Using Humidity to Control the Morphology and Properties of Electrospun BioPEGylated Polyhydroxybutyrate Scaffolds

Leslie J R Foster; Rodman T H Chan; Robert A Russell; Peter J Holden

doi:10.1021/acsomega.0c02993

Using Humidity to Control the Morphology and Properties of Electrospun BioPEGylated Polyhydroxybutyrate Scaffolds

ACS Omega. 2020 Oct 5;5(41):26476-26485. doi: 10.1021/acsomega.0c02993. eCollection 2020 Oct 20.

Authors

Leslie J R Foster^{1

2}, Rodman T H Chan³, Robert A Russell^{3

4}, Peter J Holden⁴

Affiliations

¹ Bio/Polymer Research Group, Department of Chemistry, University of Alabama in Huntsville, Huntsville, Alabama 35899, United States.
² Save Sight Institute, Faculty of Health and Medicine, University of Sydney, Sydney, NSW 2141, Australia.
³ Bio/Polymer Research Group, School of Biotechnology & Biomolecular Science, University of New South Wales, Sydney, NSW 2052, Australia.
⁴ Australian Nuclear Science & Technology Organisation, Lucas Heights, NSW 2234, Australia.

Abstract

Electrospinning produces nanofibrous scaffolds with potential for tissue engineering and wound repair. Spinning parameters control scaffold morphology and properties. BioPEGylation of polyhydroxybutyrate (PHB) introduces terminal hydrophilic groups into the hydrophobic chain, making this natural-synthetic hybrid copolymer more susceptible to humidity. Varying the humidity from 10 to 50% RH during electrospinning had a relatively little effect on polyhydroxybutyrate (PHB) average fiber and pore diameters, which remained around 3.0 and 8.7 μm, respectively. In contrast, fiber and pore diameters for electrospun bioPEGylated PHB scaffolds varied significantly with humidity, peaking at 30% RH (5.5 and 14.1 μm, respectively). While scaffolds showed little change, hydrophobicity decreased linearly with humidity during electrospinning. Compared to solvent-cast films, electrospun scaffolds showed significantly greater average cell spread. A 108% increase for olfactory ensheathing cells (OECs) cultivated on bioPEGylated PHB scaffolds was proportionally greater than their counterparts on electrospun PHB scaffolds, (70%). OECS grown on BioPEGylated PHB scaffolds were over twice the size, 260 ± 20 μm diameter, than those on PHB electrospun scaffolds, 110 ± 18 μm diameter. Electrospun scaffolds also promoted cell health compared to their solvent-cast counterparts, with increases in the mitochondrial activity of 165 ± 13 and 196 ± 13% for PHB and bioPEGylated PHB, respectively. OECS cultivated on electrospun scaffolds of bioPEGylated PHB had significantly better membrane integrities compared to their counterparts on solvent-cast films, 47 ± 5% reducing to 17 ± 6%. The combination of bioPEGylation and humidity during electrospinning permitted significant controllable changes to scaffold morphology and properties. These changes resulted in the significantly greater promotion of cell growth on electrospun bioPEGylated PHB scaffolds compared to their solvent-cast counterparts and electrospun PHB.