Ultrasound induced, easy-to-store porous poly(amino acid) based electrospun scaffolds

Abstract

• Ultrasonication affected the mechanical properties of the electrospun scaffolds. • Enhanced cellular infiltration to the electrospun scaffold. • Presented an alternative storage condition and increasing shelf life for hydrogels. • Decreasing the probability of microbiological damage of the fibrous scaffolds. • Huge step towards an off-the-shelf and effective product for tissue regeneration. The aim of tissue engineering is to develop methods to restore, maintain or improve tissue functions. To imitate the fibrous structure of the native extracellular matrix, the electrospinning technique is widely used. However, the dense packing of fibers results in small pores and hereby the inhibition of cellular penetration. In this study, we used biocompatible and biodegradable poly(aspartic acid) based fibrous hydrogel scaffolds to enhance the cell infiltration using ultrasonication (US). The US can enlarge the space between the fibers in the scaffold and create a 3D structure based on the thickness increase of the samples. To prevent the scaffolds from degradation and create an easy-to-store sample beyond the US treatment, a freeze-drying process was also introduced in this work. After all these treatments, the scaffold’s specific load capacity was 0.11 ± 0.01 Nm 2 /g which did not change after a rehydration cycle and the elongation break became almost two times higher than before the US treatment. The cytotoxicity results demonstrated that the cellular viability did not show any significant decrease compared to the control groups for none of the samples. The cellular penetration was visualized by multiphoton microscopy. In summary, we were able to overcome the major limitation of conventional electrospun scaffolds regarding their application in tissue engineering. We also improved the storing conditions of fibrous hydrogel scaffolds and extend their shelf life without degradation.