Fabrication of biopolymer-based staple electrospun fibres for nanocomposite applications by particle-assisted low temperature ultrasonication

• Nanoscaled electrospun PLLA staple fibres with lengths of 50 μm were developed.
• E-spinning and ultra-sonication procedures were used for the investigations.
• Hexane was identified as an optimal medium for fibre fragmentation and dispersion.
• Varying the sonication and particle parameters tailored the fibre aspect ratio.
• Fibre reinforced Brushite composite exhibited an increased compression strength.

We demonstrate the fabrication of staple polymer-based fibres by the ultrasound-assisted processing of electrospun meshes. Bioabsorbable Poly-L-Lactic Acid (PLLA) was electrospun from organic solvent mixtures, yielding continuous fibres with diameters in the range of 244 ± 78 nm. Subsequently, the obtained fibres were sonicated at low temperatures in the presence of nanoparticles in order to obtain fibres with small aspect ratios. The influence of the dispersion medium, the sonication process parameters (temperature and time) and the dimensions of the particles used on the respective length distribution of the obtained nanofibres was investigated. Hexane was identified as an optimal dispersion medium for the system studied in this work. When a cooling bath temperature of 0 °C was used, a slight increase in the obtained fibres' average length and distribution was observed as compared to cooling at − 80 °C (54 ± 43 μm vs 44 ± 31 μm). Moreover, in the presence of hydroxyapatite and hydrophilic and hydrophobic TiO2 nanoparticles in the dispersion medium longer fibres were obtained (44 ± 31 μm, 63 ± 47 μm, and 51 ± 52 μm). Finally, the application of the obtained PLLA-fibre–hydroxyapatite (HA) nanoparticle precursors for the fabrication of a fibre-reinforced Brushite-based cement with high compressive strength is shown. This method of obtaining nanoscaled fibre-reinforced materials opens up a wide range of perspectives for the fabrication of composites for tissue engineering applications.

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