Structural analysis of nanosystems: Solid Sorbitan esters Nanoparticles (SSN) as a case study

Sorbitan ester nanoparticles (SENS) as a novel topical ocular drug delivery system: Design, optimization, and in vitro/ex vivo evaluation

We explored the potential of two types of sorbitan ester nanoparticles (SENS) as novel tools for topical ocular drug delivery. The optimized SENS formulation (SENS-OPT) consisted of nanoparticles (NPs) of 170.5 nm, zeta potential +33.9 mV, and cyclosporine loading of 19.66%. After hyaluronic acid (HA) coating, the resulting SENS-OPT-HA NPs had a particle size of 177.6 nm and zeta potential of -20.6 mV. The NPs were stable during 3 months of storage at different temperatures and did not aggregate in the presence of protein-enriched simulated lacrimal fluid. There was no toxicity to cultured human corneal epithelial (HCE) cells when exposed to NPs up to 0.4% (w/v). Both NPs were effectively internalized by HCE cells through active mechanisms. Endocytosis of SENS-OPT NPs was caveolin-dependent whereas SENS-OPT-HA NP endocytosis was mediated by HA receptors. HA-receptor-mediated endocytosis may be responsible for the higher cellular uptake of SENS-OPT-HA NPs. After cyclosporine incorporation into the NPs, corneal penetration of this immunosuppressive drug by loaded SENS-OPT NPs was 1.3-fold higher than the commercial reference formulation Sandimmun®. For cyclosporine-loaded SENS-OPT-HA NPs, the penetration was 2.1-fold higher than for Sandimmun®. In ex vivo stimulated lymphocytes, both formulations demonstrated the same reduction in IL-2 levels as Sandimmun®.

Development and characterisation of chondroitin sulfate- and hyaluronic acid-incorporated sorbitan ester nanoparticles as gene delivery systems

Glycosaminoglycans (GAGs) are natural polymers that are broadly used in gene delivery systems to increase stability as well as decrease toxicity and nonspecific interactions, thereby increasing transfection efficiency. In this work, we propose sorbitan ester-based lipid nanoparticles (SENS) functionalised with the GAGs chondroitin sulfate (CS) and hyaluronic acid (HA) as gene delivery systems. For this purpose, we describe the design and evaluation of these nanosystems loaded with plasmid DNA, including an evaluation of their physicochemical characteristics, stability properties, ability to protect and efficiently transfect cells with Enhanced Green Fluorescent Protein plasmid (pEGFP) in vitro, and biocompatibility both in vitro and in vivo. We confirm that molecules with high biological value and targeting potential, such as HA and CS, can be successfully incorporated into our recently developed sorbitan ester-based nanoparticles (SENS) and that this incorporation leads to effective stabilisation of both nanosystems as well as protects plasmid DNA. We demonstrated that the aforementioned incorporation of HA and CS enables long-term stability of the nanosystems in both liquid and lyophilised states, which is a remarkable property that can aid in their transfer to industry. The ability of these functionalised nanosystems to transfect the A549 cell line without compromising cell viability was also shown, as well as their innocuous safety profile in vivo. Thus, we provide valuable evidence of the suitable properties and potential of these hybrid nanoparticles as gene delivery systems.

Span poly-L-arginine nanoparticles are efficient non-viral vectors for PRPF31 gene delivery: An approach of gene therapy to treat retinitis pigmentosa

Retinitis pigmentosa (RP) is the most common cause of inherited blindness in adults. Mutations in the PRPF31 gene produce autosomal dominant RP (adRP). To date there are no effective treatments for this disease. The purpose of this study was to design an efficient non-viral vector for human PRPF31 gene delivery as an approach to treat this form of adRP. Span based nanoparticles were developed to mediate gene transfer in the subretinal space of a mouse model of adRP carrying a point mutation (A216P) in the Prpf31 gene. Funduscopic examination, electroretinogram, optomotor test and optical coherence tomography were conducted to further in vivo evaluate the safety and efficacy of the nanosystems developed. Span-polyarginine (SP-PA) nanoparticles were able to efficiently transfect the GFP and PRPF31 plasmid in mice retinas. Statistically significant improvement in visual acuity and retinal thickness were found in Prpf31^A216P/+ mice treated with the SP-PA-PRPF31 nanomedicine.