Multifunctional Core-shell Nanoparticles Research Articles

Multifunctional core-shell nanoparticles for temperature sensing and anti-counterfeiting

In this paper, the multi-functional multi-layer core-shell structure NaYF4: Ce3+/Eu3+@NaYF4 @NaYF4: Ho3+/Yb3+ nanoparticles (NPs) were prepared. These multi-layer NPs can be applied in temperature sensing with high relative sensitivity. Moreover, these NPs can be used in multimode optical anti-counterfeiting. Based on structure design and doped earth ions optimized, the maximum relative sensitivity is further promoted from 0.9 %·K−1 at 234 K (Eu/Ho) to 5.1 %·K−1 at 113 K (Ce/Eu@Y@Ho/Yb) by the blocking effect of the inter layer and by cross-relaxation of introducing Ce3+ and Yb3+ ions. Meanwhile, by introducing Ce3+ and Yb3+ ions, the NPs provide multimode emissions under multiple excitations, which are beneficial for the application of optical anti-counterfeiting. The NPs present increased sensitivity of temperature sensing and improved security of optical anti-counterfeiting, which has promising applications in biological cell calibration, micro-integrated circuits, etc.

Elaboration of Superparamagnetic and Bioactive Multicore–Shell Nanoparticles (γ-Fe2O3@SiO2-CaO): A Promising Material for Bone Cancer Treatment

The past few decades have seen the development of new bone cancer therapies, triggered by the discovery of new biomaterials. When the tumoral area is small and accessible, the common clinical treatment implies the tumor mass removal followed by bone reconstruction or consolidation with a bioceramic or a metallic scaffold. Even though the treatment also involves chemotherapy or radiotherapy, resurgence of cancer cells remains possible. We have thus designed a new kind of heterostructured nanobiomaterial, composed of SiO2-CaO bioactive glass as the shell and superparamagnetic γ-Fe2O3 iron oxide as the core in order to combine the benefits of bone repair thanks to the glass bioactivity and cancer cell destruction through magnetic hyperthermia. These multifunctional core-shell nanoparticles (NPs) have been obtained using a two-stage procedure, involving the coprecipitation of 11 nm sized iron oxide NPs followed by their encapsulation inside a bioactive glass shell by sol-gel chemistry. The as-produced spherical multicore-shell NPs show a narrow size distribution of 73 ± 7 nm. Magnetothermal loss measurements by calorimetry under an alternating magnetic field and in vitro bioactivity assessment performed in simulated body fluid showed that these heterostructures exhibit a good heating capacity and a fast mineralization process (hydroxyapatite forming ability). In addition, their in vitro cytocompatibility, evaluated in the presence of human mesenchymal stem cells during 3 and 7 days, has been demonstrated. These first findings suggest that γ-Fe2O3@SiO2-CaO heterostructures are a promising biomaterial to fill bone defects resulting from bone tumor resection, as they have the ability to both repair bone tissue and act as thermoseeds for cancer therapy.

Multifunctional Core-Shell Zwitterionic Nanoparticles To Build Robust, Stable Antifouling Membranes via Magnetic-Controlled Surface Segregation.

Novel multifunctional core-shell nanoparticles (Fe3O4@PSBMA NPs) with magnetic and zwitterionic properties were first synthesized and efficiently incorporated into the poly(vinylidene fluoride) (PVDF) membranes via magnetically controlled surface segregation toward the better water-energy-food nexus. The combination of zwitterionic polymers poly(sulfobetaine methacrylate) (PSBMA) and Fe3O4 particles can improve the compatibility of additives with the PVDF matrix and significantly improve the migration of Fe3O4@PSBMA NPs onto membrane surfaces under magnetic fields during nonsolvent-induced phase separations. The modified membrane with surface-enriched multifunctional zwitterionic NPs had an enhanced water flux (168%, ∼630.5 L m-2 h-1), excellent fouling resistance (∼93.8%), and increased rejection to bovine serum albumin (94.1%). Most importantly, the PVDF/M-Fe3O4@PSBMA membrane had excellent stability under the long-term filtration test for practical water-treatment applications.

Ag@Fe3O4@C nanoparticles for multi-modal imaging-guided chemo-photothermal synergistic targeting for cancer therapy

Novel multifunctional core-shell nanoparticles (NPs) have attracted widespread attention due to their easy-to-modify surface properties and abundant functional groups. This study introduces a facile approach to synthesize Ag@ iron oxide (Fe3O4) @C NPs, and modify with amino-poly (ethylene glycol) (PEG)-carboxyl and folate (FA) on the exposed carbon surface to produce high contrast for excellent stability, good biocompatibility, cancer cell targeting, and synergistic treatment. The multi-armed PEG at the edge of Ag@Fe3O4@C NPs provides the materials an excellent capacity for doxorubicin (DOX) loading. The carbon layer could be used as a photothermal reagent due to its excellent near-infrared (NIR) absorbance capacity, and Fe3O4 was used as a reagent for magnetic resonance (MR) imaging. In vivo combination therapy with this agent was administered in a mouse tumor model, and a remarkable synergistic antitumor effect that is superior to that obtained by monotherapy was achieved. Concerning these features together, these unique multifunctional Ag@Fe3O4@C-PEG-FA/DOX NPs could be regarded as an attractive nanoplatforms for chemo-photothermal synergistic tumor therapy with dual-modal fluorescence and MR imaging-guided targeting.

Magnetic Interaction of Multifunctional Core-Shell Nanoparticles for Highly Effective Theranostics.

The controlled size and surface treatment of magnetic nanoparticles (NPs) make one-stage combination feasible for enhanced magnetic resonance imaging (MRI) contrast and effective hyperthermia. However, superparamagnetic behavior, essential for avoiding the aggregation of magnetic NPs, substantially limits their performance. Here, a superparamagnetic core-shell structure is developed, which promotes the formation of vortex-like intraparticle magnetization structures in the remanent state, leading to reduced dipolar interactions between two neighboring NPs, while during an MRI scan, the presence of a DC magnetic field induces the formation of NP chains, introducing increased local inhomogeneous dipole fields that enhance relaxivity. The core-shell NPs also reveal an augmented anisotropy, due to exchange coupling to the high anisotropy core, which enhances the specific absorption rate. This in vivo tumor study reveals that the tumor cells can be clearly diagnosed during an MRI scan and the tumor size is substantially reduced through hyperthermia therapy by using the same FePt@iron oxide nanoparticles, realizing the concept of theranostics.

Preparation of Porous γ-Fe2O3@mWO3 Multifunctional Nanoparticles for Drug Loading and Controlled Release.

The use of chemotherapy drug is hindered by relatively low selectivity toward cancer cells and severe side effects from uptake by noncancerous cells and tissue. Thus, targeted drug delivery systems are preferred to increase the efficiency of drug delivery to specific tissues as well as to decrease its side effects. The aims of this paper are develop microwave-triggered controlled-release drug delivery systems using porous γ-Fe2O3@mWO3 multifunctional core-shell nanoparticles. We also studied its magnetic- microwave to heat responsive properties and large specific surface area. We chose ibuprofen (IBU) as a model drug to evaluate the loading and release function of the γ- Fe2O3@mWO3 nanoparticles. We used a direct precipitation method and thermal decomposition of CTAB template method to synthesize core-shell structured γ-Fe2O3@mWO3 nanoparticles. The specific surface areas were calculated by the Brunauer-Emmett-Teller (BET) method. The load drug and controlled release of the γ-Fe2O3@mWO3 triggered by microwave was determined with ultraviolet-visible spectroscopic analysis. The γ-Fe2O3@mWO3 nanoparticles possesses high surface area of 100.09 m2/g, provides large accessible pore diameter of 6.0 nm for adsorption of drug molecules, high magnetization saturation value of 43.6 emu/g for drug targeting under foreign magnetic fields, quickly convert electromagnetic energy into thermal energy for controlled release by microwave-triggered which was caused by mWO3 shell. The IBU release of over 78% under microwave discontinuous irradiation out classes the 0.15% within 20s only stirring release. This multifunctional material shows good performance for targeting delivery and mWO3 microwave controlled release of anticancer drugs based on all the properties they possess. The porous shell and the introduction of absorbing material not only increased the drug loading efficiency of the nanoparticles but also realized the microwave-stimulated anticancer drug controlled release. The nanoparticles would be very promising for microwave-induced controlled drug release, targeted drug delivery and hyperthermia therapy using microwave.

Rationally Designed CeNP@MnMoS4 Core‐Shell Nanoparticles for Modulating Multiple Facets of Alzheimer's Disease

Alzheimer's disease (AD) is a complicated multifactorial syndrome. Lessons have been learned through failed clinical trials that targeting multiple key pathways of the AD pathogenesis is necessary to halt the disease progression. Here, we construct core-shell nanoparticles (CeNP@MnMoS4 ) targeting multiple key pathways of the AD pathogenesis, including elimination of toxic metal ions, decrease of oxidative stress, and promotion of neurite outgrowth. The SOD activity and copper removal capacity of CeNP@MnMoS4 -n (n represents the number of layers of MnMoS4 , n=1-5) was investigated in vitro. We found that CeNP@MnMoS4 -3 made an excellent balance between SOD activity and copper removal capacity. The effect of CeNP@MnMoS4 -3 on Cu(2+) -induced Aβ aggregation was studied by gel electrophoresis, transmission electron microscope (TEM), and atomic force microscopy (AFM). Compared with MnMoS4 or CeNP alone, a synergistic effect was observed. Moreover, CeNP@MnMoS4 -3 promoted neurite outgrowth in a dose-dependent manner. Taken together, the results reported in this work show the potential of new multifunctional core-shell nanoparticles as AD therapeutics.

Poly(Acrylic Acid) Modification of Nd3+‐Sensitized Upconversion Nanophosphors for Highly Efficient UCL Imaging and pH‐Responsive Drug Delivery

In this work, a simple method is demonstrated for the synthesis of multifunctional core–shell nanoparticles NaYF4:Yb,Er@NaYF4:Yb@NaNdF4:Yb@NaYF4:Yb@PAA (labeled as Er@Y@Nd@Y@PAA or UCNP@PAA), which contain a highly effective 808‐nm‐to‐visible UCNP core and a thin shell of poly(acrylic acid) (PAA) to achieve upconversion bioimaging and pH‐sensitive anticancer chemotherapy simultaneously. The core–shell Nd3+‐sensitized UCNPs are optimized by varying the shell number, core size, and host lattices. The final optimized Er@Y@Nd@Y nanoparticle composition shows a significantly improved upconversion luminescence intensity, that is, 12.8 times higher than Er@Y@Nd nanoparticles. After coating the nanocomposites with a thin layer of PAA, the resulting UCNP@PAA nanocomposite perform well as a pH‐responsive nanocarrier and show clear advantages over UCNP@mSiO2, which are evidenced by in vitro/in vivo experiments. Histological analysis also reveals that no pathological changes or inflammatory responses occur in the heart, lungs, kidneys, liver, and spleen. In summary, this study presents a major step forward towards a new therapeutic and diagnostic treatment of tumors by using 808‐nm excited UCNPs to replace the traditional 980‐nm excitation.

Glycine-functionalized Fe3O4@TiO2:Er3+,Yb3+ nanocarrier for microwave-triggered controllable drug release and study on mechanism of loading/release process using microcalorimetry

Objectives: The current study aimed at developing microwave-triggered controlled-release drug delivery systems using glycine-modified Fe3O4@TiO2:Er3+,Yb3+ multifunctional core-shell nanoparticles. We also studied the drug loading and release mechanisms by means of microcalorimetry.Methods: We used hydrothermal method to prepare glycine-functionalized Fe3O4@TiO2:Er3+,Yb3+ multifunctional nanoparticles. The controlled release of the Fe3O4@TiO2:Er3+,Yb3+–glycine–VP16 triggered by microwave was determined with ultraviolet-visible spectroscopic analysis. We studied the cytotoxicity of the nanocarrier by MTT assay.Results: The thermodynamic parameter values (ΔH = -17.46 kJ mol−1, ΔS = −365.20 kJ mol−1) showed that the main interaction between the carrier and drug molecules is hydrogen bonding. The molar enthalpy (ΔH) of the drug-release process was 72.01 kJ mol−1, which indicates an endothermic process. This suggests that drug release can be controlled by microwave heating. The release profile can be controlled by the duration and number of cycles of microwave application. The particles also exhibit good magnetization and upconversion luminescence properties, which will allow simultaneous targeting and monitoring of the loaded drug.Conclusion: The modification of glycine and the introduction of absorbing material not only increased the load properties of the composite materials but also realized the microwave-stimulated anticancer drug controlled release.

19F MRI Probes with Tunable Switches and Highly Sensitive 19F MRI Nanoprobes

Abstract Magnetic resonance imaging (MRI) is an imaging modality adequate for in vivo studies. Therefore, many scientists are interested in the development of MRI probes capable of detecting enzyme activities in vivo. 19F MRI is useful for monitoring particular biosignals, cells, and target tissues, due to the absence of background signals in living organisms. Therefore, highly sensitive 19F MRI contrast agents are in great demand for their practical applications. However, we have faced the following challenges: (1) increasing the number of fluorine atoms decreases the solubility of the molecular probes, and (2) the restriction of the molecular mobility attenuates the 19F MRI signals. Herein, we developed novel multifunctional core–shell nanoparticles to solve these problems. They are composed of a core micelle filled with liquid perfluorocarbon and a robust silica shell. These core–shell nanoparticles have superior properties such as high sensitivity, surface-modifiability, biocompatibility, and sufficient in vivo stability. By the adequate surface modifications, gene expression in living cells and tumor tissue in living mice were successfully detected by 19F MRI.

Drug co-loading and pH-sensitive release core–shell nanoparticles via layer-by-layer assembly

Multifunctional core–shell nanoparticles are widely used for biomedical and catalytic applications. In this work, bilayers of chitosan (Cs) and phosphorylated polyvinyl alcohol (PPVA) were sequentially deposited on 3-Aminopropyltri-ethoxysilane-modified SiO2 nanoparticles via layer-by-layer electrostatic self-assembly. The good spherical shape and size distribution were observed by DLS and transmission electron microscope analysis. 7-Hydroxycoumarin (7-HC) and rhodamine B (RhB) as model drugs were loaded in the core and shell of the nanoparticles separately. Confocal laser scanning microscopy shows the core–shell structure of HC-SiO2(PPVA/Cs)n-RhB nanoparticles and the embedded location of 7-HC and RhB. The pH-sensitive release investigation of RhB indicates that the release profiles of RhB from HC-SiO2(PPVA/Cs)3PPVA-RhB core–shell nanoparticles are totally different at pH values of 2.0, 7.4, and 9.2. These results predict that the multifunctional nanoparticle SiO2(PPVA/Cs)n has a great potential for drug delivery.

SERS-Encoded Nanogapped Plasmonic Nanoparticles: Growth of Metallic Nanoshell by Templating Redox-Active Polymer Brushes

We report a new strategy to synthesize core-shell metal nanoparticles with an interior, Raman tag-encoded nanogap by taking advantage of nanoparticle-templated self-assembly of amphiphilic block copolymers and localized metal precursor reduction by redox-active polymer brushes. Of particular interest for surface-enhanced Raman scattering (SERS) is that the nanogap size can be tailored flexibly, with the sub-2 nm nanogap leading to the highest SERS enhancement. Our results have further demonstrated that surface functionalization of the nanogapped Au nanoparticles with aptamer targeting ligands allows for specific recognition and ultrasensitive detection of cancer cells. The general applicability of this new synthetic strategy, coupled with recent advances in controlled wet-chemical synthesis of functional nanocrystals, opens new avenues to multifunctional core-shell nanoparticles with integrated optical, electronic, and magnetic properties.

Multifunctional Core–Shell Silica Nanoparticles for Highly Sensitive 19F Magnetic Resonance Imaging

19F magnetic resonance imaging (19F MRI) is useful for monitoring particular signals from biological samples, cells, and target tissues, because background signals are missing in animal bodies. Therefore, highly sensitive 19F MRI contrast agents are in great demand for their practical applications. However, we have faced the following challenges: 1) increasing the number of fluorine atoms decreases the solubility of the molecular probes, and 2) the restriction of the molecular mobility attenuates the 19F MRI signals. Herein, we developed novel multifunctional core–shell nanoparticles to solve these issues. They are composed of a core micelle filled with liquid perfluorocarbon and a robust silica shell. These core–shell nanoparticles have superior properties such as high sensitivity, modifiability of the surface, biocompatibility, and sufficient in vivo stability. By the adequate surface modifications, gene expression in living cells and tumor tissue in living mice were successfully detected by 19F MRI.

Multifunctional Core–Shell Silica Nanoparticles for Highly Sensitive 19F Magnetic Resonance Imaging

Abstract19F magnetic resonance imaging (19F MRI) is useful for monitoring particular signals from biological samples, cells, and target tissues, because background signals are missing in animal bodies. Therefore, highly sensitive 19F MRI contrast agents are in great demand for their practical applications. However, we have faced the following challenges: 1) increasing the number of fluorine atoms decreases the solubility of the molecular probes, and 2) the restriction of the molecular mobility attenuates the 19F MRI signals. Herein, we developed novel multifunctional core–shell nanoparticles to solve these issues. They are composed of a core micelle filled with liquid perfluorocarbon and a robust silica shell. These core–shell nanoparticles have superior properties such as high sensitivity, modifiability of the surface, biocompatibility, and sufficient in vivo stability. By the adequate surface modifications, gene expression in living cells and tumor tissue in living mice were successfully detected by 19F MRI.

Synthesis of Fe3O4@Y2O3:Eu3+ core–shell multifunctional nanoparticles and their magnetic and luminescence properties

A simple wet chemical route has been employed to synthesize multifunctional core–shell nanoparticles of Fe3O4@Y2O3:Eu3+ showing an interesting combination of magnetic and luminescent properties having potential for medical applications. The core–shell nanoparticles were synthesized in a two-step process wherein first step, the Fe3O4 nanoparticles were synthesized and subsequently they are coated with Y2O3:Eu3+. XRD and magnetization curves were successfully used to retrieve the particle size of Fe3O4 nanoparticles. Particle size (∼10nm) extracted from XRD and magnetization curves have been found to be consistent with the measured size from AFM and TEM. Further, the XRD analysis reveals formation of pure cubic phases of magnetite as well as of Y2O3:Eu3+. It has been shown here that through simple chemistry it is possible to change the thickness of Y2O3:Eu3+ shell. From SEM and TEM studies, the size of core shell nanoparticles seen as ∼30nm. In addition to bright red (612nm) emission, these materials also show superparamagnetic behavior at room temperature. Emission intensity has been found to significantly increase with increase in annealing temperature. The synthesized materials have extensive for applications in the area of drug delivery and bio-imaging.

Multifunctional core-shell nanoparticles: discovery of previously invisible biomarkers.

Many low-abundance biomarkers for early detection of cancer and other diseases are invisible to mass spectrometry because they exist in body fluids in very low concentrations, are masked by high-abundance proteins such as albumin and immunoglobulins, and are very labile. To overcome these barriers, we created porous, buoyant, core–shell hydrogel nanoparticles containing novel high affinity reactive chemical baits for protein and peptide harvesting, concentration, and preservation in body fluids. Poly(N-isopropylacrylamide-co-acrylic acid) nanoparticles were functionalized with amino-containing dyes via zero-length cross-linking amidation reactions. Nanoparticles functionalized in the core with 17 different (12 chemically novel) molecular baits showed preferential high affinities (KD < 10–11 M) for specific low-abundance protein analytes. A poly(N-isopropylacrylamide-co-vinylsulfonic acid) shell was added to the core particles. This shell chemistry selectively prevented unwanted entry of all size peptides derived from albumin without hindering the penetration of non-albumin small proteins and peptides. Proteins and peptides entered the core to be captured with high affinity by baits immobilized in the core. Nanoparticles effectively protected interleukin-6 from enzymatic degradation in sweat and increased the effective detection sensitivity of human growth hormone in human urine using multiple reaction monitoring analysis. Used in whole blood as a one-step, in-solution preprocessing step, the nanoparticles greatly enriched the concentration of low-molecular weight proteins and peptides while excluding albumin and other proteins above 30 kDa; this achieved a 10,000-fold effective amplification of the analyte concentration, enabling mass spectrometry (MS) discovery of candidate biomarkers that were previously undetectable.

Plasmonic Properties of Polycrystalline Hollow Au Nanoparticles: A Surface Roughness Effect

Hollow Au nanoparticles with a 25 nm polycrystalline shell and a 50 nm hollow core were produced in large amounts by using electrochemically evolved hydrogen nanobubbles as templates and reducing agents for electroless deposition from a Na3Au(SO3)2 electrolyte. The surface roughness of these nanoparticles can be tuned by adding NaSO3 into the electrolyte. Different surface roughnesses can be readily obtained for sub-100 nm particles with the same size. As surface roughness increases, surface plasmon resonance (SPR) peaks shift to longer wavelengths. Particles with an 8 nm roughness have a SPR peak centered at 750 nm, which is particularly attractive for in vivo diagnostic and therapeutic applications. A three-dimensional finite difference time domain (FDTD) simulation confirms that the red-shifts of SPR peaks are mainly caused by their surface roughness, and the hollow nature of these particles plays only a minor role. This unique plasmonic property of hollow Au nanoparticles opens up the possibility to maintain the desirable optical properties after loading other substances into the hollow core to form multifunctional core-shell nanoparticles.

Multifunctional core–shell nanoparticles: superparamagnetic, mesoporous, and thermosensitive

Multifunctional core-shell composite nanoparticles (NPs) have been developed by the combination of three functionalities into one entity, which is composed of a single Fe3O4 NP as the magnetic core ...

One-pot synthesis and characterization of rhodamine derivative-loaded magnetic core–shell nanoparticles

A new method to produce elaborate nanostructure with magnetic and fluorescent properties in one entity is reported in this article. Magnetite (Fe3O4) coated with fluorescent silica (SiO2) shell was produced through the one-pot reaction, in which one reactor was utilized to realize the synthesis of superparamagnetic core of Fe3O4, the formation of SiO2 coating through the condensation and polymerization of tetraethylorthosilicate (TEOS), and the encapsulation of tetramethyl rhodamine isothiocyanate-dextran (TRITC-dextran) within silica shell. Transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, and X-ray diffraction (XRD) were carried out to investigate the core–shell structure. The magnetic core of the core–shell nanoparticles is 60 ± 10 nm in diameter. The thickness of the fluorescent SiO2 shell is estimated at 15 ± 5 nm. In addition, the fluorescent signal of the SiO2 shell has been detected by the laser confocal scanning microscopy (LCSM) with emission wavelength (λem) at 566 nm. In addition, the magnetic properties of TRITC-dextran loaded silica-coating iron oxide nanoparticles (Fe3O4@SiO2 NPs) were studied. The hysteresis loop of the core–shell NPs measured at room temperature shows that the saturation magnetization (Ms) is not reached even at the field of 70 kOe (7T). Meanwhile, the very low coercivity (Hc) and remanent magnetization (Mr) are 0.375 kOe and 6.6 emu/g, respectively, at room temperature. It indicates that the core–shell particles have the superparamagnetic properties. The measured blocking temperature (TB) of the TRITC-dextran loaded Fe3O4@SiO2 NPs is about 122.5 K. It is expected that the multifunctional core–shell nanoparticles can be used in bio-imaging.

Multifunctional core-shell polymeric nanoparticles for transdermal DNA delivery and epidermal Langerhans cells tracking

Skin is a highly immune-reactive tissue containing abundant antigen-presenting cells such as Langerhans cells (LCs), and thus is a favorable site for DNA immunization. This study developed a multifunctional core-shell nanoparticle system, which can be delivered transdermally into the epidermis via a gene gun, for use as a DNA carrier. The developed nanoparticles comprised a hydrophobic PLGA core and a positively-charged glycol chitosan (GC) shell. The core of the nanoparticles was used to load fluorescent quantum dots (QDs) for ultrasensitive detection of Langerhans cell migration following transdermal delivery, while a reporter gene was electrostatically adsorbed onto the GC shell layer of the nanoparticles. Results of fluorescence spectrophotometry, transmission electron microscopy, energy dispersive X-ray analysis, and X-ray diffraction measurement confirmed that the prepared nanoparticles had a core-shell structure with QDs in their core area. The surface charge of nanoparticles depended strongly on pH environment, enabling the intracellular release of the loaded DNA via a pH-mediated mechanism. Using a mouse model, this study demonstrated that bombardment of nanoparticles transfected DNA directly into LCs present in the epidermis; the transfected LCs then migrated and expressed the encoded gene products in the skin draining lymph nodes. These observation results suggest that the developed nanoparticle system is suitable for monitoring and fine-tuning important functional aspects of the immune system, in conjunction with the loaded fluorescence, and thus has potential for use in immunotherapy and vaccine development.