Severe gum disease (periodontitis), which is one of the major global oral diseases, results from microbe-host dysbiosis and dysregulated immuno-inflammatory responses. It seriously affects oral health and general wellbeing with significant socio-economic implications. It has been well documented that natural flavonoids such as baicalin (BA) and baicalein (BE) possess potent anti-inflammatory effects. However, their intrinsic poor solubility and low bioavailability severely limit their biomedical applications. In the present study, BA and BE were encapsulated in our synthesized and amine-modified mesoporous silica nanoparticles (MSNs) (Nano-BA and Nano-BE, respectively), and their loading efficiencies and releasing profiles were investigated. Their cytotoxicity was examined on primary human gingival epithelial cells (hGECs), and the cellular uptake of Nano-BA or Nano-BE was visualized via a transmission electron microscope. Their anti-inflammatory effects were evaluated in IL-1β-treated hGECs using the cytokine array and enzyme-linked immunosorbent assay. The present study shows that the amine-modified MSNs could encapsulate BA and BE, and nano-encapsulation greatly enhances the drug delivery rate and prolongs the release of BA and BE up to 216 h. Moreover, both Nano-BA and Nano-BE could be internalized by hGECs and retained intracellularly in nanoparticle-free media for at least 24 h. Note that Nano-BE pre-treatment effectively down-regulates the IL-1β-induced expression of IL-6 and IL-8 in hGECs. In conclusion, nanoparticle-encapsulated BE exhibits notable anti-inflammatory effects through effective release and cellular internalization approaches. This study may facilitate the development of novel drug delivery systems for improving oral care.

A facile method was developed to synthesize Fe3O4/polydopamine (PDA) dual shelled microspheres with a hollow interior. Since the final product was obtained by in situ polymerization of dopamine (DA) on the surface of a hollow Fe3O4 spherical template, the average size of the hybrid microspheres was tunable by manipulating both the Fe3O4 size and the PDA shell thickness. Due to the hollow interior and the compatible surface, the Fe3O4/PDA demonstrated excellent adsorption performance for Eu(III) ion removal (151.05 mg g−1) in aqueous solution. In comparison to pristine Fe3O4 hollow spheres, the dual shelled particles exhibited a faster adsorption dynamic process and a higher adsorption capacity for Eu(III) entrapment. Simultaneously, the Fe3O4/polydopamine (PDA) also exhibits a higher adsorption capacity for Eu(III) entrapment compared with that of other magnetic materials. This method was also effective for synthesizing other kinds of PDA shell encapsulated core/shell nanoparticles.

Rotaxane organocatalysis presents a new direction toward controlled one-pot catalytic reactions. By combining molecular switches and catalysts, fluorescence and pH-responsive switching along with the exclusive selectivity of dual catalytic reactions are demonstrated. A newly designed [2]rotaxane catalyst containing an anthracene group was used to visualize the catalytic reaction process upon switching the macrocycle.

Photoluminescent carbon dots (CDs) have received ever-increasing attention in the application of optical bioimaging because of their low toxicity, tunable fluorescent properties, and ultracompact size. We report for the first time on enhanced photoluminescence (PL) performance influenced by structure effects among the various types of nitrogen doped (N-doped) PL CDs. These CDs were facilely synthesized from condensation carbonization of linear polyethylenic amine (PEA) analogues and citric acid (CA) of different ratios. Detailed structural and property studies demonstrated that either the structures or the molar ratio of PEAs altered the PL properties of the CDs. The content of conjugated π-domains with C═N in the carbon backbone was correlated with their PL Quantum Yield (QY) (up to 69%). The hybridization between the surface/molecule state and the carbon backbone synergistically affected the chemical/physical properties. Also, long-chain polyethylenic amine (PEA) molecule-doped CDs exhibit increasing photostability, but at the expense of PL efficiency, proving that the PL emission of high QY CDs arise not only from the sp2/sp3 carbon core and surface passivation of CDs, but also from the molecular fluorophores integrated in the CDs. In vitro and in vivo bioimaging of these N-doped CDs showed strong photoluminescence signals. Good biocompatibility demonstrates their potential feasibility for bioimaging applications. In addition, the overall size profile of the as-prepared CDs is comparable to the average size of capillary pores in normal living tissues (∼5 nm). Our study provides valuable insights into the effects of the PEA doping ratios on photoluminescence efficiency, biocompatibility, cellular uptake, and optical bioimaging of CDs.

Supramolecular amide hydrogen-bond interactions between bundles of necklace-like chains based on superparamagnetic hollow Fe3O4 nanoparticle beads could be indirectly quantified by shear stress and magnetorheological analyses. First, a facile magnetic field-induced method was developed for the preparation of the superparamagnetic Fe3O4 hierarchical chain structures. Primary Fe3O4 hollow nanospheres, hollow nanosphere-assembled chains, and partially hollow nanosphere-assembled chains were successfully prepared. These superparamagnetic nanoparticles and chains could be well dispersed in aqueous solutions. The magnetic hollow nanoparticle chains possess a strong magnetorheological effect in aqueous solutions. Bundle wire-like structures based on chains or nanospheres could be formed with different magnetic field alignments. The hollow nanostructure greatly strengthens the as-formed bundle wire-like structures such that the chains have a larger magnetorheological effect than that of the hollow nanospheres. It is envisaged that a specific cell transfection mechanism of chains and wires could involve a partial disassembly from bundles to individual chains/wires before endocytosis. The force that is exerted on this disassembly from bundles to individual chains/wires in a specific medium, which are quantified by shear stress and magnetorheological analyses, would shed light on cell magnetofection mechanisms.

A series of melanin derivatives has been prepared by functionalization with dendritic azobenzene molecules under basic conditions with (K2CO3) and without (Et3N) a potassium ion. The dendritic melanins treated with K2CO3 show excellent solubility in water and tetrahydrofuran. This may be due to the multivalent chelating properties between the heteroatoms of melanin and potassium ions. These highly soluble dendritic melanins were coupled with TiO2 nanotube arrays easily for enhanced photocurrent generation.

In this paper, we investigated the functional imaging and targeted therapeutic properties of core@multi-shell nanoparticles composed of a superparamagnetic iron oxide (SPIO) core and gold nanorods (GNRs) in the mesoporous silica shells functionalized with folic acid (Fe3O4@SiO2@GNRs@mSiO2–FA). The as-synthesized five-component hybrid nanocomposite was revealed to have insignificant cytotoxicity. Intracellular uptake of the nanoparticles was studied in the folate receptor over-expressing human epidermoid carcinoma of the nasopharynx (KB) cells. Due to their magnetic/optical properties as well as the folate targeting potential, compared with Fe3O4@SiO2@GNRs@mSiO2 nanoparticles, higher cellular uptake efficiency was observed for Fe3O4@SiO2@GNRs@mSiO2–FA nanoparticles in KB cells. Characterizations were achieved using both dark field and magnetic resonance (MR) imaging techniques. The hyperthermia induced by Fe3O4@SiO2@GNRs@mSiO2–FA nanoparticles resulted in a higher cytotoxicity in KB cells. Thus, the Fe3O4@SiO2@GNRs@mSiO2–FA hybrid nanomaterial is an effective and promising MR imaging and photothermal therapy agent for folate-receptor over-expressing cancer cells.

Type III-B first generation [3]rotaxane and second generation [4]rotaxane dendrimers have been synthesized via (1) a modified copper-catalyzed alkyne–azide cycloaddition (CuAAC), (2) Glaser–Hay's acetylenic oxidative homo-coupling, and (3) amide formation. The dendron does not reveal obvious cytotoxicities in L929 fibroblast cells. The rotaxane dendrimers can capture ammonia and are switchable both in solution and on surfaces.

Ternary composite nanomaterials based on deferoxamine-coated superparamagnetic iron oxide nanoparticles (8–10 nm), circular plasmid DNA (∼4 kb) with fluorescent/luminescent reporter group, and branched polyethylenimine (25 kDa, PDI = 2.5) were prepared and compared in terms of their efficiencies in transfecting brain tumor cells at low concentration.

Core@shell nanoparticles with superparamagnetic iron oxide core, mesoporous silica shell, and crown ether periphery were fabricated toward drug delivery and tumor cell imaging. By the concept of nanovalve based on supramolecular gatekeeper, stimuli-responsive drug delivery nanosystems Fe3O4@SiO2@meso-SiO2@crown ethers were synthesized by (i) modified solvothermal reaction; (ii) sol–gel reaction; and (iii) amide coupling reaction. The successful coupling of the dibenzo-crown ethers onto the mesoporous silica shell was confirmed by thermogravimetric analysis and Infrared spectroscopy. In this system, the “ON/OFF” switching of the gatekeeper supramolecules can be controlled by pH-sensitive intramolecular hydrogen bonding or electrostatic interaction (such as metal chelating). Biological evaluation of the nanoparticles renders them noncytotoxic and can be uptaken by L929 cells. In this work, the antitumor drug (doxorubicin) loading and release profiles which were studied by the UV/visible absorption spectroscopy. The mechanism involves the best-fit binding of crown ethers with cesium or sodium ions at different pH values with ultrasonic wave in phosphate buffered saline (PBS). Magnetic resonance imaging analysis of the particles reveals a high relaxivity, rendering them potentially useful theranostic agents.Keywords: crown ether; drug carrier; magnetic resonance imaging; nanoparticle; ultrasound;

This critical review provides an overview of current research activities that focused on the synthesis and application of multi-functional gold and iron oxide (Au–FexOy) hybrid nanoparticles and nanocomposites. An introduction of synthetic strategies that have been developed for generating Au–FexOy nanocomposites with different nanostructures is presented. Surface functionalisation and bioconjugation of these hybrid nanoparticles and nanocomposites are also reviewed. A variety of applications such as theranostics, gene delivery, biosensing, cell sorting, bio-separation, and catalysis is discussed and highlighted. Finally, future trends and perspectives of these sophisticated nanocomposites are outlined. Underpinning the fundamental requirements for effectively forming Au–FexOy hybrid nanocomposite materials would shed light on future development of nanotheranostics, nanomedicines, and chemical technologies. It would be interesting to investigate such multi-component composite nanomaterials with different novel morphologies in the near future to advance chemistry, biology, medicine, and engineering multi-disciplinary research (120 references).

Novel high magnetization microspheres with porous γ-Fe2O3 core and porous SiO2 shell were synthesized using a templating method, whereas the size of the magnetic core and the thickness of the porous shell can be controlled by tuning the experimental parameters. By way of an example, as-prepared γ-Fe2O3@meso-SiO2 microspheres (170 nm) display excellent water-dispersity and show photonic characteristics under externally applied a magnetic field. The magnetic property of the γ-Fe2O3 porous core enables the microspheres to be used as a contrast agent in magnetic resonance imaging with a high r2 (76.5 s–1 mM–1 Fe) relaxivity. The biocompatible composites possess a large BET surface area (222.3 m2/g), demonstrating that they can be used as a bifunctional agent for both MRI and drug carrier. Because of the high substrate loading of the magnetic, dual-porous materials, only a low dosage of the substrate will be acquired for potential practical applications. Hydrophobic zinc(II) phthalocyanine (ZnPC) photosensitizing molecules have been encapsulated into the dual-porous microspheres to form γ-Fe2O3@meso-SiO2–ZnPC microspheres. Biosafety, cellular uptake in HT29 cells, and in vitro MRI of these nanoparticles have been demonstrated. Photocytotoxicity (λ > 610 nm) of the HT29 cells uptaken with γ-Fe2O3@meso-SiO2–ZnPC microspheres has been demonstrated for 20 min illumination.Keywords: drug carrier; magnetic resonance imaging; nanoparticle; photocytotoxicity; porosity;

•HepG2 transfection efficacies are studied with MRI, fluorescence and luminescence.•Sensing in receptor-mediated endocytosis depends on functional groups of composites.•Magnetofection enhances uptake efficacy with at most two orders of magnitude.•Cell viabilities of HepG2 and MDCK vary from 70 to 90% with different composites.This paper describes comparative studies and protocols in (1) self-assembling of ultrasmall superparamagnetic iron oxide nanoparticle (NP), circular plasmid DNA, and branched polyethylenimine (PEI) composites; (2) magnetofection; (3) gene delivery, (4) magnetic resonance imaging (MRI), and (5) cytotoxicity of the composites toward hepatocellular carcinoma HepG2 cells.

A facile method was developed to synthesize Fe3O4/polydopamine (PDA) dual shelled microspheres with a hollow interior. Since the final product was obtained by in situ polymerization of dopamine (DA) on the surface of a hollow Fe3O4 spherical template, the average size of the hybrid microspheres was tunable by manipulating both the Fe3O4 size and the PDA shell thickness. Due to the hollow interior and the compatible surface, the Fe3O4/PDA demonstrated excellent adsorption performance for Eu(III) ion removal (151.05 mg g−1) in aqueous solution. In comparison to pristine Fe3O4 hollow spheres, the dual shelled particles exhibited a faster adsorption dynamic process and a higher adsorption capacity for Eu(III) entrapment. Simultaneously, the Fe3O4/polydopamine (PDA) also exhibits a higher adsorption capacity for Eu(III) entrapment compared with that of other magnetic materials. This method was also effective for synthesizing other kinds of PDA shell encapsulated core/shell nanoparticles.

Type III-B first generation [3]rotaxane and second generation [4]rotaxane dendrimers have been synthesized via (1) a modified copper-catalyzed alkyne–azide cycloaddition (CuAAC), (2) Glaser–Hay's acetylenic oxidative homo-coupling, and (3) amide formation. The dendron does not reveal obvious cytotoxicities in L929 fibroblast cells. The rotaxane dendrimers can capture ammonia and are switchable both in solution and on surfaces.

In this paper, we investigated the functional imaging and targeted therapeutic properties of core@multi-shell nanoparticles composed of a superparamagnetic iron oxide (SPIO) core and gold nanorods (GNRs) in the mesoporous silica shells functionalized with folic acid (Fe3O4@SiO2@GNRs@mSiO2–FA). The as-synthesized five-component hybrid nanocomposite was revealed to have insignificant cytotoxicity. Intracellular uptake of the nanoparticles was studied in the folate receptor over-expressing human epidermoid carcinoma of the nasopharynx (KB) cells. Due to their magnetic/optical properties as well as the folate targeting potential, compared with Fe3O4@SiO2@GNRs@mSiO2 nanoparticles, higher cellular uptake efficiency was observed for Fe3O4@SiO2@GNRs@mSiO2–FA nanoparticles in KB cells. Characterizations were achieved using both dark field and magnetic resonance (MR) imaging techniques. The hyperthermia induced by Fe3O4@SiO2@GNRs@mSiO2–FA nanoparticles resulted in a higher cytotoxicity in KB cells. Thus, the Fe3O4@SiO2@GNRs@mSiO2–FA hybrid nanomaterial is an effective and promising MR imaging and photothermal therapy agent for folate-receptor over-expressing cancer cells.

This critical review provides an overview of current research activities that focused on the synthesis and application of multi-functional gold and iron oxide (Au–FexOy) hybrid nanoparticles and nanocomposites. An introduction of synthetic strategies that have been developed for generating Au–FexOy nanocomposites with different nanostructures is presented. Surface functionalisation and bioconjugation of these hybrid nanoparticles and nanocomposites are also reviewed. A variety of applications such as theranostics, gene delivery, biosensing, cell sorting, bio-separation, and catalysis is discussed and highlighted. Finally, future trends and perspectives of these sophisticated nanocomposites are outlined. Underpinning the fundamental requirements for effectively forming Au–FexOy hybrid nanocomposite materials would shed light on future development of nanotheranostics, nanomedicines, and chemical technologies. It would be interesting to investigate such multi-component composite nanomaterials with different novel morphologies in the near future to advance chemistry, biology, medicine, and engineering multi-disciplinary research (120 references).

Ternary composite nanomaterials based on deferoxamine-coated superparamagnetic iron oxide nanoparticles (8–10 nm), circular plasmid DNA (∼4 kb) with fluorescent/luminescent reporter group, and branched polyethylenimine (25 kDa, PDI = 2.5) were prepared and compared in terms of their efficiencies in transfecting brain tumor cells at low concentration.