik–Fields (KF) reaction under rather mild conditions (e.g. air atmosphere, catalysts-free and solvent-free) within short reaction time (5 min). The obtained PEG-PCL-PhE FONs were characterized by a series of techniques. Results demonstrated that PEG-PCL-PhE FONs possess great water dispersibility, excellent optical properties as well as low cytotoxicity. Taken together, we developed a novel MCP strategy that based on the microwave-assisted KF reaction to fabricate AIE-active FONs with great physicochemical and biological properties. These AIE-active FONs are of great potential for biological imaging applications. Moreover, this strategy could also be adopted to fabricate many other AIE-active functional materials owing to its simple operation, high efficiency, short reaction time and substrate diversity.

The luminescent hydroxyapatite nanorods co-doped with Eu3+ and F− (named as FAp:Eu3+) were synthesized through liquid-solid-solution strategy to control their size and morphology as well as improve their fluorescence. However, these luminescent FAp:Eu3+nanorods are hydrophobic nature and cannot be directly used for biomedical applications. In this work, we developed a novel strategy for surface modification of FAp:Eu3+nanorods with the combination of the surface ligand exchange reaction and photo-initiated reversible addition-fragmentation chain transfer (photo-RAFT) polymerization using the biocompatible and hydrophilic poly(ethylene glycol) methacrylate (PEGMA) as the monomer. We demonstrated that the photo-RAFT polymerization is a facile and efficient route to fabricate hydrophilic FAp:Eu3+-polyPEGMA composites based on a series of characterization techniques. The FAp:Eu3+-polyPEGMA composites still well maintained the morphology and luminescent properties. Furthermore, the resultant FAp:Eu3+-polyPEGMA composites showed low cytotoxicity and desirable cell uptake behavior. These features suggested that the FAp:Eu3+-polyPEGMA composites are of great potential for biological imaging applications. More importantly, the photo-RAFT polymerization should be promising for preparation of many other luminescent nanocomposites owing to their advantages of photo-RAFT polymerization such as low polymerization temperature, high efficiency, absence of metal catalysts and good monomer applicability. It is therefore, the photo-RAFT could be extended for fabrication of many other multifunctional fluorescent composites for different biomedical applications.

The research in fluorescent organic nanoparticles (FONs) with aggregation-induced emission (AIE) feature shows an upward trend due to their outstanding optical properties and potential biomedical applications. In this work, a novel strategy has been developed for the first time through a catalyst-free azide-alkyne click reaction, which could directly conjugate azide containing polymers (PEGMA-AGE-N3) and alkyne terminating AIE dye (named as PhE-OE) under mild experimental conditions. The final PEGMA-AGE-PhE copolymers containing AIE-active dye could self-assemble into FONs with intense fluorescence owing to their AIE feature. These PEGMA-AGE-PhE FONs were characterized by a series of characterization techniques in details. The cell viability as well as cell uptake behavior of PEGMA-AGE-PhE FONs was also examined to evaluate their potential for biomedical applications. We demonstrated that the catalyst-free azide-alkyne click reaction is effective for fabrication of AIE-active FONs and these AIE-active FONs showed high water dispersity and AIE feature. Moreover, the PEGMA-AGE-PhE FONs also exhibited low cytotoxicity and great potential for biological imaging. Taken together, a facile catalyst-free azide-alkyne click reaction with high efficiency has been developed for the preparation of AIE-active FONs, which showed excellent physicochemical properties for biological imaging applications.

Polyethylenimine-tannins coated SiO2 (SiO2@PEI-TA) hybrid materials have been prepared via a single-step multifunctional coating with polyethylenimine (PEI) and tannins (TA), and characterized by transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The as-prepared SiO2@PEI-TA composites were examined as adsorbents to remove the Cu2+ from aqueous solution. The effects of contact time, initial Cu2+ concentration, solution pH and temperature, on Cu2+ adsorption have been investigated. The results show that the adsorption of Cu2+ onto SiO2@PEI-TA is dependent on the contact time, Cu2+ concentration, pH and temperature. The SiO2@PEI-TA composites show a 2.4-fold increase in adsorption capacity, implying that the introduction of PEI-TA coating is in favor of the Cu2+ adsorption. Based on the analysis of kinetic data, the kinetics of Cu2+ adsorption is more accurately described by the pseudo-second-order model. The equilibrium data are analyzed by Langmuir and Freundlich isotherms. Results of isotherms show that the better agreement is Freundlich isotherm model with correlation coefficient of 0.9914, which suggests that the adsorption of Cu2+ onto SiO2@PEI-TA is mainly a heterogeneous adsorption process. Thermodynamic analyses show that the adsorption interaction is actually a spontaneous and endothermic chemical process, which might involve the chemical chelation between Cu2+ and functional groups (amine and carboxyl groups) on the surface of SiO2@PEI-TA. In addition, the Cu2+ ions could desorb from SiO2@PEI-TA by using acid solution and the adsorption efficiency remains at high level after five adsorption-desorption recycles. These results provide potential applications of these novel adsorbents for the removal of heavy metal Cu2+ from aqueous solution and also provide strong evidence to support the adsorption mechanism proposed in the study.

Organic dyes with aggregation-induced emission (AIE) feature have recently attracted much research attention for biomedical applications due to their inimitable optical superiority. Although many reports have demonstrated for fabricating AIE-active nanoprobes, the synthesis of AIE-active natural polymers is still very limited. In this work, fluorescent organic nanoparticles (FONs) with AIE feature have been prepared through formation of Schiff base interaction between amino-terminated AIE dye (PhE) and oxidation sodium hyaluronate (OSH). The final copolymers (denoted as PhE-OSH) were characterized by means of 1H nuclear magnetic resonance spectroscopy, transmission electron microscopy, fluorescent spectroscopy and X-ray photoelectron spectroscopy. The potential of using PhE-OSH in biomedical applications were examined by cell viability assay as well as confocal imaging capability. Results suggested that PhE can facilely conjugate with OSH through formation of Schiff base. The synthesized PhE-OSH FONs exhibited well dispersibility in aqueous solution, small size, strong fluorescence and good biocompatibility. Taken together, we developed a novel strategy for fabrication of AIE-active FONs, which showed great potential for biomedical applications.

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.

Aggregation-induced emission (AIE) phenomenon was first reported by Tang et al. in 2001. Since then, the AIE-active functional materials have attracted more and more attention for different applications. Especially, the fabrication and biomedical applications of AIE-active polymeric probes have been the research frontiers in chemistry and materials fields recently. Great achievements and advances have been made in the fabrication and biomedical applications of AIE-active polymers. More and more attention has been paid to the fabrication of AIE-active polymers through non-covalent methods, although these AIE-active polymers from non-covalent strategies are expected to possess unique features (e.g. responsiveness and biodegradability). In this review, the recent developments in the non-covalent fabrication of AIE-active luminescent polymeric nanoparticles (LPNs) and the potential biomedical applications of these AIE-active LPNs are summarized. A number of fabrication strategies based on non-covalent methods such as encapsulation by amphiphilic copolymers, supramolecular inclusion, Schiff base and phenyl borate and electrostatic interaction are included. The potential biomedical applications included biological imaging, and theranostics based on these AIE-active LPNs were also highlighted. Finally, the issues and future direction about AIE-active LPNs were also pointed out in the end. We trust this review will inspire great research interest from scientists from different research fields in chemistry, materials, biology and interdisciplinary areas and significantly promote the development of AIE-active polymers for biomedical applications.

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.

In this paper, a novel strategy for the preparation of poly(levodopa) functionalized MgAl-layered double hydroxide (PDOPA-f-LDH) was developed based on the modified mussel inspired chemistry. The utilization of PDOPA-f-LDH for the removal of methylene blue (MB) from aqueous solution was also examined. Taken advantage of the self-polymerization of levodopa (DOPA) in alkaline solution and the strong affinity of catechol groups to the substrate surface, the LDH was covered homogeneously by a layer of polymer coating of DOPA, leading to the functionalization toward LDH. The structure, surface morphology, thermostability and elemental composition of as-prepared PDOPA-f-LDH were investigated by the transmission electron microscope, scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. Besides, the surface charge of the PDOPA-f-LDH was also investigated using zeta potential. The effects of various parameters, including contact time, initial MB concentration, solution pH and temperature, on the adsorption of MB onto PDOPA-f-LDH were systematically investigated. Results show that the adsorption capacity of functionalized LDH at 25°C could reach up to 102mg/g, which is much higher than that of pure LDH in the same experimental conditions. The adsorption kinetics and isotherm of MB adsorption were studied in batch experiments. The pseudo-second-order model is found to be the best to describe the adsorption kinetics. The isotherm result shows that the Freundlich isotherm is the better-fit-isotherm model to represent the equilibrium data. The values of thermodynamic parameters, including enthalpy change ΔH0, entropy change ΔS0 and Gibbs free energy change ΔG0, were also determined. All the ΔG0 values are negative; the ΔH0 and ΔS0 values of PDOPA-f-LDH were -7.824kJmol-1 and -0.01562kJmol-1K-1, respectively. And the activation energy of system (Ea) is calculated as 24.69kJmol-1. The fact suggests that the MB adsorption on PDOPA-f-LDH is a spontaneous and exothermic process. These obtained results indicate that the prepared PDOPA-f-LDH could be used as an interesting adsorbent with great potential to adsorb the cationic dyeing pollutants from aqueous media.

Supramolecular interactions between individual molecules are universal forces in living organisms and have been extensively investigated and utilized for fabrication of multifunctional materials over the past few decades. In this work, we reported a rather facile strategy to fabricate the fluorescent organic nanoparticles (FONs) with red fluorescence and aggregation-induced emission (AIE) feature through the supramolecular interactions between the β cyclodextrin (β-CD) and adamantine terminating AIE dye. The structures of prepared Ph-Ad/β-CD FONs were characterized by 1H nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR) spectroscopy. The size and morphology of the final self-assemblies (named as Ph-Ad/β-CD FONs) was characterized by transmission electronic microscopy (TEM). Results demonstrated that these AIE-active FONs can self-assemble into nanoparticles with excellent dispersity and strong fluorescence due to their AIE feature. Biological evaluation demonstrated that Ph-Ad/β-CD FONs has superior biocompatibility and imaging performance. These features endow the Ph-Ad/β-CD FONs good performance in biomedical fields.

Monodispersed SiO 2 particles functionalized with cationic polymers poly-((3-acrylamidopropyl)trimethylammonium chloride) (PAPTCl) were prepared using mussel inspired surface modification strategy and surface initiated atom transfer radical polymerization (SI-ATRP). Fourier transform infrared spectroscopy, transmission electron microscope, thermogravimetric analysis, X-ray photoelectron spectroscopy, and zeta potential were employed to characterize these SiO 2 samples. The adsorption performance of the functionalized SiO 2 (donated as SiO 2 -PDA-PAPTCl) towards anionic organic dye Congo red (CR) was investigated to evaluate their potential environmental applications. We demonstrated that the surface of SiO 2 particles can be successfully functionalized with cationic PAPTCl. The adsorption capability of as-prepared SiO 2 was found to increases from 28.70 and 106.65 mg/g after surface grafted with cationic polymers. The significant enhancement in the adsorption capability of SiO 2 -PDA-PAPTCl is mainly attributed to the introduction of cationic polymers. More importantly, this strategy is expected to be promising for fabrication of many other functional polymer nanocomposites for environmental applications due to the universality of mussel inspired chemistry and well designability and good monomer adaptability of SI-ATRP.

Mussel-inspired chemistry has recently emerged as one of the most important and interest surface modification method owing to its gentle experiment conditions, high modification efficiency and universality. The mussel-inspired chemistry is mainly relied on the adhesion of dopamine toward various materials and surfaces. In recent years, great efforts have been devoted to understanding the adhesion mechanism of mussel and extending its applications in different fields. In this mini-review, we present the very recent development of mussel-inspired fabrication of functional materials for environmental applications. The surface modification strategies that based on mussel-inspired chemistry were outlined in the first part. The environmental applications (e.g. oil/water separation, environmental adsorption and catalysts) based on these functional materials are also highlighted in the following sections. Although many advances have been achieved, there still have a plenty of spaces for further development of mussel-inspired surface chemistry for functional materials and their environmental applications.

In this study, we developed a new procedure to prepare monodispersed functionalized SiO2 (SiO2-PDA-PDMC) composites via mussel inspired chemistry and surface initiated atom transfer radical polymerization (SI-ATRP). Samples were characterized by transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analysis (TGA) measurements. TEM results showed that spherical morphology was unchanged after the functionalization. FT-IR results confirmed the successful modification with polydopamine (PDA) and the presence of poly-([2-(Methacryloyloxy) ethyl] trimethylammonium chloride) (PDMC) layer on the surface of SiO2 spheres. TGA data showed that the PDMC account for about 12.12 wt% in the sample of SiO2-PDA-PDMC composites. The XPS analysis further confirmed the existence of PDMC on the surface of SiO2-PDA-PDMC composites. The obtained SiO2-PDA-PDMC composites were used as adsorbent for the removal of Congo red (CR) from aqueous solution to evaluate the performance in environment application. The effect of contact time, solution pH, initial CR concentration and temperature on the adsorption of CR onto SiO2-PDA-PDMC composites was investigated. Adsorption results demonstrated that adsorption of CR onto SiO2-PDA-PDMC composites was a fast and efficient process. The adsorption equilibrium reached within 60 min, and the adsorption process followed the pseudo-second-order model. The experimental data of isotherms were better described by the Freundlich model. Thermodynamic study depicted the endothermic nature of adsorption and the process was spontaneous. Results from the effect of solution pH on the CR adsorption showed that the acidic condition favors the adsorption and provided evidence for the contribution of PDMC on the SiO2-PDA-PDMC composites in the removal of CR. This study suggests SiO2-PDA-PDMC composites can be developed as a new adsorbent for the removal of anionic dyes from aqueous solution.