Thermoresponsive polymer gated and superparamagnetic nanoparticle embedded hollow mesoporous silica nanoparticles as smart multifunctional nanocarrier for targeted and controlled delivery of doxorubicin

The design and development of drug-delivery nanocarriers with high loading capacity, excellent biocompatibility, targeting ability and controllability have been the ultimate goal of the biomedical research community. In this work, we have reported the synthesis and characterization of novel and smart thermoresponsive polymer coated and Fe₃O₄ embedded hollow mesoporous silica (HmSiO₂) based multifunctional superparamagnetic nanocarriers for the delivery of doxorubicin (Dox) for cancer treatment. P(NIPAM-MAm) coated and Fe₃O₄ nanoparticle (NP) embedded hollow mesoporous silica nanocomposite (HmSiO₂-F-P(NIPAM-MAm)) was prepared by the in situ polymerization of NIPAM and MAm monomers on the surface of hollow mesoporous silica NPs (HmSiO₂) in the presence of Fe₃O₄ NPs, oxidizer and crosslinker. TEM analysis showed nearly spherical morphology of HmSiO₂-F-P(NIPAM-MAm) nanocarrier with a diameter in the range of 100-300 nm. The coating of P(NIPAM-MAm) layer and embedding of Fe₃O₄ NPs on the surface of the HmSiO₂ NPs was revealed by HRTEM analysis. XRD and FTIR analysis also confirmed the presence of P(NIPAM-MAm) shells and Fe₃O₄ NPs on hollow mesoporous silica NPs. VSM analysis suggested the superparamagnetic nature of HmSiO₂-F-P(NIPAM-MAm) nanocarrier. DSC analysis of HmSiO₂-F-P(NIPAM-MAm) nanocarrier showed a phase transition at the temperature of ∼38 °C. The prepared HmSiO₂-F-P(NIPAM-MAm) nanocarrier was investigated for its suitability for drug-delivery application using doxorubicin as the model drug by an in vitro method. The encapsulation efficiency and encapsulation capacity were found to be 95% and 6.8%, respectively. HmSiO₂-F-P(NIPAM-MAm)-Dox has shown a pH and temperature-dependent Dox release profile. A relatively faster release of Dox from the nanocarrier was observed at temperature above the lower critical solution temperature (LCST) than below the LCST. HmSiO₂-F-P(NIPAM-MAm) nanocarrier was found to be biocompatible in nature. In vitro cytotoxicity studies against Hela cells suggested that the HmSiO₂-F-P(NIPAM-MAm)-Dox nanocomposite nanocarrier has good anticancer activity. In vitro cellular uptake study of HmSiO₂-F-P(NIPAM-MAm)-Dox nanocomposite nanocarrier demonstrated its good internalisation ability into Hela cells. Thus, the prepared nanocomposites show potential as nanocarrier for targeted and controlled drug delivery for cancer treatment.

A magnetically separable and recyclable g-C3N4/Fe3O4/porous ruthenium nanocatalyst for the photocatalytic degradation of water-soluble aromatic amines and azo dyes

Herein, we present the development of a visible-light-driven magnetically retrievable nanophotocatalyst made of porous ruthenium nanoparticles supported on magnetic carbon nitride (g-C3N4/Fe3O4/p-RuNP) for the facile removal/degradation of aromatic amines and azo dyes from wastewater. Aromatic amines and azo-based dyes in water bodies are highly toxic and carcinogenic even at very low concentrations and are difficult to separate because of their high solubility. Our nanocatalyst can efficiently degrade/decompose the aromatic amines and azo dyes under visible light (LED/sunlight) at room temperature and in a wide pH range (pH 5.0-9.0) without using any external chemicals. The magnetic property of the nanocatalyst facilitates its efficient and facile separation from the reaction mixture for reuse in multiple photocatalytic cycles. The nanocatalyst-based degradation of azo dyes and aromatic amines presented here is simple and convenient in terms of efficiency, energy, reusability and cost. The process also does not require any external chemicals and forms gaseous/less harmful end products.

Recent insights in magnetic hyperthermia: From the "hot-spot" effect for local delivery to combined magneto-photo-thermia using magneto-plasmonic hybrids

Magnetic hyperthermia which exploits the heat generated by magnetic nanoparticles (MNPs) when exposed to an alternative magnetic field (AMF) is now in clinical trials for the treatment of cancers. However, this thermal therapy requires a high amount of MNPs in the tumor to be efficient. On the contrary the hot spot local effect refers to the use of specific temperature profile at the vicinity of nanoparticles for heating with minor to no long-range effect. This magneto-thermal effect can be exploited as a relevant external stimulus to temporally and spatially trigger drug release. In this review, we focus on recent advances in magnetic hyperthermia. Indirect experimental proofs of the local temperature increase are first discussed leading to a good estimation of the temperature at the surface (from 0.5 to 6 nm) of superparamagnetic NPs. Then we highlight recent studies illustrating the hot-spot effect for drug-release. Finally, we present another recent strategy to enhance the efficacity of thermal treatment by combining photothermal therapy with magnetic hyperthermia mediated by magneto-plasmonic nanoplatforms.

Iron Oxide and Gold Based Magneto-Plasmonic Nanostructures for Medical Applications: A Review

Iron oxide and gold-based magneto-plasmonic nanostructures exhibit remarkable optical and superparamagnetic properties originating from their two different components. As a consequence, they have improved and broadened the application potential of nanomaterials in medicine. They can be used as multifunctional nanoprobes for magneto-plasmonic heating as well as for magnetic and optical imaging. They can also be used for magnetically assisted optical biosensing, to detect extreme traces of targeted bioanalytes. This review introduces the previous work on magneto-plasmonic hetero-nanostructures including: (i) their synthesis from simple “one-step” to complex “multi-step” routes, including seed-mediated and non-seed-mediated methods; and (ii) the characterization of their multifunctional features, with a special emphasis on the relationships between their synthesis conditions, their structures and their properties. It also focuses on the most important progress made with regard to their use in nanomedicine, keeping in mind the same aim, the correlation between their morphology—namely spherical and non-spherical, core-satellite and core-shell, and the desired applications.

Folate-receptor-targeted NIR-sensitive polydopamine nanoparticles for chemo-photothermal cancer therapy

We propose the use of folate-receptor-targeted, near-infrared-sensitive polydopamine nanoparticles (NPs) for chemo-photothermal cancer therapy as an enhanced type of drug-delivery system which can be synthesized by in situ polymerization and conjugation with folic acid. The NPs consist of a Fe₃O₄/Au core, coated polydopamine, conjugated folic acid, and loaded anti-cancer drug (doxorubicin). The proposed multifunctional NPs show many advantages for therapeutic applications such as good biocompatibility and easy bioconjugation. The polydopamine coating of the NPs show a higher photothermal effect and thus more effective cancer killing compared to Fe₃O₄/Au nanoparticles at the same intensity as near-infrared laser irradiation. In addition, the conjugation of folic acid was shown to enhance cancer cellular uptake efficiency via the folate receptor and thus improve chemotherapeutic efficiency. Through in vitro cancer cell treatment testing, the proposed multifunctional NPs showed advanced photothermal and chemotherapeutic performance. Based on these enhanced anti-cancer properties, we expect that the proposed multifunctional NPs can be used as a drug-delivery system in cancer therapy.

Fe3O4@Au@mSiO2 as an enhancing nanoplatform for Rose Bengal photodynamic activity

A novel nanoplatform composed of three types of materials with different functionalities, specifically core-shell Fe₃O₄@Au nanoparticles encapsulated near the outer surface of mesoporous silica (mSiO₂) nanoparticles, has been successfully synthesised and used to enhance the efficiency of a photosensitiser, namely Rose Bengal, in singlet oxygen generation. Fe₃O₄ is responsible for the unusual location of the Fe₃O₄@Au nanoparticle, while the plasmonic shell acts as an optical antenna. In addition, the mesoporous silica matrix firmly encapsulates Rose Bengal by chemical bonding inside the pores, thus guaranteeing its photostability, and in turn making the nanosystem biocompatible. Moreover, the silica surface of the nanoplatform ensures further functionalisation on demand.

Investigation on a smart nanocarrier with a mesoporous magnetic core and thermo-responsive shell for co-delivery of doxorubicin and curcumin: a new approach towards combination therapy of cancer

A novel and smart MIO-P(NIPAM-MAm) nanocomposite has been prepared for combinational delivery of Dox and Cur for cancer treatment.

One-step synthesis of poly(ethyleneglycol dimethacrylate)-microspheres-supported nano-Au catalyst in methanol–water solution under γ-ray radiation

Highly-crosslinked poly(ethyleneglycol dimethacrylate) (PEGDMA) microspheres supported nano-Au catalyst (PEGDMA@AuNP) was first prepared through a one-step synthesis method, taking advantage of the γ-ray radiation effect on a simple one-pot system.

Preparation and characterization of magnetic nanocomposite catalysts with double Au nanoparticle layers

Nanocomposite catalysts, with single and double gold layers, and with one gold layer and one silver layer were prepared through simple steps, and showed excellent activity in the reduction of nitrophenols.

Facile synthesis of high dispersion γ-Fe2O3–Au nanoparticles within mesoporous silica spheres

γ-Fe₂O₃–Au@m-SiO₂ composite were successfully prepared by a facile one-pot method, which showed good magnetic property, high nanoparticles dispersion, uniform mesopore size, high surface area and big pore volume.

Synthesis, structure and magnetic properties of graphite carbon encapsulated Fe3C nanoparticles for applications as adsorbents

This paper reports the synthesis of graphite carbon encapsulated Fe₃C nanoparticles (Fe₃C/GC NPs).

In situ loading of gold nanoparticles on Fe3O4@SiO2 magnetic nanocomposites and their high catalytic activity

In this work, a facile approach was successfully developed for in situ catalyzing Au nanoparticles loaded on Fe3O4@SiO2 magnetic nanospheres via Sn(2+) linkage and reduction. After the Fe3O4@SiO2 MNPs were first prepared via a sol-gel process, only one step was needed to synthesize the Fe3O4@SiO2-Au magnetic nanocomposites (Fe3O4@SiO2-Au MNCs), so that both the synthesis step and the reaction cost were remarkably decreased. Significantly, the as-synthesized Fe3O4@SiO2-Au MNCs showed high performance in the catalytic reduction of 4-nitrophenol to 4-aminophenol and could be reused for several cycles with convenient magnetic separability. This approach provided a useful platform based on Fe3O4@SiO2 MNPs for the fabrication of Au or other noble metal magnetic nanocatalysts, which would be very useful in various catalytic reductions.

Magnetically recyclable nanocatalysts (MRNCs): a versatile integration of high catalytic activity and facile recovery

Recent advances in wet chemical synthesis of magnetically recyclable nanocatalysts (MRNCs), a versatile integration of high catalytic activity and facile recovery, have led to a dramatic expansion of their potential applications. This review focuses on the recent work in the development of metal and metal oxide based MRNCs for catalytic conversion of organic compounds in solution phase. This will be discussed in detail, according to the two main synthesis methods of MRNCs as classified by us. The two methods are: template-assisted synthetic strategy and direct synthetic strategy. And the template-assisted synthesis is further divided into three subcategories, synthetic strategies assisted by hard-, soft-, and mixed hard-soft coupling layers. At the end, we outline future trends and perspectives in these research areas.