Preparation of a porous scaffold based on polypropylene grafted with monomethylitaconate as potential bone graft

Abstract

Based on polypropylene (PP) grafted with different percentages of maleic anhydride (PP-g-MA) or monomethylitaconate (PP-g-MMI) a new porous scaffold was prepared with porosities in the range of 50–200 μm. The swelling capacity was analyzed, and
morphological, mechanical, and elemental analyses of these scaffolds were carried out. In vitro swelling in the simulated body fluid (SBF), chitosan (CHI) of low (70 kDa) and high (350 kDa) molecular weight, and chitosan-hydroxyapatite
solutions were assayed at 37 °C from 24 h to 4 weeks. The swelling degree (SD) of these scaffolds was in the range of 25%–125%.
The highest SD value was found in the low-molecular weight (LMW) chitosan solution. The PP-g-MMI and PP-g-MA with 0.7% and 1% of grafting, respectively, showed the highest SD values in the CHI solution. The in vitro treatment of the scaffold was performed by immersion in LMW chitosan and/or the double ionic diffusion (DID) method. The
pore structure of the scaffolds was unaltered after these treatments, as revealed by scanning electron microscopy (SEM). Mechanical
properties, that is, fracture resistance and deformation of the porous scaffolds depended on the percentage of grafting. Scaffolds
with a smaller pore size showed higher mechanical properties. Energy Dispersive Spectroscopy (EDS) measurements of PP-g-MMI with 0.7% of grafting after in vitro treatment revealed the formation of hydroxyapatite (HA) crystals with different morphologies on the porous scaffold. It was
concluded that the porous scaffold based on PP-g-MMI could be used as a potential prototype bone graft.

Keywordsporous scaffold–polypropylene–monomethylitaconate–maleic anhydride–hydroxyapatite