Ferritin at different iron loading: From biological to nanotechnological applications.

The characterization of the structure of ferritin in solution and the arrangement of iron stored in its cavity are intriguing subjects for both cell biology and applied science, since the protein structure, stability, and easiness of production make it an ideal tool for biomedical applications. We characterized the ferritin structure over a wide range of iron loadings by visible light, X-ray, and neutron scattering techniques. We found that the arrangement of iron ions inside the protein cage resulted in a more disposable arrangement at lower loading factors and then in a crystalline structure. At very high iron content the inner core is composed of magnetite more than ferrihydrite, and the shell of the protein is elastically deformed by the iron crystal growth in an ellipsoidal arrangement. The application of an external radiofrequency (RF) magnetic field affected ferritins at low iron loading factors. Notably the RF modified the iron disposition towards a more dispersed arrangement. The structural characterization of the ferritin at different LFs and in presence of magnetic fields provides useful insights into their physiological behaviour and can help in the design and fine-tuning of ferritin-based nanosystems for biotechnological applications.

Bioactive pH-sensitive nanoemulsion in melanoma cell lines.

Melanoma is an aggressive form of skin cancer with elevated propensity to metastasize. One of the major critical issues in the treatment of oncological patients is represented by the development of toxicity and resistance to the available therapies. Great progress has been made in the field of nanotechnologies to limit the unwanted effects of anti-cancer treatments. We explored the potential of creating oil-in-water nanoemulsions composed of oleic acid, as a bioactive carrier for lipophilic drug delivery. This bioactive nanoemulsion was loaded with Curcumin, a natural fluorescent lipophilic compound, used as a model drug to evaluate nanoemulsion capability to: i) encapsulate the lipophilic moiety; ii) interact with the specific cells, and iii) improve the efficacy of the loaded model drug compared to the free one. Therefore, we evaluated the physical-chemical features of Curcumin-loaded nanoemulsions, confirming their pH sensibility and their stability over time. Moreover, the nanoemulsions were able to preserve the loaded Curcumin by degradation/destabilization phenomena. Finally, we verified some of the biological functions of Curcumin delivered by nanoemulsions in the B16F10 melanoma cell line. We obtained evidence of the biological action of Curcumin, suggesting oleic-based nanoemulsions as an efficient nanocarrier for lipophilic drug delivery.

Targeting pentamidine towards CD44-overexpressing cells using hyaluronated lipid-polymer hybrid nanoparticles.

Biodegradable nanocarriers possess enormous potential for use as drug delivery systems that can accomplish controlled and targeted drug release, and a wide range of nanosystems have been reported for the treatment and/or diagnosis of various diseases and disorders. Of the various nanocarriers currently available, liposomes and polymer nanoparticles have been extensively studied and some formulations have already reached the market. However, a combination of properties to create a single hybrid system can give these carriers significant advantages, such as improvement in encapsulation efficacy, higher stability, and active targeting towards specific cells or tissues, over lipid or polymer-based platforms. To this aim, this work presents the formulation of poly(lactic-co-glycolic) acid (PLGA) nanoparticles in the presence of a hyaluronic acid (HA)-phospholipid conjugate (HA-DPPE), which was used to anchor HA onto the nanoparticle surface and therefore create an actively targeted hybrid nanosystem. Furthermore, ionic interactions have been proposed for drug encapsulation, leading us to select the free base form of pentamidine (PTM-B) as the model drug. We herein report the preparation of hybrid nanocarriers that were loaded via ion-pairing between the negatively charged PLGA and HA and the positively charged PTM-B, demonstrating an improved loading capacity compared to PLGA-based nanoparticles. The nanocarriers displayed a size of below 150 nm, a negative zeta potential of -35 mV, a core-shell internal arrangement and high encapsulation efficiency (90%). Finally, the ability to be taken up and exert preferential and receptor-mediated cytotoxicity on cancer cells that overexpress the HA specific receptor (CD44) has been evaluated. Competition assays supported the hypothesis that PLGA/HA-DPPE nanoparticles deliver their cargo within cells in a CD44-dependent manner.

Chondroitin sulfate and caseinophosphopeptides doped polyurethane-based highly porous 3D scaffolds for tendon-to-bone regeneration.

Tendon disorders are common injuries, which can be greatly debilitating as they are often accompanied by great pain and inflammation. Moreover, several problems are also related to the laceration of the tendon-to-bone interface (TBI), a specific region subjected to great mechanical stresses. The techniques used nowadays for the treatment of tendon and TBI injuries often involve surgery. However, one critical aspect of this procedure involves the elevated risk of fail due to the tissues weakening and the postoperative alterations of the normal joint mechanics. Synthetic polymers, such as thermoplastic polyurethane, are of special interest in the tissue engineering field as they allow the production of scaffolds with tunable elastic and mechanical properties, that could guarantee an effective support during the new tissue formation. Based on these premises, the aim of this work was the design and the development of highly porous 3D scaffolds based on thermoplastic polyurethane, and doped with chondroitin sulfate and caseinophosphopeptides, able to mimic the structural, biomechanical, and biochemical functions of the TBI. The obtained scaffolds were characterized by a homogeneous microporous structure, and by a porosity optimal for cell nutrition and migration. They were also characterized by remarkable mechanical properties, reaching values comparable to the ones of the native tendons. The scaffolds promoted the tenocyte adhesion and proliferation when caseinophosphopetides and chondroitin sulfate are present in the 3D structure. In particular, caseinophosphopeptides' optimal concentration for cell proliferation resulted 2.4 mg/mL. Finally, the systems evaluation in vivo demonstrated the scaffolds' safety, since they did not cause any inflammatory effect nor foreign body response, representing interesting platforms for the regeneration of injured TBI.

Cyclosporine A micellar nasal spray characterization and antiviral action against SARS-CoV-2.

The upper airways represent the point of entrance from where Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection spreads to the lungs. In the present work, α-tocopheryl-polyethylene-glycol succinate (TPGS) micelles loaded with cyclosporine A (CSA) were developed for nasal administration to prevent or treat the viral infection in the very first phases. The behavior of the micelles in presence of simulated nasal mucus was investigated in terms of stability and mucopenetration rate, evidencing long-term stability and fast diffusion across the glycoproteins matrix. Moreover, the spray characteristics of the micellar formulation and deposition profile in a silicon nasal model were studied using three nasal spray devices. Results allowed to identify the nasal spray pump (BiVax, Aptar) able to provide the wider and uniform deposition of the nasal cavity. The cyclosporine A micelles antiviral activity against SARS-CoV-2 was tested on the Omicron BA.1 variant using Vero E6 cells with protocols simulating treatment before, during and after the infection of the upper airways. Complete viral inactivation was observed for the cyclosporine-loaded micelles while a very low activity was evidenced for the non-formulated drug, suggesting a synergistic activity of the drug and the formulation. In conclusion, this work showed that the developed cyclosporine A-loaded micellar formulations have the potential to be clinically effective against a wide spectrum of coronavirus variants.

Nanoclay-Doped Electrospun Nanofibers for Tissue Engineering: Investigation on the Structural Modifications in Physiological Environment.

Background: Clay minerals are nanomaterials that have recently been recognized as enabling excipients that can promote cell adhesion, proliferation, and differentiation. When nanoclays are loaded in a 3D polymeric nanostructure, the cell-substrate interaction is enhanced, and other bioactive properties are optimized. Purpose: In this study, hectorite (HEC)- and montmorillonite (MMT)-doped polymeric scaffolds were explored for the treatment of deep and chronic skin lesions. Methods: Scaffolds were manufactured by means of electrospinning and then crosslinked by heating. Physicochemical analyses were correlated with in vitro biopharmaceutical characterization to predict the in vivo fate of the clay-doped scaffolds. Results and Discussion: The addition of MMT or HEC to the polymeric scaffold framework modifies the surface arrangement and, consequently, the potential of the scaffolds to interact with biological proteins. The presence of nanoclays alters the nanofiber morphology and size, and MMT doping increases wettability and protein adhesion. This has an impact on fibroblast behavior in a shorter time since scaffold stiffness facilitates cell adhesion and cell proliferation. Conclusion: MMT proved to perform better than HEC, and this could be related to its higher hydrophilicity and protein adhesion.