Mesoporous silica-magnetite nanocomposite synthesized by using a neutral surfactant

Folate receptor-mediated delivery of 1-MDT-loaded mesoporous silica magnetic nanoparticles to target breast cancer cells

Aims: The efficiency of mesoporous silica magnetic nanoparticles (MSMNP) as a targeted drug-delivery system was investigated. Methods: The superparamagnetic iron oxide nanoparticles (NP) were synthesized, coated with mesoporous silica and conjugated with polyethylene glycol and methotrexate. Next, 1-methyl-D-tryptophan was loaded into the prepared nanosystems (NS). They were characterized using transmission electron microscopy, scanning electron microscopy, dynamic light scattering, vibrating sample magnetometer, x-ray powder diffraction, Fourier transform-infrared spectroscopy and the Brunauer-Emmett-Teller method and their biological impacts on breast cancer cells were evaluated. Results: The prepared NSs displayed suitable properties and showed enhanced internalization by folate-receptor-expressing cells, exerting efficient cytotoxicity, which was further enhanced by the near-infrared radiation irradiation. Conclusion: On the basis of our findings, the engineered NS is a promising multifunctional nanomedicine/theranostic for solid tumors.

Nano-Neurotheranostics: Impact of Nanoparticles on Neural Dysfunctions and Strategies to Reduce Toxicity for Improved Efficacy

Nanotheranostics is one of the emerging research areas in the field of nanobiotechnology offering exciting promises for diagnosis, bio-separation, imaging mechanisms, hyperthermia, phototherapy, chemotherapy, drug delivery, gene delivery, among other uses. The major criteria for any nanotheranostic-materials is 1) to interact with proteins and cells without meddling with their basic activities, 2) to maintain their physical properties after surface modifications and 3) must be nontoxic. One of the challenging targets for nanotheranostics is the nervous system with major hindrances from the neurovascular units, the functional units of blood-brain barrier. As blood-brain barrier is crucial for protecting the CNS from toxins and metabolic fluctuations, most of the synthetic nanomaterials cannot pass through this barrier making it difficult for diagnosing or targeting the cells. Biodegradable nanoparticles show a promising role in this aspect. Certain neural pathologies have compromised barrier creating a path for most of the nanoparticles to enter into the cells. However, such carriers may pose a risk of side effects to non-neural tissues and their toxicity needs to be elucidated at preclinical levels. This article reviews about the different types of nanotheranostic strategies applied in nervous dysfunctions. Further, the side effects of these carriers are reviewed and appropriate methods to test the toxicity of such nano-carriers are suggested to improve the effectiveness of nano-carrier based diagnosis and treatments.

Integrating Nanotherapeutic Platforms to Image Guided Approaches for Management of Cancer

Cancer is a leading cause of mortality worldwide, accounting for 8.8 million deaths in 2015. The landscape of cancer therapeutics is rapidly advancing with development of new and sophisticated approaches to diagnostic testing. Treatment plan for early diagnosed patients include radiation therapy, tumor ablation, surgery, immunotherapy and chemotherapy. However the treatment can only be initiated when the cancer has been diagnosed thoroughly. Theranostics is a term that combines diagnostics with therapeutics. It embraces multiple techniques to arrive at comprehensive diagnosis, molecular images and an individualized treatment regimen. Recently, there is an effort to tangle the emerging approach with nanotechnologies, in an attempt to develop theranostic nanoplatforms and methodologies. Theranostic approach to management of cancer offers numerous advantages. They are designed to monitor cancer treatment in real time. A wide variety of theranostic nanoplatforms that are based on diverse nanostructures like magnetic nanoparticles, carbon nanotubes, gold nanomaterials, polymeric nanoparticles and silica nanoparticles showed great potential as cancer theranostics. Nano therapeutic platforms have been successful in integrating image guidance with targeted approach to treat cancer.

Sonochemical synthesis of Fe3O4@NH2-mesoporous silica@Polypyrrole/Pd: A core/double shell nanocomposite for catalytic applications

There is a growing interest in sonochemistry for either the controlled design of nanostructured materials or for the synthesis of polymers and polymer composites. It is fast and highly efficient method that provides materials with exceptional and enhanced structural and chemical properties. Herein, we take advantage of the versatile sonochemical process in order to design core/double layered shell nanocomposite denoted by Fe₃O₄@NH₂-mesoporous silica@ PPy/Pd. This magnetic, multicomponent material was designed in a three-step sono-process: (i) synthesis of magnetic core, (ii) cure of mesoporous silica, and (iii) sonochemical deposition of PPy/Pd. This last step was achieved within 1 h, a much shorter duration compared to conventional routes which usually take several hours to few days. The final nanocomposite can be recovered with a simple magnetic stick. X-ray diffraction patterns highlighted the presence of zerovalent palladium on the surface of the magnetic nanocomposite. The catalytic activity of the solid support was investigated by the study of the p-nitrophenol (p-NP) reduction and the Methyl Orange (MO) degradation in aqueous media. Results showed a very high catalytic efficiency, a high conversion yield of p-NP into 4-aminophenol (more than 94%) and an almost entire degradation of MO (99%) with a fast kinetics fitting to the first order model. This work demonstrates conclusively the benefits of sonochemistry in the design of metal nanoparticle-decorated inorganic/polymer hybrid system with outstanding performances.

Biodegradable Magnetic Silica@Iron Oxide Nanovectors with Ultra-Large Mesopores for High Protein Loading, Magnetothermal Release, and Delivery

The delivery of large cargos of diameter above 15nm for biomedical applications has proved challenging since it requires biocompatible, stably-loaded, and biodegradable nanomaterials. In this study, we describe the design of biodegradable silica-iron oxide hybrid nanovectors with large mesopores for large protein delivery in cancer cells. The mesopores of the nanomaterials spanned from 20 to 60nm in diameter and post-functionalization allowed the electrostatic immobilization of large proteins (e.g. mTFP-Ferritin, ~534kDa). Half of the content of the nanovectors was based with iron oxide nanophases which allowed the rapid biodegradation of the carrier in fetal bovine serum and a magnetic responsiveness. The nanovectors released large protein cargos in aqueous solution under acidic pH or magnetic stimuli. The delivery of large proteins was then autonomously achieved in cancer cells via the silica-iron oxide nanovectors, which is thus a promising for biomedical applications.

Nanotechnology in dermatology

The scientific community and general public have been exposed to a series of achievements attributed to a new area of knowledge: Nanotechnology. Both abroad and in Brazil, funding agencies have launched programs aimed at encouraging this type of research. Indeed, for many who come into contact with this subject it will be clear the key role that chemical knowledge will play in the evolution of this subject. And even more, will see that it is a science in which the basic structure is formed by distilling different areas of inter-and multidisciplinary knowledge along the lines of new paradigms. In this article, we attempt to clarify the foundations of nanotechnology, and demonstrate their contribution to new advances in dermatology as well as medicine in general. Nanotechnology is clearly the future.

Magnetic solid-phase extraction based on mesoporous silica-coated magnetic nanoparticles for analysis of oral antidiabetic drugs in human plasma

In the present work, magnetic nanoparticles embedded into mesoporous silica were prepared in two steps: first, magnetite was synthesized by oxidation-precipitation method, and next, the magnetic nanoparticles were coated with mesoporous silica by using nonionic block copolymer surfactants as structure-directing agents. The mesoporous SiO2-coated Fe3O4 samples were functionalized using octadecyltrimethoxysilane as silanizing agent. The pure and functionalized silica nanoparticles were physicochemically and morphologically characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N2 adsorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The resultant magnetic silica nanoparticles were applied as sorbents for magnetic solid-phase extraction (MSPE) of oral antidiabetic drugs in human plasma. Our results revealed that the magnetite nanoparticles were completely coated by well-ordered mesoporous silica with free pores and stable pore walls, and that the structural and magnetic properties of the Fe3O4 nanoparticles were preserved in the applied synthesis route. Indeed, the sorbent material was capable of extracting the antidiabetic drugs from human plasma, being useful for the sample preparation in biological matrices.

Magnetic nanocomposites with mesoporous structures: synthesis and applications

Magnetic nanocomposites with well-defined mesoporous structures, shapes, and tailored properties are of immense scientific and technological interest. This review article is devoted to the progress in the synthesis and applications of magnetic mesoporous materials. The first part briefly reviews various general methods developed for producing magnetic nanoparticles (NPs). The second presents and categorizes the synthesis of magnetic nanocomposites with mesoporous structures. These nanocomposites are broadly categorized into four types: monodisperse magnetic nanocrystals embedded in mesoporous nanospheres, microspheres encapsulating magnetic cores into perpendicularly aligned mesoporous shells, ordered mesoporous materials loaded with magnetic NPs inside the porous channels or cages, and rattle-type magnetic nanocomposites. The third section reviews the potential applications of the magnetic nanocomposites with mesoporous structures in the areas of heath care, catalysis, and environmental separation. The final section offers a summary and future perspectives on the state-of-the art in this area.

Multifunctional magnetoplasmonic nanoparticle assemblies for cancer therapy and diagnostics (theranostics)

In this work, we describe the preparation and biomedical functionalities of complex nanoparticle assemblies with magnetoplasmonic properties suitable for simultaneous cancer therapy and diagnostics (theranostics). Most commonly magnetoplasmonic nanostructures are made by careful adaptation of metal reduction protocols which is both tedious and restrictive. Here we apply the strategy of nanoscale assemblies to prepare such systems from individual building blocks. The prepared superstructures are based on magnetic Fe(3) O(4) nanoparticles encapsulated in silica shell representing the magnetic module. The cores are surrounded in a corona-like fashion by gold nanoparticles representing the plasmonic module. As additional functionality they were also coated by poly(ethyleneglycol) chains as a cloaking agent to extend the blood circulation time. The preparation is exceptionally simple and allows one to vary the contribution of each function. Both modules can carry drugs and, in this study, they were loaded with the potential anticancer drug curcumin. A comprehensive set of microscopy, spectroscopy and biochemical methods were applied to characterize both imaging and therapeutic function of the nanoparticle assemblies against leukemia HL-60 cells. High contrast magnetic resonance images and high apoptosis rates demonstrate the success of assembly approach for the preparation of magnetoplasmonic nanoparticles. This technology allows one to easily "dial in" the functionalities in the clinical setting for personalized theranostic regiments.

Crosslinking metal nanoparticles into the polymer backbone of hydrogels enables preparation of soft, magnetic field-driven actuators with muscle-like flexibility

The combination of force and flexibility is at the core of biomechanics and enables virtually all body movements in living organisms. In sharp contrast, presently used machines are based on rigid, linear (cylinders) or circular (rotator in an electrical engine) geometries. As a potential bioinspired alternative, magnetic elastomers can be realized through dispersion of micro- or nanoparticles in polymer matrices and have attracted significant interest as soft actuators in artificial organs, implants, and devices for controlled drug delivery. At present, magnetic particle loss and limited actuator strength have restricted the use of such materials to niche applications. We describe the direct incorporation of metal nanoparticles into the backbone of a hydrogel and application as an ultra-flexible, yet strong magnetic actuator. Covalent bonding of the particles prevents metal loss or leaching. Since metals have a far higher saturation magnetization and higher density than oxides, the resulting increased force/volume ratio afforded significantly stronger magnetic actuators with high mechanical stability, elasticity, and shape memory effect.

Study of mesoporous silica/magnetite systems in drug controlled release

Ordered mesoporous materials like SBA-15 have a network of channels and pores with well-defined size in the nanoscale range. This particular silica matrix pore architecture makes them suitable for hosting a broad variety of compounds in very promising materials in a range of applications, including drug release magnetic carriers. In this work, magnetic nanoparticles embedded into mesoporous silica were prepared in two steps: first, magnetite was synthesized by oxidation-precipitation method, and next, the magnetic nanoparticles were coated with mesoporous silica by using nonionic block copolymer surfactants as structure-directing agents. The materials were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), N(2) adsorption, and scanning electron microscopy (SEM). The influence of magnetic nanoparticles on drug release kinetics was studied with cisplatin, carboplatin, and atenolol under in vitro conditions in the absence and in the presence of an external magnetic field (0.25 T) by using NdFeB permanent magnet. The constant external magnetic field did not affect drug release significantly. The low-frequency alternating magnetic field had a large influence on the cisplatin release profile.