High Water Dispersibility Research Articles

Encapsulation of non-dewaxed propolis by freeze-drying and spray-drying using gum Arabic, maltodextrin and inulin as coating materials

The aim was to obtain alcohol-free, water-dispersible propolis powder from non-dewaxed propolis extract, with high levels of phenols, with either freeze-drying or spray-drying. Optimisation was performed with different wall materials, centrifugation settings and propolis:carrier ratios, and was carried out by monitoring the effect of one parameter at a time on the dependable variables. The powders obtained contained high phenol levels, which included known bioactive components, and also showed high dispersibility in cold water and high antioxidant activity. Furthermore, the propolis powders were stable in water for up to 24h, and the release of encapsulated phenols did not change across different environmental values, as pH 3–6. Differential scanning calorimetry showed that propolis interacts with and stabilises the carrier material (gum Arabic), also high pressure liquid chromatography showed that the profiles of the powders remained unchanged across all encapsulation techniques. This study demonstrates that the same propolis formulations can be fine-tuned to suit specific final applications and confirms that freeze-drying is a viable alternative to the more established spray-drying for encapsulation of propolis. This study also demonstrates that non-dewaxed propolis extract is a better alternative for encapsulation purposes, as no phenolic compounds are lost during its processing.

Highly conductive functionalized reduced graphene oxide

Graphene oxide (GO) is a derivative of graphene that is formed by the exfoliation of graphite oxide; product of graphite treatment with strong oxidants [1–4]. GO nanosheets are decorated by epoxy and hydroxyl groups at the bulk and carboxylates mainly at the edges, while small isolated aromatic areas complete the surface [4–6]. The hydrophilic character of GO, due to the oxygen groups, induces high dispersibility in water or other polar solvents such as ethanol or dimethylformamide (DMF) [6,7]. On the other hand, due to the very low aromatic character, GO is practically non conductive. 1,3 dipolar cycloaddition of azomethine ylide on GO in DMF was followed by a simultaneous reduction of GO. The as prepared functionalized reduced graphene oxide showed excellent stability in water and high electrical conductivity.

Solvent-Dependent Nanostructures Based on Active π-Aggregation Induced Emission Enhancement of New Carbazole Derivatives of Triphenylacrylonitrile.

In the present study, the carbazole and 2,3,3-triphenylacrylonitrile (TPAN) nanostructures (2-CTPAN and 2,2'-CTPAN) have been designed and synthesized by Pd-catalyzed Sonogashira cross-coupling reaction. CTPAN exhibit aggregation-induced emission enhancement (AIEE) behavior in water with high fluorescence quantum yield. Both the compounds show tunable self-assembly in water as well as in N,N-dimethylformamide (DMF) by extended π-π stacking interactions. CTPAN can be self-assembled into spherical particles in water and the structures of these self-assemblies have been investigated using X-ray diffraction. Interestingly, 2-CTPAN and 2,2'-CTPAN form organogels with a critical gelation concentration (CGC) of 11 and 15 mg mL-1 , respectively, in DMF and exhibit acicular and rod shaped morphology, respectively. The single-crystal structure of 2-CTPAN shows that the intermolecular C-H⋅⋅⋅π interactions lock the molecular conformation into a staircase-shaped supramolecular assembly. These AIEE active compounds reveal high water dispersibility, strong yellow fluorescence with high quantum yield, promising photostability and excellent biocompatibility, which make them potential bioimaging agents.

Polyaspartamide based hydrogel with cell recruitment properties for the local administration of hydrophobic anticancer drugs

By exploiting the chemical versatility and the high water dispersibility of α,β-poly(N-2-hydroxyethyl)D,L-aspartamide, in this work, two different polymer derivatives were synthesized for the first time. Obtained macromolecules were characterized and used to produce hydrogels exploitable for the local release of hydrophobic anticancer drugs. The first derivative, bearing pendant β-cyclodextrins, was employed to solubilize tamoxifen, chosen as a model drug, and to produce a water soluble supramolecular complex, as evidenced through tamoxifen phase solubility studies. The second derivative, bearing pendant Cyclo(Arginine-Glyicine-Asparagine-D-Phenilyalanine-Cysteine) peptide moieties, was used as a macromolecular crosslinker to obtain a hydrogel with cellular recruitment properties. The occurrence of crosslinking between the two derivatives was studied through rheological analysis and different procedures were employed to obtain tamoxifen medicated hydrogels. In vitro release studies, together with cytotoxicity and recruitment experiments, reveal that the obtained hydrogels can control the release of anticancer drugs, have a cytotoxic effect on human breast carcinoma cells and, thanks to the presence of adhesion moieties, are able to recruit cancer cells.

Polysulfonate Cappings on Upconversion Nanoparticles Prevent Their Disintegration in Water and Provide Superior Stability in a Highly Acidic Medium.

The stability of organic cappings on hexagonal NaYF4:Ln3+ upconversion nanoparticles (UCNPs) is crucial for their luminescence efficiency in aqueous solutions. The capping removal quickens as the acidity of the medium increases. We demonstrate here that polysulfonates, namely poly(2-acrylamido-2-methyl-1-propanesulfonate) (PAMPS) and poly(sodium 4-styrene sulfonate) (PSS), remain anchored to the surface of NaYF4:Yb3+,Er3+/Tm3 UCNPs even at a pH as low as 2 due to strong acidity of the sulfonate anchoring groups (pKa of ca. −3). Bare UCNPs progressively disintegrate into their compositional F–, Na+, Y3+, and Ln3+ ions. Their disintegration is particularly worrying in highly diluted dispersions of nanoparticles because both the lanthanide ions and/or the bare UCNPs can cause undesirable interference in a chemical or biological environment. Remarkably, the UC@PSS nanohybrid is particularly chemically stable, exhibiting an amazingly low release of Y3+ and Ln3+ ions for up to 96 h in highly diluted water dispersions (10 μg/mL). Additional advantages of the use of PSS as capping layer are its biocompatibility and its high dispersibility in water, together with easy further functionalization of the UCNP@PSS nanohybrids.

Ultrafast fabrication of fluorescent organic nanoparticles with aggregation-induced emission feature through the microwave-assisted Biginelli reaction

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.

Plasmonic MoO3-x nanoparticles incorporated in Prussian blue frameworks exhibit highly efficient dual photothermal/photodynamic therapy.

Development of near infrared (NIR) light-responsive nanomaterials for high performance multimodal phototherapy within a single nanoplatform is still challenging in technology and biomedicine. Herein, a new phototherapeutic nanoagent based on FDA-approved Prussian blue (PB) functionalized oxygen-deficient molybdenum oxide nanoparticles (MoO3-x NPs) is strategically designed and synthesized by a facile one-pot size/morphology-controlled process. The as-prepared PB-MoO3-x nanocomposites (NCs) with a uniform particle size of ∼90 nm and high water dispersibility exhibited strong optical absorption in the first biological window, which is induced by plasmon resonance in an oxygen-deficient MoO3-x semiconductor. More importantly, PB-MoO3-x NCs not only exhibited a high photothermal conversion efficiency of ∼63.7% and photostability but also offered a further approach for the generation of reactive oxygen species (ROS) upon singular NIR light irradiation which significantly improved the therapeutic efficiency of the PB agent. Furthermore, PB-MoO3-x NCs showed a negligible cytotoxic effect in the dark, but an excellent therapeutic effect toward two triple-negative breast cancer (TNBC) cell lines at a low concentration (20 μg mL-1) of NCs and a moderate NIR laser power density. Additionally, efficient tumor ablation and metastasis inhibition in a 4T1 TNBC mouse tumor model can also be realized by synergistic photothermal/photodynamic therapy (PTT/PDT) under a single continuous NIR wave laser. Taken together, this study paved the way for the use of a single nanosystem for multifunctional therapy.

Facile fabrication of cross-linked fluorescent organic nanoparticles with aggregation-induced emission characteristic via the thiol-ene click reaction and their potential for biological imaging

Over the past several years, the biomedical applications of fluorescent organic nanoparticles (FONs) with aggregation-induced emission (AIE) feature have been extensively explored because the AIE-active FONs could effectively overcome the aggregation caused quenching (ACQ) effect of FONs based on conventional organic dyes. The development of novel methods for synthesis of AIE-active FONs plays a centre role for their biomedical applications. In this work, we reported a facile one-step thiol-ene click reaction for fabrication of AIE-active FONs through conjugation of acrylated PEG and AIE-active tetraphenylethylene (TPE) with two ene bonds using pentaerythritol tetra(3-mercaptopropionate) as the linkage. The successful synthesis of TPE containing AIE-active copolymers was evidenced by various characterization techniques. The particle size and fluorescence properties of the resultant TPE-S-PEG copolymers were evaluated by transmission electronic microscopy and fluorescence spectroscopy. Moreover, the cell viability and cell uptake behavior was also examined to evaluate their potential for biological imaging. We demonstrated that the cross-linked TPE-S-PEG show small size, high water dispersibility, low cytotoxicity and strong fluorescence for tracing. All of these advantages endow the TPE-S-PEG FONs great potential for biological imaging applications. Furthermore, this novel click reaction can take place under mild experimental conditions with high efficiency. It could be also further expanded for preparation of multifunctional AIE-active materials due to the universality of the thiol-ene click reaction and good precursor applicapability. Taken together, we have developed a novel and effective thiol-ene click reaction to fabricate the cross-linked AIE-active FONs, which display excellent physicochemical and biological properties and are promising for biomedical applications.

Plasma-functionalized exfoliated multilayered graphene as cement reinforcement

A fast, facile, nonhazardous, environment-friendly, and high yield process was developed for the plasma treatment of graphite particles and the production of plasma-functionalized multilayered graphene (pf-MLG). Graphite particles (<20 μm) were functionalized using a subatmospheric 13.56 MHz radio frequency-excited oxygen plasma followed by liquid-phase exfoliation to produce pf-MLG with a high aspect ratio (>2585) with <20 graphene layers. The exfoliated graphene also exhibited high dispersibility in water after plasma functionalization without the use of surfactants. The pf-MLG nanoflakes were incorporated into a cement mixture with 0.1 and 0.5 wt% pf-MLG loading. A 56% increase in compressive strength of cement mortars was achieved for the 0.5 wt% pf-MLG after 28 days curing. This is attributed to the strong interfacial interaction between graphene and the cement matrix and the promotion of hydration. The highly scalable process of pf-MLG-reinforced cement will make a positive impact on the environment, especially in the construction industry.

Development of a Water‐Dispersible SBA‐15‐Benzothiazole‐Derived Fluorescence Nanosensor by Physisorption and Its Use in Organic‐Solvent‐Free Detection of Perborate and Hydrazine

AbstractWe have synthesized a water dispersible SBA‐15 based sensing material (nanosensor 1) for the detection of perborate ions and hydrazine in water. The nanosensor was prepared by simple physisorption of chemosensing unit 2‐(benzo[d]thiazol‐2‐yl)phenyl acetate (2) onto PEG‐stabilized SBA‐15. The probe molecule undergoes spontaneous cleavage of acetate group in the presence of both perborate ions and hydrazine to produce corresponding phenol (3), which results in greenish blue fluorescence by excited state intra‐molecular proton transfer (ESIPT) mechanism. The limit of detection (LOD) for both analytes was observed in ppb level; 49.9 ppb for perborate ions and 8.0 ppb for hydrazine. Simple synthesis, effortless modification, high water dispersibility make this nanosensor very efficient for perborate ions and hydrazine. Finally, this is a demonstration of the physisorption strategy in building useful sensing materials which can be applied to any analyte based on the choice of a suitable chemosenors.

Preparation of PEGylated and biodegradable fluorescent organic nanoparticles with aggregation-induced emission characteristics through direct ring-opening polymerization

Abstract 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.

Surface PEGylation and biological imaging of fluorescent Tb3+-doped layered double hydroxides through the photoinduced RAFT polymerization

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.

Paclitaxel-Induced Ultrasmall Gallic Acid-Fe@BSA Self-Assembly with Enhanced MRI Performance and Tumor Accumulation for Cancer Theranostics.

Ultrasmall nanoparticles have attracted great attention because of their efficient renal clearance. However, their bioapplication is still severely hampered by the poor performance derived from low tumor accumulation. Here, a large, self-assembled nanoparticle was designed for cancer theranostics and used with paclitaxel (PTX) to assemble bovine serum albumin-coated ultrasmall gallic acid-Fe(III) (GA-Fe@BSA-PTX) nanoparticles by the hydrophobic effect. The GA-Fe@BSA-PTX self-assembled nanoparticles featured appropriate size (∼115 nm), high water dispersity and stability, and low cell toxicity. Importantly, the magnetic resonance imaging performance and tumor accumulation of GA-Fe@BSA-PTX self-assembled nanoparticles were much better than those of the ultrasmall GA-Fe@BSA nanoparticles. Furthermore, the GA-Fe@BSA-PTX self-assembled nanoparticles exhibited an excellent therapeutic effect on tumors, owing to the combined chemo- and photothermal effects. This work highlights the great potential of the as-synthesized GA-Fe@BSA-PTX self-assembled nanoparticles as a multifunctional theranostic nanoplatform, offering compelling opportunities for theranostic applications in the clinic.

Effect of Anionic Surfactant on Adsorption Properties of Nano Calcium Carbonate

Because of its superior surface properties, nanocalcium carbonate can be applied to the adsorption of heavy metals in wastewater. However, because of the easy aggregation of nanocalcium carbonate, high surface energy and poor dispersibility in water, it is not conducive to the process of adsorption. Therefore, surface modification of nanocalcium carbonate is needed. In this paper, nanocalcium carbonate was prepared by liquid phase method. And the nanocalcium carbonate was surface modified by sodium dodecyl sulfate. The effects of modifier amount, modification temperature, and modification time on the activation and absorbance of nanocalcium carbonate were investigated. And the morphology and particle size of modified nanocalcium carbonate were tested by SEM and XRD patterns.The results show that the dispersion and surface activity of the modified nanocalcium carbonate have been improved remarkably. Moreover, the Cu2+ was adsorbed by sodium dodecyl sulfate modified nanocalcium carbonate and unmodified nanocalcium carbonate under the optimum modification conditions. And the effects of nanocalcium carbonate initial concentration on the adsorption performance were studied. The results show that the adsorption performance of modified calcium carbonate is better than that of the unmodified. Moreover, the adsorption process is studied by adsorption isotherm. By drawing the adsorption isotherms lines and by comparing the fitting result of the experimental data based on the Langmuir model and that of Freundlich model, it is found that the adsorption of Cu2+ by modified nanocalcium carbonate meets the Langmuir model.

A one-step ultrasonic irradiation assisted strategy for the preparation of polymer-functionalized carbon quantum dots and their biological imaging

Fluorescent carbon nanoparticles (FCNs) have gradually become the most promising alternative candidates to other traditional fluorescent nanomaterials for biological applications on account of their excellent fluorescence property and remarkable biocompatibility. Although many methods have reported on the preparation of FCNs, to date, no studies have reported the preparation of polymers of functionalized FCNs. A high-efficiency method was developed in this work to synthesize high-quality poly(ethylene oxide) (PEG)-functionalized FCNs from cigarette ash and thiol group-containing PEG via a facile one-pot ultrasonic irradiation treatment. A series of characterization techniques demonstrated the uniform nanoscale size, good fluorescence stability, high water dispersibility and remarkable biocompatibility of the generated FCNs. Furthermore, cell imaging was easily achieved at high resolution using the synthetic FCNs as probes, which validates their potential for bioimaging applications. In summary, an efficient one-pot strategy is reported for the first time on the preparation of PEG-functionalized FCNs with the assistance of ultrasonic irradiation. This method should be of great research interest for the fabrication of other polymer-functionalized FCNs with designable properties and functions.

In vivo delineation of glioblastoma by targeting tumor-associated macrophages with near-infrared fluorescent silica coated iron oxide nanoparticles in orthotopic xenografts for surgical guidance

Glioblastoma multiforme (GBM) is the most aggressive and lethal type of human brain cancer. Surgery is a current gold standard for GBM treatment but the complete surgical resection of GBM is almost impossible due to their diffusive characteristics into surrounded normal brain tissues. There is an urgent need to develop a sensitive imaging tool for accurate delineation of GBM in the operating room to guide surgeons. Here we illustrate the feasibility of using near-infrared fluorescent silica coated iron oxide nanoparticles (NF-SIONs) with high water dispersion capacity and strong fluorescence stability for intraoperative imaging of GBM by targeting tumor-associated macrophages. Abundant macrophage infiltration is a key feature of GBM margins and it is well associated with poor prognosis. We synthesized NF-SIONs of about 37 nm to maximize endocytosis activity for macrophage uptake. The NF-SIONs selectively visualized tumor-associated macrophage populations by in vitro live-cell imaging and in vivo fluorescence imaging. In the orthotopic GBM xenograft models, the NF-SIONs could successfully penetrate blood-brain barrier and delineated tumor burden specifically. Taken together, this study showcased the potential applications in GBM treatment for improved intraoperative staging and more radical surgery as well as dual modality benefit in order to circumvent previous clinical failure.

A novel strategy for fabrication of fluorescent hydroxyapatite based polymer composites through the combination of surface ligand exchange and self-catalyzed ATRP

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.

AIE-active self-assemblies from a catalyst-free thiol-yne click reaction and their utilization for biological imaging

Aggregation-induced emission (AIE) should be the most interest fluorescent phenomenon over the past few decades. The luminescence polymeric nanoparticles (LPNs) with AIE characteristic have attracted great research attention for biological imaging and many other biomedical applications owing to their good biocompatibility and negative toxicity. However, the preparation of LPNs with desirable optical properties using traditional organic dyes still remains a great challenge for the aggregation-caused quenching (ACQ) effect and aggregation of hydrophobic dyes in the core of LPNs. In this work, we reported a novel and simple method for fabrication of biodegradable AIE-active LPNs via the combination of condensation and click reactions. For preparation of these AIE-active LPNs, the thiol groups-containing hydrophilic copolymers (PEG-MA) were first synthesized through the condensation reaction between polyethylene glycol and mercaptosuccinic acid. The PEG-MA copolymers were further reacted with AIE dye PhE-OE through a catalyst-free thiol-yne click reaction. These obtained PEG-MA-PhE LPNs were fully characterized by a number of characterization techniques. All the results confirmed that PEG-MA-PhE LPNs possess excellent compatibility, intense red luminescence, great photostability and high water dispersibility. These features make PEG-MA-PhE LPNs promising candidates for various biomedical applications.

A New Photosensitized Oxidation-Responsive Nanoplatform for Controlled Drug Release and Photodynamic Cancer Therapy.

Abnormal biochemical alteration such as unbalanced reactive oxygen species (ROS) levels has been considered as a potential disease-specific trigger to deliver therapeutics to target sites. However, in view of their minute variations in concentration, short lifetimes, and limited ranges of action, in situ generation of ROS with specific manipulations should be more effective for ROS-responsive drug delivery. Here we present a new delivery nanoplatform for photodynamic therapy (PDT) with on-demand drug release regulated by light irradiation. Rose bengal (RB) molecules, which exhibit a high yield of ROS generation, were encapsulated in a mixture of chitosan (CTS), poly(vinyl alcohol) (PVA), and branched polyethylenimine ( bPEI) with hydrophobic iron oxide nanoparticles through an oil-in-water emulsion method. The as-prepared magnetic nanoclusters (MNCs) with a tripolymer coating displayed high water dispersibility, efficient cellular uptake, and the cationic groups of CTS and bPEI were effective for RB loading through electrostatic interaction. The encapsulation efficiency of RB in MNCs could be further improved by increasing the amount of short bPEI chains. During the photodynamic process, controlled release of the host molecules (i.e., RB) or guest molecules (i.e., paclitaxel) from the bPEI-based nanoplatform was achieved simultaneously through a photooxidation action sensitized by RB. This approach promises specific payload release and highly effective PDT or PDT combined therapy in various cancer cell lines including breast (MCF-7 and multidrug resistant MCF-7 subline), SKOV-3 ovarian, and Tramp-C1 prostate. In in vivo xenograft studies, the nanoengineered light-switchable carrier also greatly augments its PDT efficacy against multidrug resistant MCF-7/MDR tumor as compared with free drugs. All the above findings suggest that the substantial effects of enhanced drug distribution for efficient cancer therapy was achieved with this smart nanocarrier capable of on demand drug release and delivery, thus exerting its therapeutic activity to a greater extent.

Surface grafting of rare-earth ions doped hydroxyapatite nanorods (HAp:Ln(Eu/Tb)) with hydrophilic copolymers based on ligand exchange reaction: Biological imaging and cancer treatment

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.