A core–shell structured, magnetic nanocomposite (SDMA) modified by a new organic fluorescent probe and selective chelating groups was prepared for simultaneous detection and removal of low Cu2+ concentrations. A series of experiments was designed to detect and adsorb copper ions in aqueous solution via SDMA. Results showed that SDMA could detect Cu2+ from copper ion solution qualitatively and quantifiably with a certain degree of selectivity, and remove Cu2+ with a respectable removal efficiency of about 80%. In comparative adsorption experiments, the adsorption capacity of SDMA was significantly higher than that of another two common magnetic nanoadsorbents (Fe3O4@mSiO2–SH and Fe3O4@mSiO2–NH2). The adsorption behavior of SDMA was studied through equilibrium and kinetic experiments. The adsorption isotherm was perfectly fitted via the Freundlich model and the pseudo-second-order model could fit the kinetic adsorption. Moreover, the SDMA could reach the adsorption equilibrium in only 20 min, which showed a fast kinetic adsorption to Cu2+. Prepared SDMA can be an effective and potential nanoadsorbent for detecting and removing copper ions from wastewater.

Herein, a core–shell nanocomposite was fabricated by self-assembly of the photo-responsive copolymer with silica-coated upconversion nanoparticles for near-infrared light-controlled drug release and cancer therapy. Firstly, lanthanide upconversion nanoparticles (UCNPs) co-doped with Yb3+ and Tm3+ were encapsulated with mesoporous silica as the core (MUCNPs). Then a folate conjugated light-responsive copolymer (PSMN-FA) was synthesized and coated on MUCNP as the shell via self-assembly. Anti-cancer drugs could be loaded into the mesopores of the silica layer before polymer coating. Upon near-infrared (NIR) light irradiation at 980 nm, the caged UCNPs emitted luminescence in the UV region, which could change the structure of the amphiphilic copolymer and separate it from the MUCNPs, immediately followed by the release of the pre-loaded drugs to the targeted cancer cells. Our model experiments in vitro verified that the nanocarrier MUCNPs@C18@PSMN-FAcan provide active tumor targeting to folate receptor over-expressed (FR+) tumor cells. Both in vitro and in vivo studies were carried out to evaluate the NIR-controlled drug release strategy and the promising application in anticancer therapy based on the polymer-UCNPs nanocomposites.

The light-triggered controlled release of anticancer drugs accompanied with NIR-responsive photodynamic therapy was prepared via a self-assembly process. Firstly, Mn2+-doped upconversion nanoparticles (UCNPs) were coated with a mesoporous silica shell and modified with photosensitizer (Chlorin e6) and long alkyl chains. And then the NIR light-responsive amphiphilic copolymer containing 9,10-dialkoxyanthracene groups was synthesized and then coated as the outermost layer. Upon irradiation with a 980 nm laser, the CCUCNPs@PM would absorb and then convert the NIR light to higher-energy visible red light (660 nm) via the UCNPs-based core, which could excite Chlorin e6 (Ce-6) to produce singlet oxygen (1O2). Then the 1O2-sensitive dialkoxyanthracene group in the amphiphilic copolymer would be degraded and detach from the surface of the CCUCNPs@PM, followed by the controlled release of the pre-loaded drugs and the photodynamic therapy for cancer cells caused by the excess 1O2. In vitro and in vivo experiments also demonstrated that the drug-loaded CCUCNPs@PM possessed better therapeutic efficacy compared with vacant ones. Therefore, the NIR light-controlled chemotherapy and photodynamic therapy could be realized simultaneously by CCUCNPs@PM.

Herein, light-responsive nanocarriers based on hollow mesoporous silica (HMS) nanoparticles modified with spiropyran-containing light-responsive copolymer (PRMS-FA) were fabricated via a simple self-assembly process. HMS modified with long-chain hydrocarbon octadecyltrimethoxysilane was an ideal base material owing to its good biocompatibility and drug capability. The spiropyran-containing amphiphilic copolymer could shift its hydrophilic–hydrophobic balance to become hydrophilic upon UV (λ = 365 nm) irradiation and then break away from the hydrophobic surface of the HMS core, followed by the uncaging and release of the pre-loaded anticancer drug. Simultaneously, the fluorescence resonance energy transfer (FRET) process based on the structural transformation of PRMS-FA was observed, which could act as a real-time monitor for the light-controlled drug release. Our model experiments in vitro tested and verified that this composite nanocarrier has good biocompatibility, active tumour targeting to the folate receptor over-expressed in tumour cells, is non-toxic to normal cells and that light-controlled drug release with real-time monitoring can be achieved.

A multi-functional core–shell nanocarrier was successfully prepared for near-infrared light- and pH-controlled drug release as well as magnetic resonance imaging (MRI) and fluorescence imaging. On the one hand, the hollow porous Fe3O4 (HPFe3O4, ∼20 nm) which could be etched under acidic conditions inside the cancer cells was prepared as the “core” to load anti-cancer drugs. On the other hand, the targeting NIR light-responsive copolymer (DDACMM-PEG-FA) was synthesized by polymerization of coumarin-containing monomer (DDACMM), poly(ethylene glycol) (PEG) methyl ether methacrylate and N-hydroxysuccinimide (NHS) and then modified by folic acid (FA). The core–shell nanocarriers (HPFe3O4@DDACMM-PEG-FA) were obtained by coating the amphiphilic copolymers onto the hollow porous “core”. Since the copolymer could be disrupted under the irradiation of NIR light laser (800 nm) via a two-photon absorption process, the pre-loaded drugs (∼65–80%) could be released from the nanocarriers. More importantly, the subacid environment in the tumour could further etch the boundary area of uncovered HPFe3O4, which further improved the efficiency of the drug release (about 20% increase in 24 h). The in vitro experiments indicated that the nanocarriers were biocompatible and could easily target the tumour cells that over-expressed folic acid receptor (FR(+)) and release the pre-loaded drugs successfully. In addition, because of the superparamagnetism of HPFe3O4 and the fluorescence of the polymer, the MRI and cell fluorescence imaging could be used to track the process of drug delivery.

Polymeric micelles (∼10 nm) have been prepared from the amphiphilic oligomer comprising oligomeric polystyrene as the hydrophobic inner core and half of EDTA (–N(CH2COOH)2) as the hydrophilic outermost shell. After chelating cisplatin with –N(CH2COOH)2 in water, polymeric micelles containing Pt on the spherical surface have been easily obtained. Since the chelate group is introduced into the amphiphilic oligomer as the terminal group by a RAFT agent, the chelation of cisplatin with PS(COOH)2 is almost stoichiometric. The drug carrier based on PS(COOH)2 showed a high loading efficiency (>70%) towards cisplatin. The release of the therapeutic Pt from the cisplatin-loaded composites (PS(COOH)2–Pt) triggered under weak acidic conditions resulted in good Pt-release and accumulation in tumor cells. Both in vitro and in vivo, the chelated cisplatin inhibited Sk-Br3 cancer more effectively than the intact cisplatin does. Furthermore, neither PS(COOH)2 nor PS(COOH)2–Pt showed obvious systematic toxicity.

A new multifunctional nanovehicle for tumor therapy and cell imaging was fabricated by coating NIR light-responsive polymers (HAMAFA-b-DDACMM) onto the surface of octadecyltrimethoxysilane (C18)-modified hollow mesoporous silica nanoparticles (HMS@C18) via self-assembly. First, the targeting NIR light-responsive block copolymer was synthesized by the RAFT living polymerization of [7-(didodecylamino) coumarin-4-yl] methyl methacrylate with hydroxyethylacrylate and N-(3-aminopropyl) methacrylamide hydrochloride and then grafted with folic acid (FA). The copolymers could be disrupted by excitation by a femtosecond NIR light laser (800 nm) via a two-photon absorption process due to the high two-photon absorption cross-section of the coumarin moiety. In order to enhance the drug loading capacity and biological stability of the nanovehicle, HMS nanoparticles modified by hydrophobic octadecyl chains were selected as the “core”, which had a considerable drug loading efficiency of more than 70%. Then the core–shell nanocomposites (HMS@C18@HAMAFA-b-DDACMM) were obtained by coating the amphiphilic copolymers onto the core via self-assembly. Under excitation by NIR light at 800 nm, the pre-loaded drugs could be released from the nanocomposites due to the degradation of the light-responsive copolymers and the release efficiency was correlated with the irradiation time and light power. The in vitro experiments indicated that the nanocomposites were easily targeted into the tumor cells that over-expressed folic acid receptor (FR(+)) such as KB cells by endocytosis. Furthermore, the copolymer itself had strong fluorescence, which could be used to track the process of drug delivery.

A core–shell nanocomposite based on photo-degradable polymer coated hollow mesoporous silica nanoparticles (HMS) was successfully prepared for targeted drug delivery and visible-light triggered release, as well as fluorescence cell imaging. The HMS nanoparticles were first modified by the long-chain hydrocarbon octadecyltrimethoxysilane (C18) and fluorescent agent Rhodamine B isothiocyanate (RITC), and then encapsulated by a photodegradable amphiphilic copolymer via a self-assembly process. The obtained nanocarrier showed a high drug loading content due to the hollow core and mesopores of the HMS and could target folic acid receptor over-expressed tumor cells efficiently for conjugating folic acid (FA) in the amphiphilic polymer. The drug release could be triggered by the irradiation of green light (500–540 nm) due to the photodegradation of amphiphilic copolymer coated on the HMS. Furthermore, the targeted drug delivery and controlled release processes could be tracked by fluorescence imaging for the doping of RITC on the HMS. The In vitro results suggested that a smart visible light responsive drug delivery system was successfully prepared for the potential applications of cancer diagnosis and therapy.

Novel multifunctional nanocomposites were successfully prepared for the controlled release of anti-cancer drug and magnetic resonance imaging (MRI) via a simple self-assembly process. In this strategy, superparamagnetic iron oxide nanoparticles (SPIONPs) were “fixed” between the hydrophobic segment of the pH-sensitive amphiphilic polymer (HAMAFA-b-DBAM) and the surface of hollow mesoporous silica nanoparticles (HMS) which were modified by the long-chain hydrocarbon octadecyltrimethoxysilane (C18). Since the amphiphilic polymer was conjugated with a folic acid (FA) group, the nanocomposites could target the folic acid receptor (FR) of over-expressed tumor cells efficiently. Moreover, high drug loading content was obtained simultaneously due to the hollow core of HMS. The loaded drug could release from the HMS core triggered by the mildly acidic pH environment in the cancer cells due to the hydrolysis of the pH-sensitive polymer shell. The targeting process of the nanocomposites could be easily tracked by MRI due to the magnetism of the SPIONPs. Therefore, a nanocarrier with high drug-loading capacity and controlled drug release property for tumor diagnosis and therapy was obtained via the self-assembly of HMS core, magnetic Fe3O4 nanoparticles and targetable pH-sensitive polymer shell.

Hollow mesoporous silica nanoparticles (HMSs) were modified by β-cyclodextrin via a “click” reaction, an amphiphilic copolymer with a trans-azobenzene structure was then assembled onto β-cyclodextrin to cover the surface of the HMSs. The prepared nanocomposites can release drugs in a “release-stop-release” manner by converting light irradiation.

A smart fluorescent drug carrier based on hollow mesoporous silica (HMS) nanoparticles was prepared step by step. First, HMS nanoparticles were doped with lanthanide rare-earth nanocrystals (YVO4:Eu3+). Then the surface of HMS@YVO4:Eu3+ was modified by octadecyltrimethoxysilane (C18). Afterwards, it was coated by designed pH-sensitive amphiphilic diblock copolymer (poly(MPEG-b-DBAM), PMD) through hydrophobic van der Waals interactions. The results of characterization such as transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR) reveal that the material shows excellent monodisperse spherical morphology and narrow size distribution (180 nm) with hollow-core@mesoporous-silica-shell@thin-polymer-film structure. The multifunctional system HMS@YVO4:Eu3+@C18@PMD was utilized to deliver the model drug ibuprofen (IBU), and the drug loading content of the system is as high as 834 mg/g (drug/carrier). Due to the coated pH-sensitive polymer film, the loaded drug is selectively released in mildly acidic environment. The time of release of about 80% drug was however prolonged from 50 to 150 h (at pH = 5.0) by the effect of modified C18, which has thus achieved longer-term release. Besides, the prepared material is easily imported into human mouth epidermal carcinoma (KB) cells and showed good and stable red fluorescence, which is suitable for cell imaging.

A pH-sensitive amphiphilic diblock polymer (poly(PDM-b-PEGMA)) was grafted from the surface of hollow mesoporous silica nanoparticles (HMS) via atom transfer radical polymerization (ATRP). The morphology of the obtained core–shell nanocomposites, HMS@poly(PDM-b-PEGMA), was determined by transmission electron microscopy (TEM) and scanning electron microscope (SEM). The nanocomposites could be used as drug carriers due to the excellent biocompatibility with a high drug loading efficiency as 80%. Furthermore, less than 10 wt.% of DOX was released from the nanocomposites in neutral condition. When the solution is adjusted to acidic, more than 80 wt.% of DOX was released. In addition, in vitro experiments with human hepatoma 7402 cells and L02 lung cancer cells demonstrated that the nanocomposites could be internalized by both kinds of cells effectively but only release drug in cancer cells.Graphical abstractA nanocomposite with hollow core and silica-polymer shell structure was prepared via pH-sensitive amphiphilic diblock polymer that grafted from the surface of hollow mesoporous silica nanoparticles by atom transfer radical polymerization, and the resulting nanocomposites were used for stimuli-responsive controlled drug release.Highlights► We prepared the nanocomposites with hollow core and porous silica-functional polymer shell. ► The nanocomposites are uniform and monodisperse. ► Hollow core can store much more drug molecules. ► The functional polymer shell can achieve controlled drug release.

Multifunctional drug delivery systems with favorable compatibility, high selectivity and efficiency are appropriate candidates for future medical applications. For this purpose, a multifunctional nanocomposite that enables selective magnetic resonance imaging and anticancer therapy by encapsulating hydrophobic superparamagnetic nanoparticles and chemotherapeutic agent doxorubicin with a novel biodegradable pH-activated polymeric carrier was synthesized. The as-synthesized amphiphilic polymer has excellent biocompatibility and pH-responsivity. The obtained nanocomposites selectively release the encapsulated drug and magnetic nanoparticles in mildly acidic endosomal/lysosomal compartments due to the degradation of the pH-responsive bonds, resulting in a change of imaging signal and cancer therapy. Furthermore, when compared with the nanocomposites without a targeting moiety, as studied from over-expression of the folic acid receptor tumor cell culturing, the conjugates with folic acid showed a significantly more potent targeting capability.

•A recyclable photocatalyst was facilely fabricated by immobilization and grafting.•Contribution from each component in the composite towards enhanced performance.•High removal efficiency was achieved under adsorption-combined degradation.•The composite photocatalyst can be easily separated from water for direct reuse.A recyclable photocatalyst with adsorption property was prepared for high-efficient complete removal of anionic dyes from water by synergetic adsorption and photocatalytic degradation. Firstly, binary bismuth oxyhalide composed as BiOI0.5Cl0.5 was immobilized on activated carbon fibers (ACF) to get a recyclable photocatalyst (ACF@BiOI0.5Cl0.5) via one-step solvothermal method. Then it was modified with branched polyethylene imine (PEI) whose abundant amino groups can adsorb contaminants from water by electrostatic interaction. SEM images showed that the nanosheets-based flower-like photocatalytic microspheres uniformly distributed on the ACF surface after grafting of small amount of PEI. But from TGA results we can deduce that the percentage of PEI grafted onto ACF@BiOI0.5Cl0.5 is about 18 wt%. During the synergistic process, the grafted PEI and immobilized BiOI0.5Cl0.5 are worked as the adsorbent and the photocatalyst, respectively. In addition, ACF, as flexible, conductive and corrosion-resistant supports, are beneficial to the photocatalytic degradation process. So the obtained composite PEI-g-ACF@BiOI0.5Cl0.5 has a high removal efficiency of contaminants under visible light irradiation with the synergistic effect of adsorption and photocatalytic degradation. And after facial separation without centrifuge, it can be reused without regeneration because of the real-time complete degradation of the adsorbed contaminants on the surface of the composite photocatalyst.

Novel multifunctional nanocomposites were successfully prepared for the controlled release of anti-cancer drug and magnetic resonance imaging (MRI) via a simple self-assembly process. In this strategy, superparamagnetic iron oxide nanoparticles (SPIONPs) were “fixed” between the hydrophobic segment of the pH-sensitive amphiphilic polymer (HAMAFA-b-DBAM) and the surface of hollow mesoporous silica nanoparticles (HMS) which were modified by the long-chain hydrocarbon octadecyltrimethoxysilane (C18). Since the amphiphilic polymer was conjugated with a folic acid (FA) group, the nanocomposites could target the folic acid receptor (FR) of over-expressed tumor cells efficiently. Moreover, high drug loading content was obtained simultaneously due to the hollow core of HMS. The loaded drug could release from the HMS core triggered by the mildly acidic pH environment in the cancer cells due to the hydrolysis of the pH-sensitive polymer shell. The targeting process of the nanocomposites could be easily tracked by MRI due to the magnetism of the SPIONPs. Therefore, a nanocarrier with high drug-loading capacity and controlled drug release property for tumor diagnosis and therapy was obtained via the self-assembly of HMS core, magnetic Fe3O4 nanoparticles and targetable pH-sensitive polymer shell.

Hollow mesoporous silica nanoparticles (HMSs) were modified by β-cyclodextrin via a “click” reaction, an amphiphilic copolymer with a trans-azobenzene structure was then assembled onto β-cyclodextrin to cover the surface of the HMSs. The prepared nanocomposites can release drugs in a “release-stop-release” manner by converting light irradiation.

A core–shell structured, magnetic nanocomposite (SDMA) modified by a new organic fluorescent probe and selective chelating groups was prepared for simultaneous detection and removal of low Cu2+ concentrations. A series of experiments was designed to detect and adsorb copper ions in aqueous solution via SDMA. Results showed that SDMA could detect Cu2+ from copper ion solution qualitatively and quantifiably with a certain degree of selectivity, and remove Cu2+ with a respectable removal efficiency of about 80%. In comparative adsorption experiments, the adsorption capacity of SDMA was significantly higher than that of another two common magnetic nanoadsorbents (Fe3O4@mSiO2–SH and Fe3O4@mSiO2–NH2). The adsorption behavior of SDMA was studied through equilibrium and kinetic experiments. The adsorption isotherm was perfectly fitted via the Freundlich model and the pseudo-second-order model could fit the kinetic adsorption. Moreover, the SDMA could reach the adsorption equilibrium in only 20 min, which showed a fast kinetic adsorption to Cu2+. Prepared SDMA can be an effective and potential nanoadsorbent for detecting and removing copper ions from wastewater.

Multifunctional drug delivery systems with favorable compatibility, high selectivity and efficiency are appropriate candidates for future medical applications. For this purpose, a multifunctional nanocomposite that enables selective magnetic resonance imaging and anticancer therapy by encapsulating hydrophobic superparamagnetic nanoparticles and chemotherapeutic agent doxorubicin with a novel biodegradable pH-activated polymeric carrier was synthesized. The as-synthesized amphiphilic polymer has excellent biocompatibility and pH-responsivity. The obtained nanocomposites selectively release the encapsulated drug and magnetic nanoparticles in mildly acidic endosomal/lysosomal compartments due to the degradation of the pH-responsive bonds, resulting in a change of imaging signal and cancer therapy. Furthermore, when compared with the nanocomposites without a targeting moiety, as studied from over-expression of the folic acid receptor tumor cell culturing, the conjugates with folic acid showed a significantly more potent targeting capability.

A new multifunctional nanovehicle for tumor therapy and cell imaging was fabricated by coating NIR light-responsive polymers (HAMAFA-b-DDACMM) onto the surface of octadecyltrimethoxysilane (C18)-modified hollow mesoporous silica nanoparticles (HMS@C18) via self-assembly. First, the targeting NIR light-responsive block copolymer was synthesized by the RAFT living polymerization of [7-(didodecylamino) coumarin-4-yl] methyl methacrylate with hydroxyethylacrylate and N-(3-aminopropyl) methacrylamide hydrochloride and then grafted with folic acid (FA). The copolymers could be disrupted by excitation by a femtosecond NIR light laser (800 nm) via a two-photon absorption process due to the high two-photon absorption cross-section of the coumarin moiety. In order to enhance the drug loading capacity and biological stability of the nanovehicle, HMS nanoparticles modified by hydrophobic octadecyl chains were selected as the “core”, which had a considerable drug loading efficiency of more than 70%. Then the core–shell nanocomposites (HMS@C18@HAMAFA-b-DDACMM) were obtained by coating the amphiphilic copolymers onto the core via self-assembly. Under excitation by NIR light at 800 nm, the pre-loaded drugs could be released from the nanocomposites due to the degradation of the light-responsive copolymers and the release efficiency was correlated with the irradiation time and light power. The in vitro experiments indicated that the nanocomposites were easily targeted into the tumor cells that over-expressed folic acid receptor (FR(+)) such as KB cells by endocytosis. Furthermore, the copolymer itself had strong fluorescence, which could be used to track the process of drug delivery.

Herein, light-responsive nanocarriers based on hollow mesoporous silica (HMS) nanoparticles modified with spiropyran-containing light-responsive copolymer (PRMS-FA) were fabricated via a simple self-assembly process. HMS modified with long-chain hydrocarbon octadecyltrimethoxysilane was an ideal base material owing to its good biocompatibility and drug capability. The spiropyran-containing amphiphilic copolymer could shift its hydrophilic–hydrophobic balance to become hydrophilic upon UV (λ = 365 nm) irradiation and then break away from the hydrophobic surface of the HMS core, followed by the uncaging and release of the pre-loaded anticancer drug. Simultaneously, the fluorescence resonance energy transfer (FRET) process based on the structural transformation of PRMS-FA was observed, which could act as a real-time monitor for the light-controlled drug release. Our model experiments in vitro tested and verified that this composite nanocarrier has good biocompatibility, active tumour targeting to the folate receptor over-expressed in tumour cells, is non-toxic to normal cells and that light-controlled drug release with real-time monitoring can be achieved.

A core–shell nanocomposite based on photo-degradable polymer coated hollow mesoporous silica nanoparticles (HMS) was successfully prepared for targeted drug delivery and visible-light triggered release, as well as fluorescence cell imaging. The HMS nanoparticles were first modified by the long-chain hydrocarbon octadecyltrimethoxysilane (C18) and fluorescent agent Rhodamine B isothiocyanate (RITC), and then encapsulated by a photodegradable amphiphilic copolymer via a self-assembly process. The obtained nanocarrier showed a high drug loading content due to the hollow core and mesopores of the HMS and could target folic acid receptor over-expressed tumor cells efficiently for conjugating folic acid (FA) in the amphiphilic polymer. The drug release could be triggered by the irradiation of green light (500–540 nm) due to the photodegradation of amphiphilic copolymer coated on the HMS. Furthermore, the targeted drug delivery and controlled release processes could be tracked by fluorescence imaging for the doping of RITC on the HMS. The In vitro results suggested that a smart visible light responsive drug delivery system was successfully prepared for the potential applications of cancer diagnosis and therapy.