Core-shell electrospun nanofibers based on soy protein isolate for tissue engineering applications

M.D. POPOV PEREIRA DA CUNHA; G.A. ABRAHAM

Mar del Plata

Congreso; XII Latin-American Congress of Artificial Organs and Biomaterials; 2023

INTEMA (CONICET-UNMdP)

Introduction and objective: The properties combination from two polymeric phases enabled by coaxial electrospinning have drawn significant attention in the tissue engineering. The core-shell structure proves instrumental in leveraging distinct polymeric phases to their fullest potential. Among the various strategic combinations, researchers have employed this structure to integrate mechanically robust polymers in the core, while utilizing more biocompatible polymers for the shell. This dual approach enhances both the mechanical resilience and biocompatibility of the resultant fibers. Electrospun soy protein isolate (SPI) is being studied to be applied in the tissue engineering field, but the obtained mats lack of optimal mechanical properties, being highly brittle. Therefore, the aim of this work is to obtain core-shell fibers using the coaxial electrospinning technique using PCL, an FDA approved polymer, and SPI as core and shell phases, respectively, and conduct morphological and physicochemical characterizations. Methodology: The core solution was prepared by dissolving PCL (Mn=80 kDa) in glacial acetic acid, and the shell solution was prepared by dissolving SPI and oxidized sucrose (a cross-linker) in 10 mol/L acetic acid. Both solutions were electrospun using a coaxial configuration by applying optimized process parameters. A thermal posttreatment was carried out to complete the SPI cross-linking process. Morphological analysis was performed using SEM, TEM, confocal microscopy, and fluorescence microscopy. Thermal analysis was carried out using DSC and TGA; and surface chemistry study was conducted using FTIR. Lastly, the mats’ wettability was analyzed through contact angle measurements.Results and discussion: The SEM micrographs show that a fibrous structure was obtained and the average fiber diameter before and after the thermal treatment was 635 ± 128 nm and 665 ± 152 nm, respectively. A statistical analysis showed that the thermal treatment did not induce a significant change in the fiber diameter distribution. The results of TEM, confocal microscopy and fluorescence microscopy showed inconclusive results about the coaxiality of the polymeric phases. The coaxiality could not be detected through TEM micrographs because the polymer phases did not show enough density differences, therefore there was no contrast between them. Through the confocal and fluorescence microscopy, it was possible to observe that both polymeric phases were continuous throughout the fibers. However, it was not possible to determine whether the SPI phase was inside the PCL one. On the other hand, the contact angle results showed that the mats’ wettability were more like the SPI fibers, which gives a hint that the fiber surface is composed by the SPI phase. Both thermal analyses yielded similar results, the mats presented an overlap of the raw materials thermal events. Lastly, the electrospun mat FTIR spectra also showed the raw material characteristic vibrational peaks.Conclusions: The SPI-PCL coaxial mats were successfully obtained ant the characterization results showed that they have an overall great potential. The in vitro characterizations are ongoing to determine their aptitude in the tissue engineering field.