Using Factorial Experimental Design To Prepare Size-Tuned Nanovesicles

Polymers in Engineering Extracellular Vesicle Mimetics: Current Status and Prospective

The maintenance of a high delivery efficiency by traditional nanomedicines during cancer treatment is a challenging task. As a natural mediator for short-distance intercellular communication, extracellular vesicles (EVs) have garnered significant attention owing to their low immunogenicity and high targeting ability. They can load a variety of major drugs, thus offering immense potential. In order to overcome the limitations of EVs and establish them as an ideal drug delivery system, polymer-engineered extracellular vesicle mimics (EVMs) have been developed and applied in cancer therapy. In this review, we discuss the current status of polymer-based extracellular vesicle mimics in drug delivery, and analyze their structural and functional properties based on the design of an ideal drug carrier. We anticipate that this review will facilitate a deeper understanding of the extracellular vesicular mimetic drug delivery system, and stimulate the progress and advancement of this field.

Nanovesicles as Vanillin Carriers for Antimicrobial Applications

Vanillin is a natural compound easily extracted from plants. It has neuroprotective, anti-carcinogenic, antioxidant, antimicrobial, and anti-biofilm properties. It also presents high volatility, high hydrophilicity, and low bioavailability. Nanomaterials can be used to improve pharmacodynamics, solubility, and stability and to enhance pharmacokinetics. In this work, non-ionic surfactant vesicles were synthesized as vanillin carriers: neutral niosomes formed by Span60 and cholesterol, positive charged niosomes formulated with cetyltrimethylammonium bromide (CTAB), and negatively charged niosomes formulated with sodium dodecyl sulfate (SDS). Niosomes synthesis was carried out with two commonly used methods: thin film hydration (TFH) and ethanol injection method (EIM). The niosomes synthesized were used to prepare two different materials: (i) a powder containing the lyophilized noisome with vanillin systems and (ii) a gelatin matrix film containing niosomes with vanillin. Lyophilization was carried out using maltodextrin as a cryoprotectant. The lyophilization of colloidal structures allows for storage at room temperature for long periods of time, keeping their organoleptic characteristics invariable. Niosomes were characterized before and after the lyophilization process in terms of morphological characterization, size, polydispersity index (PDI), and zeta potential. Moreover, niosomes cargo was evaluated by calculating the encapsulation efficiency (EE) and loading capacity (LC). Results showed that the use of the TFH method allowed us to obtain niosomes of 255 nm with high EE (up to 40%) and LC values higher than EIM. The lyophilization process decreased the LC of the vesicles prepared, but this decrease was mitigated by up to 20% when ionic surfactants were used on the membrane bilayer. Gelatin films are biodegradable materials suitable for food packing applications. The incorporation of a natural compound with antimicrobial activity would be a clear advantage for such an application. The films prepared were characterized in terms of morphology, water solubility, color, and transparency. Niosomes synthesized by thin film hydration had better chemical and physical properties to load vanillin. Especially in the case of application in films, niosomes with a negative charge, formed by SDS, and vanillin loaded gave better mechanical and chemical characteristics to the film.

Development and In Vitro and In Vivo Evaluation of an Antineoplastic Copper(II) Compound (Casiopeina III-ia) Loaded in Nonionic Vesicles Using Quality by Design

In recent decades, the interest in metallodrugs as therapeutic agents has increased. Casiopeinas are copper-based compounds that have been evaluated in several tumor cell lines. Currently, casiopeina III-ia (CasIII-ia) is being evaluated in phase I clinical trials. The aim of the present work is to develop a niosome formulation containing CasIII-ia for intravenous administration through a quality-by-design (QbD) approach. Risk analysis was performed to identify the factors that may have an impact on CasIII-ia encapsulation. The developed nanoformulation optimized from the experimental design was characterized by spectroscopy, thermal analysis, and electronic microscopy. In vitro drug release showed a burst effect followed by a diffusion-dependent process. The niosomes showed physical stability for at least three months at 37 °C and 75% relative humidity. The in vitro test showed activity of the encapsulated CasIII-ia on a metastatic breast cancer cell line and the in vivo test of nanoencapsulated CasIII-ia maintained the activity of the free compound, but showed a diminished toxicity. Therefore, the optimal conditions obtained by QbD may improve the scaling-up process.

Nano-Encapsulation of Mithramycin in Transfersomes and Polymeric Micelles for the Treatment of Sarcomas

Sarcomas are aggressive tumors which often show a poor response to current treatments. As a promising therapeutic alternative, we focused on mithramycin (MTM), a natural antibiotic with a promising anti-tumor activity but also a relevant systemic toxicity. Therefore, the encapsulation of MTM in nano-delivery systems may represent a way to increase its therapeutic window. Here, we designed novel transfersomes and PLGA polymeric micelles by combining different membrane components (phosphatidylcholine, Span 60, Tween 20 and cholesterol) to optimize the nanoparticle size, polydispersity index (PDI) and encapsulation efficiency (EE). Using both thin film hydration and the ethanol injection methods we obtained MTM-loaded transferosomes displaying an optimal hydrodynamic diameter of 100–130 nm and EE values higher than 50%. Additionally, we used the emulsion/solvent evaporation method to synthesize polymeric micelles with a mean size of 228 nm and a narrow PDI, capable of encapsulating MTM with EE values up to 87%. These MTM nano-delivery systems mimicked the potent anti-tumor activity of free MTM, both in adherent and cancer stem cell-enriched tumorsphere cultures of myxoid liposarcoma and chondrosarcoma models. Similarly to free MTM, nanocarrier-delivered MTM efficiently inhibits the signaling mediated by the pro-oncogenic factor SP1. In summary, we provide new formulations for the efficient encapsulation of MTM which may constitute a safer delivering alternative to be explored in future clinical uses.

Vitamin D3 Loaded Niosomes and Transfersomes Produced by Ethanol Injection Method: Identification of the Critical Preparation Step for Size Control

Vesicular nanocarriers have an important role in drug delivery and dietary supplements. Size control and optimization of encapsulation efficiency (EE) should be optimized for those applications. In this work, we report on the identification of the crucial step (injection, evaporation, or sonication) innanovesicles (transfersomes and niosomes) preparation by theethanol injection method (EI). The identification of each production step on the final vesicle size was analyzed in order to optimize further scale-up process. Results indicated that the final size of transfersomeswas clearly influenced by the sonication step while the final size of niosomes was mainly governed by the injection step. Measurements of final surface tension of the different vesicular systems prepared indicate a linear positive tendency with the vesicle size formed. This relation could help to better understand the process and design a vesicular size prediction model for EI. Vitamin D3 (VitD3) was encapsulated in the systems formulated with encapsulation efficiencies larger than 90%. Interaction between the encapsulated compound and the membrane layer components is crucial for vesicle stability. This work has an impact on the scaling-up production of vesicles for further food science applications.

Fail-safe nano-formulation of prodrug of sulfapyridine: Preparation and evaluation for treatment of rheumatoid arthritis

Aim of the present study was to give a second life to the long-abandoned drug, sulfapyridine (SP) for its anti-arthritic potential by design of nano-vesicular delivery system. For this, intra-articular delivery of its liposomal formulation was tried. As the prepared formulation exhibited rapid drug leakage, an arthritis responsive prodrug of SP showing lability towards synovial enzymes was synthesized to exploit the over-expression of arthritis specific enzymes. Prodrug (SP-PD) exhibited better retention in liposomes as compared to the drug, preventing its escape from synovium. Hydrolysis of SP-PD in human plasma and synovial fluid indicated its high susceptibility to enzymes. The liposomes of SP-PD exhibited larger mean size, less PDI and higher zeta potential as compared to those for SP liposomes. In arthritic rats, prodrug liposomes were found to reverse the symptoms of inflammation, including the levels of biochemical markers. Liposomes of bio-responsive prodrug, therefore, offer a revolutionary approach in the treatment of rheumatoid arthritis.

Cu Nanoparticle-Loaded Nanovesicles with Antibiofilm Properties. Part I: Synthesis of New Hybrid Nanostructures

Copper nanoparticles (CuNPs) stabilized by quaternary ammonium salts are well known as antimicrobial agents. The aim of this work was to study the feasibility of the inclusion of CuNPs in nanovesicular systems. Liposomes are nanovesicles (NVs) made with phospholipids and are traditionally used as delivery vehicles because phospholipids favor cellular uptake. Their capacity for hydrophilic/hydrophobic balance and carrier capacity could be advantageous to prepare novel hybrid nanostructures based on metal NPs (Me-NPs). In this work, NVs were loaded with CuNPs, which have been reported to have a biofilm inhibition effect. These hybrid materials could improve the effect of conventional antibacterial agents. CuNPs were electro-synthesized by the sacrificial anode electrolysis technique in organic media and characterized in terms of morphology through transmission electron microscopy (TEM). The NVs were prepared by the thin film hydration method in aqueous media, using phosphatidylcholine (PC) and cholesterol as a membrane stabilizer. The nanohybrid systems were purified to remove non-encapsulated NPs. The size distribution, morphology and stability of the NV systems were studied. Different quaternary ammonium salts in vesicular systems made of PC were tested as stabilizing surfactants for the synthesis and inclusion of CuNPs. The entrapment of charged metal NPs was demonstrated. NPs attached preferably to the membrane, probably due to the attraction of their hydrophobic shell to the phospholipid bilayers. The high affinity between benzyl-dimethyl-hexadecyl-ammonium chloride (BDHAC) and PC allowed us to obtain stable hybrid NVs c.a. 700 nm in diameter. The stability of liposomes increased with NP loading, suggesting a charge-stabilization effect in a novel antibiofilm nanohybrid material.

Vesicles as antibiotic carrier: State of art

Antimicrobial resistance (AMR) has become a global health problem. Bacteria are able to adapt to different environments, with the presence or absence of a host, forming colonies and biofilms. In fact, biofilm formation confers chemical protection to the microbial cells, thus making most of the conventional antibiotics ineffective. Prevention and destruction of biofilms is a challenging task that should be addressed by a multidisciplinary approach from different research fields. One of the medical strategies used against biofilms is the therapy with drug delivery systems. Lipidic nanovesicles are a good choice for encapsulating drugs, increasing their pharmacodynamics and reducing side effects. These soft nanovesicles show significant advantages for their high biocompatibility, physical and chemistry properties, good affinity with drugs, and easy route of administration. This review summarizes the current knowledge on different types of vesicles which may be used as antibiotic carriers. The main preparation and purification methods for the synthesis of these vesicles are also presented. The advantages of drug encapsulation are critically reviewed. In addition, recent works on endolysin formulations as novel, "greener" and efficient antibiofilm solution are included. This paper can provide useful background for the design of novel efficient formulations and synergistic nanomaterials and could be also useful at the pharmaceutical industry to develop wastewater treatments and reduce the antibiotics in the environmental waters.

Selected Tetraspanins Functionalized Niosomes as Potential Standards for Exosome Immunoassays

Quantitative detection of exosomes in bio-fluids is a challenging task in a dynamic research field. The absence of a well-established reference material (RM) for method development and inter-comparison studies could be potentially overcome with artificial exosomes: lab-produced biomimetic particles with morphological and functional properties close to natural exosomes. This work presents the design, development and functional characteristics of fully artificial exosomes based on tetraspanin extracellular loops-coated niosomes, produced by bio-nanotechnology methods based on supra-molecular chemistry and recombinant protein technology. Mono- and double-functionalized particles with CD9/CD63 tetraspanins have been developed and characterized from a morphological and functional point of view. Produced bio-particles showed close similarities with natural entities in terms of physical properties. Their utility for bioanalysis is demonstrated by their detection and molecular-type discrimination by enzyme-linked immunosorbent assays (ELISAs), one of the most frequent bio-analytical method found in routine and research labs. The basic material based on streptavidin-coated niosomes allows the surface functionalization with any biotinylated protein or peptide, introducing versatility. Although promising results have been reported, further optimizations and deeper characterization will help this innovative biomaterial become a robust RM for validation and development of diagnostic tools for exosomes determination.

Investigating the potential of utilizing glycerosomes as a novel vesicular platform for enhancing intranasal delivery of lacidipine

Lacidipine is a potent dihydropyridine calcium channel blocker used for management of hypertension and atherosclerosis. The drug has low and fluctuating oral bioavailability owing to its extensive hepatic first-pass metabolism and reduced water solubility. Accordingly, this work aimed at overcoming the aforementioned challenges through the formulation of intranasal nano-sized lacidipine glycerosomes. Box-Behnken was successfully employed for the formulation and in vitro optimization of the glycerosomes. Statistical analysis revealed that cholesterol concentration exhibited a significant effect on the vesicle size, while Phospholipon® 90G and glycerol concentrations exhibited significant effects on both entrapment efficiency and deformability index. The optimized formulation showed spherical shape, good deformability, vesicular size of 220.25 nm, entrapment efficiency of 61.97%, and enhanced ex vivo permeation by 3.65 fold compared to lacidipine suspension. Confocal laser scattering microscope revealed higher penetration depth via nasal mucosa for rhodamine labelled glycerosomes (up to 60 µm) in comparison to rhoadamine dye solution (26 µm). In addition, the optimized lacidipine glycerosomes caused significant reduction in methylprednisolone acetate-induced hypertension in rats for up to 24 h in comparison to oral drug suspension. Histopathological assessment showed intact nasal mucosal epithelial lining with no signs of inflammation or necrosis confirming the safety and tolerability of the proposed glycerosomes. The declared results highlights the potential of utilizing the proposed glycerosomes as safe and effective platform for intranasal delivery of lacidipine.

The Why, Where, Who, How, and What of the vesicular delivery systems

Though vesicular delivery systems have been widely explored and reviewed, no comprehensive review exists that covers their development from the inception of the concept to its culmination in the form of regulated marketed formulations. With the advancement of scientific research in the field of nanomedicine, certain category of vesicular delivery systems have successfully reached the global market. Despite extensive research and highly encouraging results in a plethora of pathological conditions in the preclinical studies, translation of these nanomedicines from laboratory to market has been very limited. Aim of this review is to describe comprehensively the various colloidal delivery systems, focusing mainly on their conventional and advanced methods of preparation, different characterization techniques and main success stories of their journey from bench to bedside of the patient. The review also touches the finer nuances of the use of modern formulation approach of DoE (Design of Experiments) in their formulation and the status of regulatory guidelines for the approval of these nanomedicines.

Continuous flow production of size-controllable niosomes using a thermostatic microreactor

The new roles of vesicular systems in advanced biomedical, analytical and food science applications demand novel preparation processes designed to reach the new standards. Particle size and monodispersity have become essential properties to control. In this work, key parameters, involved in a microfluidic reactor with hydrodynamic flow focusing, were investigated in order to quantify their effects on niosomes morphology. Particular attention was given to temperature, which is both a requirement to handle non-ionic surfactants with phase transition temperature above RT, and a tailoring variable for size and monodispersity control. With this aim, niosomes with two different sorbitan esters and cholesterol as stabilizer were formulated. High resolution and conventional 3D-printing technologies were employed for the fabrication of microfluidic reactor and thermostatic systems, since this additive technology has been essential for microfluidics development in terms of cost-effective and rapid prototyping. A customised device to control temperature and facilitate visualization of the process was developed, which can be easily coupled with commercial inverted microscopes. The results demonstrated the capability of microfluidic production of niosomes within the full range of non-ionic surfactants and membrane stabilizers.

Self-Assembly Behavior of Amphiphilic Janus Dendrimers in Water: A Combined Experimental and Coarse-Grained Molecular Dynamics Simulation Approach

Amphiphilic Janus dendrimers (JDs) are repetitively branched molecules with hydrophilic and hydrophobic components that self-assemble in water to form a variety of morphologies, including vesicles analogous to liposomes with potential pharmaceutical and medical application. To date, the self-assembly of JDs has not been fully investigated thus it is important to gain insight into its mechanism and dependence on JDs’ molecular structure. In this study, the aggregation behavior in water of a second-generation bis-MPA JD was evaluated using experimental and computational methods. Dispersions of JDs in water were carried out using the thin-film hydration and ethanol injection methods. Resulting assemblies were characterized by dynamic light scattering, confocal microscopy, and atomic force microscopy. Furthermore, a coarse-grained molecular dynamics (CG-MD) simulation was performed to study the mechanism of JDs aggregation. The obtaining of assemblies in water with no interdigitated bilayers was confirmed by the experimental characterization and CG-MD simulation. Assemblies with dendrimersome characteristics were obtained using the ethanol injection method. The results of this study establish a relationship between the molecular structure of the JD and the properties of its aggregates in water. Thus, our findings could be relevant for the design of novel JDs with tailored assemblies suitable for drug delivery systems.

Therapeutic biomaterials based on extracellular vesicles: classification of bio-engineering and mimetic preparation routes

Extracellular vesicles (EVs) are emerging as novel theranostic tools. Limitations related to clinical uses are leading to a new research area on design and manufacture of artificial EVs. Several strategies have been reported in order to produce artificial EVs, but there has not yet been a clear criterion by which to differentiate these novel biomaterials. In this paper, we suggest for the first time a systematic classification of the terms used to build up the artificial EV landscape, based on the preparation method. This could be useful to guide the derivation to clinical trial routes and to clarify the literature. According to our classification, we have reviewed the main strategies reported to date for their preparation, including key points such as: cargo loading, surface targeting strategies, purification steps, generation of membrane fragments for the construction of biomimetic materials, preparation of synthetic membranes inspired in EV composition and subsequent surface decoration.