Enhancing Biocompatibility without Compromising Material Properties: An Optimised NaOH Treatment for Electrospun Polycaprolactone Fibres

Abstract

This research presents the first optimised protocol for submersion of electrospun polycaprolactone (PCL) fibres in sodium hydroxide (NaOH) to improve surface hydrophilicity, and hence biocompatibility, without compromising material properties. The study comprised two aims: (1) identify the leading NaOH concentration (0, 0.1, 1, and 10 M) and submersion time (0, 1, 4, and 24 h) to improve hydrophilicity with minimal impact on tensile properties and (2) once identified, undertake material characterisation and in vitro testing for validation. 1 M 4 h (NaOH concentration: 1 M, submersion time: 4 h) improved hydrophilicity (aligned fibres at 0 M NaOH and 0 h submersion time reduced from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mn>97</mml:mn><mml:mo>±</mml:mo><mml:msup><mml:mrow><mml:mn>3</mml:mn></mml:mrow><mml:mrow><mml:mo>°</mml:mo></mml:mrow></mml:msup></mml:math> to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mn>6</mml:mn><mml:mo>±</mml:mo><mml:msup><mml:mrow><mml:mn>2</mml:mn></mml:mrow><mml:mrow><mml:mo>°</mml:mo></mml:mrow></mml:msup></mml:math>; and random fibres at 0 M 0 h reduced from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mn>105</mml:mn><mml:mo>±</mml:mo><mml:msup><mml:mrow><mml:mn>4</mml:mn></mml:mrow><mml:mrow><mml:mo>°</mml:mo></mml:mrow></mml:msup></mml:math> to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M4"><mml:mn>15</mml:mn><mml:mo>±</mml:mo><mml:msup><mml:mrow><mml:mn>7</mml:mn></mml:mrow><mml:mrow><mml:mo>°</mml:mo></mml:mrow></mml:msup></mml:math>) with minimal impact on tensile strength (9% and 6% loss aligned and random, respectively). 1 M 4 h-treated scaffolds demonstrated no significant change in material properties, yet notably improved protein adsorption and attachment, viability and elongation of 3T3 fibroblasts 4 h postseeding. Thus, 1 M 4 h is optimal for successful wet chemical treatment of electrospun PCL and presents a simple and economical method to easily enhance biocompatibility without compromising scaffold integrity.