Sistemi adesivi con applicazioni in campo biomedicale

Polymeric adhesives have been used for many applications like suture and embolization, instead of classic surgical methods or as for dental uses. In this work both subjects have been investigated and the results separated in two parts. In the first, new dentinal adhesives with different polymerizable groups (methacrylic or vinyl-ethereal) were synthesized. A low sensitivity to hydrolysis and equal or enhanced properties, compared to existing commercial products, were considered essentials. Moreover, these monomers need to polymerize by radical photopolymerization and functional groups of different characteristics were tested. All these products were characterized by microtensile bond strength test to determine the bonding strength between the adhesive and tooth. Concerning embolization, cyanoacrylates are nowadays the most-used adhesives in surgery. Thus, they must respond to several requirements. For instance, polymerization time and adhesive strength need to be low, to avoid diffusion of the products in the body and adhesion to the catheter. In order to overcome these problems we developed new cyanoacrylates, which practically instantly polymerize upon contact with blood but do not demonstrate strong adhesion to the catheter, thank to the presence of fluorine atoms, linked to the ester chain. The synthesis of these products was carried out in several steps, such as the depolymerization of the corresponding oligomers at high temperature in acid conditions. Two types of adhesion strengths were determined. Bonding strength between human veins and a microcatheter was determined in vitro by using organic materials as the most realistic model. Another test, on two layers of skin, was conducted to verify the possible use of these new cyanoacrylates as a glue for sutures. As a conclusion, we were able to demonstrate that some of the prepared monomers posses adhesive strength and polymerization time lower than the commercial product Glubran2.

Silk Fibroin: a biopolymer platform for innovative pharmaceutical formulation and biomedical devices.

The protein silk fibroin (SF) from the silkworm Bombyx mori is a FDA-approved biomaterial used over centuries as sutures wire. Importantly, several evidences highlighted the potential of silk biomaterials obtained by using so-called regenerated silk fibroin (RSF) in biomedicine, tissue engineering and drug delivery. Indeed, by a water-based protocol, it is possible to obtain protein water-solution, by extraction and purification of fibroin from silk fibres. Notably, RSF can be processed in a variety of biomaterials forms used in biomedical and technological fields, displaying remarkable properties such as biocompatibility, controllable biodegradability, optical transparency, mechanical robustness. Moreover, RSF biomaterials can be doped and/or chemical functionalized with drugs, optically active molecules, growth factors and/or chemicals In this view, activities of my PhD research program were focused to standardize the process of extraction and purification of protein to get the best physical and chemical characteristics. The analysis of the chemo-physical properties of the fibroin involved both the RSF water-solution and the protein processed in film. Chemo-physical properties have been studied through: vibrational (FT-IR and Raman-FT) and optical (absorption and emission UV-VIS) spectroscopy, nuclear magnetic resonance (1H and 13C NMR), thermal analysis and thermo-gravimetric scan (DSC and TGA). In the last year of my PhD, activities were focused to study and define innovative methods of functionalization of the silk fibroin solution and films. Indeed, research program was the application of different methods of manufacturing approaches of the films of fibroin without the use of harsh treatments and organic solvents. New approaches to doping and chemical functionalization of the silk fibroin were studied. Two different methods have been identified: 1) biodoping that consists in the doping of fibroin with optically active molecules through the addition of fluorescent molecules in the standard diet used for the breeding of silkworms; 2) chemical functionalization via silylation.

Fistole retto-vaginali Crohn-relate trattate mediante trasposizione del muscolo gracile: risultati a lungo termine e qualità della vita

OBIETTIVO: Le fistole retto-vaginali Crohn-relate hanno un impatto significativo sulla qualità della vita. Quando il canale anale è alterato da ulcerazioni e stenosi o in pazienti con difetti estesi del perineo, la chirurgia locale produce risultati insoddisfacenti. Lo scopo di questo studio è quello di valutare l'efficacia della trasposizione del muscolo gracile nelle fistole retto-vaginali Crohn-relate e determinare i suoi effetti sulla qualità della vita. MATERIALI E METODI: Da gennaio 2012 a ottobre 2014 sono state trattate 10 pazienti; sono state raccolte alcune variabili (età, BMI, il fumo, CDAI, setone perioperatorio, precedenti procedure, uso di immunomodulatori e steroidi). Tutte le pazienti sono state sottoposte ad ileostomia temporanea prima della graciloplastica. La percentuale di successo è stata misurata come numero di pazienti con fistola guarita dopo la chiusura della stomia. Sono stati utilizzati tre questionari prima della graciloplastica e 3 mesi dopo la chiusura della stomia al fine di valutare la qualità della vita (SF-36), l’ incontinenza fecale e la funzione sessuale. RISULTATI: La fistola retto-vaginale è stata chiusa in 9 pazienti su 10 dopo graciloplastica, con un follow-up medio di chiusura della stomia di 19 mesi (range 4 -34). È stata documentata una recidiva di RVF. Il tempo operatorio era 90-150 minuti (media, 120). La degenza postoperatoria era 7-16 giorni (media 10). Complicanze postoperatorie precoci includevano deiscenza delle suture perineali in 2 casi. Le complicanze a lungo termine includevano disestesia della cicatrice perineale. Nei dati post-operatori abbiamo riportato un miglioramento della qualità di vita, della funzione sessuale e della continenza fecale. CONCLUSIONI: La chiusura della fistola retto-vaginale utilizzando la trasposizione del muscolo gracile è associata a morbidità minima e un alto tasso di successo.