Facile synthesis of magnetic core-shell nanocomposites for MRI and CT bimodal imaging

Toxicity and magnetometry evaluation of the uptake of core-shell maghemite-silica nanoparticles by neuroblastoma cells

Nanoparticle uptake by cells is a key parameter in their performance in biomedical applications. However, the use of quantitative, non-destructive techniques to obtain the amount of nanoparticles internalized by cells is still uncommon. We have studied the cellular uptake and the toxicity of core-shell maghemite-silica magnetic nanoparticles (MNPs), with a core diameter of 9 nm and a shell thickness of 3 nm. The internalization of the nanoparticles by mouse neuroblastoma 2a cells was evaluated by sensitive and non-destructive Superconducting Quantum Interference Device (SQUID) magnetometry and corroborated by graphite furnace atomic absorption spectroscopy. We were thus able to study the toxicity of the nanoparticles for well-quantified MNP uptake in terms of nanoparticle density within the cell. No significant variation in cell viability or growth rate was detected for any tested exposure. Yet, an increase in both the amount of mitochondrial superoxide and in the lysosomal activity was detected for the highest concentration (100 μg ml-1) and incubation time (24 h), suggesting the onset of a disruption in ROS homeostasis, which may lead to an impairment in antioxidant responses. Our results validate SQUID magnetometry as a sensitive technique to quantify MNP uptake and demonstrate the non-toxic nature of these core-shell MNPs under our culture conditions.

Enhanced radiosensitivity and chemoradiation efficacy in nasopharyngeal carcinoma via a dual-targeted SPION@polymer hybrid nanosensitizer

Cisplatin-based nanoparticles show good potential in enhancing the effect of nasopharynx carcinoma (NPC) therapy but are still limited by their low radiation sensitization and poor tumor targeting ability. Herein, an ingenious design of multifunctional superparamagnetic iron oxide nanoparticle (SPION)@polymer hybrid nanosensitizer (SPHN) with enhanced radiosensitization and dual-targeting capability is described. SPHN have a core-shell structure, in which radiosensitizer superparamagnetic iron oxide particle (SPION) and cis-platinum (CDDP) are encapsulated in RGD-conjugated amphiphilic block copolymers. These unique structures endow SPHN with outstanding radiosensitization and tumor targeting abilities. When combined with X-rays, SPHN showed strong promotion of the apoptosis of CNE-1 cells in vitro. In addition, RNA-seq and KEGG enrichment analyses indicated that the PI3K-Akt and TNF signaling pathways were closely related to the molecular mechanism of SPHN in chemoradiotherapy. Furthermore, gene set enrichment analysis (GSEA) revealed that SPHN + X-rays treatment decreased translation initiation pathways and the cytoplasmic translation pathway. Through a combination of radiation and chemotherapy, SPHN can achieve remarkable inhibition of tumor growth in vivo, making this nanotechnology a general platform for the chemoradiation therapy of NPC in the future.

XFCT-MRI hybrid multimodal contrast agents for complementary imaging

Multimodal contrast agents in biomedical imaging enable the collection of more comprehensive diagnostic information. In the present work, we design hybrid ruthenium-decorated superparamagnetic iron oxide nanoparticles (NPs) as the contrast agents for both magnetic resonance imaging (MRI) and X-ray fluorescence computed tomography (XFCT). The NPs are synthesized via a one-pot polyol hot injection route, in diethylene glycol. In vivo preclinical studies demonstrate the possibility of correlative bioimaging with these contrast agents. The complementarity allows accurate localization, provided by the high contrast of the soft tissues in MRI combined with the elemental selectivity of XFCT, leading to NP detection with high specificity and resolution. We envision that this multimodal imaging could find future applications for early tumor diagnosis, improved long-term treatment monitoring, and enhanced radiotherapy planning.

Erythrocyte-Inspired Functional Materials for Biomedical Applications

Erythrocytes are the most abundant cells in the blood. As the results of long-term natural selection, their specific biconcave discoid morphology and cellular composition are responsible for gaining excellent biological performance. Inspired by the intrinsic features of erythrocytes, various artificial biomaterials emerge and find broad prospects in biomedical applications such as therapeutic delivery, bioimaging, and tissue engineering. Here, a comprehensive review from the fabrication to the applications of erythrocyte-inspired functional materials is given. After summarizing the biomaterials mimicking the biological functions of erythrocytes, the synthesis strategies of particles with erythrocyte-inspired morphologies are presented. The emphasis is on practical biomedical applications of these bioinspired functional materials. The perspectives for the future possibilities of the advanced erythrocyte-inspired biomaterials are also discussed. It is hoped that the summary of existing studies can inspire researchers to develop novel biomaterials; thus, accelerating the progress of these biomaterials toward clinical biomedical applications.

Multifunctional Magnetic Nanoagents for Bioimaging and Therapy

Multifunctional magnetic nanoagents (MMNs) have drawn increasing attention in cancer precision therapy, attributed to their good biocompatibility and the potential applications for multimodal imaging and multidisciplinary therapy. The noble metal or isotopes contained in MMNs could not only perform superparamagnetism, providing an outstanding magnetic targeting property for drug delivery, but also endow the MMNs with a magnetocaloric effect, photothermal performance, and radiotherapy sensitization, arriving at a multimode combination therapy for cancer. Also, the composite component can endow MMNs with various imaging performance, such as magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography (PET), and single-photon emission computed tomography (SPECT), thereby achieving accurate image-guided therapy for cancer. However, the joint function of MMNs is closely correlated with their functional nanocomponents and nanostructures. In this article, we will systematically discuss the design, synthesis, and structure optimization of MMNs, as well as their potential in multimodal diagnosis and therapy, scientifically providing an integrated diagnosis and treatment of nanomedicine for the future cancer therapy.

Bistratal Au@Bi2S3 nanobones for excellent NIR-triggered/multimodal imaging-guided synergistic therapy for liver cancer

To fabricate a highly biocompatible nanoplatform enabling synergistic therapy and real-time imaging, novel Au@Bi2S3 core shell nanobones (NBs) (Au@Bi2S3 NBs) with Au nanorods as cores were synthesized. The combination of Au nanorods with Bi2S3 film made the Au@Bi2S3 NBs exhibit ultrahigh photothermal (PT) conversion efficiency, remarkable photoacoustic (PA) imaging and high computed tomography (CT) performance; these Au@Bi2S3 NBs thus are a promising nanotheranostic agent for PT/PA/CT imaging. Subsequently, poly(N-vinylpyrrolidone)-modified Au@Bi2S3 NBs (Au@Bi2S3-PVP NBs) were successfully loaded with the anticancer drug doxorubicin (DOX), and a satisfactory pH sensitive release profile was achieved, thus revealing the great potential of Au@Bi2S3-PVP NBs in chemotherapy as a drug carrier to deliver DOX into cancer cells. Both in vitro and in vivo investigations demonstrated that the Au@Bi2S3-PVP NBs possessed multiple desired features for cancer therapy, including extremely low toxicity, good biocompatibility, high drug loading ability, precise tumor targeting and effective accumulation. Highly efficient ablation of the human liver cancer cell HepG2 was achieved through Au@Bi2S3-PVP NB-mediated photothermal therapy (PTT). As both a contrast enhancement probe and therapeutic agent, Au@Bi2S3-PVP NBs provided outstanding NIR-triggered multi-modal PT/PA/CT imaging-guided PTT and effectively inhibited the growth of HepG2 liver cancer cells via synergistic chemo/PT therapy.

GO/Bi2S3 Doped PVDF/TPU Nanofiber Membrane with Enhanced Photothermal Performance

Photothermal conversion materials have attracted wide attention due to their efficient utilization of light energy. In this study, a (GO)/Bi2S3-PVDF/TPU composite nanofiber membrane was systematically developed, comprising GO/Bi2S3 nanoparticles (NPs) as a photothermal conversion component and PVDF/TPU composite nanofibers as the substrate. The GO/Bi2S3 NPs were synthesized in a one-step way and the PVDF/TPU nanofibers were obtained from a uniformly mixed co-solution by electrospinning. GO nanoparticles with excellent solar harvesting endow the GO/Bi2S3-PVDF/TPU membrane with favorable photothermal conversion. In addition, the introduction of Bi2S3 NPs further enhances the broadband absorption and photothermal conversion properties of the GO/Bi2S3-PVDF/TPU composite membrane due to its perfect broadband absorption performance and coordination with GO. Finally, the results show that the GO/Bi2S3-PVDF/TPU composite membrane has the highest light absorption rate (about 95%) in the wavelength range of 400-2500 nm. In the 300 s irradiation process, the temperature changes in the GO/Bi2S3-PVDF/TPU composite membrane were the most significant and rapid, and the equilibrium temperature of the same irradiation time was 81 °C. Due to the presence of TPU, the mechanical strength of the composite film was enhanced, which is beneficial for its operational performance. Besides this, the morphology, composition, and thermal property of the membranes were evaluated by corresponding test methods.

Synthesis of gadolinium-based Bi2S3 nanoparticles as cancer theranostics for dual-modality computed tomography/magnetic resonance imaging-guided photothermal therapy

Development of a safe, efficient and inexpensive multifunctional nanoplatform using a facile approach for multimodal imaging and therapeutic functions becomes more and more practically relevant but challenging. In this work, we demonstrated a novel nanocomposites (Bi₂S₃-Gd) for computed tomography (CT)/magnetic resonance (MR) imaging-guided photothermal therapy (PTT) for cancer in vitro. It was achieved by modification of hydrophobic Bi₂S₃ with a smart amphiphilic gadolinium-chelated ligand. The as-prepared nanocomposites composed of low-cost Bi₂S₃ and gadolinium complexes, showed high stability, excellent biocompatibility and good photostability. It was observed that Bi₂S₃-Gd nanocomposites can efficiently convert the NIR light into heat, and then suppressed the growth of tumor cells under NIR laser irradiation. Apart from serving as an effective photothermal agent, the as-prepared nanomaterials could induce an efficient contrast enhancement for both CT and MR imaging at low concentrations of Bi and Gd, rendering more accurate diagnosis. This work suggests the potential of Bi₂S₃-Gd nanomaterials as a novel multifunctional nanoplatform for CT/MR imaging-guided PTT for cancer.

Modified core–shell magnetic mesoporous zirconia nanoparticles formed through a facile “outside-to-inside” way for CT/MRI dual-modal imaging and magnetic targeting cancer chemotherapy

Iron oxide based magnetic nanoparticles (MNPs) as typical theranostic nanoagents have been popularly used in various biomedical applications. Conventional core–shell MNPs are usually synthesized from inside to outside. This method has strict requirements on the interface properties of magnetic cores and the precursors of the coating shell. The shape and size of MNPs are significantly influenced by that of the pre-synthesized magnetic cores. Most core–shell MNPs have only single T2W MRI imaging ability. Herein, we propose a new synthetic strategy for core-mesoporous shell structural MNPs, where hollow mesoporous nanospheres which exhibit an intrinsic property for both CT imaging and drug loading were used as the shell and the magnetic cores were produced in the cavity of the shell. A new type of MNPs, Fe₃O₄@ZrO₂ nanoparticles (M-MZNs), were developed using this facile outside-to-inside way, where multiple Fe₃O₄ nanoparticles grew inside the cavity of the mesoporous hollow ZrO₂ nanospheres through chemical coprecipitation. The obtained MNPs not only exhibited superior magnetic properties and CT/MR imaging ability but also high drug loading capacity. In vitro experiment results revealed that M-MZNs-PEG loaded with doxorubicin (DOX) presented selective growth inhibition against cancer cells due to pH-sensitive DOX release and enhanced endocytosis by cancer cells under a magnetic field. Furthermore, the proposed MNPs exhibited CT/MRI dual modal imaging ability and effective physical targeting to tumor sites in vivo. More importantly, experiments of magnetic targeting chemotherapy on tumor bearing mice demonstrated that the nanocomposites significantly suppressed tumor growth without obvious pathological damage to major organs. Henceforth, this study provides a new strategy for CT/MRI dual-modal imaging guided and magnetic targeting cancer therapy.

Magnetic mesoporous zirconia nanoparticle was synthesized by producing multiple iron oxide cores inside the cavity of mesoporous ZrO₂ hollow nanospheres and was used for CT/MRI dual-modal imaging and magnetic targeting chemotherapy.

Dual-Responsive SPMA-Modified Polymer Photonic Crystals and Their Dynamic Display Patterns

Light and electrothermal responsive polymer photonic crystals (PCs) modified with 1'-acryloyl chloride-3',3'-dimethyl-6-nitro-spiro(2H-1-benzopyran-2,2'-indoline) (SPMA) are proposed, and their dynamic display patterns are achieved through the combination of the SPMA-modified PCs and a patterned graphite layer. These PCs exhibit fluorescence under UV light irradiation because of the isomerization of the SPMA, which is restricted in the shell of the polymer colloidal spheres. After a voltage is applied to the patterned graphite layer, the fluorescence of PCs in the specific area disappears, and dynamic display patterns are obtained. Under UV light irradiation, the PCs change from the "partial-fluorescence" state to the initial "fluorescence" state, and the patterns disappear. Using this technique, the PC pattern "M L N" on the glass substrate and PC patterns from "0" to "9" on the paper substrate are fabricated. Thus, these dual-responsive PCs have potential applications in information recording, anticounterfeiting, dynamic display, and photoelectric devices.

Multifunctional Porous Iron Oxide Nanoagents for MRI and Photothermal/Chemo Synergistic Therapy

Nanoagents of integrating multiple imaging and therapeutic modalities have attracted tremendous attention for biomedical applications. Herein, we synthesize porous hollow Fe₃O₄ as a theranostic agent for MRI and combined photothermal/chemo cancer therapy. The as-prepared porous iron oxide nanoagents allow for T₂-weighted MR imaging. Interestingly, we demonstrate that the porous structure endows the nanoagents an outstanding photothermal property for cancer cell killing, in comparison with other types of iron oxide nanomaterials. Under the exposure of an NIR laser, the heat produced by porous Fe₃O₄ can accelerate the release of the loaded drug (e.g., DOX) to enhance chemotherapeutic efficacy, promoting the ablation of cancer cells with synergistic photothermal/chemotherapy.

Synthesis, Functionalization, and Design of Magnetic Nanoparticles for Theranostic Applications

In order to translate nanotechnology into medical practice, magnetic nanoparticles (MNPs) have been presented as a class of non-invasive nanomaterials for numerous biomedical applications. In particular, MNPs have opened a door for simultaneous diagnosis and brisk treatment of diseases in the form of theranostic agents. This review highlights the recent advances in preparation and utilization of MNPs from the synthesis and functionalization steps to the final design consideration in evading the body immune system for therapeutic and diagnostic applications with addressing the most recent examples of the literature in each section. This study provides a conceptual framework of a wide range of synthetic routes classified mainly as wet chemistry, state-of-the-art microfluidic reactors, and biogenic routes, along with the most popular coating materials to stabilize resultant MNPs. Additionally, key aspects of prolonging the half-life of MNPs via overcoming the sequential biological barriers are covered through unraveling the biophysical interactions at the bio-nano interface and giving a set of criteria to efficiently modulate MNPs' physicochemical properties. Furthermore, concepts of passive and active targeting for successful cell internalization, by respectively exploiting the unique properties of cancers and novel targeting ligands are described in detail. Finally, this study extensively covers the recent developments in magnetic drug targeting and hyperthermia as therapeutic applications of MNPs. In addition, multi-modal imaging via fusion of magnetic resonance imaging, and also innovative magnetic particle imaging with other imaging techniques for early diagnosis of diseases are extensively provided.

Surface Functionalization of Iron Oxide Nanoparticles with Gallic Acid as Potential Antioxidant and Antimicrobial Agents

In this research, we report the size-controlled synthesis and surface-functionalization of magnetite with the natural antioxidant gallic acid (GA) as a ligand, using in situ and post-synthesis methods. GA functionalization provided narrow size distribution, with an average particle size of 5 and 8 nm for in situ synthesis of gallic acid functionalized magnetite IONP@GA1 and IONP@GA2, respectively, which are ultra-small particles as compared to unfunctionalized magnetite (IONP) and post functionalized magnetite IONP@GA3 with average size of 10 and 11 nm respectively. All the IONPs@GA samples were found hydrophilic with stable aggregation state. Prior to commencement of experimental lab work, PASS software was used to predict the biological activities of GA and it is found that experimental antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and antimicrobial studies using well diffusion method are in good agreement with the simulated results. Furthermore, the half maximal inhibitory concentration (IC50) values of DPPH antioxidant assay revealed a 2-4 fold decrease as compared to unfunctionalized IONP. In addition to antioxidant activity, all the three IONP@GA proved outstanding antimicrobial activity while testing on different bacterial and fungal strains. The results collectively indicate the successful fabrication of novel antioxidant, antimicrobial IONP@GA composite, which are magnetically separable, efficient, and low cost, with potential applications in polymers, cosmetics, and biomedical and food industries.

Clickable and imageable multiblock polymer micelles with magnetically guided and PEG-switched targeting and release property for precise tumor theranosis

Targeted delivery of therapeutics and diagnostics using nanotechnology holds great promise to minimize the side effects of conventional chemotherapy and enable specific and real-time detection of diseases. To realize this goal, we report a clickable and imageable nanovehicle assembled from multiblock polyurethanes (MPUs). The soft segments of the polymers are based on detachable poly(ethylene glycol) (PEG) and degradable poly(ε-caprolactone) (PCL), and the hard segments are constructed from lysine- and cystine-derivatives bearing reduction-responsive disulfide linkages and click-active alkynyl moieties, allowing for post-conjugation of targeting ligands via a click chemistry. It was found that the cleavage of PEG corona bearing a pH-sensitive benzoic-imine linkage (BPEG) could act as an on-off switch, which is capable of activating the clicked targeting ligands under extracellular acidic condition, followed by triggering the core degradation and payload release within tumor cells. In combination with superparamagnetic iron oxide nanoparticles (SPION) clustered within the micellar core, the MPUs exhibit excellent magnetic resonance imaging (MRI) contrast effects and T₂ relaxation in vitro, as well as magnetically guided MR imaging and multimodal targeting of therapeutics to tumor precisely, leading to significant inhibition of cancer with minimal side effect. This work provides a safe and versatile platform for the further development of smart theranostic systems for potential magnetically-targeted and imaging-guided personalized medicine.

Functional magnetic hybrid nanomaterials for biomedical diagnosis and treatment

Magnetic nanomaterials integrating supplemental functional materials are called magnetic hybrid nanomaterials (MHNs). Such MHNs have drawn increasing attention due to their biocompatibility and the potential applications either as alternative contrast enhancing agents or effective heat nanomediators in hyperthermia therapy. The joint function comes from the hybrid nanostructures. Hybrid nanostructures of different modification can be easily achieved owing to the large surface-area-to-volume ratio and sophisticated surface characteristic. In this focus article, we mainly discussed the design and synthesis of MHNs and their applications as multimodal imaging probes and therapy agents in biomedicine. These MHNs consisting magnetic nanomaterials with functional nanocomponents such as noble metal or isotopes could perform not only superparamagnetism but also features that can be adapted in, for example, enhancing computed tomography contrast modalities, positron emission tomography, and single-photon emission computed tomography. The combination of several techniques provides more comprehensive information by both synergizing the advantages, such as quantitative evaluation, higher sensitivity and spatial resolution, and mitigating the disadvantages. Such hybrid nanostructures could also provide a unique nanoplatform for enhanced medical tracing, magnetic field, and light-triggered hyperthermia. Moreover, potential advantages and opportunities will be achieved via a combination of diagnostic and therapeutic agents within a single platform, which is so-called 'theranostics.' We expect the combination of unique structural characteristics and integrated functions of multicomponent magnetic hybrid nanomaterials will attract increasing research interest and could lead to new opportunities in nanomedicine and nanobiotechnology. WIREs Nanomed Nanobiotechnol 2018, 10:e1476. doi: 10.1002/wnan.1476 This article is categorized under: Diagnostic Tools > Diagnostic Nanodevices.

Preparation of highly dispersed γ-Fe2O3 and GdPO4 co-functionalized mesoporous carbon spheres for dual-mode MR imaging and anti-cancer drug carrying

Dual-mode MR imaging and drug carrying properties have been integrated into carbon nanospheres by using Wells–Dawson like clusters.

Synthesis of gadolinium oxide nanodisks and gadolinium doped iron oxide nanoparticles for MR contrast agents

Herein, we report the synthesis of differently sized gadolinium oxide nanodisks and gadolinium doped iron oxide spherical and cubic nanoparticles through the thermal decomposition of an oleate precursor.

Imaging of carotid artery inflammatory plaques with superparamagnetic nanoparticles and an external magnet collar

Stroke is one of the top three fatal diseases in human history.

Highly porous PEGylated Bi2S3 nano-urchins as a versatile platform for in vivo triple-modal imaging, photothermal therapy and drug delivery

Biocompatible single-component nanoplatforms simultaneously integrating multiple therapeutic functions with multiple imaging modes are desirable for anticancer treatments. Herein, elaborately-designed highly porous PEGylated bismuth sulfide nano-urchins (Bi2S3-PEG NUs) have been successfully synthesized by using Bi2O3 nanospheres as the sacrificial template via the hydrothermal process. It is demonstrated that the Bi2S3-PEG NUs possess high compatibility, stability, X-ray attenuation ability, near-infrared (NIR) absorbance and photothermal conversion capability, without noticeable toxicity. Based on both in vitro and in vivo results, the product shows excellent performance in highly effective photothermal therapy (PTT) guided by triple-modal imaging, including X-ray computed tomography (CT), and photoacoustic (PA) and infrared thermal (IRT) imaging, without noticeable toxicity in vivo. Importantly, the NUs are highly porous with a high specific surface area and copious mesopores, providing high loading capacity to accommodate drugs (or guest biomolecules) for further applications in chemotherapy and other additional functions. Doxorubicin is loaded as an example, showing a rather high loading capacity (∼37.9%) together with a bimodal on-demand pH/photothermal-sensitive drug release property. Such fascinating multifunctional nanoagents may have considerable applications in antitumor diagnosis and therapy in the clinic.

Facile preparation of hybrid core-shell nanorods for photothermal and radiation combined therapy

The hybrid platinum@iron oxide core-shell nanorods with high biocompatibility were synthesized and applied for combined therapy. These hybrid nanorods exhibit a good photothermal effect on cancer cells upon irradiation with a NIR laser. Furthermore, due to the presence of a high atomic number element (platinum core), the hybrid nanorods show a synergistic effect between photothermal and radiation therapy. Therefore, the as-prepared core-shell nanorods could play an important role in facilitating synergistic therapy between photothermal and radiation therapy to achieve better therapeutic efficacy.

Nanoparticle-based highly sensitive MRI contrast agents with enhanced relaxivity in reductive milieu

A gadolinium containing nanoparticle exhibiting a 10-fold higher r₁ relaxivity than Dotarem® and further increase in relaxivity in reductive milieu is proposed.

Facile one-pot synthesis of carbon/calcium phosphate/Fe3O4 composite nanoparticles for simultaneous imaging and pH/NIR-responsive drug delivery

We report herein a facile one-pot synthesis of carbon/calcium phosphate/Fe₃O₄ composite nanoparticles, which were employed as pH/NIR-responsive drug delivery vehicles for simultaneous MRI and chemo-photothermal therapy.

PEGylated Gd(OH)3 nanorods as metabolizable contrast agents for computed tomography imaging

PEGylated Gd(OH)₃ nanorods have been efficiently prepared via a facile and green hydrothermal route and used as a metabolizable computed tomography contrast agent for in vivo imaging.

Water-dispersible polyphosphate-grafted Fe3O4 nanomagnets for cancer therapy

Development of water-dispersible polyphosphate-grafted Fe₃O₄ nanomagnets for hyperthermia and drug delivery applications.