1,721,007 research outputs found
Application of Microfluidic Chips to the Preparation of Polysaccharidic Microbeads for Cell Entrapment
No full textCell encapsulation systems based on hybrid hydrogels
No full textThe entrapment of cells into biomaterials is one of the most appealing and usefulness tool in tissue engineering and cell based therapy applications. Cell encapsulation procedures allow the immunoisolation of cells from the surrounding environment, after their transplantation and the maintenance of the normal cellular physiology. In the current PhD work, various microencapsulation cell procedures are reported, based on a gas driven mono-jet device, a vibrating-nozzle procedure and microfluidics. All the analysed procedures were critically evaluated and applied to cells from different sources. The obtained microcapsules were characterized by excellent morphological characteristics and a very narrow size distribution. Interestingly, the results demonstrated that the microencapsulation procedures did not alter the morphology, viability and functions of the embedded cells. Moreover, the production of engineered microcapsules or microfibres has been also developed with the aim of enhancing mechanical characteristics, viability and functional life-span of the entrapped cells. In conclusion, the encapsulation technologies, here presented, represent a promising strategy for the treatment of many pathologies open to further development and scaling up towards regulatory agencies approval
Design, production and optimization of solid lipid microparticles (SLM) by a coaxial microfluidic device
No full textThis paper describes a method for the production of lipid microparticles (SLM) based on microfluidics using a newly designed modular device constituted of three main parts: a temperature control, a co-flow dripping element and a congealing element
Rheological and functional characterization of new antiinflammatory delivery systems designed for buccal administration
No full textThe aim of the present paper was to investigate the influence of different formulation parameters on the rheological and functional properties of emulgels (gelified emulsions), intended for the buccal administration of the antiinflammatory drug flurbiprofen. The influence of formulation parameters, such as (a) the amount of gelling polymeric emulsifier (Pemulen® 1621 TR-1) used, (b) the oil to water ratio present in the O/W emulgel and finally (c) the pH of the formulation, was studied by a experimental design (DoE) approach. Formulations were analyzed in term of size and morphology of the internal semi-solid oil droplets as well as in term of rheological properties in the presence or in the absence of flurbiprofen by "shear stress vs. shear rate tests" and "frequency sweep tests". Emulgels were also characterized in vitro both by bioadhesion tests and release studies. In particular release studies demonstrated that flurbiprofen is released by the emulgels in a controlled manner, the drug release efficacy within the first 100 min was comprised between 50 and 80% of the total amount of the drug. Finally, in vivo tests on healthy volunteers have demonstrated that emulgels were able to remain on buccal mucosa for an average period of 1 h, moreover emulgels did not have bad taste and volunteers referred that were agreeable and pleasant. © 2007 Elsevier B.V. All rights reserved
Design, production and optimization of solid lipid microparticles by flow-focusing technology
No full textHydrogel blends with adjustable properties as patches for transdermal delivery.
No full textThe effect of different preparation parameters were analyzed with respect to the rheological and pharmaceutical characteristics of hydrogel blend patches, as transdermal delivery formulation. Mixtures of pectin and gelatin were employed for the production of patches, with adjustable properties, following a two-step gelation procedure. The first gelation, a thermal one, is trigged by the presence of gelatin, whereas, the second gelation, an ionic one, is due to the formation of the typical egg box structure of pectin. In particular, the patch structural properties were assessed by oscillation stress sweep measurements which provided information concerning their viscolelastic properties. In addition, different modalities for drug loading were analyzed with respect to drug homogeneous distribution; testosterone was employed as model drug for transdermal administration. Finally, the performances of the produced transdermal patches were studied, in term of reproducibility and reliability, by determination of in vitro drug release profiles
Effect of the gelation process on the production of alginate microbeads by microfluidic chip technology
No full textThe present paper reports the production of Ba-alginate microspheres by microfluidic chip technology. The general production strategy is based on the formation of an alginate multiphase flow by a 'Y' junction squeezing mechanism. Special emphasis is given to the relationship existing between the gelation process and the final morphological characteristics of the produced microbeads. A series of different gelation strategies, namely: 'external gelation', 'internal gelation' and 'partial gelation' were compared in terms of size, size distribution and morphology of the produced microbeads. © The Royal Society of Chemistry
Oligonucleotide transport and cellular uptake by positively charged microparticles
No full textThe production and characterization of cationic microparticles based on methacrylate copolymer constituted of acrylic and methacrylic acid esters (Eudragit RS) and the cationic agent dioctadecyl-dimethyl-ammonium bromide (DDAB18) for the delivery of nucleic acids is described. It was found that morphological and dimensional characteristics of microparticles were influenced by some experimental parameters such as stirring speed, emulsifying agent and type of rotor. The deoxyribonucleotide Defibrotide (DFT) was associated to positively charged microparticles and its in vitro release kinetics from microparticles was determined. A study on the in vitro toxicity of cationic microparticles on cultured human cell line K562 was also performed which demonstrated that the cationic surfactant dioctadecyl-dimethyl-ammonium bromide (DDAB18) microparticles display very low cytotoxicity
Induction by TNF-a of IL-6 and IL-8 in cystic fibrosis bronchial IB3-1 epithelial cells encapsulated in alginate microbeads.
No full textAbstract: We have developed a microencapsulation procedure for the entrapment and manipulation of IB3-1 cystic fibrosis cells. The applied method is based on generation of monodisperse droplets by a vibrational nozzle. Different experimental parameters were analyzed, including frequency and amplitude of vibration, polymer pumping rate and distance between the nozzle and the gelling bath. We have found that the microencapsulation procedure does not alter the viability of the encapsulated IB3-1 cells. The encapsulated IB3-1 cells were characterized in term of secretomic profile, analyzing the culture medium by Bio-Plex strategy. The experiments demonstrated that most of the analyzed proteins, were secreted both by the free and encapsulated cells, even if in a different extent. In order to determine the biotechnological applications of this procedure, we determined whether encapsulated IB3-1 cells could be induced to pro-inflammatory responses, after treatment with TNF-a. In this experimental set-up, encapsulated and free IB3-1 cells were treated with TNF-a, thereafter the culture media from both cell populations were collected. As expected, TNF-a induced a sharp increase in the secretion of interleukins, chemokines and growth factors. Of great interest was the evidence that induction of interleukin-6 and interleukin-8 occurs also by encapsulated IB3-1 cells
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