Browsing by Author "Martins-Lopes, P."
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Application of nanotechnology in the agro-food sectorPublication . Lopes, Carla Martins; Fernandes, J.R.; Martins-Lopes, P.Nanotechnology is an emerging field of research that has been widely applied in different scientific and engineering areas. The agro-food sector is not an exception, which considers its applicability in several areas of major interest for both consumers and producers. This review considers major concepts related to nanostructures and nano-based instruments used in the food sector, as well as their applications in agro-food products. Food safety through the use of nanosensors for pathogen detection, smart packaging, and valorisation of food products by nanoencapsulation/nanodelivery of food ingredients (e.g. flavours) are examples of important areas of nanotechnology. Consumers' apprehension regarding food stability and safety issues is also considered.
- Cationic solid lipid nanoparticles (cSLN): structure, stability and DNA binding capacity correlation studiesPublication . Doktorovova, S.; Shegokar, R.; Rakovsky, E.; Gonzalez-Mira, E.; Lopes, Carla Martins; Silva, A.M.; Martins-Lopes, P.; Muller, R.H.; Souto, Eliana B.Cationic solid lipid nanoparticles (cSLN) are promising lipid nanocarriers for intracellular gene delivery based on well-known and widely accepted materials. cSLN containing single-chained cationic lipid cetyltrimethylammonium bromide were produced by high pressure homogenization and characterized in terms of(a) particle size distribution by photon correlation spectroscopy (PCS) and laser diffractometry (LD), (b) thermal behaviour using differential scanning calorimetry (DSC) and (c) the presence of various polymorphic phases was confirmed by X-ray diffraction (WAXD). SLN composed of Imwitor 900PTM (IMW) showed different pDNA stability and binding capacity in comparison to those of Compritol 888 ATOTM (COM). IMW-SLN, having z-ave = 138–157 nm and d(0.5) = 0.15–0.158 m could maintain this size for 14 days at room temperature. COM-SLN had z-ave = 334 nm and d(0.5) = 0.42 m on the day of production and could maintain similar size during 90 days. IMW-SLN revealed improved pDNA binding capacity. We attempted to explain these differences by differentinteractions between the solid lipid and the tested cationic lipid.
- Modified rose bengal assay for surface hydrophobicity evaluation of cationic solid lipid nanoparticles (cSLN)Publication . Doktorovova, S.; Shegokar, R.; Martins-Lopes, P.; Silva, A.M.; Lopes, Carla Martins; Müller, R.H.; Souto, Eliana B.Surface hydrophobicity of nanocarriers influences protein binding and subsequently fate of nanoparticles in blood circulation. Therefore, characterization of surface hydrophobicity of nanocarriers provides important preclinical information. Here, a modified classical adsorption method for the needs of characterization of cationic solid lipid nanoparticles (cSLN) was developed. We have identified possible method limitations that should be considered when performing the analysis, i.e. the problems associated with particle separation from the dispersion and their own absorbance in visible spectrum. We propose two modified methods for performing the assay overcoming the stated limitations. We also discuss here evaluation by different approaches (calculation of binding constants or partitioning quotient) and their suitability for the prepared cSLN formulation. Overall, we confirmed that our modified adsorption method can provide useful information about surface properties of (cationic) SLN, however, performing and evaluation of the assay need special attention in order to obtain the desired results.
- Nanoparticulate carriers (NPC) for oral pharmaceutics and nutraceuticsPublication . Lopes, Carla Martins; Martins-Lopes, P.; Souto, Eliana B.The introduction of nanoparticulate carriers (NPC) in the pharmaceutic and nutraceutic fields has changed the definitions of disease management and treatment, diagnosis, as well as the supply food chain in the agri-food sector. NPC composed of synthetic polymers, proteins or polysaccharides gather interesting properties to be used for oral administration of pharmaceutics and nutraceutics. Oral administration remains the most convenient way of delivering drugs (e.g. peptides, proteins and nucleic acids) since these suffer similar metabolic pathways as food supply. Recent advances in biotechnology have produced highly potent new molecules however with low oral bioavailability. A suitable and promising approach to overcome their sensitivity to chemical and enzymatic hydrolysis as well as the poor cellular uptake, would be their entrapment within suitable gastrointestinal (GI) resistant NPC. Increasing attention has been paid to the potential use of NPC for peptides, proteins, antioxidants (carotenoids, omega fatty acids, coenzyme Q10), vitamins, probiotics, for oral administration. This review focuses on the most important materials to produce NPC for oral administration, and the most recent achievements in the production techniques and bioactives successfully delivered by these means.