Manganese-enhanced MRI of rat brain based on slow cerebral delivery of manganese(II) with silica-encapsulated Mn x Fe(1-x) O nanoparticles

Chitosan Aerogel Particles as Nasal Drug Delivery Systems

The nasal drug delivery route has distinct advantages, such as high bioavailability, a rapid therapeutic effect, non-invasiveness, and ease of administration. This article presents the results of a study of the processes for obtaining chitosan aerogel particles that are promising as nasal or inhalation drug delivery systems. Obtaining chitosan aerogel particles includes the following steps: the preparation of a chitosan solution, gelation, solvent replacement, and supercritical drying. Particles of chitosan gels were obtained by spraying and homogenization. The produced chitosan aerogel particles had specific surface areas of up to 254 m²/g, pore volumes of up to 1.53 cm³/g, and porosities of up to 99%. The aerodynamic diameters of the obtained chitosan aerogel particles were calculated, the values of which ranged from 13 to 59 µm. According to the calculation results, a CS1 sample was used as a matrix for obtaining the pharmaceutical composition "chitosan aerogel-clomipramine". X-ray diffraction (XRD) analysis of the pharmaceutical composition determined the presence of clomipramine, predominantly in an amorphous form. Analysis of the high-performance liquid chromatography (HPLC) data showed that the mass loading of clomipramine was 35%. Experiments in vivo demonstrated the effectiveness of the pharmaceutical composition "chitosan aerogel-clomipramine" as carrier matrices for the targeted delivery of clomipramine by the "Nose-to-brain" mechanism of nasal administration. The maximum concentration of clomipramine in the frontal cortex and hippocampus was reached 30 min after administration.

Developing of SiO2 Nanoshells Loaded with Fluticasone Propionate for Potential Nasal Drug Delivery: Determination of Pro-Inflammatory Cytokines through mRNA Expression

Mesoporous Silica Nanoparticles (MSN) are porous inorganic materials that have been extensively used for drug delivery due to their special qualities, such as biocompatibility, biodegradability, and non-toxicity. MSN is a promising drug delivery system to enhance the efficacy and safety of drug administration in nasal diseases like chronic rhinitis (CR). In this study, we used the sol-gel technique for MSN synthesis and incorporate fluticasone propionate (FP) for intranasal drug administration for the treatment of chronic rhinitis (CR). In order to confirm the particle size, shape, drug release, and compatibility, various instruments were used. MSN was effectively prepared with average sizes ranging between 400 ± 34 nm (mean ± SD) as measured by dynamic light scattering (DLS), while zeta potential verified in all cases their positive charged surface. To investigate MSN features, the Fourier transform infrared spectrometer (FTIR), scanning electron microscopy (SEM), transmission electron microscope (TEM), thermal analysis, X-ray diffraction (XRD), and nitrogen adsorption/desorption measurement were used. The loaded compound was submitted to in vitro dissolution tests, and a remarkable dissolution rate improvement was observed compared to the crystalline drug in both pH conditions (1.2 and 7.4 pH). By using an MTT assay cell viability was assessed. The expression levels of the anti-inflammatory cytokines IL-4 and IL-5 were also measured using mRNA extraction from rat blood. Other characterizations like acute toxicity and hemolytic activity were also performed to confirm loaded MSN safety. Loaded MSN was incorporated in nasal spray prepared by using innovator excipients including poloxamer. After this, its nasal spray's physical characteristics were also determined and compared with a commercial product (Ticovate).

Magnetic Nylon 6 Nanocomposites for the Microextraction of Nucleic Acids from Biological Samples

Magnetic Fe3O4 nanoparticles (MNPs) have great potential for nucleic acid separation, detection, and delivery. MNPs are considered a valuable tool in biomedicine due to their cost-effectiveness, stability, easy surface functionalization, and the possibility of the manipulations under a magnetic field. Herein, the synthesis of magnetic nylon 6 nanocomposites (MNPs@Ny6) was investigated. Transmission electron microscopy (TEM) was used for morphology and size analysis. A new method of UV-induced immobilization of oligonucleotides on MNPs@Ny6 for nucleic acid magnetic separation was proposed. MNPs@Ny6 shows a high oligonucleotide binding capacity of 2.2 nmol/mg with 73.3% loading efficiency. The proposed system has been applied to analyze model mixtures of target RNA on the total yeast RNA background. The RNA target isolation efficiency was 60% with high specificity. The bind RNA release was 88.8% in a quantity of 0.16 nmol/mg. The total RNA capture efficiency was 53%. Considering this, the MNPs@Ny6 is an attractive candidate for nucleic acids-specific magnetic isolation.

Intranasal Administration of a TRAIL Neutralizing Monoclonal Antibody Adsorbed in PLGA Nanoparticles and NLC Nanosystems: An In Vivo Study on a Mouse Model of Alzheimer’s Disease

Alzheimer’s disease (AD) is a neurodegenerative disorder that progressively compromises cognitive functions. Tumor necrosis factor (TNF)-Related Apoptosis Inducing Ligand (TRAIL), a proinflammatory cytokine belonging to the TNF superfamily, appears to be a key player in the inflammatory/immune orchestra of the AD brain. Despite the ability of an anti-TRAIL monoclonal antibody to reach the brain producing beneficial effects in AD mice, we attempted to develop such a TRAIL-neutralizing monoclonal antibody adsorbed on lipid and polymeric nanocarriers, for intranasal administration, in a valid approach to overcome issues related to both high dose and drug transport across the blood–brain barrier. The two types of nanomedicines produced showed physico-chemical characteristics appropriate for intranasal administration. As confirmed by enzyme-linked immunosorbent assay (ELISA), both nanomedicines were able to form a complex with the antibody with an encapsulation efficiency of ≈99%. After testing in vitro the immunoneutralizing properties of the nanomedicines, the latter were intranasally administered in AD mice. The antibody–nanocarrier complexes were detectable in the brain in substantial amounts at concentrations significantly higher compared to the free form of the anti-TRAIL antibody. These data support the use of nanomedicine as an optimal method for the delivery of the TRAIL neutralizing antibody to the brain through the nose-to-brain route, aiming to improve the biological attributes of anti-TRAIL-based therapy for AD treatment.

Intranasal Cerium Oxide Nanoparticles Ameliorate Cognitive Function in Rats with Alzheimer's via Anti-Oxidative Pathway

Cerium oxide nanoparticles (CNPs), owing to their antioxidant property, have recently emerged as therapeutic candidate for Alzheimer's disease (AD). However, intravenous CNPs are limited due to their poor physicochemical properties, rapid blood clearance and poor blood-brain penetration. Thus, we developed intranasal CNPs and evaluated its potential in experimental AD. CNPs were synthesized using homogenous precipitation method and optimized through Box-Behnken Design. The formation of CNPs was confirmed by UV spectroscopy and FTIR. The optimized CNP were spherical, small (134.0 ± 3.35 nm), uniform (PDI, 0.158 ± 0.0019) and stable (ZP, -21.8 ± 4.94 mV). The presence of Ce in CNPs was confirmed by energy-dispersive X-ray analysis. Further, the X-ray diffraction spectra revealed that the CNPs were nano-crystalline. The DPPH assay showed that at concentration of 50 µg/mL, the percentage radical scavenging was 95.40 ± 0.006%. Results of the in vivo behavioral studies in the scopolamine-induced Alzheimer rat model showed that intranasal CNPs dose dependently reversed cognitive ability. At dose of 6 mg/kg the morris water maze results (escape latency, path length and dwell time) and passive avoidance results (retention latency) were significantly different from untreated group but not significantly different from positive control group (rivastigmine patch, 13.3 mg/24 h). Further, biochemical estimation showed that intranasal CNP upregulated the levels of SOD and GSH in brain. In conclusion, intranasal CNPs, through its antioxidant effect, could be a prospective therapeutics for the treatment of cognitive impairment in AD.

Pharmacokinetics and Pharmacodynamics of Intranasal Solid Lipid Nanoparticles and Nanostructured Lipid Carriers for Nose-to-Brain Delivery

Nose-to-brain drug delivery has been of great interest for the treatment of many central nervous system (CNS) diseases and psychiatric disorders over past decades. Several nasally administered formulations have been developed to circumvent the blood-brain barrier and directly deliver drugs to the CNS through the olfactory and trigeminal pathways. However, the nasal mucosa's drug absorption is insufficient and the volume of the nasal cavity is small, which, in combination, make nose-to-brain drug delivery challenging. These problems could be minimized using formulations based on solid lipid nanoparticles (SLNs) or nanostructured lipid carriers (NLCs), which are effective nose-to-brain drug delivery systems that improve drug bioavailability by increasing drug solubility and permeation, extending drug action, and reducing enzymatic degradation. Various research groups have reported in vivo pharmacokinetics and pharmacodynamics of SLNs and NLCs nose-to-brain delivery systems. This review was undertaken to provide an overview of these studies and highlight research performed on SLN and NLC-based formulations aimed at improving the treatment of CNS diseases such neurodegenerative diseases, epilepsy, and schizophrenia. We discuss the efficacies and brain targeting efficiencies of these formulations based on considerations of their pharmacokinetic parameters and toxicities, point out some gaps in current knowledge, and propose future developmental targets.

Expanding nanoparticle multifunctionality: size-selected cargo release and multiple logic operations

Physically stimulated nanoparticles that deliver size-selected cargo and function as logic gates are reported. To achieve this goal the particle requires multiple components, and we recognized early on that the components, not just the released cargo, could be used to demonstrate logic operations (OR and AND logic). For stimuli, we chose two non-invasive types, red light and alternating magnetic fields (AMF), because they both have potential biological relevance. To realize cargo delivery with size selection and logic operations, we mechanized the surface of core@shell nanoparticles with a superparamagnetic core that generates localized heating when exposed to an AMF, and a mesoporous silica shell into which cargo molecules with different sizes were loaded. We demonstrate the core@shell nanoparticles can load the dual cargos with different sizes and subsequently release the smaller (∼0.5 nm) and bigger (∼2 nm) cargos in succession when stimulated by a red light followed by an AMF. Finally, we demonstrate that the multi-component nanoparticles could function as nanoparticle-based Boolean logic gates where AMF and red light served as the two inputs and the release of small cargo, and free cyclodextrin served as the outputs. The construction of two Boolean logic gates (OR, and AND) was realized.

A Responsive Mesoporous Silica Nanoparticle Platform for Magnetic Resonance Imaging-Guided High-Intensity Focused Ultrasound-Stimulated Cargo Delivery with Controllable Location, Time, and Dose

Magnetic resonance imaging (MRI) is an essential modality for clinical diagnosis, and MRI-guided high-intensity focused ultrasound (MRgHIFU) is a powerful technology for targeted therapy. Clinical applications of MRgHIFU primarily utilize hyperthermia and ablation to treat cancerous tissue, but for drug delivery applications thermal damage is undesirable. A biofriendly MRgHIFU-responsive mesoporous silica nanoparticle (MSN) platform that is stimulated within a physiological safe temperature range has been developed, reducing the possibility of thermal damage to the surrounding healthy tissues. Biocompatible polyethylene glycol (PEG) was employed to cap the pores of MSNs, and the release of cargo molecules by HIFU occurs without substantial temperature increase (∼4 °C). To visualize by MRI and measure the stimulated delivery in situ, a U.S. Food and Drug Administration (FDA)-approved gadolinium-based contrast agent, gadopentetate dimeglumine (Gd(DTPA)^2-), was used as the imageable cargo. Taking advantage of the three-dimensional (3-D) imaging and targeting capabilities of MRgHIFU, the release of Gd(DTPA)^2- stimulated by HIFU was pinpointed at the HIFU focal point in 3-D space in a tissue-mimicking gel phantom. The amount of Gd(DTPA)^2- released was controlled by HIFU stimulation times and power levels. A positive correlation between the amount of Gd(DTPA)^2- released and T₁ was found. The MRgHIFU-stimulated cargo release was further imaged in a sample of ex vivo animal tissue. With this technology, the biodistribution of the nanocarriers can be tracked and the MRgHIFU-stimulated cargo release can be pinpointed, opening up an opportunity for future image-guided theranostic applications.

Spatial, Temporal, and Dose Control of Drug Delivery using Noninvasive Magnetic Stimulation

Noninvasive stimuli-responsive drug delivery using magnetic fields in conjunction with superparamagnetic nanoparticles offers the potential for the spatial and temporal control of drug release. When hyperthermia is not desired and control of the dosage is required, it is necessary to design a platform in which local heating on the nanoscale releases the therapeutic cargo without the bulk heating of the surrounding medium. In this paper, we report a design using a stimuli-responsive nanoparticle platform to control the dosage of the cargo released by an alternating magnetic field (AMF) actuation. A core@shell structure with a superparamagnetic doped iron oxide (MnFe₂O₄@CoFe₂O₄) nanoparticle core in a mesoporous silica shell was synthesized. The core used here has a high saturation magnetization value and a high specific loss power for heat generation under an AMF. The mesoporous shell has a high cargo-carrying capacity. A thermoresponsive molecular-based gatekeeper containing an aliphatic azo group was modified on the core@shell nanoparticles to regulate the cargo release. The mesoporous structure of the silica shell remained intact after exposure to an AMF, showing that the release of cargo is due to the removal of the gatekeepers instead of the destruction of the structure. Most importantly, we demonstrated that the amount of cargo released could be adjusted by the AMF exposure time. By applying multiple sequential exposures of AMF, we were able to release the cargo step-wise and increase the total amount of released cargo. In vitro studies showed that the death of pancreatic cancer cells treated by drug-loaded nanoparticles was controlled by different lengths of AMF exposure time due to different amount of drugs released from the carriers. The strategy developed here holds great promise for achieving the dosage, temporal, and spatial control of therapeutics delivery without the risk of overheating the particles' surroundings.

Targeting T1 and T2 dual modality enhanced magnetic resonance imaging of tumor vascular endothelial cells based on peptides-conjugated manganese ferrite nanomicelles

Tumor angiogenesis plays very important roles for tumorigenesis, tumor development, metastasis, and prognosis. Targeting T₁/T₂ dual modality magnetic resonance (MR) imaging of the tumor vascular endothelial cells (TVECs) with MR molecular probes can greatly improve diagnostic sensitivity and specificity, as well as helping to make an early diagnosis of tumor at the preclinical stage. In this study, a new T₁ and T₂ dual modality nanoprobe was successfully fabricated. The prepared nanoprobe comprise peptides CL 1555, poly(ε-caprolactone)-block-poly(ethylene glycol) amphiphilic copolymer shell, and dozens of manganese ferrite (MnFe₂O₄) nanoparticle core. The results showed that the hydrophobic MnFe₂O₄ nanoparticles were of uniform spheroidal appearance and narrow size distribution. Due to the self-assembled nanomicelles structure, the prepared probes were of high relaxivity of 281.7 mM⁻¹ s⁻¹, which was much higher than that of MnFe₂O₄ nanoparticles (67.5 mM 1 s⁻¹). After being grafted with the targeted CD105 peptide CL 1555, the nanomicelles can combine TVECs specifically and make the labeled TVECs dark in T₂-weighted MR imaging. With the passage on, the Mn²⁺ ions were released from MnFe₂O₄ and the size decreased gradually, making the signal intensity of the second and third passage of labeled TVECs increased in T₁-weighted MR imaging. Our results demonstrate that CL-poly(ethylene glycol)-MnFe₂O₄ can conjugate TVECs and induce dark and bright contrast in MR imaging, and act as a novel molecular probe for T₁- and T₂-enhanced MR imaging of tumor angiogenesis.

Synthesis of Ferromagnetic Fe0.6 Mn0.4 O Nanoflowers as a New Class of Magnetic Theranostic Platform for In Vivo T1 -T2 Dual-Mode Magnetic Resonance Imaging and Magnetic Hyperthermia Therapy

Uniform wüstite Fe0.6 Mn0.4 O nanoflowers have been successfully developed as an innovative theranostic agent with T1 -T2 dual-mode magnetic resonance imaging (MRI), for diagnostic applications and therapeutic interventions via magnetic hyperthermia. Unlike their antiferromagnetic bulk counterpart, the obtained Fe0.6 Mn0.4 O nanoflowers show unique room-temperature ferromagnetic behavior, probably due to the presence of an exchange coupling effect. Combined with the flower-like morphology, ferromagnetic Fe0.6 Mn0.4 O nanoflowers are demonstrated to possess dual-modal MRI sensitivity, with longitudinal relaxivity r1 and transverse relaxivity r2 as high as 4.9 and 61.2 mm(-1) s(-1) [Fe]+[Mn], respectively. Further in vivo MRI carried out on the mouse orthotopic glioma model revealed gliomas are clearly delineated in both T1 - and T2 -weighted MR images, after administration of the Fe0.6 Mn0.4 O nanoflowers. In addition, the Fe0.6 Mn0.4 O nanoflowers also exhibit excellent magnetic induction heating effects. Both in vitro and in vivo magnetic hyperthermia experimentation has demonstrated that magnetic hyperthermia by using the innovative Fe0.6 Mn0.4 O nanoflowers can induce MCF-7 breast cancer cell apoptosis and a complete tumor regression without appreciable side effects. The results have demonstrated that the innovative Fe0.6 Mn0.4 O nanoflowers can be a new magnetic theranostic platform for in vivo T1 -T2 dual-mode MRI and magnetic thermotherapy, thereby achieving a one-stop diagnosis cum effective therapeutic modality in cancer management.

Fluorescent Heterodoped Nanotetrapods as Synergistically Enhancing Positive and Negative Magnetic Resonance Imaging Contrast Agents

In this work, we report Mn-Fe heterodoped ZnSe tetrapod nanocrystals (NCs) synthesized to synergistically enhance contrast in both T1- and T2-weighted magnetic resonance imaging (MRI). The proposed NCs were prepared using a customized heteroarchitecture such that the manganese (Mn) is confined in the core and iron (Fe) in the branches of the tetrapods. The elemental composition and profile of these NCs were studied using X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, and inductively coupled plasma mass spectroscopy. Photoluminescence quantum yield of these heterodoped NCs in water is ∼30%. Magnetic measurements reveal the simultaneous presence of superparamagnetic and paramagnetic behavior in these NCs because of the coexistence of Mn(2+) and Fe(2+) dopants. Their potential as simultaneous positive and negative MRI contrast agents was demonstrated by relaxivity measurements and in vivo MRI. From the in vivo studies, we also found that these NCs (with a hydrodynamic diameter of 20 nm) are excreted from the body within 24 h after the injection. Therefore, these heterodoped tetrapods NCs, while being fluorescent and safe, hold great future as a synergistically enhancing dual-modal MRI contrast agent.

L-DOPA-Coated Manganese Oxide Nanoparticles as Dual MRI Contrast Agents and Drug-Delivery Vehicles

Manganese oxide nanoparticles (MONPs) are capable of time-dependent magnetic resonance imaging contrast switching as well as releasing a surface-bound drug. MONPs give T2/T2* contrast, but dissolve and release T1-active Mn(2+) and L-3,4-dihydroxyphenylalanine. Complementary images are acquired with a single contrast agent, and applications toward Parkinson's disease are suggested.

Highly monodisperse low-magnetization magnetite nanocubes as simultaneous T(1)-T(2) MRI contrast agents

We report the first study of highly monodisperse and crystalline iron oxide nanocubes with sub-nm controlled size distribution (9.7 ± 0.5 nm in size) that achieve simultaneous contrast enhancement in both T1- and T2-weighted magnetic resonance imaging (MRI). Here, we confirmed the magnetite structure of iron oxide nanocubes by X-ray diffraction (XRD), selected area electron diffraction (SAED) pattern, optical absorption and Fourier transformed infrared (FT-IR) spectra. These magnetite nanocubes exhibit superparamagnetic and paramagnetic behavior simultaneously by virtue of their finely controlled shape and size. The magnetic measurements reveal that the magnetic moment values are favorably much lower because of the small size and cubic shape of the nanoparticles, which results in an enhanced spin canting effect. As a proof-of-concept demonstration, we showed their potential as dual contrast agents for both T1- and T2-weighted MRI via phantom studies, in vivo imaging and relaxivity measurements. Therefore, these low-magnetization magnetite nanocubes, while being non-toxic and bio-compatible, hold great promise as excellent dual-mode T1 and T2 contrast agents for MRI.