Cell electrospinning goes live

First patented in 1934, electrospinning draws a charged, viscous material out of a hollow conducting needle by means of an electric field. For more than 70 years, electrospun fibers have been used in a multitude of applications from sensors to protective clothing. Scaffolds made from spun fibers for tissue engineering have been used for at least a decade, yet challenges remain. For example, it is difficult to evenly spread enough viable cells onto a scaffold and expose them to the nutrients they need to survive; ultrasonic agitation helps to move nutrients around, but it compromises the integrity of the fibers and has not been demonstrated in vivo. A recent development is the large-diameter coaxial needle, which provides an outer sheath of a biopolymer that electrically shields an inner core of functional molecules or cells. Using such a needle, researchers led by Suwan Jayasinghe of University College London have now engineered living tissue scaffolds both in vitro and in vivo. Their thick (up to 1.5 mm) coaxial fibers have a core of mouse neuroblastoma tumor cells and nutrients. The figure shows part of a scaffold of those fibers, with fluorescently tagged live cells embedded. The electrospun cells grew and proliferated at the same rates as control samples. With the scaffold implanted in live mice, the cells continued to thrive for the full two weeks of the study, with no signs of rejection. That, says Jayasinghe, now makes possible human trials involving tissues generated with such scaffolds. (S. L. Sampson et al., Small, in press.)