Cell encapsulation systems based on hybrid hydrogels

The 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

Induction by TNF- α

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-α. In this experimental set-up, encapsulated and free IB3-1 cells were treated with TNF-α, thereafter the culture media from both cell populations were collected. As expected, TNF-α 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

Mithramycin encapsulated in polymeric micelles by microfluidic technology as novel therapeutic protocol for beta-thalassemia

This report shows that the DNA-binding drug, mithramycin, can be efficiently encapsulated in polymeric micelles (PM-MTH), based on Pluronic® block copolymers, by a new microfluidic approach. The effect of different production parameters has been investigated for their effect on PM-MTH characteristics. The compared analysis of PM-MTH produced by microfluidic and conventional bulk mixing procedures revealed that microfluidics provides a useful platform for the production of PM-MTH with improved controllability, reproducibility, smaller size, and polydispersity. Finally, an investigation of the effects of PM-MTH, produced by microfluidic and conventional bulk mixing procedures, on the erythroid differentiation of both human erythroleukemia and human erythroid precursor cells is reported. It is demonstrated that PM-MTH exhibited a slightly lower toxicity and more pronounced differentiative activity when compared to the free drug. In addition, PM-MTH were able to upregulate preferentially ?-globin messenger ribonucleic acid production and to increase fetal hemoglobin (HbF) accumulation, the percentage of HbF-containing cells, and their HbF content without stimulating ?-globin gene expression, which is responsible for the clinical symptoms of ß-thalassemia. These results represent an important first step toward a potential clinical application, since an increase in HbF could alleviate the symptoms underlying ß-thalassemia and sickle cell anemia. In conclusion, this report suggests that PM-MTH produced by microfluidic approach warrants further evaluation as a potential therapeutic protocol for ß-thalassemia.<br/

Delivery of Suramin as an Antiviral Agent through Liposomal Systems

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Acceleration of Functional Maturation and Differentiation of Neonatal Porcine Islet Cell Monolayers Shortly In Vitro Cocultured with Microencapsulated Sertoli Cells

The limited availability of cadaveric human donor pancreata as well as the incomplete success of the Edmonton protocol for human islet allografts fasten search for new sources of insulin the producing cells for substitution cell therapy of insulin-dependent diabetes mellitus (T1DM). Starting from isolated neonatal porcine pancreatic islets (NPIs), we have obtained cell monolayers that were exposed to microencapsulated monolayered Sertoli cells (ESCs) for different time periods (7, 14, 21 days). To assess the development of the cocultured cell monolayers, we have studied either endocrine cell phenotype differentiation markers or c-kit, a hematopoietic stem cell marker, has recently been involved with growth and differentiation of β-cell subpopulations in human as well as rodent animal models. ESC which were found to either accelerate maturation and differentiation of the NPIs β-cell phenotype or identify an islet cell subpopulation that was marked positively for c-kit. The insulin/c-kit positive cells might represent a new, still unknown functionally immature β-cell like element in the porcine pancreas. Acceleration of maturation and differentiation of our NPI cell monolayers might generate a potential new opportunity to develop insulin-producing cells that may suite experimental trials for cell therapy of T1DM

Oligonucleotide transport and cellular uptake by positively charged microparticles

The 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

A Statistical Approach to Optimize the Spray Drying of Starch Particles: Application to Dry Powder Coating

This article describes the preparation of starch particles, by spray drying, for possible application to a dry powder coating process. Dry powder coating consists of spraying a fine powder and a plasticizer on particles. The efficiency of the coating is linked to the powder morphological and dimensional characteristics. Different experimental parameters of the spray-drying process were analyzed, including type of solvent, starch concentration, rate of polymer feeding, pressure of the atomizing air, drying air flow, and temperature of drying air. An optimization and screening of the experimental parameters by a design of the experiment (DOE) approach have been done. Finally, the produced spray-dried starch particles were conveniently tested in a dry coating process, in comparison to the commercial initial starch. The obtained results, in terms of coating efficiency, demonstrated that the spray-dried particles led to a sharp increase of coating efficiency value

Microfluidic and lab-on-a-chip preparation routes for organic nanoparticles and vesicular systems for nanomedicine applications

In recent years, advancements in the fields of microfluidic and lab-on-a-chip technologies have provided unique opportunities for the implementation of nanomaterial production processes owing to the miniaturisation of the fluidic environment. It has been demonstrated that microfluidic reactors offer a range of advantages compared to conventional batch reactors, including improved controllability and uniformity of nanomaterial characteristics. In addition, the fast mixing achieved within microchannels, and the predictability of the laminar flow conditions,can be leveraged to investigate the nanomaterial formation dynamics. In this article recent developments in the field of microfluidic production of nanomaterials for drug delivery applications are reviewed. The features that make microfluidic reactors a suitable technological platform are discussed in terms of controllability of nanomaterials production. An overview of the various strategies developed for the production of organic nanoparticles and colloidal assemblies is presented, focusing on those nanomaterials that could have an impact on nanomedicine field such as drug nanoparticles, polymeric micelles, liposomes, polymersomes, polyplexes and hybrid nanoparticles. The effect of microfluidic environment on nanomaterials formation dynamics, as well as the use of microdevices as tools for nanomaterial investigation is also discussed