Biomechanical characterization of fibrous polymeric scaffolds for the regeneration of urethral segments

C. BUSATTO; F. MONTINI BALLARIN; A. TESIS; R.L. ARMENTANO; D. ESTENOZ; G.A. ABRAHAM

Mar del Plata

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

Introduction and objective: Hypospadias and urethral strictures are among most common penile pathologies [1]. To address these conditions, the transplantation of autologous tissues, such as buccal mucosa and penile skin, has been commonly employed for urethral repair. However, this approach can be associated with potential complications, and there are limitations in the availability of donor tissue [2]. In this direction, tissue engineering offers a promising regenerative alternative to overcome these challenges. The objective of this work is to investigate the mechanical properties of tubular scaffolds that combine syntheticand natural polymers, with the aim of exploring their potential for urethra regeneration.Methodology: The fibrous materials were fabricated by electrospinning and co-electrospinning using benign solvents. The polymer solutions employed include polycaprolactone (PCL) in acetic acid, poly(ethylene oxide) (PEO) in water/ethanol and PEO/hyaluronic acid (HA) aqueous solutions. Three different constructs were created: PCL scaffolds, PCL/PEO-HA scaffolds and PCL/PEO scaffolds infiltrated with HA. In the case of PCL/PEO scaffolds, thelow molecular weight PEO fibers were removed by water washing, followed by infiltration with a HA solution. SEM was employed to assess the fiber size and morphology, while the characteristic functional groups of the constructs were analyzed using FTIR. The mechanical properties of the scaffolds were evaluated using a continuous circulation biodynamic simulator. This allow for subjecting the urethral graftsto sinusoidal variations of internal pressure, mimicking the physiological bladder pressure ranges, and assessing their compliance and mechanical response in vitro.Results and discussion: SEM observations revealed that both PCL and and hybrid scaffolds exhibited homogeneous fibrous mats with randomly oriented and defect-free fibers. The mean fiber diameter for PCL mats, PEO-HA mats and hybrid PCL/PEO-HA scaffold were 1470 ± 720, 110 ± 20 and 830 ± 350 nm, respectively. The incorporation of PEOAH nanofibers resulted in a reduction in the average fiber diameter for the hybrid scaffolds. The fiber size measurements of the PCL/PEO scaffold indicated a slight increase in the mean fiber size after washing of PEO fibers and HA infiltration. In the FTIR-ATR analysis, the signals associated to PEO disappeared after thewashing step, and the characteristics bands of HA were detected after the infiltration process. The elasticity values oftheconstructs were 3.36 ± 1.80, 0.61 ± 1.77 and 0.09 ± 0.17 Pa/m for PCL, PCL/PEO-HA and PCL/PEO infiltrated with HA, respectively.Conclusions: The fabrication of tubular structures through electrospinning is a promising technology to mimic the ECM and the biomechanical response of urethral tissue. By controlling the composition, structure and arrangement of fibers, it is possible to replicate the native tissue characteristics. The biomechanical characterization of the fibrous constructs demonstrated a performance comparable to synthetic scaffolds.