Üretral Onarımda Kullanılmak Üzere Nanobiyomalzemelerin Hazırlanması ve Karakterizasyonu

Abstract

Urethral injuries; it still constitutes one of the important problems in the field of urology due to the difficulties in its treatment and the high rate of complications occurring after surgical intervention. These injuries have a complex structure and are difficult to treat with endoscopy. Urethral injuries are mostly seen in falls or as a result of injuries that cause pelvic fractures. These conditions can affect the front or back part of the urethra and lead to serious complications. Urethral strictures may occur due to reasons such as infection or injury and can cause serious problems if left untreated. Nanotechnology stands out as a promising field in the treatment of urethra injuries and strictures. This study aimed to prepare and characterize nanobiomaterials for use in urethral repair. In this thesis study, it is aimed to synthesize, characterize and examine the properties of Papaverine (PPV) hydrochloride loaded Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/Gelatin (PHBV/Gel) nanofiber membranes by electrostatic spinning method for use in urethral repair. PHBV has biodegradable, biocompatible, non-toxic and semi-crystalline properties and is a suitable biopolymer for tissue engineering applications with its high mechanical strength and easy electrostatic spinnability. Gelatin (Gel) is a biopolymer with low cost, high biocompatibility, biodegradability, non-cytotoxicity, non-antigen properties, high water retention capacity, structural and functional similarity with the natural extracellular matrix (ECM), and supporting properties of cell adhesion, differentiation and proliferation. Therefore, it is another natural polymer that is frequently preferred in tissue engineering applications. However, rapid degradation and poor mechanical strength properties of electrostatically spun gelatin nanofibers limit their use in the biomedical field. By mixing gel with other natural or synthetic polymers, superior tissue scaffolds can be produced in terms of mechanical, physicochemical and biological properties. PPV hydrochloride is a vasodilator that dilates blood vessels by relaxing smooth muscle cells. Thanks to these properties, it is aimed to increase the effectiveness of nanofiber membranes in tissue regeneration and urethral repair by adding PPV hydrochloride. Within the scope of the characterization studies carried out for this purpose, viscosity measurements, morphological analysis, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA) of PHBV, PHBV/Gel and PPV hydrochloride loaded PHBV/Gel nanofiber membranes, Mechanical tests, in vitro papaverine hydrochloride release studies, contact angle (wettability) tests and in vitro biodegradation studies were carried out. Viscosity measurements show that the solution viscosity decreases with the addition of pure gelatin and with the increase of PPV hydrochloride loading rate. The gel additive reduced the viscosity by breaking the resistance of the PHBV solution. Morphological analysis, FEGSEM images and measurements with Image J software reveal that solution ratios with different concentrations affect membrane morphology and fiber diameters. Gel additive reduced the breaking force and elongation values. Falling occurred due to the softening effect of the gel polymer. As a result of PPV hydrochloride loading, PPV hydrochloride substance entered the fibers and increased the strength. While the tensile strength increased due to the tension between the polymer fibers in the tensile direction, the increase in PPV hydrochloride additive reduced the elongation values. A brittle membrane form is obtained with increasing PPV hydrochloride additive. FTIR analyzes confirmed the incorporation of gel and PPV hydrochloride into the PHBV nanofiber structure. DSC thermal analyzes reveal that the thermal behavior of the membranes changes with the addition of PPV hydrochloride. Gel additive affected the melting point and enthalpy values of PHBV. TGA analyzes show that the degradation times of membranes are accelerated with PPV hydrochloride loading. With PPV hydrochloride loading, PHBV/Gel membrane structures began to rapidly degrade. A faster degradation reaction occurred with increasing PPV hydrochloride. The gel additive provided thermal protection against heat by providing softening properties. With the increase in PPV hydrochloride, the membrane structure became more brittle and thermal decomposition with heat accelerated. Mechanical tests show that membrane elongation values decrease and breaking force increases with the addition of PPV hydrochloride. Gel additive reduced the breaking force of PHBV but improved the elongation values. It was concluded that when the elastic modulus value is high, the membrane is durable, and when it is low, the membrane is brittle. The obtained in vitro release profile confirmed the controlled-delayed release from the 10% PHBV/5% Gel nanofiber membrane loaded with 0.25% (w/v) PPV hydrochloride. Following the rapid burst release of PPV hydrochloride within the first 30 minutes, a slower and controlled release rate was observed. In vitro biodegradation studies show that the addition of PPV hydrochloride accelerates biodegradation. PHBV nanofiber membranes produced with gel additives caused obvious morphological changes such as damage, curling, disintegration and fiber aggregation during the biodegradation process. Within the scope of cell culture studies, its interaction with cells was examined. In vitro cytotoxicity tests (MTT) and cell adhesion and proliferation were analyzed. Addition of gel significantly increased cell adhesion and viability. The addition of PPV hydrochloride negatively affected cell adhesion and proliferation by causing deterioration in nanofiber membrane morphology and fiber agglomeration. In in vitro cytotoxicity tests, it was observed that cell viability decreased and toxic effects occurred as PPV hydrochloride concentration increased. As a result of cell adhesion and proliferation analyses, the best cell adhesion and proliferation was achieved in PHBV/Gel nanofiber membranes, while the best cell adhesion and proliferation was achieved in the 0.25% (w/v) PPV hydrochloride loaded 10% PHBV/5% Gel nanofiber membrane among the PPV hydrochloride loaded membranes. It was determined that . As a result of viscosity, morphological, thermal and biological analyses, it was observed that the addition of PPV hydrochloride improved certain properties but negatively affected cell viability. As a result, PHBV/Gel nanofiber membranes loaded with PPV hydrochloride at different concentrations (0.25%, 0.50% and 1% (w/v)) prepared in this thesis study were successfully synthesized and characterized. Therefore, it is thought that it can be used as a promising, innovative and effective tissue regeneration material in urethral repair. Key Words: Urethra, Nanofiber Membrane, Electrospinning, PHBV, Gelatin, Papaverine Hydrochloride