Uniform iron oxide hollow spheres for high-performance delivery of insoluble anticancer drugs

Tumor-targeting cell membrane-coated nanorings for magnetic-hyperthermia-induced tumor ablation

Magnetic hyperthermia has attracted considerable attention for efficient cancer therapy because of its noninvasive nature, deep tissue penetration, and minimal damage to healthy tissues. Herein, we have fused cancer cell membrane fragments with lipids and cloaked them on magnetic nanorings to form targeted Fe nanorings (TF) for tumor-targeted magnetic hyperthermia-induced tumor ablation. In our approach, cell membrane fragments from cancer cells were fused with lipids to form vesicles, which could efficiently encapsulate magnetic nanorings, thereby forming TF. We observed that TF have high tumor uptake via homotypic targeting, where cancer cells take up TF through membrane fusion. Under an external alternating magnetic field (AMF), TF accumulated in the tumors are heated, driving magnetic-hyperthermia-induced tumor cell death. Our in vitro studies show that self-targeting TF efficiently localized in cancer cells and induced cell death with an AMF, which was shown by a live/dead assay. Our findings demonstrate the potential of TF in tumor ablation, thereby making them promising and efficient nanosystems for tumor-targeted theranostics.

Antimicrobial Activity of Ca-Alginate/Chitosan Nanocomposite Loaded with Camptothecin

The main aim of this study was to prepare antimicrobial nanocomposites consisting of alginate, chitosan, and camptothecin (CPT). CPT-loaded calcium alginate (Ca-Alg₂) and calcium alginate/chitosan (Ca-Alg₂-CH) nanomaterials were synthesized and characterized using infrared (IR) spectroscopy, X-ray diffraction (XRD), UV-Vis spectroscopy, and scanning electron microscopy (SEM). The antimicrobial activity and the genetic effects of Ca-Alg₂/CPT and Ca-Alg₂-CH/CPT nanomaterials on Staphylococcus aureus, Escherichia coli, and Klebsiella pneumonia were studied. The repetitive element polymerase chain reaction analysis technique was used to assess the changes in the bacterial genetic material due to the processing of the nanomaterials. The results showed the presence of a strong chemical interaction between alginate and chitosan, and CPT was loaded successfully in both Ca-Alg₂/CPT and Ca-Alg₂-CH/CPT nanomaterials. Furthermore, the antimicrobial test showed that the Ca-Alg₂/CPT nanocomposite was susceptible to S. aureus, E. coli, and K. pneumonia; on the other hand, Ca-Alg₂-CH/CPT nanocomposite was more susceptible to E. coli and K. pneumonia and was resistant to S. aureus. The results showed that the Ca-Alg₂/CPT nanocomposite was less efficient than Ca-Alg₂-CH/CPT nanocomposite in killing Gram-negative treated bacteria. Moreover, results revealed that the PCR analysis revealed a polymorphic banding pattern. This observation provides an excellent guide to the ability of some polymers to induce point mutations in DNA.

The role of hollow magnetic nanoparticles in drug delivery

The increasing number of scientific publications focusing on nanomaterials in the biomedical field indicates growing interest from the broader scientific community. Nanomedicine is a modern science, and research continues into the application of nanoscale materials for the therapy and diagnosis of damaged tissues. In this regard, substantial progress has been made in the synthesis of magnetic materials with desired sizes, morphologies, chemical compositions, and surface chemistry. Among these, magnetic iron oxide nanoparticles have demonstrated great promise as unique carriers in the delivery of chemical drugs due to their combinations of hollow structures. Importantly, due to the combination of the ability to respond to an external magnetic field and the rich possibilities of their coatings, magnetic materials are universal tools for the magnetic separation of small molecules, biomolecules, and cells. This review provides an overview of the synthesis and biological applications of hollow magnetic nanoparticles in drug delivery systems.

Macromolecules with Different Charges, Lengths, and Coordination Groups for the Coprecipitation Synthesis of Magnetic Iron Oxide Nanoparticles as T1 MRI Contrast Agents

Considerable efforts have been focused on the exploitation of macromolecule ligands for synthesis of magnetic Fe3O4 nanoparticles as T1 magnetic resonance imaging (MRI) contrast agents, but studies that concern macromolecule ligands with different charges and coordination groups are still limited. Herein, we used poly(acrylic acid) (PAA), poly(allylamine hydrochloride) (PAH), and polyvinyl alcohol (PVA), which possess negative, positive and neutral charges with carboxylic acid, amino and hydroxyl groups respectively, as templates and stabilizers to fabricate Fe3O4 nanoparticles through coprecipitation reaction. The obtained Fe3O4-PAA, Fe3O4-PAH, and Fe3O4-PVA nanoparticles showed T1 contrast performance with r1 relaxivities of 23.4, 60.3, and 30.6 mM s-1 at 0.5 T (25 °C), and a r2/r1 ratio of 2.62, 3.82, and 7.26, respectively. The cell viability assay revealed that Fe3O4-PAA and Fe3O4-PVA exhibited good biocompatibility, while Fe3O4-PAH displayed high cytotoxicity. In vivo T1-weighted (1 T) mice showed that both Fe3O4-PAA and Fe3O4-PVA were able to display remarkably brighten the contrast enhancement for the mice tumor and kidney sites, but Fe3O4-PAA had better contrast performance. This work highlights that the macromolecule ligands play an important role in the biocompatibility and T1 contrast performance of magnetic Fe3O4 nanoparticles.

Magnet Patterned Superparamagnetic Fe3 O4 /Au Core-Shell Nanoplasmonic Sensing Array for Label-Free High Throughput Cytokine Immunoassay

Rapid and accurate immune monitoring plays a decisive role in effectively treating immune-related diseases especially at point-of-care, where an immediate decision on treatment is needed upon precise determination of the patient immune status. Derived from the emerging clinical demands, there is an urgent need for a cytokine immunoassay that offers unprecedented sensor performance with high sensitivity, throughput, and multiplexing capability, as well as short turnaround time at low system complexity, manufacturability, and scalability. In this paper, a label-free, high throughput cytokine immunoassay based on a magnet patterned Fe3 O4 /Au core-shell nanoparticle (FACSNP) sensing array is developed. By exploiting the unique superparamagnetic and plasmonic properties of the core-shell nanomaterials, a facile microarray patterning technique is established that allows the fabrication of a uniform, self-assembled microarray on a large surface area with remarkable tunability and scalability. The sensing performance of the FACSNP microarray is validated by real-time detection of four cytokines in complex biological samples, showing high sensitivity (≈20 pg mL-1 ), selectivity and throughput with excellent statistical accuracy. The developed immunoassay is successfully applied for rapid determination of the functional immunophenotype of leukemia tumor-associated macrophages, manifesting its potential clinical applications for real-time immune monitoring, early cancer detection, and therapeutic drug stratification toward personalized medicine.

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.

Safe approaches for camptothecin delivery: Structural analogues and nanomedicines

Twenty-(S)-camptothecin is a strongly cytotoxic molecule with excellent antitumor activity over a wide spectrum of human cancers. However, the direct formulation is limited by its poor water solubility, low plasmatic stability and severe toxicity, which currently limits its clinical use. As a consequence, two strategies have been developed in order to achieve safe and efficient delivery of camptothecin to target cells: structural analogues and nanomedicines. In this review, we summarize recent advances in the design, synthesis and development of camptothecin molecular derivatives and supramolecular vehicles, following a systematic classification according to structure-activity relationships (structural analogues) or chemical nature (nanomedicines). A series of organic, inorganic and hybrid materials are presented as nanoplatforms to overcome camptothecin restrictions in administration, biodistribution, pharmacokinetics and toxicity. Nanocarriers which respond to a variety of stimuli endogenously (e.g., pH, redox potential, enzyme activity) or exogenously (e.g., magnetic field, light, temperature, ultrasound) seem the best positioned therapeutic materials for optimal spatial and temporal control over drug release. The main goal of this review is to be used as a source of relevant literature for others interested in the field of camptothecin-based therapeutics. To this end, final remarks on the most important formulations currently under clinical trial are provided.

Fabrication of Fe3O4@Au hollow spheres with recyclable and efficient catalytic properties

A view of the preparation process and the evaluation of the catalysis activity of Fe₃O₄@Au hollow spheres.

Fabrication of magnetic bimetallic Fe3O4@Au–Pd hybrid nanoparticles with recyclable and efficient catalytic properties

View of the preparation process and evaluation of the catalytic activity of Fe₃O₄@Pd and Fe₃O₄@Au–Pd NPs.

Ultrasonic-spray-assisted synthesis of metal oxide hollow/mesoporous microspheres for catalytic CO oxidation

Various transition metal oxide hollow or mesoporous microspheres with improved catalytic activities towards CO oxidation were prepared via a general ultrasonic-spray-assisted method.

Comparison of NiS2 and α-NiS hollow spheres for supercapacitors, non-enzymatic glucose sensors and water treatment

NiS₂ and α-NiS hollow spheres are prepared via a template-free method. When NiS₂ and α-NiS hollow spheres were evaluated for supercapacitors, glucose sensors and water treatment, it was found that the hollow α-NiS spheres exhibited better performance than the NiS₂.

Biocompatible PEGylated Fe₃O₄ nanoparticles as photothermal agents for near-infrared light modulated cancer therapy

In accordance with the World Cancer Report, cancer has become the leading cause of mortality worldwide, and various therapeutic strategies have been developed at the same time. In the present study, biocompatible magnetic nanoparticles were designed and synthesized as high-performance photothermal agents for near-infrared light mediated cancer therapy in vitro. Via a facile one-pot solvothermal method, well-defined PEGylated magnetic nanoparticles (PEG-Fe3O4) were prepared with cheap inhesion as a first step. Due to the successful coating of PEG molecules on the surface of PEG-Fe3O4, these nanoparticles exhibited excellent dispersibility and dissolvability in physiological condition. Cytotoxicity based on MTT assays indicated these nanoparticles revealed high biocompatibility and low toxicity towards both Hela cells and C6 cells. After near-infrared (NIR) laser irradiation, the viabilities of C6 cells were effectively suppressed when incubated with the NIR laser activated PEG-Fe3O4. In addition, detailed photothermal anti-cancer efficacy was evaluated via visual microscope images, demonstrating that our PEG-Fe3O4 were promising for photothermal therapy of cancer cells.