Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
Browse
2 results
Search Results
Article Citation - WoS: 37Citation - Scopus: 39Shape Fidelity Evaluation of Alginate-Based Hydrogels Through Extrusion-Based Bioprinting(MDPI, 2022-11-07) Temirel, Mikail; Dabbagh, Sajjad Rahmani; Tasoglu, SavasExtrusion-based 3D bioprinting is a promising technique for fabricating multi-layered, complex biostructures, as it enables multi-material dispersion of bioinks with a straightforward procedure (particularly for users with limited additive manufacturing skills). Nonetheless, this method faces challenges in retaining the shape fidelity of the 3D-bioprinted structure, i.e., the collapse of filament (bioink) due to gravity and/or spreading of the bioink owing to the low viscosity, ultimately complicating the fabrication of multi-layered designs that can maintain the desired pore structure. While low viscosity is required to ensure a continuous flow of material (without clogging), a bioink should be viscous enough to retain its shape post-printing, highlighting the importance of bioink properties optimization. Here, two quantitative analyses are performed to evaluate shape fidelity. First, the filament collapse deformation is evaluated by printing different concentrations of alginate and its crosslinker (calcium chloride) by a co-axial nozzle over a platform to observe the overhanging deformation over time at two different ambient temperatures. In addition, a mathematical model is developed to estimate Young's modulus and filament collapse over time. Second, the printability of alginate is improved by optimizing gelatin concentrations and analyzing the pore size area. In addition, the biocompatibility of proposed bioinks is evaluated with a cell viability test. The proposed bioink (3% w/v gelatin in 4% alginate) yielded a 98% normalized pore number (high shape fidelity) while maintaining >90% cell viability five days after being bioprinted. Integration of quantitative analysis/simulations and 3D printing facilitate the determination of the optimum composition and concentration of different elements of a bioink to prevent filament collapse or bioink spreading (post-printing), ultimately resulting in high shape fidelity (i.e., retaining the shape) and printing quality.Article Citation - WoS: 1Citation - Scopus: 1Enhancing Bioink Potential of Hyaluronic Acid by Microwave-Induced Methacrylation(Elsevier, 2025-10) Ishtyah, Yazan R. B.; Cosgun, Seyma Nur Kirmic; Ceylan, Deniz; Demirtas, Tugrul Tolga; Isoglu, Sevil DincerThis study reports the development of a light-curable methacrylated hyaluronic acid (HAMA) synthesized using microwave irradiation. The methacrylation process was carried out with AEMA as the methacrylating agent via an EDC/NHS protocol at varying microwave energy levels and compared comprehensively with those synthesized using the conventional heating method. The HAMA synthesis by microwave was optimized by applying different power levels (100 W, 250 W, and 800 W). The products were characterized by 1H NMR to determine the degree of methacrylation (DoM). The microwave-assisted synthesis significantly reduced the reaction time from 24 h to 6 min, improved reaction efficiency, and shortened the purification period from 3 days to 1 day. Additionally, it enhanced the mechanical, rheological, and swelling properties of the resulting hydrogels. The highest DoM was achieved at 78 % for HAMA-100 hydrogels synthesized at 100 W microwave energy. Rheological analysis demonstrated that microwave-assisted HAMA hydrogels could withstand nearly 100 % strain, outperforming those produced by conventional methods. This indicated the presence of an improved energy distribution mechanism at the molecular level within the polymer network structure of the microwave-assisted hydrogels. It was also observed that the microwave-assisted hydrogels exhibited strain-hardening behavior, ensuring the stability of bioactive structures in bioinks. Furthermore, the printing conditions for HAMA-100 gels were optimized in terms of printing pressure and speed. These findings highlight the significant role of microwave energy in achieving superior hydrogel properties, making it a promising green method for preparing bioinks for 3D printing applications.