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

Aligned nano and micron-sized electrospun scaffolds are advantageous for 3D in vitro models of fibrous, aligned tissue. A common approach to induce alignment is to collect on a rotating mandrel at high rotational speeds. Historically, rotating mandrel speed has been considered the major driver in tuning the degree of alignment even though mandrel diameter is known to modulate linear velocity and increase alignment. However, the comparative impact of mandrel diameter vs. rotating mandrel speed has not been systemically investigated. As such, this study aimed to investigate the role of mandrel diameter on fiber alignment, fiber fraction, and fiber diameter under controlled modulation of common processing parameters including applied voltage, distance to collector, and mandrel rotational speed. Analysis of all samples was performed using scanning electron microscopy (SEM) and image analysis by the DiameterJ and OrientationJ plugins in ImageJ. Using linear regression analysis in JMP software, mandrel diameter was shown to be the dominant factor influencing fiber diameter, fiber fraction, and fiber alignment of samples at all tested conditions including increased rotational speed. Overall, these findings suggest that rather than increasing rotational speed of the collector, fiber alignment can be more finely tuned by increasing mandrel diameter. Graphical Abstract