Structuring electrospun polycaprolactone nanofiber tissue scaffolds by femtosecond laser ablation

Abstract

Meshes of electrospun ͑ES͒ polycaprolactone ͑PCL͒ and polyethylene terephthalate nanofiber meshes were structured by ablation of linear grooves with a scanned femtosecond laser. Focus spot size, pulse energy, and scanning speed were varied to determine their affects on groove size and the characteristics of the electrospun fiber at the edges of these grooves. The femtosecond laser was seen to be an effective means for flexibly structuring the surface of ES PCL scaffolds. Femtosecond ablation resulted in much more uniformly ablated patterns compared to Q-switched nanosecond pulse laser ablation. Also, the width of the ablated grooves was well controlled by laser energy and focus spot size, although the grooves were significantly larger than the spot size. Also, some melting of fibers was observed at the edges of grooves. These affects were attributed to optical radiation from laser-induced plasma at higher pulse energies and melting of fibers at laser fluences lower than the ablation threshold. The ablation threshold for the PCL mesh was estimated to be significantly larger than that of bulk ͑solid͒ PCL, a result attributed to multiple scattering of the laser energy within the volume of the nanofiber mesh.

Evaluation of Mechanical Properties and Medical Applications of Polycaprolactone Small Diameter Artificial Blood Vessels

“…Different frequencies caused channel creation and cavities on the scaffold and thus by surface modification, hydrophilic property was somewhat increased. 43,44 Another factor that affects cell infiltration is vascular scaffolds' wall thickness. For this purpose, a team of researchers after electrospinning the PCL microfibers, began spinning PCL nanofiber on previous scaffolds and by increasing the electrospinning time, found different thicknesses.…”

A review of electrospinning manipulation techniques to direct fiber deposition and maximize pore size

“…Laser ablation involves rapid precise, intense heating of electrospun scaffolds to create controlled patterns and pores [151]. Variations and patterns can be created by controlling power, pulse, and orientation of ablation, which can be then optimized for cell infiltration [150,[152][153][154]. Cell infiltration can be significantly enhanced using a method of electrospinning that spins a polymer around a needle array as opposed to a solid or hollow mandrel and creates a focused, low density, uncompressed three-dimensional electrospun nanofibrous scaffold [155].…”

Ultrashort Pulsed Laser Machining for Biomolecule Trapping

“…The UV laser is one promising and frequently used laser for micromachining, but corrosive gas handling and UV radiation damages on the optics is still an issue, making it a less attractive tool for micro machining [5]. Use of a nanosecond laser with relatively longer pulse temporal duration was attempted for dielectric nano-fibers, however heat accumulation and irregular machining quality was found to be one challenging issue [16].…”