Mucus-Mimicking Mucin-Based Hydrogels By Tandem Chemical And Physical Crosslinking

Mucosal tissues represent a major interface between the body and the external environment and are covered by a highly hydrated mucins gel called mucus. Mucus lubricates, protects and modulate the moisture levels of the tissue and has been capitalized in transmucosal drug delivery. Pharmaceutical researchers often use freshly excised animal mucosal membranes to assess mucoadhesion and muco-penetration of pharmaceutical formulations which may struggle with limited accessibility and ethical questions. Aiming to develop a platform for the rationale study of the interaction of drugs and delivery systems with mucosal tissues, in this work we synthesize mucus-mimicking mucin-based hydrogels by the tandem chemical and physical crosslinking of 4% w/v mucin aqueous solutions. Chemical crosslinking is achieved with glutaraldehyde (0.3% and 0.75% w/v), while physical crosslinking by one or two freeze-thawing cycles. Hydrogels after one freeze-thawing cycle show water content of 97.6-98.1%, density of 0.0529-0.0648 g/cm3, and storage and loss moduli of ∼40-60 Pa and ∼3-5 Pa, respectively, that resemble the properties of native gastrointestinal mucus. The mechanical stability of the hydrogels increased over the number of freeze-thawing cycles. Overall results highlight the potential of this simple, reproducible and scalable method to produce artificial mucus-mimicking hydrogels for different applications in pharmaceutical research. This article is protected by copyright. All rights reserved.

Glucosylated Hybrid TiO2 /Polymer Nanomaterials for Actively Targeted Sonodynamic Therapy of Cancer

Sonodynamic therapy (SDT) is an anti-cancer therapeutic strategy based on the generation of reactive oxygen species (ROS) upon local ultrasound (US) irradiation of sono-responsive molecules or nanomaterials that accumulate in the tumor. In this work, the sonodynamic efficiency of sono-responsive hybrid nanomaterials composed of amorphous titanium dioxide and an amphiphilic poly(ethylene oxide)-b-poly(propylene oxide) block copolymer is synthesized, fully characterized, and investigated both in vitro and in vivo. The modular and versatile synthetic pathway enables the control of the nanoparticle size between 30 and 300 nm (dynamic light scattering) and glucosylation of the surface for active targeting of tumors overexpressing glucose transporters. Studies on 2D and 3D rhabdomyosarcoma cell cultures reveal a statistically significant increase in the sonodynamic efficiency of glucosylated hybrid nanoparticles with respect to unmodified ones. Using a xenograft rhabdomyosarcoma murine model, it is demonstrated that by tuning the nanoparticle size and surface features, the tumor accumulation is increased by ten times compared to main off-target clearance organs such as the liver. Finally, the SDT of rhabdomyosarcoma-bearing mice is investigated with 50-nm glucosylated nanoparticles. Findings evidence a dramatic prolongation of the animal survival and tumor volumes 100 times smaller than those treated only with ultrasound or nanoparticles.

Pulmonary arterial hypertension nanotherapeutics: New pharmacological targets and drug delivery strategies

Pulmonary arterial hypertension (PAH) is a rare, serious, and incurable disease characterized by high lung pressure. PAH-approved drugs based on conventional pathways are still not exhibiting favorable therapeutic outcomes. Drawbacks like short half-lives, toxicity, and teratogenicity hamper effectiveness, clinical conventionality, and long-term safety. Hence, approaches like repurposing drugs targeting various and new pharmacological cascades and/or loaded in non-toxic/efficient nanocarrier systems are being investigated lately. This review summarizes the status of conventional, repurposed, either in vitro, in vivo, and/or in clinical trials of PAH treatment. In-depth description, discussion, and classification of the new pharmacological targets and nanomedicine strategies with a description of all the nanocarriers that showed promising efficiency in delivering drugs are discussed. Ultimately, an illustration of the different nucleic acids tailored and nanoencapsulated within different types of nanocarriers to restore the pathways affected by this disease is presented.

Solid-State Dewetting of Thin Au Films for Surface Functionalization of Biomedical Implants

Biomaterial-centered infections of orthopedic implants remain a significant burden in the healthcare system due to sedentary lifestyles and an aging population. One approach to combat infections and improve implant osteointegration is functionalizing the implant surface with anti-infective and osteoinductive agents. In this framework, Au nanoparticles are produced on the surface of Ti-6Al-4V medical alloy by solid-state dewetting of 5 nm Au film and used as the substrate for the conjugation of a model antibiotic vancomycin via a mono-thiolated poly(ethylene glycol) linker. Produced Au nanoparticles on Ti-6Al-4V surface are equiaxed with a mean diameter 19.8 ± 7.2 nm, which is shown by high-resolution scanning electron microscopy and atomic force microscopy. The conjugation of the antibiotic vancomycin, 18.8 ± 1.3 nm-thick film, is confirmed by high resolution-scanning transmission electron microscopy and X-ray photoelectron spectroscopy. Overall, showing a link between the solid-state dewetting process and surface functionalization, we demonstrate a novel, simple, and versatile method for functionalization of implant surfaces.

Poly(ethylene glycol)-b-poly(epsilon-caprolactone) nanoparticles as a platform for the improved oral delivery of cannabidiol

Cannabidiol (CBD), a non-psychoactive constituent of Cannabis, has proven neuroprotective, anti-inflammatory and antioxidant properties though his therapeutic use, especially by the oral route, is still challenged by the poor aqueous solubility that results in low oral bioavailability. In this work, we investigate the encapsulation of CBD within nanoparticles of a highly hydrophobic poly(ethylene glycol)-b-poly(epsilon-caprolactone) block copolymer produced by a simple and reproducible nanoprecipitation method. The encapsulation efficiency is ~ 100% and the CBD loading 11% w/w (high performance liquid chromatography). CBD-loaded nanoparticles show a monomodal size distribution with sizes of up to 100 nm (dynamic light scattering), a spherical morphology, and the absence of CBD crystals (high resolution-scanning electron microscopy and cryogenic-transmission electron microscopy) which is in line with a very efficient nanoencapsulation. Then, the CBD release profile from the nanoparticles is assessed under gastric- and intestine-like conditions. At pH 1.2, only 10% of the payload is released after 1 h. Conversely, at pH 6.8, a release of 80% is recorded after 2 h. Finally, the oral pharmacokinetics is investigated in rats and compared to a free CBD suspension. CBD-loaded nanoparticles lead to a statistically significant ~ 20-fold increase of the maximum drug concentration in plasma (Cmax) and a shortening of the time to the Cmax (tmax) from 4 to 0.3 h, indicating a more complete and faster absorption than in free form. Moreover, the area-under-the-curve (AUC), a measure of oral bioavailability, increased by 14 times. Overall results highlight the promise of this simple, reproducible, and scalable nanotechnology strategy to improve the oral performance of CBD with respect to common oily formulations and/or lipid-based drug delivery systems associated with systemic adverse effects.

First transcriptomic insight into the reprogramming of human macrophages by levan-type fructans

Based on stimuli in the biological milieu, macrophages can undergo classical activation into the M1 pro-inflammatory (anti-cancer) phenotype or to the alternatively activated M2 anti-inflammatory one. Drug-free biomaterials have emerged as a new therapeutic strategy to modulate macrophage phenotype. Among them, polysaccharides polarize macrophages to M1 or M2 phenotypes based on the surface receptors they bind. Levan, a fructan, has been proposed as a novel biomaterial though its interaction with macrophages has been scarcely explored. In this study, we investigate the interaction of non-hydrolyzed and hydrolyzed Halomonas levan and its sulfated derivative with human macrophages in vitro. Viability studies show that these levans are cell compatible. In addition, RNA-sequencing analysis reveals the upregulation of pro-inflammatory pathways. These results are in good agreement with real time-quantitative polymerase chain reaction that indicates higher expression levels of C-X-C Motif Chemokine Ligand 8 and interleukin-6 genes and the M2-to-M1 reprogramming of these cells upon levan treatment. Finally, cytokine release studies confirm that hydrolyzed levans increase the secretion of pro-inflammatory cytokines and reprogram IL-4-polarized macrophages to the M1 state. Overall findings indicate that Halomonas levans trigger a classical macrophage activation and pave the way for their application in therapeutic interventions requiring a pro-inflammatory phenotype.

Dermatan Sulfate/Chitosan Nanoparticles Loaded with an Anti-Inflammatory Peptide Increase the Response of Human Colorectal Cancer Cells to 5-Fluorouracil

The gold standard drug for colorectal cancer (CRC) treatment, 5-Fluorouracil (5-FU), induces pharmacological tolerance in long-term management. The transcriptional factor nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) plays a key role in 5-FU resistance. The aim of this work is to study the capability of polyelectrolytes complex nanoparticles of dermatan sulfate (DS) and chitosan (CS), loaded with the anti-inflammatory tripeptide IRW, to sensitize colorectal cancer cells to 5-FU. Fluorescence and flow cytometry studies confirmed the recognition by the nanoformulation, of the cluster of differentiation 44 (CD44) receptor, involved in the initiation and progression of colorectal tumors. Dynamic light scattering (DLS) and flow cytometry reinforced the importance of DS and CD44 receptor in the interaction, as the addition of DS or anti-CD44 antibody blocked the binding. Moreover, the nanoformulation also interacts with 3D colon cancer cultures, namely colonospheres, enriched in cancer stem cells (CSC), subpopulation responsible for drug resistance and metastasis. To evaluate the consequences of this interaction, the subcellular distribution of the transcriptional factor NFκB, is determined by immunofluorescence analysis. Internalization and the intracellular release of IRW inhibited nuclear translocation of NFκB and increased cellular sensitivity to 5-FU. Altogether, the nanoformulation could provide a selective delivery platform for IRW distribution to colorectal tumors, being an innovative strategy toward overcoming 5-FU resistance in CRC therapy.

Gout therapeutics and drug delivery

Gout is a common inflammatory arthritis caused by persistently elevated uric acid levels. With the improvement of people's living standards, the consumption of processed food and the widespread use of drugs that induce elevated uric acid, gout rates are increasing, seriously affecting the human quality of life, and becoming a burden to health systems worldwide. Since the pathological mechanism of gout has been elucidated, there are relatively effective drug treatments in clinical practice. However, due to (bio)pharmaceutical shortcomings of these drugs, such as poor chemical stability and limited ability to target the pathophysiological pathways, traditional drug treatment strategies show low efficacy and safety. In this scenario, drug delivery systems (DDS) design that overcome these drawbacks is urgently called for. In this review, we initially describe the pathological features, the therapeutic targets, and the drugs currently in clinical use and under investigation to treat gout. We also comprehensively summarize recent research efforts utilizing lipid, polymeric and inorganic carriers to develop advanced DDS for improved gout management and therapy.

Galactomannan-graft-poly(methyl methacrylate) nanoparticles induce an anti-inflammatory phenotype in human macrophages

Macrophages are immune cells that can be activated into either pro-inflammatory M1 or anti-inflammatory M2 phenotypes. Attempts to modulate macrophage phenotype using drugs have been limited by targeting issues and systemic toxicity. This study investigates the effect of drug-free self-assembled hydrolyzed galactomannan-poly(methyl methacrylate) (hGM-g-PMMA) nanoparticles on the activation of the human monocyte-derived macrophage THP-1 cell line. Nanoparticles are cell compatible and are taken up by macrophages. RNA-sequencing analysis of cells exposed to NPs reveal the upregulation of seven metallothionein genes. Additionally, the secretion of pro-inflammatory and anti-inflammatory cytokines upon exposure of unpolarized macrophages and M1-like cells obtained by activation with lipopolysaccharide + interferon-γ to the NPs is reduced and increased, respectively. Finally, nanoparticle-treated macrophages promote fibroblast migration in vitro. Overall, results demonstrate that hGM-g-PMMA nanoparticles induce the release of anti-inflammatory cytokines by THP-1 macrophages, which could pave the way for their application in the therapy of different inflammatory conditions, especially by local delivery.

An experimental and theoretical approach to understand the interaction between particles and mucosal tissues

Nanonization of poorly water-soluble drugs has shown great potential in improving their oral bioavailability by increasing drug dissolution rate and adhesion to the gastrointestinal mucus. However, the fundamental features that govern the particle-mucus interactions have not been investigated in a systematic way before. In this work, we synthesize mucin hydrogels that mimic those of freshly excised porcine mucin. By using fluorescent pure curcumin particles, we characterize the effect of particle size (200 nm, and 1.2 and 1.3 μm), concentration (18, 35, and 71 μg mL^-1), and hydrogel crosslinking density on the diffusion-driven particle penetration in vitro. Next, we derive a phenomenological model that describes the physics behind the diffusion-derived penetration and considers the contributions of the key parameters assessed in vitro. Finally, we challenge our model by assessing the oral pharmacokinetics of an anti-cancer model drug, namely dasatinib, in pristine and nanonized forms and two clinically relevant doses in rats. For a dose of 10 mg kg^-1, drug nanonization leads to a significant ∼8- and ∼21-fold increase of the drug oral bioavailability and half-life, respectively, with respect to the unprocessed drug. When the dose of the nanoparticles was increased to 15 mg kg^-1, the oral bioavailability increased though not significantly, suggesting the saturation of the mucus penetration sites, as demonstrated by the in vitro model. Our overall results reveal the potential of this approach to pave the way for the development of tools that enable a more rational design of nano-drug delivery systems for mucosal administration. STATEMENT OF SIGNIFICANCE: The development of experimental-theoretical tools to understand and predict the diffusion-driven penetration of particles into mucus is crucial not only to rationalize the design of nanomedicines for mucosal administration but also to anticipate the risks of the exposure of the body to nano-pollutants. However, a systematic study of such tools is still lacking. Here we introduce an experimental-theoretical approach to predict the diffusion-driven penetration of particles into mucus and investigate the effect of three key parameters on this interaction. Then, we challenge the model in a preliminary oral pharmacokinetics study in rats which shows a very good correlation with in vitro results. Overall, this work represents a robust platform for the modelling of the interaction of particles with mucosae under dynamic conditions.

Polymeric nanoparticles surface-complexed with boric acid actively target solid tumors overexpressing sialic acid

Sialic acid is a fundamental component of the tumor microenvironment, modulates cell-cell and cell-extracellular matrix interactions and is associated with bad prognosis and clinical outcomes in different cancers. Capitalizing on the ability of boric acid to form cyclic esters with diols, in this work, we design self-assembled multi-micellar colloidal systems of an amphiphilic poly(vinyl alcohol)-g-poly(methyl methacrylate) copolymer surface-modified with boric acid for the active targeting of solid tumors that overexpress sialic acid. Nanoparticles display sizes in the 100-200 nm range and a spherical morphology, as determined by dynamic light scattering and high resolution-scanning electron microscopy, respectively. The uptake and anti-proliferative activity are assessed in 2D and 3D models of rhabdomyosarcoma in vitro. Surface boration increases the nanoparticle permeability and uptake, especially in rhabdomyosarcoma spheroids that overexpress sialic acid to a greater extent than 2D cultures. The biodistribution of non-borated and borated nanoparticles upon intravenous injection to a subcutaneous rhabdomyosarcoma murine xenograft model confirm a statistically significant increase in the intertumoral accumulation of the modified nanocarriers with respect to the unmodified counterparts and a sharp decrease in major clearance organs such as the liver. Overall, our results highlight the promise of these borated nanomaterials to actively target hypersialylated solid tumors.

Antibiotic-Loaded Amphiphilic Chitosan Nanoparticles Target Macrophages and Kill an Intracellular Pathogen

In this work, levofloxacin (LVX), a third-generation fluoroquinolone antibiotic, is encapsulated within amphiphilic polymeric nanoparticles of a chitosan-g-poly(methyl methacrylate) produced by self-assembly and physically stabilized by ionotropic crosslinking with sodium tripolyphosphate. Non-crosslinked nanoparticles display a size of 29 nm and a zeta-potential of +36 mV, while the crosslinked counterparts display 45 nm and +24 mV, respectively. The cell compatibility, uptake, and intracellular trafficking are characterized in the murine alveolar macrophage cell line MH-S and the human bronchial epithelial cell line BEAS-2B in vitro. Internalization events are detected after 10 min and the uptake is inhibited by several endocytosis inhibitors, indicating the involvement of complex endocytic pathways. In addition, the nanoparticles are detected in the lysosomal compartment. Then, the antibacterial efficacy of LVX-loaded nanoformulations (50% w/w drug content) is assessed in MH-S and BEAS-2B cells infected with Staphylococcus aureus and the bacterial burden is decreased by 49% and 46%, respectively. In contrast, free LVX leads to a decrease of 8% and 5%, respectively, in the same infected cell lines. Finally, intravenous injection to a zebrafish larval model shows that the nanoparticles accumulate in macrophages and endothelium and demonstrate the promise of these amphiphilic nanoparticles to target intracellular infections.

Adsorption of SARS CoV-2 spike proteins on various functionalized surfaces correlates with the high transmissibility of Delta and Omicron variants

The SARS-CoV-2 virus emerged at the end of 2019 and rapidly developed several mutated variants, specifically the Delta and Omicron, which demonstrate higher transmissibility and escalating infection cases worldwide. The dominant transmission pathway of this virus is via human-to-human contact and aerosols which once inhaled interact with the mucosal tissue, but another possible route is through contact with surfaces contaminated with SARS-CoV-2, often exhibiting long-term survival. Here we compare the adsorption capacities of the S1 and S2 subunits of the spike (S) protein from the original variant to that of the S1 subunit from the Delta and Omicron variants on self-assembled monolayers by Quartz Crystal ​Microbalance. The results clearly show a significant difference in adsorption capacity between the different variants, as well as between the S1 and S2 subunits. Overall, our study demonstrates that while the Omicron variant is able to adsorb much more successfully than the Delta, both variants show enhanced adsorption capacity than that of the original strain. We also examined the influence of pH conditions on the adsorption ability of the S1 subunit and found that adsorption was strongest at pH 7.4, which is the physiological pH. The main conclusion of this study is that there is a strong correlation between the adsorption capacity and the transmissibility of the various SARS-CoV-2 variants.

Amphiphilic galactomannan nanoparticles trigger the alternative activation of murine macrophages

Macrophages are highly plastic phagocytic cells that can exist in distinct phenotypes and play key roles in physiological and pathological pathways. They can be classically activated to the pro-inflammatory M1 phenotype or alternatively activated to an M2 anti-inflammatory one by various stimuli in the biological milieu. Different biomaterials polarize macrophages to M1 or M2 phenotypes and emerged as a very promising strategy to modulate their activation and performance. In this work, we investigate the ability of drug-free amphiphilic nanoparticles (hydrodynamic diameter of ~130 nm) produced by the self-assembly of a graft copolymer of hydrolyzed galactomannan, a natural polysaccharide of galactose and mannose, that was hydrophobized in the side-chain with poly(methyl methacrylate) blocks and that can encapsulate hydrophobic drugs, to trigger macrophage polarization. The compatibility and uptake of the nanoparticles are demonstrated in the murine macrophage cell line RAW264.7 by a metabolic assay, confocal laser scanning fluorescence microscopy (CLSFM) and imaging flow cytometry in the absence and the presence of endocytosis inhibitors. Results indicate that they are internalized by both clathrin- and caveolin-mediated endocytosis. The ability of these drug-free nanoparticles to polarize these cells to the M2-like phenotype and to switch an M1 to an M2 phenotype is confirmed by the downregulation of the M1 marker cluster of differentiation 80 (CD80), and upregulation of M2 markers CD163 and CD206, as measured by flow cytometry and CLSFM. In addition, we preliminarily assess the effect of the nanoparticles on wound healing by tracking the closure of an artificial wound of RAW264.7 macrophages in a scratch assay. Findings indicate a faster closure of the wound in the presence of the nanoparticles with respect to untreated cells. Finally, a migration assay utilizing a macrophage/fibroblast co-culture model in vitro demonstrates that M2 polarization increases fibroblast migration by 24-fold with respect to untreated cells. These findings demonstrate the ability of this nanotechnology platform to interfere and change the macrophages phenotype in vitro and represent robust evidence for the investigation of their therapeutic performance alone or in combination with an encapsulated hydrophobic drug in wound models in vivo.

Multifunctional silica-coated mixed polymeric micelles for integrin-targeted therapy of pediatric patient-derived glioblastoma

Glioblastoma multiforme (GBM) remains a major cause of mortality because treatments are precluded by to the limited transport and penetration of chemotherapeutics across the blood-brain barrier. Pitavastatin (PTV) is a hydrophobic Food and Drug Administration (FDA)-approved anticholesterolemic agent with reported anti-GBM activity. In the present study, we encapsulate PTV in silica-coated polymeric micelles (SiO₂ PMs) surface-modified with the cyclic peptide Arg-Gly-Asp-Phe-Val (cRGDfV) that actively targets the α_vβ₃ integrin overexpressed in the BBB endothelium and GBM. A central composite design is utilized to optimize the preparation process and improve the drug encapsulation ratio from 131 to 780 μg/mL. The silica shell provides full colloidal stability upon extreme dilution and enables a better control of the release kinetics in vitro with 28% of the cargo released after 12 h. Furthermore, SiO₂ PMs show excellent compatibility and are internalized by human BBB endothelial cells, astrocytes and pericytes, as shown by confocal laser scanning fluorescence microscopy and flow cytometry. Finally, the anticancer efficacy is assessed in a pediatric patient-derived glioma cell line expressing high levels of the integrin subunits αv, β3 and β5. This PTV-loaded nanocarrier triggers apoptosis by reducing the mRNA level of anti-apoptotic genes NF-kβ, IL-6, BIRC1 and BIRC5 by 89%, 33%, 81% and 63%, respectively, and the cell viability by >60%. Overall, our results suggest the potential of these hybrid nanocarriers for the targeted therapy of GBM and other tumors overexpressing integrin receptors.

Structured edible lipid-based particle systems for oral drug-delivery

Oral administration is the most popular and patient-compliant route for drug delivery, though it raises great challenges due to the involvement of the gastro-intestine (GI) system and the drug bioavailability. Drug bioavailability is directly related to its ability to dissolve, transport and/or absorb through the physiological environment. A great number of drugs are characterized with low water solubility due to their hydrophobic nature, thus limiting their oral bioavailability and clinical use. Therefore, new strategies aiming to provide a protective shell through the GI system and improve drug solubility and permeability in the intestine were developed to overcome this limitation. Lipid-based systems have been proposed as good candidates for such a task owing to their hydrophobic nature which allows high drug loading, drug micellization ability during intestinal digestion due to the lipid content, and the vehicle physical protective environment. The use of edible lipids with high biocompatibility paves the bench-to-bedside translation. Four main types of structured lipid-based drug delivery systems differing in the physical state of the lipid phase have been described in the literature, namely emulsions, solid lipid nanoparticles, nanostructured lipid carriers, and oleogel-based particles. The current review provides a comprehensive overview of the different structured edible lipid-based oral delivery systems investigated up to date and emphasizes the contribution of each system component to the delivery performance, and the oral delivery path of lipids.

High-grade extracellular vesicles preparation by combined size-exclusion and affinity chromatography

Extracellular vesicles (EVs) have recently gained growing interest for their diagnostic and therapeutic potential. Despite this, few protocols have been reported for the isolation of EVs with preserved biological function. Most EV purification methods include a precipitation step that results in aggregation of vesicles and most available techniques do not efficiently separate the various types of EVs such as exosomes and ectosomes, which are involved in distinct biological processes. For this reason, we developed a new two-step fast performance liquid chromatography (FPLC) protocol for purification of large numbers of EVs. The method comprises size exclusion chromatography followed by immobilized metal affinity chromatography, which is enabled by expression of poly-histidine tagged folate receptor α in the parental cells. Characterisation and comparison of the EVs obtained by this method to EVs purified by differential centrifugation, currently the most common method to isolate EVs, demonstrated higher purity and more selective enrichment of exosomes in EV preparations using our FPLC method, as assessed by comparison of marker proteins and density distribution. Our studies reveal new possibilities for the isolation of defined subpopulations of EVs with preserved biological function that can easily be upscaled for production of larger amounts of EVs.

Enhanced photoluminescence of boron nitride quantum dots by encapsulation within polymeric nanoparticles

Boron nitride quantum dots (BNQDs) have been proposed as probes for bioimaging owing their to outstanding photoluminescent properties, although their hydrophobic nature and strong aggregation tendency in aqueous media limit their application in the biomedical field. In this work, we synthesize BNQDs by a liquid exfoliation-solvothermal process under pressure from boron nitride nanoparticles in N,N-dimethylformamide. The BNQDs display an average size of 3.3 ± 0.6 nm, as measured by transmission electron microscopy, and a (100) crystalline structure. In addition, a quantum yield of 21.75 ± 0.20% was achieved. To ensure complete dispersibility in water and prevent possible elimination by renal filtration upon injection, the BNQDs (20% w/w) are encapsulated within poly(ethylene glycol)-b-poly(epsilon-caprolactone) nanoparticles by a simple and scalable nanoprecipitation method, and hybrid nanocomposite particles with significantly stronger photoluminescence than their free counterparts are produced. Finally, their optimal cell compatibility and bioimaging features are demonstrated in vitro in murine macrophage and human rhabdomyosarcoma cell lines.

Excipient-Free Pure Drug Nanoparticles Fabricated by Microfluidic Hydrodynamic Focusing

Nanoprecipitation is one of the most versatile methods to produce pure drug nanoparticles (PDNPs) owing to the ability to optimize the properties of the product. Nevertheless, nanoprecipitation may result in broad particle size distribution, low physical stability, and batch-to-batch variability. Microfluidics has emerged as a powerful tool to produce PDNPs in a simple, reproducible, and cost-effective manner with excellent control over the nanoparticle size. In this work, we designed and fabricated T- and Y-shaped Si-made microfluidic devices and used them to produce PDNPs of three kinase inhibitors of different lipophilicity and water-solubility, namely imatinib, dasatinib and tofacitinib, without the use of colloidal stabilizers. PDNPs display hydrodynamic diameter in the 90-350 nm range as measured by dynamic light scattering and a rounded shape as visualized by high-resolution scanning electron microscopy. Powder X-ray diffraction and differential scanning calorimetry confirmed that this method results in highly amorphous nanoparticles. In addition, we show that the flow rate of solvent, the anti-solvent, and the channel geometry of the device play a key role governing the nanoparticle size.

Stimulating Extracellular Vesicles Production from Engineered Tissues by Mechanical Forces

Extracellular vesicles (EVs) have emerged as a promising strategy to promote tissue regeneration. However, overcoming the low EV production yield remains a big challenge in translating EV-based therapies to the clinical practice. Current EV production relies heavily on 2D cell culture, which is not only less physiologically relevant to cells but also requires substantial medium and space. In this study, we engineered tissues seeded with stem cells from dental pulp or adipose tissues, or skeletal muscle cells, and significantly enhanced the EV production yield by applying mechanical stimuli, including flow and stretching, in bioreactors. Further mechanistic investigation revealed that this process was mediated by yes-associated protein (YAP) mechanosensitivity. EVs from mechanically stimulated dental pulp stem cells on 3D scaffolds displayed superior capability in inducing axonal sprouting than the 2D counterparts. Our results demonstrate the promise of this strategy to boost EV production and optimize their functional performance toward clinical translation.

Heterocellular spheroids of the neurovascular blood-brain barrier as a platform for personalized nanoneuromedicine

Nanoneuromedicine investigates nanotechnology to target the brain and treat neurological diseases. In this work, we biofabricated heterocellular spheroids comprising human brain microvascular endothelial cells, brain vascular pericytes and astrocytes combined with primary cortical neurons and microglia isolated from neonate rats. The structure and function are characterized by confocal laser scanning and light sheet fluorescence microscopy, electron microscopy, western blotting, and RNA sequencing. The spheroid bulk is formed by neural cells and microglia and the surface by endothelial cells and they upregulate key structural and functional proteins of the blood-brain barrier. These cellular constructs are utilized to preliminary screen the permeability of polymeric, metallic, and ceramic nanoparticles (NPs). Findings reveal that penetration and distribution patterns depend on the NP type and that microglia would play a key role in this pathway, highlighting the promise of this platform to investigate the interaction of different nanomaterials with the central nervous system in nanomedicine, nanosafety and nanotoxicology.

Aerogels in drug delivery: From design to application

Aerogels are the lightest processed solid materials on Earth and with the largest empty volume fraction in their structure. Composition versatility, modularity, and feasibility of industrial scale manufacturing are behind the fast emergence of aerogels in the drug delivery field. Compared to other 3D materials, the high porosity (interconnected mesopores) and high specific surface area of aerogels may allow faster loading of small-molecule drugs, less constrained access to inner regions of the matrix, and more efficient interactions of the biological milieu with the polymer matrix. Processing in supercritical CO₂ medium for both aerogel production (drying) and drug loading (impregnation) has remarkable advantages such as absence of an oxidizing environment, clean manufacture, and easiness for the scale-up under good manufacturing practices. The aerogel solid skeleton dictates the chemical affinity to the different drugs, which in turn determines the loading efficiency and the release pattern. Aerogels can be used to increase the solubility of BCS Class II and IV drugs because the drug can be deposited in amorphous state onto the large surface area of the skeleton, which facilitates a rapid contact with the body fluids, dissolution, and release. Conversely, tuning the aerogel structure by functionalization with drug-binding moieties or stimuli-responsive components, application of coatings and incorporation of drug-loaded aerogels into other matrices may enable site-specific, stimuli-responsive, or prolonged drug release. The present review deals with last decade advances in aerogels for drug delivery. An special focus is paid first on the loading efficiency of active ingredients and release kinetics under biorelevant conditions. Subsequent sections deal with aerogels intended to address specific therapeutic demands. In addition to oral delivery, the physical properties of the aerogels appear to be very advantageous for mucosal administration routes, such as pulmonary, nasal, or transdermal. A specific section devoted to recent achievements in gene therapy and theranostics is also included. In the last section, scale up strategies and life cycle assessment are comprehensively addressed.

Molecular and cellular cues governing nanomaterial-mucosae interactions: from nanomedicine to nanotoxicology

Mucosal tissues constitute the largest interface between the body and the surrounding environment and they regulate the access of molecules, supramolecular structures, particulate matter, and pathogens into it. All mucosae are characterized by an outer mucus layer that protects the underlying cells from physicochemical, biological and mechanical insults, a mono-layered or stratified epithelium that forms tight junctions and controls the selective transport of solutes across it and associated lymphoid tissues that play a sentinel role. Mucus is a gel-like material comprised mainly of the glycoprotein mucin and water and it displays both hydrophilic and hydrophobic domains, a net negative charge, and high porosity and pore interconnectivity, providing an efficient barrier for the absorption of therapeutic agents. To prolong the residence time, absorption and bioavailability of a broad spectrum of active compounds upon mucosal administration, mucus-penetrating and mucoadhesive particles have been designed by tuning the chemical composition, the size, the density, and the surface properties. The benefits of utilizing nanomaterials that interact intimately with mucosae by different mechanisms in the nanomedicine field have been extensively reported. To ensure the safety of these nanosystems, their compatibility is evaluated in vitro and in vivo in preclinical and clinical trials. Conversely, there is a growing concern about the toxicity of nanomaterials dispersed in air and water effluents that unintentionally come into contact with the airways and the gastrointestinal tract. Thus, deep understanding of the key nanomaterial properties that govern the interplay with mucus and tissues is crucial for the rational design of more efficient drug delivery nanosystems (nanomedicine) and to anticipate the fate and side-effects of nanoparticulate matter upon acute or chronic exposure (nanotoxicology). This review initially overviews the complex structural features of mucosal tissues, including the structure of mucus, the epithelial barrier, the mucosal-associated lymphatic tissues and microbiota. Then, the most relevant investigations attempting to identify and validate the key particle features that govern nanomaterial-mucosa interactions and that are relevant in both nanomedicine and nanotoxicology are discussed in a holistic manner. Finally, the most popular experimental techniques and the incipient use of mathematical and computational models to characterize these interactions are described.

Multidomain drug delivery systems of β-casein micelles for the local oral co-administration of antiretroviral combinations

The antiretroviral (ARV) cocktailrevolved the treatment of the human immunodeficiency virus (HIV) infection. Drug combinations have been also tested to treat other infectious diseases, including the recentcoronavirus disease 2019 (COVID-19) outbreak. To simplify administration fixed-dose combinationshave been introduced, however, oral anti-HIV therapy still struggles with low oral bioavailability of many ARVs.This work investigated the co-encapsulation of two clinically relevant ARV combinations,tipranavir (TPV):efavirenz (EFV) anddarunavir (DRV):efavirenz (EFV):ritonavir (RTV),within the core of β-casein (bCN) micelles. Encapsulation efficiency in both systems was ~100%. Cryo-transmission electron microscopy and dynamic light scattering of the ARV-loaded colloidaldispersions indicatefull preservation of the spherical morphology, and x-ray diffraction confirm that the encapsulated drugs are amorphous. To prolong the physicochemical stabilitythe formulations were freeze-driedwithout cryo/lyoprotectant, and successfully redispersed, with minor changes in morphology.Then, theARV-loaded micelles were encapsulated within microparticles of Eudragit® L100, which prevented enzymatic degradation and minimized drug release under gastric-like pH conditionsin vitro. At intestinal pH, the coating polymer dissolved and released the nanocarriers and content. Overall, our results confirm the promise of this flexible and modular technology platform for oral delivery of fixed dose combinations.

Mixed Amphiphilic Polymeric Nanoparticles of Chitosan, Poly(vinyl alcohol) and Poly(methyl methacrylate) for Intranasal Drug Delivery: A Preliminary In Vivo Study

Intranasal (i.n.) administration became an alternative strategy to bypass the blood-brain barrier and improve drug bioavailability in the brain. The main goal of this work was to preliminarily study the biodistribution of mixed amphiphilic mucoadhesive nanoparticles made of chitosan-g-poly(methyl methacrylate) and poly(vinyl alcohol)-g-poly(methyl methacrylate) and ionotropically crosslinked with sodium tripolyphosphate in the brain after intravenous (i.v.) and i.n. administration to Hsd:ICR mice. After i.v. administration, the highest nanoparticle accumulation was detected in the liver, among other peripheral organs. After i.n. administration of a 10-times smaller nanoparticle dose, the accumulation of the nanoparticles in off-target organs was much lower than after i.v. injection. In particular, the accumulation of the nanoparticles in the liver was 20 times lower than by i.v. When brains were analyzed separately, intravenously administered nanoparticles accumulated mainly in the "top" brain, reaching a maximum after 1 h. Conversely, in i.n. administration, nanoparticles were detected in the "bottom" brain and the head (maximum reached after 2 h) owing to their retention in the nasal mucosa and could serve as a reservoir from which the drug is released and transported to the brain over time. Overall, results indicate that i.n. nanoparticles reach similar brain bioavailability, though with a 10-fold smaller dose, and accumulate in off-target organs to a more limited extent and only after redistribution through the systemic circulation. At the same time, both administration routes seem to lead to differential accumulation in brain regions, and thus, they could be beneficial in the treatment of different medical conditions.

A Microscopically Motivated Model for Particle Penetration into Swollen Biological Networks

Biological gels (bio-gels) are hydrated polymer networks that serve diverse biological functions, which often lead to intentional or unintentional exposure to particulate matter. In this work, we derive a microscopically motivated framework that enables the investigation of penetration mechanisms into bio-gels. We distinguish between two types of mechanisms: spontaneous (unforced) penetration and forced penetration. Using experimental data available in the literature, we exploit the proposed model to characterize and compare between the microstructures of respiratory, intestinal, and cervicovaginal mucus and two types of biofilms. Next, we investigate the forced penetration process of spherical and ellipsoidal particles into a locally quadrilateral network. The proposed framework can be used to improve and complement the analysis of experimental findings in vitro, ex vivo, and in vivo. Additionally, the insights from this work pave the way towards enhanced designs of nano-medicines and allow the assessment of risk factors related to the nano-pollutants exposure.

The Nose-To-Brain Transport of Polymeric Nanoparticles Is Mediated by Immune Sentinels and Not by Olfactory Sensory Neurons

The nose-to-brain (N-to-B) transport mechanism of nanoparticles through the olfactory epithelium (OE) is not fully understood. Most research utilized nasal epithelial cell models completely deprived of olfactory cells. Aiming to shed light into key cellular pathways, in this work, for the first time, the interaction of polymeric nanoparticles in a 17-483 nm size range and with neutral and negatively and positively charged surfaces with primary olfactory sensory neurons, cortical neurons, and microglia isolated from olfactory bulb (OB), OE, and cortex of newborn rats is investigated. After demonstrating the good cell compatibility of the different nanoparticles, the nanoparticle uptake by confocal laser scanning fluorescence microscopy is monitored. Our findings reveal that neither olfactory nor forebrain neurons internalize nanoparticles. Conversely, it is demonstrated that olfactory and cortical microglia phagocytose the nanoparticles independently of their features. Overall, our findings represent the first unambiguous evidence of the possible involvement of microglia in N-to-B nanoparticle transport and the unlikely involvement of neurons. Furthermore, this approach emerges as a completely new experimental tool to screen the biocompatibility, uptake, and transport of nanomaterials by key cellular players of the N-to-B pathway in nanosafety and nanotoxicology and nanomedicine.

Oral Pharmacokinetics of a Chitosan-Based Nano- Drug Delivery System of Interferon Alpha

Interferon alpha (IFNα) is a protein drug used to treat viral infections and cancer diseases. Due to its poor stability in the gastrointestinal tract, only parenteral administration ensures bioavailability, which is associated with severe side effects. We hypothesized that the nanoencapsulation of IFNα within nanoparticles of the mucoadhesive polysaccharide chitosan would improve the oral bioavailability of this drug. In this work, we produced IFNα-loaded chitosan nanoparticles by the ionotropic gelation method. Their hydrodynamic diameter, polydispersity index and concentration were characterized by dynamic light scattering and nanoparticle tracking analysis. After confirming their good cell compatibility in Caco-2 and WISH cells, the permeability of unmodified and poly(ethylene glycol) (PEG)-modified (PEGylated) nanoparticles was measured in monoculture (Caco-2) and co-culture (Caco-2/HT29-MTX) cell monolayers. Results indicated that the nanoparticles cross the intestinal epithelium mainly by the paracellular route. Finally, the study of the oral pharmacokinetics of nanoencapsulated IFNα in BalbC mice revealed two maxima and area-under-the-curve of 56.9 pg*h/mL.

Folate Receptor α-Modified Nanoparticles for Targeting of the Central Nervous System

Effective and timely delivery of therapeutic agents from the systemic circulation to the central nervous system (CNS) is often precluded by the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB). A new pathway of folate uptake mediated by folate receptor alpha (FRα, molecular weight of 28.29 kg mol^-1) occurring in various epithelial cells of the CNS (e.g., choroid plexus) was described. Aiming to investigate this mechanism for the delivery of nanomedicines to the CNS, in this work, we initially produced nanoparticles (NPs) made of a highly hydrophobic poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG-b-PCL) block copolymer functionalized with an amine moiety in the edge of the PEG block by a simple nanoprecipitation method. Hydrophilic PEG blocks migrated to the NP surface during formation, exposing primary amine groups that were used to conjugate the targeting ligand, FRα. The size of the NPs was in the 58-98 nm range and standard deviation (S.D., a measure of the size population peak width) of 26-41 nm, as measured by dynamic light scattering (DLS). The FRα conjugation yield ranged between 50% and 75% (determined indirectly by the bicinchoninic acid protein assay). Pristine and FRα-modified NPs showed good compatibility with primary human choroid plexus epithelial cells (HCPEpiCs). The uptake of FRα-conjugated NPs by HCPEpiCs was qualitatively evaluated in vitro using inverted optical fluorescence and confocal microscopy. FRα-modified NPs were internalized by HCPEpiCs to a greater extent than the unmodified counterparts. Then, their permeability was characterized in standard and inverted HCPEpiC monolayers. In both cases, NPs surface modified with the FRα and complexed to folic acid (FA) showed significantly higher apparent permeability coefficient (P_app) values than the pristine ones. Finally, the biodistribution of unmodified and FRα-FA-modified NPs following intravenous (i.v.) administration was compared in ICR mice. Results indicated that conjugation of the FRα-FA complex to the NP surface promotes higher accumulation in the brain, highlighting the promise of FRα-FA-modified NPs to serve as a platform for the targeting of active molecules to the CNS from the systemic circulation.

Enhanced Thermostability and Anticancer Activity in Breast Cancer Cells of Laccase Immobilized on Pluronic-Stabilized Nanoparticles

Laccases are multi-copper oxidase enzymes having widespread applications in various biotechnological fields. However, low stability of free enzymes restricts their industrial use. Development of effective methods to preserve and even increase the enzymatic activity is critical to maximize their use, though this remains a challenge. In the present study we immobilized Trametes versicolor laccase on pH-responsive (and charge-switchable) Pluronic-stabilized silver nanoparticles (AgNPs^Trp). Our results demonstrate that colloidal stabilization of AgNPs^Trp with the amphiphilic copolymer Pluronic F127 enhances enzyme activity (AgNPsTrpF1 + Lac6) by changing the active site microenvironment, which is confirmed by circular dichroism (CD) and fluorescence spectroscopy. Detailed kinetic and thermodynamic studies reveal a facile strategy to improve the protein quality by lowering the activation energy and expanding the temperature window for substrate hydrolysis. The immobilized nanocomposite did not show any change in flow behavior which indirectly suggests that the enzyme stability is maintained, and the enzyme did not aggregate or unfold upon immobilization. Finally, assessing the anticancer efficacy of this nanocomposite in breast cancer MCF-7 cells shows the inhibition of cell proliferation through β-estradiol degradation and cells apoptosis. To understand the molecular mechanism involved in this process, semi qRT-PCR experiments were performed, which indicated significant decrease in the mRNA levels of anti-apoptotic genes, for example, BCL-2 and NF-kβ, and increase in the mRNA level of pro-apoptotic genes like p53 in treated cells, compared to control. Overall, this study offers a completely new strategy for tailoring nano-bio-interfaces with improved activity and stability of laccase.

Selective Accumulation of Galactomannan Amphiphilic Nanomaterials in Pediatric Solid Tumor Xenografts Correlates with GLUT1 Gene Expression

In this work, we designed, characterized, and investigated the performance of hydrolyzed galactomannan (hGM)-based amphiphilic nanoparticles for selective intratumoral accumulation in pediatric patient-derived sarcomas. To create a self-assembly amphiphilic copolymer, the side chain of hGM was hydrophobized with poly(methyl methacrylate) (PMMA) by utilizing a graft free radical polymerization reaction. Different hGM and MMA weight feeding ratios were used to adjust the critical aggregation concentration and the size and size distribution of the nanoparticles. The ability to actively target glucose transporter-1 (GLUT-1) was studied by fluorescence confocal microscopy and imaging flow cytometry in vitro on Rh30 (rhabdomyosarcoma) and patient-derived Ewing sarcoma (HSJD-ES-001) cell lines with different expression levels of GLUT-1. Results confirmed that the nanoparticles are internalized by ∼100% of the cells at 37 °C. Furthermore, we investigated the biodistribution of the nanoparticles in pediatric patient-derived models of two deadly musculoskeletal tumors, rhabdomyosarcoma and Ewing sarcoma. Outstandingly, the intratumoral accumulation of the nanoparticles correlated very well with the expression level of GLUT1 gene in each patient-derived tumor (P = 0.0141; Pearson's correlation test). Finally, we demonstrated the encapsulation capacity of these nanoparticles by loading 7.5% (w/w) of the hydrophobic first-generation tyrosine kinase inhibitor imatinib. These findings point out the potential of this new type of nanoparticle to target GLUT-1-expressing tumors and selectively deliver anticancer agents.

Enhanced Nanoencapsulation of Sepiapterin within PEG-PCL Nanoparticles by Complexation with Triacetyl-Beta Cyclodextrin

In this work, we aimed to improve the encapsulation efficiency of sepiapterin (SP), the natural precursor of the essential cofactor tetrahydrobiopterin (BH4) that displays mild water-solubility and a short biological half-life, within methoxy-poly(ethylene-glycol)-poly(epsilon-caprolactone)(mPEG-PCL) nanoparticles (NPs) by means of its complexation and hydrophobization with 2,3,6-triacetyl-β-cyclodextrin (TAβCD). For this, SP/TAβCD complexes were produced by spray-drying of SP/TAβCD binary solutions in ethanol using the Nano Spray Dryer B-90 HP. Dry powders were characterized by differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), and transmission and scanning electron microscopy (TEM and SEM, respectively) and compared to the pristine components and their physical mixtures (PMs). Next, SP was encapsulated within mPEG-PCL NPs by nano-precipitation of an SP/TAβCD complex/mPEG-PCL solution. In addition to the nano-encapsulation of a preformed complex within the polymeric NPs, we assessed an alternative encapsulation approach called drying with copolymer (DWC) in which pristine SP, TAβCD, and mPEG-PCL were co-dissolved in a mixture of acetone and methanol at the desired weight ratio, dried under vacuum, re-dissolved, and nano-precipitated in water. The dissolution-drying step was aimed to promote the formation of molecular hydrophobic interactions between SP, TAβCD, and the PCL blocks in the copolymer. SP-loaded mPEG-PCL NPs were characterized by dynamic light scattering (DLS) and SEM. NPs with a size of 74-75 nm and standard deviation (S.D., a measure of the peak width) of 21-22 nm were obtained when an SP:TAβCD (1:1 molar ratio) spray-dried complex was used for the nano-encapsulation and SEM analysis revealed the absence of free SP crystals. The encapsulation efficiency (%EE) and drug loading (%DL) were 85% and 2.6%, respectively, as opposed to the much lower values (14% and 0.6%, respectively) achieved with pristine SP. Moreover, the NPs sustained the SP release with relatively low burst effect of 20%. Overall, our results confirmed that spray-drying of SP/TAβCD solutions at the appropriate molar ratio leads to the hydrophobization of the relatively hydrophilic SP molecule, enabling its encapsulation within mPEG-PCL NPs and paves the way for the use of this strategy in the development of novel drug delivery systems of this vital biological precursor.

Mixed Mucoadhesive Amphiphilic Polymeric Nanoparticles Cross a Model of Nasal Septum Epithelium in Vitro

Intranasal administration of nano-drug-delivery systems emerged as an appealing strategy to surpass the blood-brain barrier and thus increase drug bioavailability in the central nervous system. However, a systematic study of the effect of the structural properties of the nanoparticles on the nose-to-brain transport is missing. In this work, we synthesized and characterized mixed amphiphilic polymeric nanoparticles combining two mucoadhesive graft copolymers, namely, chitosan- g-poly(methyl methacrylate) and poly(vinyl alcohol)- g-poly(methyl methacrylate), for the first time. Chitosan enables the physical stabilization of the nanoparticles by ionotropic cross-linking with tripolyphosphate and confers mucoadhesiveness, while poly(vinyl alcohol) is also mucoadhesive and, owing to its nonionic nature, it improves nanoparticle compatibility in nasal epithelial cells by reducing the surface charge of the nanoparticles. After a thorough characterization of the mixed nanoparticles by dynamic light scattering and nanoparticle tracking analysis, we investigated the cell uptake by fluorescence light and confocal microscopy and imaging flow cytometry. Mixed nanoparticles were readily internalized at 37 °C, while the uptake was inhibited almost completely at 4 °C, indicating the involvement of energy-dependent mechanisms. Finally, we assessed the nanoparticle permeability across liquid-liquid and air-liquid monolayers of a nasal septum epithelial cell line and studied the effect of nanoparticle concentration and temperature on the apparent permeability. Overall, our findings demonstrate that these novel amphiphilic nanoparticles cross this in vitro model of intranasal epithelium mainly by a passive (paracellular) pathway involving the opening of epithelial tight junctions.

Chitosan-graft-poly(methyl methacrylate) amphiphilic nanoparticles: Self-association and physicochemical characterization

In this work, we synthesized and characterized the self-assembly behavior of a chitosan-poly(methyl methacrylate) graft copolymer and the properties of the formed nanoparticles by static and dynamic light scattering, small-angle neutron scattering, and transmission electron microscopy. Overall, our results indicate that the hydrophobization of the chitosan side-chain with PMMA leads to a complex array of small unimolecular and/or small-aggregation number "building blocks" that further self-assemble into larger amphiphilic nanoparticles.

Tissue Compatibility of SN-38-Loaded Anticancer Nanofiber Matrices

Delivery of chemotherapy in the surgical bed has shown preclinical activity to control cancer progression upon subtotal resection of pediatric solid tumors, but whether this new treatment is safe for tumor-adjacent healthy tissues remains unknown. Here, Wistar rats are used to study the anatomic and functional impact of electrospun nanofiber matrices eluting SN-38-a potent chemotherapeutic agent-on several body sites where pediatric tumors such as neuroblastoma, Ewing sarcoma, and rhabdomyosarcoma arise. Blank and SN-38-loaded matrices embracing the femoral neurovascular bundle or in direct contact with abdominal viscera (liver, kidney, urinary bladder, intestine, and uterus) are placed. Foreign body tissue reaction to the implants is observed though no histologic damage in any tissue/organ. Skin healing is normal. Tissue reaction is similar for SN-38-loaded and blank matrices, with the exception of the hepatic capsule that is thicker for the former although within the limits consistent with mild foreign body reaction. Tissue and organ function is completely conserved after local treatments, as assessed by the rotarod test (forelimb function), hematologic tests (liver and renal function), and control of clinical signs. Overall, these findings support the clinical translation of SN-38-loaded nanofiber matrices to improve local control strategies of surgically resected tumors.

Nanoparticle-in-microparticle oral drug delivery system of a clinically relevant darunavir/ritonavir antiretroviral combination

Nanonizationhas been extensively investigated to increase theoral bioavailability of hydrophobicdrugsin general andantiretrovirals(ARVs)used inthe therapy of the human immunodeficiency virus (HIV) infection in particular. Weanticipatedthatin the caseofprotease inhibitors, a family of pH-dependent ARVsthatdisplay high aqueous solubility undertheacidconditionsof thestomach andextremely low solubilityunder the neutral ones ofthe small intestine, this strategy might failowing to an uncontrolled dissolution-re-precipitation process that will take place along the gastrointestinal tract.To tackle thisbiopharmaceutical challenge, in this work, wedesigned, produced and fully characterized a novelNanoparticle-in-MicroparticleDelivery System(NiMDS)comprised of pure nanoparticlesofthefirst-line protease inhibitor darunavir(DRV) and itsboosting agentritonavir (RIT) encapsulated within film-coated microparticles.For this, a clinically relevant combination of pure DRV and RIT nanoparticles wassynthesized by a sequential nanoprecipitation/solvent diffusion and evaporation method employing sodium alginateas viscosity stabilizer. Then, pure nanoparticles were encapsulated within calcium alginate/chitosanmicroparticlesthat were film-coated with a series ofpoly(methacrylate) copolymers with differential solubility in the gastrointestinal tract. This coating ensured full stability under gastric-like pH and sustained drug release under intestinal one. PharmacokineticstudiesconductedinalbinoSpragueDawleyratsshowed that DRV/RIT-loadedNiMDSs containing 17% w/w drug loading based on dry weight significantlyincreasedthe oral bioavailabilityof DRVby 2.3-foldwith respect to both theunprocessedandthenanonized DRV/RIT combinations that showed statistically similar performance. Moreover, they highlighted the limited advantage of only drugnanonizationto improve the oral pharmacokinetics of protease inhibitors and the potential of our novel delivery approach to improve the oral pharmacokinetics of nanonized poorly water-soluble drugs displaying pH-dependent solubility.

STATEMENT OF SIGNIFICANCE

Protease inhibitors (PIs) are gold-standard drugs in many ARV cocktails. Darunavir (DRV) is the latest approved PI and it is included in the 20th WHO Model List of Essential Medicines. PIs poorly-water soluble at intestinal pH and more soluble under gastric conditions. Drug nanonization represents one of the most common nanotechnology strategies to increase dissolution rate of hydrophobic drugs and thus, their oral bioavailability. For instance, pure drug nanosuspensions became the most clinically relevant nanoformulation. However, according to the physicochemical properties of PIs, nanonization does not appear as a very beneficial strategy due to the fast dissolution rate anticipated under the acid conditions of the stomach and their uncontrolled recrystallization and precipitation in the small intestine that might result in the formation of particles of unpredictable size and structure (e.g., crystallinity and polymorphism) and consequently, unknown dissolution rate and bioavailability. In this work, we developed a sequential nanoprecipitation method for the production of pure nanoparticles of DRV and its boosting agent ritonavir in a clinically relevant 8:1 wt ratio using alginate as viscosity stabilizer and used this nanosuspension to produce a novel kind of nanoparticle-in-microparticle delivery system that was fully characterized and the pharmacokinetics assessed in rats. The most significant points of the current manuscript are.

Novel poly(vinyl alcohol)-based amphiphilic nanogels by non-covalent boric acid crosslinking of polymeric micelles

In this work, we report a new type of poly(vinyl alcohol)-g-poly(N-isopropylacrylamide) (PVA-g-PNiPAAm) amphiphilic nanogel produced by the non-covalent crosslinking of PVA polyol domains in preformed polymeric micelles with boric acid. The nanomaterials showed sizes in the 100-250 nm range (DLS) and a spherical morphology (HR-SEM). We demonstrated that the size of the polymeric micelles could be fine-tuned by changing the concentration (and the aggregation pattern) of the polymeric amphiphile in water. Upon crosslinking, the polymeric micelles turned into physically stable amphiphilic nanogels that displayed both size and size distribution similar to the micellar precursor for up to two weeks, even under disfavored conditions of concentration and temperature that, in the case of non-crosslinked counterparts, resulted in quick disassembly. In addition, we show for the first time the feasibility of spray-drying technology to consolidate the 3D network formed between PVA and boric acid and to produce stable powders that can be reconstituted upon use at any desired concentration. Moreover, the formation of a borated surface conferred the nanogels with good mucoadhesiveness in vitro. Finally, these novel nanomaterials showed optimal cell compatibility in a model of the intestinal epithelium, the Caco2 cell line. Overall results demonstrate the unprecedented versatility of the proposed modular approach and opens completely new horizons in the application of polymeric micelles and other self-assembled polymeric nanomaterials in diagnostics and therapeutics.

Electrohydrodynamic atomization and spray-drying for the production of pure drug nanocrystals and co-crystals

In recent years, nanotechnology has offered attractive opportunities to overcome the (bio)pharmaceutical drawbacks of most drugs such as low aqueous solubility and bioavailability. Among the numerous methodologies that have been applied to improve drug performance, a special emphasis has been made on those that increase the dissolution rate and the saturation solubility by the reduction of the particle size of pure drugs to the nanoscale and the associated increase of the specific surface area. Different top-down and bottom-up methods have been implemented, each one with its own pros and cons. Over the last years, the latter that rely on the dissolution of the drug in a proper solvent and its crystallization or co-crystallization by precipitation in an anti-solvent or, conversely, by solvent evaporation have gained remarkable impulse owing to the ability to adjust features such as size, size distribution, morphology and to control the amorphous/crystalline nature of the product. In this framework, electrohydrodynamic atomization (also called electrospraying) and spray-drying excel due to their simplicity and potential scalability. Moreover, they do not necessarily require suspension stabilizers and dry products are often produced during the formation of the nanoparticles what ensures physicochemical stability for longer times than liquid products. This review overviews the potential of these two technologies for the production of pure drug nanocrystals and co-crystals and discusses the recent technological advances and challenges for their implementation in pharmaceutical research and development.

Permeability of Novel Chitosan-g-Poly(Methyl Methacrylate) Amphiphilic Nanoparticles in a Model of Small Intestine In Vitro

Engineering of drug nanocarriers combining fine-tuned mucoadhesive/mucopenetrating properties is currently being investigated to ensure more efficient mucosal drug delivery. Aiming to improve the transmucosal delivery of hydrophobic drugs, we designed a novel nanogel produced by the self-assembly of amphiphilic chitosan graft copolymers ionotropically crosslinked with sodium tripolyphosphate. In this work, we synthesized, for the first time, chitosan-g-poly(methyl methacrylate) nanoparticles thiolated by the conjugation of N-acetyl cysteine. First, we confirmed that both non-crosslinked and crosslinked nanoparticles in the 0.05⁻0.1% w/v concentration range display very good cell compatibility in two cell lines that are relevant to oral delivery, Caco-2 cells that mimic the intestinal epithelium and HT29-MTX cells that are a model of mucin-producing goblet cells. Then, we evaluated the effect of crosslinking, nanoparticle concentration, and thiolation on the permeability in vitro utilizing monolayers of (i) Caco-2 and (ii) Caco-2:HT29-MTX cells (9:1 cell number ratio). Results confirmed that the ability of the nanoparticles to cross Caco-2 monolayer was affected by the crosslinking. In addition, thiolated nanoparticles interact more strongly with mucin, resulting in a decrease of the apparent permeability coefficient (Papp) compared to the pristine nanoparticles. Moreover, for all the nanoparticles, higher concentration resulted in lower Papp, suggesting that the transport pathways can undergo saturation.

Protoporphyrin IX-modified chitosan-g-oligo(NiPAAm) polymeric micelles: from physical stabilization to permeability characterization in vitro

Two main hurdles persist towards the more extensive bench-to-bed side translation of non-parenteral polymeric micelles. The first pertains to their thermodynamically-driven disassembly under uncontrolled dilution conditions in the biological milieu and upon interaction with biomacromolecules (e.g., proteins). The second is related to the relatively poor understanding of the pathways by which polymeric micelles improve the bioavailability of the payload by mucosal routes (e.g., intestinal). In this work, a chitosan-g-oligo(N-isopropylacrylamide) (CS-g-oligo(NiPAAm)) copolymer was modified with non-cytotoxic amounts of protoporphyrin IX (PP), a planar molecule of amphiphilic character that undergoes self-aggregation in water by forming π-π stacked supramolecular structures, to induce micellization under disfavored conditions and to serve as a fluorescent tracer for the measurement of the micelle permeability across a model of the intestinal epithelium in vitro. Findings indicated that the conjugation of PP amounts as low as 2% w/w induced the formation of micelles at temperatures below the lower critical solution temperature of oligo(NiPAAm) (30-32 °C). Moreover, permeability studies conducted at both 4 °C and 37 °C strongly suggested that despite the relatively large size of the micelles (200-300 nm), they cross the epithelial monolayer mainly by a paracellular pathway due to the opening of tight junctions. Complementary uptake studies by flow cytometry indicated that no endocytosis, though due to passive or facilitated diffusion, some internalization takes place.

Composite films for vaginal delivery of tenofovir disoproxil fumarate and emtricitabine

Prevention of male-to-female HIV transmission remains a huge challenge and topical pre-exposure prophylaxis (PrEP) using microbicides may help overcoming the problem. In this work, different types of films containing the antiretroviral drugs tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) were developed. Formulations based in poly(vinyl alcohol) and pectin were produced as single- or double-layered films. Films containing TDF/FTC or TDF/FTC-loaded Eudragit® L 100 nanoparticles (NPs) obtained by nano spray-drying were tested for physicochemical, technological and biological properties relevant to microbicide development. All systems featured organoleptic and mechanical properties considered suitable for vaginal use and potentially favoring users' acceptability. Film design (single- or double-layered, and the incorporation or not of NPs) had a greater impact on disintegration time and drug release in a simulated vaginal fluid. Upon film disintegration, pH and osmolality of the fluid remained within values considered compatible with the vaginal environment. Double-layered films significantly reduced burst effect and the overall release of both drugs as compared to fast releasing, single-layered films. The effect on delaying drug release was most noticeable when TDF/FTC-loaded NPs were incorporated into double-layered films. This last design seems particularly advantageous for the development of a coitus-independent, on-demand microbicide product. Moreover, all film types were shown potentially safe when evaluated by the MTT metabolic activity and lactate dehydrogenase release assays using HeLa and CaSki cervical cell lines. Overall, results support that proposed films may be suitable for the vaginal delivery of TDF/FTC in the context of topical PrEP.

Development of a Drug Delivery System Based on Chitosan Nanoparticles for Oral Administration of Interferon-α

Despite the good clinical efficacy of interferon-alpha (IFNα) to treat some types of cancer and viral infections, this biological drug is underused given its severe adverse effects and high dosing parenteral regimens. Aiming to achieve a breakthrough in therapy with IFNα, this work reports for the first time on the design and full characterization of a novel nanomedicine of IFNα-2b-loaded chitosan nanoparticles (IFN-CT NPs) for oral delivery. IFN-CT NPs produced by ionotropic gelation, encapsulating approximately 100% of the drug, showed a size of 36 ± 8 nm, zeta potential of +30 mV (dynamic light scattering), and spherical morphology (transmission electron microscopy). The antiviral activity of IFN-CT NPs in vitro was comparable to that of commercial IFNα. Remarkably, both treatments stimulated the expression of IFN response genes to a similar extent in both noninfected and infected cells with Human Lymphotropic-T Virus type 1. Finally, oral administration of IFN-CT NPs (0.3 MIU) to CF1 mice showed detectable levels of IFNα in plasma after 1 h, whereas no IFNα was detected with a commercial formulation. These results are encouraging and open a new avenue for the administration of this biological drug in a minimally invasive, safer, and more patient-compliant way.