The effects of gellan gum concentration on electrospinning and degradation of flexible, crosslinker-free scaffolds for bone tissue engineering

Low acyl type gellan gum (GG) is a biocompatible gelling agent with lower degradation rates compared to its high acyl counterpart. This study investigated the hypothesis whether the incorporation of various low acyl GG concentrations into a constant concentration of poly(vinyl alcohol) (PVA) would facilitate the electrospinning towards the production of stable nanofibrous PVA-GG membranes, and how thermal treatment would affect the degradation rate of the membranes rendering them suitable as flexible scaffolds for bone tissue engineering and avoiding crosslinking agents. All compositions displayed fiber diameters ranging from 70 to 200 nm. Thermally treated membranes indicated a mass loss of 20-32 %, while non-treated ones 32-54 %, with the higher GG concentrations exhibiting lower degradation rates, and swelling capacity of at least 500 %. Rheological analysis illustrated differences in gelling capacity, ranging from fluid-like to critical gelation state with increasing GG content, with G ' values ranging between 3.5 +/- 0.5 Pa for the lowest and 23.4 +/- 1.5 for the highest GG concentration. Proliferation of strongly adhered pre-osteoblasts significantly increased over culture time. Osteogenic markers including alkaline phosphatase activity and calcium deposition were significantly upregulated compared to the control, and calcium secretion gradually increased up to three weeks, validating the capacity of the scaffolds to support osteogenesis.