Microemulsions as Potential Carriers of Nisin: Effect of Composition on Structure and Efficacy.

Water-in-oil (W/O) microemulsions based on either refined olive oil (ROO) or sunflower oil (SO), distilled monoglycerides (DMG), and ethanol were used as nisin carriers in order to ensure its effectiveness as a biopreservative. This work presents experimental evidence on the effects of ethanol concentration, hydration, the nature of oil, and the addition of nisin on the nanostructure of the proposed inverse microemulsions as revealed by electrical conductivity measurements, dynamic light scattering (DLS), small angle X-ray scattering (SAXS), and electron paramagnetic resonance (EPR) spectroscopy. Modeling of representative SAXS profiles was applied to gain further insight into the effects of ethanol and solubilized water content on the inverse swollen micelles' size and morphology. With increasing ethanol content, the overall size of the inverse micelles decreased, whereas hydration resulted in an increase in the micellar size due to the penetration of water into the hydrophilic core of the inverse swollen micelles (hydration-induced swelling behavior). The dynamic properties of the surfactant monolayer were also affected by the nature of the used vegetable oil, the ethanol content, and the presence of the bioactive molecule, as evidenced by EPR spin probing experiments. According to simulation on the experimental spectra, two populations of spin probes at different polarities were revealed. The antimicrobial effect of the encapsulated nisin was evaluated using the well diffusion assay (WDA) technique against Lactococccus lactis. It was found that this encapsulated bacteriocin induced an inhibition of the microorganism growth. The effect was more pronounced at higher ethanol concentrations, but no significant difference was observed between the two used vegetable oils (ROO and SO).

Bringing pathology to nanomedicine: a comparison of in vivo toxicity of polymeric nanoparticle carriers with and without chitosan coating.

Over the last years, there has been an increasing number of proposals for the use of nanomaterials in medicine. The safety of novel technologies must be verified, prior to their clinical application. Pathology has much to contribute towards this end. In this study, we compared the in vivo toxicity effects of poly- (lactic-co-glycolic acid) nanoparticles with and without chitosan shell. Both nanoparticle types were loaded with curcumin. The nanoparticles were assessed in vitro for potential cytotoxicity with cell viability studies. For the in vivo test, 36 adult Wistar rats were used, four of which were the control group. The remaining 32 were divided into 2 groups, each of which was administered differentially coated drug carriers: (A) nanoparticles without chitosan coating and (B) nanoparticles with chitosan coating. For both groups, the subcutaneous route was used for administration. Each group was further divided into 2 sub-groups of 8 animals each. The animals of the first sub-groups were sacrificed 24 h after the injection and those of the second on the 7th day. The control group was also divided into 2 subgroups of 2 animals each. At the appointed post-administrative date, the rats were sacrificed, and specimens from the brain, liver, kidneys, heart, stomach, lungs, and from the skin at the injection site were collected and studied histopathologically. The evaluation of both in vitro and in vivo testing shows that nanoparticles with chitosan have significantly less, if any, toxic effects compared to those without chitosan.

Morphological Characteristics of Drug-Eluting Biodegradable Polymeric Thin Films Developed on the Surface of Intraocular Lenses by Three Techniques: A Comparative Study.

Background Cataract surgery is a very popular operation that requires a postoperative period of frequent instillation of antibiotic and anti-inflammatory eye drops. Modified drug-eluting intraocular lenses (IOLs) may eliminate the need for eye drops after surgery. Aim The purpose of this study is to compare the morphological characteristics of dexamethasone eluting biodegradable polymeric thin films developed on the surface of commercially available IOLs by three different methods. Method This experimental study was conducted between May and August of 2021 in the Lab for Thin Films - Nanobiomaterials - Nanosystems & Nanometrology (LTFN) of the Aristotle University of Thessaloniki. A mixture of two organic polymers [Poly (D, L-lactide-co-glycolide)(PLGA), lactide: glycolide (75:25) and Polycaprolactone (PCL)] and dexamethasone was prepared and then deposited on the surface of three-piece IOLs by spin coating, by spray coating, and by gravure printing. The modified IOLs were sterilized with the use of ultraviolet (UV) radiation and plasma treatment. Their structural properties were studied with the use of atomic force microscopy (AFM). Results Spin coating and gravure printing produced uniform thin films on the surface of the IOLs which were not damaged during the sterilization process. Spray coating led to the partial coating of the surface of the IOLs; the thin films underwent alterations following plasma treatment. Conclusions Thin films developed by spin coating and gravure printing on IOLs demonstrate the desired morphological characteristics that make them suitable candidates for further research.