Tunning morphology of electrospun scaffold based on poly (l-lactic acid)/ poly (amidoamine)

Aim and Background: The aminolysis reaction might be triggered by adding poly(amidoamine) (PAMAM) as an amine-terminated dendrimer to poly(L-lactic acid) (PLLA). This reaction would also result in alterations to the electrospun scaffold s morphology. Therefore, the aim of this study was focused on tuning the aminolysis reaction parameters to acquire a proper electrospun scaffold. Methods: At first, neat PLLA fibers with a concentration of 9% w/v and blended PLLA/PAMAM fibers at various concentrations of PAMAM (7, 6, and 5 % w/w) were prepared. secondly, Fourier transform infrared (FTIR) spectroscopy was used to characterize the potential aminolysis reaction. Afterward, images from the scanning electron microscope (SEM) were taken to assess the morphological features of the scaffolds. Results and discussion: The nucleophilic attack via amines of PAMAM on the C=O bonds in PLLA cleaves the polymer chain (aminolysis reaction). Thereby causing a reduction in physical entanglement between chains as well as a drop in molecular mass, ultimately leading to bead formation on the fibers. The progress of the aminolysis reaction in the presence of PAMAM depended on the number of amine groups in the PAMAM molecule. The higher the percentage of PAMAM, the more active amine groups. Moreover, the bead formation was affected by the aminolysis reaction time, where it was completely eliminated at a shortened reaction time (decreasing from 2 h to 0.5 h). Conclusion: By tuning the PAMAM content and reaction time, a suitable combination of electrospun PLLA and PAMAM was achieved.