1,721,327 research outputs found
Preparazione e caratterizzazione di miscele di polimeri naturali e sintetici per applicazioni come materiali biocompatibili e/o a basso impatto ambientale
No full textIl lavoro di tesi è stato rivolto alla produzione e caratterizzazione di materiali con proprietà idonee prevalentemente per applicazioni nel settore biomedicale, in taluni casi considerando, più in generale, il loro utilizzo come plastiche eco-compatibili. Sono state prodotte e caratterizzate tre classi di materiali con caratteristiche di degradabilità in ambiente acquoso: 1) polimeri sintetici a base di policaprolattone (PCL), tra cui due tipi di PCL a diverso peso molecolare, un copolimero a tre blocchi PCL-POE-PCL e una serie di poliuretani (PU) e poliuretani-uree (PUU), sintetizzati in precedenti lavori di tesi; miscele a base di PCL (sia con polimeri naturali sia con un polimero sintetico, il poli(idrossibutirrato-co-idrossivalerato), PHBHV) e miscele tra i polimeri naturali chitosano e gelatina. I materiali sono stati sottoposti ad una caratterizzazione fisico-chimica di utilità generale e ad una specifica caratterizzazione, nella prospettiva di un loro utilizzo nel settore dell'Ingegneria Tissutale. Sono state adoperate diverse tecniche di produzione degli scaffolds, alcune non-convenzionali, come il sistema di deposizione tramite microsiringa (PAM), la sinterizzazione selettiva tramite laser (SLS) e la tecnica di litografia soft (SL), e alcune convenzionali, come l'estrusione di guide cave dal fuso e la filatura di fibre cave da soluzione polimerica. Inizialmente, è stato effettuato uno screening di biocompatibilità dei materiali tra le tre classi di materiali studiate e, con i materiali risultati più adatti per applicazioni nell'Ingegneria Tissutale, sono stati prodotti scaffolds, attraverso le tecniche di microfabbricazione. In una seconda fase del lavoro, sono stati prodotti scaffolds in forma di guide, tramite filatura dal fuso e da soluzione, per impieghi nel settore della rigenerazione neuronale, usando i materiali maggiormente biocompatibili tra quelli studiati. Il lavoro ha approfondito soprattutto l'aspetto delle applicazioni in campo biomedicale anche se la maggiore parte dei materiali oggetto di studio in questo lavoro sono adatti anche per applicazioni come plastiche eco-compatibil
Zein as a renewable material for the preparation of green nanoparticles for drug delivery
Full text linkEnvironmental sustainability is a key challenge driven by the increased consumption of natural resources with limited availability. In this scenario agriculture has emerged as a privileged source of renewable resources, hence more efforts should be addressed to the study of plant-derived materials for medical applications. Zein is a biocompatible, biodegradable and amphiphilic prolamin protein extracted from the endosperm tissue of corn. For these reasons, its applications span from coatings for edible capsules, to the fabrication of bi- and tridimensional scaffolds for tissue engineering, and to develop drug delivery systems. This review aims at describing the properties and main applications of zein with a focus on the most recent and updated state of the art literature on zein based nanoparticles for the controlled delivery of various drugs. The main focus is to analyze the state of the art literature to understand how to implement sustainable methods for the preparation of zein NPs and to propose their exploitation as novel drug delivery systems for multiple applications, including oligonucleotide delivery. Main methods for zein NP preparation are described under an ecofriendly point of view, highlighting their environmental sustainability based on used solvents, waste products and energy consumption
European Research Council-funded grant: development of a novel cardiac tissue model
No full textHeart diseases (HDs) represent a major health challenge, being the leading cause of mortality and morbidity worldwide.1 HDs impose a huge economic burden to the healthcare system and the whole society, which is expected to increase due to the growth and aging of the population.2 Hence, safe and effective therapies for HD treatment are highly demanded. However, their development has been mostly limited by pre-clinical testing in poorly predictive in vitro 2D cell cultures and in vivo animal models affected by interspecies differences.3 Limitations in pre-clinical testing also impose safety risks for patients involved in the next clinical trials, which may include impaired cardiac function at different levels up to fatal arrhythmias, ischaemic events, myocardial infarction, and injuries to cardiac valves, the conduction system and the pericardium. In other cases, patient-specific cardiotoxicity risks have been detected only after drug approval causing their withdrawal from the market.4 Notably, drugs developed for other purposes than HD treatment (e.g. chemotherapeutics) also need early cardiotoxicity risk assessment as they may have adverse effects on the heart
Materials for Peripheral Nerve Regeneration
No full textRecent efforts in scientific research in the field of peripheral nerve regeneration have been directed towards the development of artificial nerve guides. We have studied various materials with the aim of obtaining a biocompatible and biodegradable two layer guide for nerve repair. The candidate materials for use as an external layer for the nerve guides were poly(caprolactone) (PCL), a biosynthetic blend between PCL and chitosan (CS) and a synthesised poly(esterurethane) (PU). Blending PCL, which is a biocompatible synthetic polymer, with a natural polymer enhanced the system biocompatibility and biomimetics, fastened the degradation rates and reduced the production costs. Various novel block poly(ester-urethane)s are being synthesised by our group with tailored properties for specific tissue engineering applications. One of these poly(ester-urethane)s, based on a low molecular weight poly(caprolactone) as the macrodiol, cycloesandimethanol as the chain extender and hexamethylene diisocyanate as the chain linker, was investigated for the production of melt extruded nerve guides. We studied natural polymers such as gelatin (G), poly(L-lysine) (PL) and blends between chitosan and gelatin (CS/G) as internal coatings for nerve guides. In vitro and in vivo tests were performed on PCL guides internally coated either with G or PL to determine the differences in the quality of nerve regeneration associated with the type of adhesion protein. CS/G natural blends combined the good cell adhesion properties of the protein phase with the ability to promote nerve regeneration of the polysaccharide phase. Natural blends were crosslinked both by physical and chemical crosslinking methods. In vitro neuroblast adhesion tests were performed on CS/G film samples, PCL/CS and PU guides internally coated with G to evaluate the ability of such materials towards nerve repai
Direct Reprogramming of Adult Human Cardiac Fibroblasts into Induced Cardiomyocytes Using miRcombo
No full textDirect reprogramming of fibroblasts into induced cardiomyocytes (iCMs) through microRNAs (miRNAs) is a new emerging strategy for myocardial regeneration after ischemic heart disease. Previous studies have reported that murine fibroblasts can be directly reprogrammed into iCMs by transient transfection with four miRNAs (miRs-1, 133, 208 and 499 – termed “miRcombo”). While advancement in the knowledge of direct cell reprogramming molecular mechanism is in progress, it is important to investigate if this strategy may be translated to humans. Recently, we demonstrated that miRcombo transfection is able to induce direct reprogramming of adult human cardiac fibroblasts (AHCFs) into iCMs. Although additional studies are needed to achieve iCM maturation, our early findings pave the way toward new therapeutic strategies for cardiac regeneration in humans. This chapter describes methods for inducing direct reprogramming of AHCFs into iCMs through miRcombo transient transfection, showing experiments to perform for assessing iCM generation
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