Targeted treatment of atherosclerosis with protein-polysaccharide nanoemulsion co-loaded with photosensitiser and upconversion nanoparticles

Macrophages are the most abundant cell group in atherosclerosis (AS) lesions and play a vital role in all stages of AS progression. Recent research has shown that reactive oxygen species (ROS) generation from photodynamic therapy (PDT) induces macrophage autophagy to improve abnormal lipid metabolism and inflammatory environment. Especially in macrophage-derived foam cells, which has become a potential strategy for the treatment of AS. In this study, we prepared the conjugate (DB) of dextran (DEX) and bovine serum albumin (BSA). The DB was used as the emulsifier to prepare nanoemulsion loaded with upconversion nanoparticles (UCNPs) and chlorin e6 (Ce6) (UCNPs-Ce6@DB). The DEX modified on the surface of the nanoemulsion can recognise and bind to the scavenger receptor class A (SR-A) highly expressed on macrophages and promote the uptake of macrophage-derived foam cells in AS plates through SR-A-mediated endocytosis. In addition, UCNPs-Ce6@DB-mediated PDT enhanced ROS generation and induced autophagy in macrophage-derived foam cells, enhanced the expression of ABCA1, a protein closely related to cholesterol efflux, and inhibited the secretion of pro-inflammatory cytokines. Ultimately, UCNPs-Ce6@DB was shown to inhibit plaque formation in mouse models of AS. In conclusion, UCNPs-Ce6@DB offers a promising treatment for AS.

Recent Advances in the Development of Drug Delivery Applications of Magnetic Nanomaterials

With the predicted rise in the incidence of cancer, there is an ever-growing need for new cancer treatment strategies. Recently, magnetic nanoparticles have stood out as promising nanostructures for imaging and drug delivery systems as they possess unique properties. Moreover, magnetic nanomaterials functionalized with other compounds can lead to multicomponent nanoparticles with innovative structures and synergetic performance. The incorporation of chemotherapeutic drugs or RNA in magnetic drug delivery systems represents a promising alternative that can increase efficiency and reduce the side effects of anticancer therapy. This review presents a critical overview of the recent literature concerning the advancements in the field of magnetic nanoparticles used in drug delivery, with a focus on their classification, characteristics, synthesis and functionalization methods, limitations, and examples of magnetic drug delivery systems incorporating chemotherapeutics or RNA.

Fabrication of a Polysaccharide-Protein/Protein Complex Stabilized Oral Nanoemulsion to Facilitate the Therapeutic Effects of 1,8-Cineole on Atherosclerosis

Atherosclerosis (AS) is a systemic disease characterized by lipid deposition in the blood vessel wall that urgently requires effective and safe therapeutic drugs for long-term treatment. An essential oil monomer-1,8-cineole (CIN) with ameliorative effects on vascular injuries has considerable potential for preventing the progression of AS because of its antioxidant, anti-inflammation, and cholesterol regulatory effects. However, the high volatility and instability of CIN result in low oral bioavailability and a short half-life, thereby limiting its clinical application. We formulated a nanoemulsion using a polysaccharide-protein/protein complex (dextran-bovine serum albumin/protamine, DEX_5k-BSA/PTM) as an emulsifier, with vitamin B12 (VB₁₂) as the ligand to facilitate the transportation across the small intestine. An emulsion preparation method using a microjet followed by ultraviolet irradiation was developed to obtain the CIN-loaded oral nanoemulsion CIN@DEX_5k-BSA/PTM/VB₁₂. The nanoemulsion improved the stability of CIN both in vitro and in vivo, prolonged the retention time in the gastrointestinal tract (GIT), and enhanced the permeability across the mucus layer and intestinal epithelial cells to increase oral bioavailability and plaque accumulation of CIN. Validated in an AS mouse model, CIN@DEX_5k-BSA/PTM/VB₁₂ achieved prominent therapeutic efficacy combating AS. This study highlights the advantages of DEX_5k-BSA/PTM and VB₁₂ in the development of nanoemulsions for CIN and provides a promising oral nanoplatform for the delivery of essential oils.

Dextran mediated MnFe2O4/ZnS magnetic fluorescence nanocomposites for controlled self-heating properties

Dextran mediated MnFe2O4/ZnS opto-magnetic nanocomposites with different concentrations of ZnS were competently synthesized adopting the co-precipitation method. The structural, morphological, magnetic, and optical properties of the nanocomposites were exhaustively characterized by XRD, HRTEM, FTIR, VSM techniques, and PL spectroscopy. XRD spectra demonstrate the existence of the cubic spinel phase of MnFe2O4 and the cubic zinc blend phase of ZnS in the nanocomposites. HRTEM images show the average crystallite size ranges of 15-21 nm for MnFe2O4 and 14-45 nm for ZnS. Investigation of the FTIR spectra reveals the incorporation of ZnS nanoparticles on the surface of MnFe2O4 nanoparticles by dint of biocompatible surfactant dextran. The nanocomposites exhibit both magnetic and photoluminescence properties. Photoluminescence analysis confirmed the redshift of the emission peaks owing to the trap states in the ZnS nanocrystals. The room temperature VSM analysis shows that the saturation magnetization and coercivity of MnFe2O4 nanoparticles initially increase then decrease with the increasing concentration of ZnS in the nanocomposite. The induction heating analysis shows that the presence of dextran enhances the self heating properties of the MnFe2O4/ZnS nanocomposites which can also be controlled by tailoring the concentration of the ZnS nanoparticles. These suggest that MnFe2O4/Dex/ZnS is a decent candidate for hyperthermia applications.

PEGylated Magnetic Nano-Assemblies as Contrast Agents for Effective T2-Weighted MR Imaging

We designed a high-sensitivity magnetic resonance imaging contrast agent that could be used to diagnose diseases. First, magnetic nanocrystals were synthesized by a thermal decomposition method on an organic solvent to obtain a high magnetism and methoxy poly(ethylene glycol)-poly(lactic acid) as an amphiphilic polymer using the ring-opening polymerization method to stably disperse the magnetic nanocrystals in an aqueous phase. Subsequently, the magnetic nanoclusters simultaneously self-assembled with methoxy poly(ethylene glycol)-poly(lactic acid) using the nano-emulsion method to form magnetic nanoclusters. Because their shape was similar to a raspberry, they were named PEGylated magnetic nano-assemblies. The PEGylated magnetic nano-assemblies were dispersed stably in the aqueous phase with a uniform size of approximately 65–70 nm for an extended period (0 days: 68.8 ± 5.1 nm, 33 days: 69.2 ± 2.0 nm, and 44 days: 63.2 ± 5.6). They exhibited both enough of a magnetic resonance (MR) contrast effect and biocompatibility. In an in vivo study, the PEGylated magnetic nano-assemblies provided a high contrast effect for magnetic resonance images for a long time after one treatment, thereby improving the diagnostic visibility of the disease site.

Rapid and simple detection of Tamiflu-resistant influenza virus: Development of oseltamivir derivative-based lateral flow biosensor for point-of-care (POC) diagnostics

We have developed a novel oseltamivir derivative (oseltamivir hexylthiol; OHT) that exhibits a higher binding affinity for Tamiflu-resistant virus (Tamiflu resistance) than for the wild-type virus (Tamiflu-susceptible virus; WT) as an antibody. First, OHT-modified gold nanoparticles (OHT-GNPs) are used in a simple colorimetric assay as nanoprobes for the Tamiflu-resistant virus. In the presence of Tamiflu-resistant virus, they show a colorimetric change from deep red to purple because of the OHT-GNP aggregation driven by strong interactions between OHT and neuraminidase (NA) on the surface of the Tamiflu-resistance. Moreover, the color gradually turns purple as the concentration of the Tamiflu-resistant virus increases, allowing the determination of the presence of the virus with the naked eye. Furthermore, an OHT-based lateral flow assay (LFA) has been developed as a rapid and easy detection device for Tamiflu resistance. It shows detection specificity for various virus concentrations of Tamiflu-resistant virus even for the mixture of WT and Tamiflu-resistant viruses, where the limit of detection (LOD) is 5 × 10² ~ 10³ PFU per test (=1 × 10⁴ PFU/mL). It has been confirmed that this platform can provide accurate information on whether a virus exhibits Tamiflu resistance, thus supporting the selection of appropriate treatments using point-of-care (POC) diagnostics.

Preparation, characterization and in vitro photodynamic therapy of a pyropheophorbide-a-conjugated Fe3O4 multifunctional magnetofluorescence photosensitizer

Core–shell structure magneto-fluorescence chlorin pyropheorbide-a photosensitizer (MFNPs) with good water-dispersity and strong superparamagnetic for photodynamic therapy.

Colorimetric detection of influenza A (H1N1) virus by a peptide-functionalized polydiacetylene (PEP-PDA) nanosensor

​We developed a peptide-functionalized polydiacetylene nanosensor for pH1N1 virus detection with the naked eye.

Compensatory UTE/T2W Imaging of Inflammatory Vascular Wall in Hyperlipidemic Rabbits

OBJECTIVES

To obtain compensatory ultra-short echo time (UTE) imaging and T2-weighted (T2W) imaging of Watanabe heritable hyperlipidemic (WHHL) rabbits following dextran-coated magnetic nanocluster (DMNC) injection for the effective in vivo detection of inflammatory vascular wall.

METHODS

Magnetic nanoparticle was synthesized by thermal decomposition and encapsulated with dextran to prepare DMNC. The contrast enhancement efficiency of DMNC was investigated using UTE (repetition time [TR] = 5.58 and TE = 0.07 ms) and T2W (TR = 4000 and TE = 60 ms) imaging sequences. To confirm the internalization of DMNC into macrophages, DMNC-treated macrophages were visualized by cellular transmission electron microscope (TEM) and magnetic resonance (MR) imaging. WHHL rabbits expressing macrophage-rich plaques were subjected to UTE and T2W imaging before and after intravenous DMNC (120 μmol Fe/kg) treatment. Ex vivo MR imaging of plaques and immunostaining studies were also performed.

RESULTS

Positive and negative contrast enhancement of DMNC solutions with increasing Fe concentrations were observed in UTE and T2W imaging, respectively. The relative signal intensities of the DMNC solution containing 2.9 mM Fe were calculated as 3.53 and 0.99 in UTE and T2W imaging, respectively. DMNC uptake into the macrophage cytoplasm was visualized by electron microscopy. Cellular MR imaging of DMNC-treated macrophages revealed relative signals of 3.00 in UTE imaging and 0.98 in T2W imaging. In vivo MR images revealed significant brightening and darkening of plaque areas in the WHHL rabbit 24 h after DMNC injection in UTE and T2W imaging, respectively. Ex vivo MR imaging results agreed with these in vivo MR imaging results. Histological analysis showed that DMNCs were localized to areas of inflammatory vascular wall.

CONCLUSIONS

Using compensatory UTE and T2W imaging in conjunction with DMNC is an effective approach for the noninvasive in vivo imaging of atherosclerotic plaque.

Assembly-mediated interplay of dipolar interactions and surface spin disorder in colloidal maghemite nanoclusters

Controlled assembly of single-crystal, colloidal maghemite nanoparticles is facilitated via a high-temperature polyol-based pathway. Structural characterization shows that size-tunable nanoclusters of 50 and 86 nm diameters (D), with high dispersibility in aqueous media, are composed of ∼13 nm (d) crystallographically oriented nanoparticles. The interaction effects are examined against the increasing volume fraction, φ, of the inorganic magnetic phase that goes from individual colloidal nanoparticles (φ = 0.47) to clusters (φ = 0.72). The frozen-liquid dispersions of the latter exhibit weak ferrimagnetic behaviour at 300 K. Comparative Mössbauer spectroscopic studies imply that intra-cluster interactions come into play. New insight emerges from the clusters' temperature-dependent ac susceptibility that displays two maxima in χ''(T), with strong frequency dispersion. Scaling-law analysis together with the observed memory effects suggests that a superspin-glass state settles-in at TB ∼ 160-200 K, while at lower-temperatures, surface spin-glass freezing is established at Tf ∼ 40-70 K. In such nanoparticle-assembled systems, with increased φ, Monte Carlo simulations corroborate the role of the inter-particle dipolar interactions and that of the constituent nanoparticles' surface spin disorder in the emerging spin-glass dynamics.

Colloidal assemblies of oriented maghemite nanocrystals and their NMR relaxometric properties

¹H-NMR relaxometric experiments over an extended frequency range show that ferrimagnetic colloidal nanoclusters exhibit enhanced transverse relaxivity, r₂.

Chitosan-based intelligent theragnosis nanocomposites enable pH-sensitive drug release with MR-guided imaging for cancer therapy

Smart drug delivery systems that are triggered by environmental conditions have been developed to enhance cancer therapeutic efficacy while limiting unwanted effects. Because cancer exhibits abnormally high local acidities compared to normal tissues (pH 7.4) due to Warburg effects, pH-sensitive systems have been researched for effective cancer therapy. Chitosan-based intelligent theragnosis nanocomposites, N-naphthyl-O-dimethymaleoyl chitosan-based drug-loaded magnetic nanoparticles (NChitosan-DMNPs), were developed in this study. NChitosan-DMNPs are capable of pH-sensitive drug release with MR-guided images because doxorubicin (DOX) and magnetic nanocrystals (MNCs) are encapsulated into the designed N-naphthyl-O-dimethymaleoyl chitosan (N-nap-O-MalCS). This system exhibits rapid DOX release as acidity increases, high stability under high pH conditions, and sufficient capacity for diagnosing and monitoring therapeutic responses. These results demonstrate that NChitosan-DMNPs have potential as theragnosis nanocomposites for effective cancer therapy.

Multifunctional magnetic nanoparticles modified with polyethylenimine and folic acid for biomedical theranostics

This paper describes the preparation of magnetic nanoparticles modified with polyethylenimine (PEI)-folic acid (PF) conjugate and their potential biomedical applications. Magnetic nanoparticles modified with (3-(2-aminoethylamino)propyltrimethoxysilane) (AEAPS) were first prepared using a ligand exchange method to provide biocompatibility and hydrophilicity, and further conjugated with PF to carry gene and enhance specific uptake into cancer cells. We demonstrated the feasibility of the multifunctional magnetic nanoparticles as contrast agents in magnetic resonance imaging (MRI) and as gene carriers for gene delivery. In vitro results revealed that the cytotoxicity of the multifunctional magnetic nanoparticles was lower compared to that of pristine magnetic nanoparticles. Furthermore, we demonstrated the specific uptake of the magnetic nanoparticles modified with PF to KB cells using WI-38 cells as comparison by confocal microscopy. The PF-modified magnetic nanoparticles can potentially be employed as theranostic nanoplatforms for targeted gene delivery to cancer cells and simultaneous magnetic resonance imaging.

Aptamer-conjugated magnetic nanoparticles enable efficient targeted detection of integrin αvβ3 via magnetic resonance imaging

An understanding of neovascularization and/or angiogenesis in cancer is acutely required for effective cancer therapy due to concerns about tumor growth and metastasis. In particular, integrin αvβ3 is closely associated with cell migration and invasion during angiogenesis. Hence, we developed aptamer(αvβ3)-conjugated magnetic nanoparticles (Apt(αvβ3)-MNPs) to enable precise detection of integrin-expressing cancer cells using magnetic resonance imaging. Apt(αvβ3)-MNPs exhibited not only cytocompatibility, but also an efficient targeting ability with high magnetic sensitivity through in vitro/in vivo studies. The results of this study demonstrate that Apt(αvβ3)-MNPs have the potential to be used for accurate tumor diagnosis and therapy.

Efficient CD44-targeted magnetic resonance imaging (MRI) of breast cancer cells using hyaluronic acid (HA)-modified MnFe2O4 nanocrystals

Targeted molecular imaging with hyaluronic acid (HA) has been highlighted in the diagnosis and treatment of CD44-overexpressing cancer. CD44, a receptor for HA, is closely related to the growth of cancer including proliferation, metastasis, invasion, and angiogenesis. For the efficient detection of CD44, we fabricated a few kinds of HA-modified MnFe2O4 nanocrystals (MNCs) to serve as specific magnetic resonance (MR) contrast agents (HA-MRCAs) and compared physicochemical properties, biocompatibility, and the CD44 targeting efficiency. Hydrophobic MNCs were efficiently phase-transferred using aminated polysorbate 80 (P80) synthesized by introducing spermine molecules on the hydroxyl groups of P80. Subsequently, a few kinds of HA-MRCAs were fabricated, conjugating different ratios of HA on the equal amount of phase-transferred MNCs. The optimized conjugation ratio of HA against magnetic content was identified to exhibit not only effective CD44 finding ability but also high cell viability through in vitro experiments. The results of this study demonstrate that the suggested HA-MRCA shows strong potential to be used for accurate tumor diagnosis.

Double-ligand modulation for engineering magnetic nanoclusters

Magnetic nanoclusters (MNCs) are agglomerated individual magnetic nanoparticles (MNPs) that show great promise in increasing magnetic resonance imaging (MRI) sensitivity. Here, we report an effective strategy to engineer MNCs based on double-ligand modulation to enhance MRI sensitivity. The oleic acid-coated individual MNPs self-assembled and then were enveloped by polysorbate 80, using a nanoemulsion method to prepare MNCs. By modulating the amounts of the two ligands, and thus the size and magnetic content of the resultant MNCs, we were able to enormously improve MRI sensitivity.