Lo scopo di questa tesi era di comprendere come alcune proprietà molecolari dei polimeri potessero influenzare la loro capacità di interagire con le membrane biologiche. A questo scopo si è valutata, tramite DSC, la capacità di quattro differenti polimeri di modificare l’andamento della transizione gel – liquido di membrane liposomiali costituite da DPPC (zwitterionica) e DPPG (anionica). Il PEG ha confermato la sua biocompatibilità non interagendo né con la DPPC né con la DPPG, mentre per i tre polimeri cationici sono state rilevate interazioni di rilevante entità nei confronti della membrana anionica DPPG. Solo la PAMAM G5 ha invece instaurato una debole interazione con la membrana zwitterionica DPPC, peraltro solo alla massima concentrazione testata. Le interazioni, quando presenti, sono risultate concentrazione – dipendenti, aumentando d’intensità con l’aumentare della concentrazione di polimero in soluzione. La presenza di cariche sul polimero sembra essere la principale caratteristica necessaria perché si osservi un’ interazione, dal momento che il principale meccanismo di interazione sembra essere il legame elettrostatico. In ogni caso, ulteriori studi sono necessari per comprendere l’effetto del peso molecolare e della presenza di cariche negative sulla superficie del polimero, nonché la presenza di sali e specie ioniche, in modo da mimare con più precisione i sistemi biologici. Sebbene la DSC sia risultata un metodo utile, altre tecniche calorimetriche come la calorimetria isotermica di titolazione (ITC) o tecniche non calorimetriche come la microscopia a forza atomica (AFM) potrebbero essere utili per comprendere meglio alcune modalità di interazione.
Detto ciò, tenendo conto della maggiore complessità delle membrane biologiche rispetto alle membrane liposomiali studiate in questo lavoro, ricerche future potrebbero orientarsi verso l’utilizzo di modelli di membrana più realistici, ad esempio doppi strati fosfolipidici o membrane costituite da più tipi di fosfolipidi e/o contenenti carboidrati e proteine, i quali potrebbero portare a risultati molto diversi.
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