Superporous poly(2-hydroxyethyl methacrylate) based scaffolds: Preparation and characterization

Abstract

Superporous poly(2-hydroxyethyl methacrylate) (PHEMA) scaffolds with pore size from 101 to 102μm range were prepared by radical polymerization of 2-hydroxyethyl methacrylate (HEMA) with 2wt.% ethylene dimethacrylate (EDMA) with the aim to obtain a support for cell cultivation. Superpores were formed by salt-leaching technique using NaCl or (NH4)2SO4 as a porogen. Addition of liquid porogen (cyclohexanol/dodecan-1-ol (CyOH/DOH)=9/1 w/w) to the polymerization mixture did not substantially affect the formation of meso- and macropores. The prepared slabs were characterized by several methods including water and cyclohexane regain by centrifugation, water regain by suction, scanning electron microscopy (SEM), mercury porosimetry and dynamic desorption of nitrogen. High-vacuum scanning electron microscopy (HVSEM) confirmed permeability of hydrogel slabs to 8-μm microspheres, whereas low-vacuum scanning electron microscopy (LVSEM) at cryo-conditions showed the undeformed structure of the frozen slabs. Interconnection of pores in the PHEMA slabs was proved. Water regain estimated by centrifugation method did not include volume of large superpores (imprints of porogen crystals), in contrast to water regain by suction method. The porosities of the slabs ranging from 81 to 91% were proportional to the volume of porogen in the feed.