Mandrel Diameter Is a Dominating Parameter for Fiber Alignment Control in Rotating Mandrel Electrospinning Systems

Aligned nano- and microscale polymer electrospun scaffolds are advantageous for 3D in vitro models of fibrous aligned tissues. A common approach to induce alignment of electrospun polymer fibers is collection on a cylindrical mandrel rotating at high speed. Historically, rotational speed has been considered the major driver in tuning fiber alignment. The comprehensive impact of variable mandrel diameter on fiber alignment in comparison to rotational speed has been minimally investigated. Therefore, this study aimed to investigate the role of mandrel diameter on fiber alignment, fiber volume fraction, and fiber diameter under controlled modulation of common processing parameters. Analysis was performed using scanning electron microscopy (SEM) and the DiameterJ and OrientationJ plugins in ImageJ. Linear regression analysis showed mandrel diameter to be the dominant factor influencing fiber diameter, fiber fraction, and fiber alignment of all samples. These findings suggest that fiber alignment can be more finely and consistently tuned by increasing mandrel diameter rather than increasing rotational speed. This work offers a guide for collecting highly aligned electrospun fibers at low rotational speeds using a rotating mandrel collector for use as tissue engineering scaffolds.