Polyhydroxyalkanoates-Based Nanoparticles as Essential Oil Carriers

Plant-derived essential oils (EOs) represent a green alternative to conventional antimicrobial agents in food preservation. Due to their volatility and instability, their application is dependent on the development of efficient encapsulation strategies allowing their protection and release control. Encapsulation in Polyhydroxyalkanoate (PHA)-based nanoparticles (NPs) addresses this challenge, providing a biodegradable and biobased material whose delivery properties can be tuned by varying polymer composition. In this work, EO from Mexican oregano was efficiently encapsulated in Polyhydroxybutyrate (PHB) and Poly-3-hydroxybutyrate-co-hydroxyhexanoate (PHB-HHx)-based NPs by solvent evaporation technique achieving high encapsulation efficiency, (>60%) and loading capacity, (about 50%). The obtained NPs displayed a regular distribution with a size range of 150–210 nm. In vitro release studies in food simulant media were fitted with the Korsmeyer–Peppas model, indicating diffusion as the main factor controlling the release. The cumulative release was affected by the polymer composition, possibly related to the more amorphous nature of the copolymer, as confirmed by WAXS and DSC analyses. Both the EO-loaded nanosystems displayed antimicrobial activity against Micrococcus luteus, with PHB-HHx-based NPs being even more effective than the pure EO. The results open the way to the effective exploitation of the developed nanosystems in active packaging.

Layer-By-Layer Assembled, Amphiphilic And Antibacterial Hybrid Electrospun Mat Made From Polypropylene And Chitosan Fibers

In this study, hybrid fiber mat (HFPP-CS) consisting of both chlorinated polypropylene and chitosan fibers (FPP-Cl and FCS) is obtained by assembling layer-by-layer (LBL) for the first time using electrospinning process. Morphological, wettability, structural and thermal properties of HFPP-CS are investigated in detail by Scanning electron microscopy (SEM), water contact angle (WCA) measurement, fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analyses, respectively, comparing with FPP-Cl and FCS. Furthermore, the antibacterial activity of all samples was evaluated against to gram positive Staphylococcus aureus (S. aureus) and gram negative Escherichia coli (E. coli) bacteria. SEM analysis proves to HFPP-CS has a circular and smooth morphology and also comprises of microscale FPP-Cl and nanoscale FCS layers. The incorporation of nano-FCS layer on micro-FPP-Cl layer leads to diminution in the hydrophobicity, but enhancement in the thermostability and glass transition temperature of the resulting fiber mat. The antibacterial activity results show that HFPP-CS has inhibition effect against to S. aureus and E. coli. In general, it is anticipated that the prepared amphiphilic and antibacterial HFPP-CS can be employed as potential biomaterial for a variety of bioengineering applications.

Synthesis, spectral and thermal characterization, biological activity of a new amino acide ester containing substituted salicylaldimine Schiff base ligand and its Ru(II)bipyridyl complex

The new salicylaldimine, as O,N-bidentate ligand (HL), containing amino acide ester and its Ru(II) complex [Ru(bpy)2(HL)]Cl2 have been prepared. Synthesized compounds have been structurally characterized by IR, 1H NMR, LC-MS, fluorescence spectroscopy, elemental and thermal (TGA-DSC) analyses. The metal to the ligand ratio of the Ru(II) complex was found to be 1:1. Antifungal activities of the ligand and complex have been investigated. The Ru(II) complex have strong antifungal activity than the ligand against Aspergillus niger.

Styrenated Oil Synthesis with Cyclic Carbonate Functional Groups on Polystyrene Segment

In this study, an oil-modified copolymer of 4-[(prop-2-en-1-yloxy)methyl]-1,3-dioxolan- 2-one (AGC) with styrene was synthesized, and the resulting copolymer (OBMI-St-AGC) was silane functionalized by inserting (3-aminopropyl) triethoxysilane (APTES) into the polymer backbone. OBMI-St-AGC was prepared by using an oil-based macroinitiator (OBMI) obtained by the esterification of linseed oil partial glycerides (PGs) with 4,4-azobis-4-cyanopentanoyl chloride (ACPC). In the characterization, FTIR, 1H NMR, TGA, and DSC analyses were applied. The silane-functionalized copolymer (OBMI-St-AGC-APTES) was crosslinked through the sol–gel process, and its crosslinked structure was determined.

N-acylhydrazone Derivative-Loaded Cellulose Acetate Films: Thermoanalytical, Spectroscopic, Mechanical and Morphological Characterization

Cellulose acetate (ACT) is one of the most important cellulose derivatives due to its biodegradability and low toxicity, presenting itself as one of the main substitutes for synthetic materials in the development of wound dressing films. The incorporation of a N-acylhydrazonic derivative (JR19), with its promising anti-inflammatory activity, may represent an alternative for the treatment of skin wounds. This work aims to develop and to physicochemically and mechanically characterize ACT films containing JR19. The films were prepared using the ‘casting’ method and further characterized by thermoanalytical and spectroscopic techniques. In addition, mechanical tests and morphological analysis were performed. Thermogravimetry (TG) and differential scanning calorimetry (DSC) analyses showed that the thermal events attributed to excipients and films were similar, indicating the absence of physical incompatibilities between ACT and JR19. Infrared spectroscopy showed that JR19 was incorporated into ACT films. The characteristic band attributed to C≡N (2279 to 2264 cm−1) was observed in the spectra of JR19, in that of the physical mixture of JR19/ACT, and, to a lesser extent, in the spectra of JR19 incorporated into the ACT film, suggesting some interaction between JR19 and ACT. X-ray diffraction (XRD) evidenced the suppression of the crystallinity of JR19 (diffraction peaks at 8.54°, 12.80°, 14.09°, 16.08°, 18.19°, 22.65°, 23.59°, 24.53°, 25.70°, 28.16° and 30.27°2θ) after incorporation into ACT films. The mechanical tests indicated the adequate integrity of the films and their resistance to bending. The morphological characterization showed JR19 crystals along with a homogeneously distributed porous structure throughout the surface of the films with an average diameter of 21.34 µm and 22.65 µm of the films alone and of those incorporating JR19F, respectively. This study was able to characterize the ACT films incorporating JR19, showing their potential to be further developed as wound healing dressings.

Aluminum Powder Preparation for Additive Manufacturing Using Electrostatic Classification

This work aims to study the possibility of using an electrostatic drum-type separator to prepare a powder with a narrow size distribution curve for usage in additive manufacturing. The size distributions of the uncoated commercial aluminum powders ASP-30, ASP-22, and ASP-5 were analyzed. It was shown that the powders ASP-30 and ASP-22 have similar asymmetric distributions with a SPAN of 1.480 and 1.756, respectively. ASP-5 powder, in turn, has a narrow distribution with a SPAN of 0.869. ASP-30 powder was chosen for further experiment because, traditionally, separators are used to classify large-sized materials with particle size more than 100 μm. The optimal mode of electrostatic classification was proposed for the selected powder. Various classification methods, including centrifugal and electrostatic, were compared. The powders before and after classification were studied by XRD, SEM, TEM, and TG–DSC analyses. The obtained results showed that electrostatic classification does not lead to the formation of coatings on the processed powders. Electrostatic separation effectively narrows the particle size distribution, making it a suitable and valuable method to classify initial powders for additive manufacturing.

OPTIMIZATION AND CHARACTERIZATION OF RIVASTIGMINE-LOADED NANOSTRUCTURED LIPID CARRIERS

Objective: The objective of the present study was to develop Nanostructured lipid carriers (NLCs) for improvement in the oral bioavailability of RT. Methods: RT-loaded NLCs were prepared by high shear homogenization technique using fish oil and flaxseed oil respectively. The prepared RT-NLCs were characterized using a phase-contrast microscope, scanning electron microscope (SEM), atomic force microscope (AFM), Fourier transform-infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Further, particle size, entrapment efficiency and sustained release of the drug were also studied. Results: SEM results revealed that the RT-NLCs were spherical in shape with a smooth surface. AFM results confirmed the formation of spherical particle dispersions by the NLCs in nanoscale. FTIR spectroscopy and DSC analyses revealed that there is no chemical interaction between the ingredients of RT-NLCs. The particle size of the RT-NLCs was found to be exponentially decreased with the increase in a surfactant solution. Conclusion: The results confirmed pronounced improvement in entrapment efficiency of optimized formulation of RT-NLCs. In vitro, drug release studies showed that RT-NLCs were capable of releasing the drug in a sustained manner. The experimental results showed that the NLCs are potential carriers for providing sustained delivery of rivastigmine.

Nanocarriers From Natural Lipids With In Vitro Activity Against Campylobacter jejuni

Campylobacter jejuni (CJ) is the most prevalent zoonotic pathogen of chicken meat and related products, which may lead to gastroenteritis and autoimmune diseases in humans. Although controlling this bacterium is important, CJ strains resistance against traditional antibiotic therapy has been increased. Vegetable oils and fats are natural biomaterials explored since the Ancient times, due to their therapeutic properties. Nanotechnology has promoted the miniaturization of materials, improving bioavailability and efficacy, while reducing the toxicity of loaded active molecules. In this work, a screening of 28 vegetable oils was firstly performed, in order to select anti-CJ candidates by the disc diffusion test. Thus, the selected liquid lipids were used as active molecules in nanostructured lipid carriers (NLC) formulations. The three resultant systems were characterized in terms of particle size (~200 nm), polydispersity index (~0.15), and zeta potential (~-35mV), and its physicochemical stability was confirmed for a year, at 25°C. The structural properties of NLC were assessed by infrared (FTIR-ATR) and differential scanning calorimetry (DSC) analyses. The spherical nanoparticle morphology and narrow size distribution was observed by transmission electron microscopy (TEM) and field emission scanning electron (FE-SEM) analyses, respectively. Then, the in vitro antimicrobial activity test determined the minimum inhibitory concentration (MIC) of each formulation against CJ strains, in both free (1–3 mg/ml−1) and sessile (0.78 mg/ml−1) forms. Finally, the in vitro biocompatibility of NLC was demonstrated through cell viability using VERO cell line, in which F6 was found twice less cytotoxic than pure olibanum oil. Considering the abovementioned achieved, F6 formulation is able to be evaluated in the in vivo anti-CJ efficacy assays.

Antioxidant Activity and Biocompatibility of Fructo-Polysaccharides Extracted from a Wild Species of Ornithogalum from Lebanon

The present study aims to investigate the properties of biopolymers extracted from a Lebanese onion non edible plant. The extraction was performed under mild conditions by varying the percentage of ultra-sound (US) treatment duration to a total extraction time of 30 min (0, 50, 100% US). The extracts were characterized using FTIR, SEC, GC-MS, TGA, and DSC analyses. The composition of the extracts was determined from the total carbohydrate content and protein content measurements. The thermal analyses indicate that all samples have high thermal stability. The antioxidant activities of the extracts were investigated, using β-carotene bleaching, scavenging activity of ABTS, metal chelating ability, and total antioxidant activity tests. The results indicate that the 50% US treatment leads to the best antioxidant activity. Biocompatibility of the extracts was evaluated using hemolysis and cytotoxicity assays. The results showed that 0 and 50% US samples are not toxic to human cells, in contrary to 100% US.

Effects of sticky rice addition on the properties of lime-tile dust mortars

The present study focused on the characteristics of lime-tile dust mortars with sticky rice addition, which were prepared according to historic Chinese accounts. Results showed that addition of sticky rice into mortars could improve water retention capacity, prolong setting time, and reduce bulk density values. Sticky rice addition also had long-term detrimental impacts on mortar strength development, concurrently increasing their water absorption values. FTIR, XRD and TG-DSC analyses revealed that the addition of sticky rice into mortars could slow down the carbonation as well as hydration process, at the same time forming both calcite and aragonite as carbonation products.