Scientific research in the field of regenerative medicine of bone tissue has been moving, in recent years, in the direction of developing injectable bone substitutes, in order to create materials capable of reaching the pathological site in a minimally invasive way, with the aim to reduce the risks, damages and costs of a surgical operation. In this regard, hydrogels certainly represent some of the most studied and innovative materials. Hydrogels are hydrophilic polymeric materials capable of exhibiting, in many cases, excellent biocompatibility and low inflammatory response, being able, moreover, to be loaded with numerous biomolecules capable of speeding up the process of formation of a new bone matrix. Among these innovative materials, a relevant position is occupied by thermo-responsive hydrogels, capable of undergoing a transition from the liquid state to the gel state as a function of temperature. Property that makes them ideal for in vivo injection. Their use in bone tissue engineering (BTE) is, therefore, a valid option to more traditional treatments and many studies are still needed to identify the physical and biological properties of these promising polymeric materials. In this thesis work a thermo-responsive polymeric hydrogel in methylcellulose (MC) was synthesized and characterized. Moreover, the effect of the addition of hydroxyapatite (HA) and hydroxyapatite with graphene oxide (HAGO) on its physical, chemical and mechanical characteristics was evaluated. The results of the swelling tests showed the long-term stability of the gels. Through the inversion tests it was possible to identify the Na2SO4 concentration capable of tuning MC gelation temperature (LCST) in a physiological range. FT-IR and XRD analysis allowed to evaluate the ability of HA and HAGO not only to integrate properly in the gel, but also to increase its mechanical properties, studied with appropriate rheological tests, and the mineralization process. Finally, the injectability tests showed that all the samples tested are suitable for in vivo injection.
La ricerca scientifica nell’ambito della medicina rigenerativa del tessuto osseo si sta muovendo, negli ultimi anni, nella direzione di sviluppare dei sostituti ossei iniettabili, al fine di creare dei materiali in grado di raggiungere in modalità mininvasive il sito patologico, allo scopo di diminuire i rischi, i danni ed il costo di un’operazione chirurgica. A tal proposito, gli idrogeli rappresentano, sicuramente, alcuni tra i materiali più studiati ed innovativi. Gli idrogeli sono materiali polimerici idrofilici in grado di esibire, in molti casi, eccellente biocompatibilità e bassa risposta infiammatoria, potendo, inoltre, essere caricati con numerose biomolecole in grado di velocizzare il processo di formazione di nuova matrice ossea. Tra questi innovativi materiali, una posizione rilevante è occupata dagli idrogeli termo-responsivi, in grado di subire una transizione dallo stato liquido allo stato gel in funzione della temperatura. Proprietà che li rende ideali per l’iniezione in vivo. Il loro utilizzo in ingegneria del tessuto osseo (BTE) è, dunque, una valida opzione ai trattamenti più tradizionali e molti studi sono ancora necessari per identificare le proprietà fisiche e biologiche di questi promettenti materiali polimerici. In questo lavoro di tesi è stato sintetizzato e caratterizzato un idrogelo polimerico termo-responsivo in metilcellulosa (MC) e valutato l’effetto che l’addizione di idrossiapatite (HA) e idrossiapatite con ossido di grafene (HAGO) può generare sulle sue caratteristiche fisiche, chimiche e meccaniche. I risultati dei test di swelling hanno evidenziato la stabilità dei gel a lungo termine. Tramite i test di inversione è stato possibile identificare la concentrazione di Na2SO4 in grado di far coincidere la temperatura di gelificazione (LCST) della MC con quella fisiologica. Le analisi FT-IR e XRD hanno permesso di valutare la capacità di HA e HAGO non solo di integrarsi opportunamente nel gel, ma anche di incrementare le sue proprietà meccaniche, studiate con opportuni test reologici, ed il processo di mineralizzazione. Infine, i test di iniettabilità hanno dimostrato che tutti i campioni testati risultano idonei all’iniezione in vivo.
Sviluppo e caratterizzazione di idrogeli termo-responsivi a base di metilcellulosa per la rigenerazione del tessuto osseo
BOCCALI, ALBERTO
2019/2020
Abstract
Scientific research in the field of regenerative medicine of bone tissue has been moving, in recent years, in the direction of developing injectable bone substitutes, in order to create materials capable of reaching the pathological site in a minimally invasive way, with the aim to reduce the risks, damages and costs of a surgical operation. In this regard, hydrogels certainly represent some of the most studied and innovative materials. Hydrogels are hydrophilic polymeric materials capable of exhibiting, in many cases, excellent biocompatibility and low inflammatory response, being able, moreover, to be loaded with numerous biomolecules capable of speeding up the process of formation of a new bone matrix. Among these innovative materials, a relevant position is occupied by thermo-responsive hydrogels, capable of undergoing a transition from the liquid state to the gel state as a function of temperature. Property that makes them ideal for in vivo injection. Their use in bone tissue engineering (BTE) is, therefore, a valid option to more traditional treatments and many studies are still needed to identify the physical and biological properties of these promising polymeric materials. In this thesis work a thermo-responsive polymeric hydrogel in methylcellulose (MC) was synthesized and characterized. Moreover, the effect of the addition of hydroxyapatite (HA) and hydroxyapatite with graphene oxide (HAGO) on its physical, chemical and mechanical characteristics was evaluated. The results of the swelling tests showed the long-term stability of the gels. Through the inversion tests it was possible to identify the Na2SO4 concentration capable of tuning MC gelation temperature (LCST) in a physiological range. FT-IR and XRD analysis allowed to evaluate the ability of HA and HAGO not only to integrate properly in the gel, but also to increase its mechanical properties, studied with appropriate rheological tests, and the mineralization process. Finally, the injectability tests showed that all the samples tested are suitable for in vivo injection.| File | Dimensione | Formato | |
|---|---|---|---|
|
Sviluppo e caratterizzazione di idrogeli termo-responsivi a base di metilcellulosa per la rigenerazione del tessuto osseo.pdf
non accessibile
Dimensione
2.41 MB
Formato
Adobe PDF
|
2.41 MB | Adobe PDF | Visualizza/Apri |
I documenti in POLITesi sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
https://hdl.handle.net/10589/176021