posted on 2021-03-15, 17:04authored byBalchandar Navaneethan, Gnaneshwar Puvala Vijayakumar, Laiva Ashang Luwang, Stalin Karuppiah, Venugopal Jayarama Reddy, Seeram Ramakrishna, Chia-Fu Chou
Electrospinning is
a promising technique for the fabrication of
bioscaffolds in tissue engineering applications. Pertaining issues
of multiple polymer jets and bending instabilities result in random
paths which lend poor controllability over scaffolds morphology for
affecting the porosity and mechanical stability. The present study
alleviates these challenges by demonstrating a novel self-directing
single jet taking a specifically patterned path to deposit fibers
into circular and uniform scaffolds without tuning any externally
controlled parameters. High-speed camera observation revealed that
the charge retention and dissipation on the collected fibers caused
rapid autojet switching between the two jetting modes, namely, a microcantilever-like
armed jet motion and a whipping motion, which sequentially expand
the area and thickness of the scaffolds, respectively, in a layered-like
fashion. The physical properties showed that the self-switching dual-jet
modes generated multilayered microfibrous scaffolds (MFSs) with dual
morphologies and varied fiber packing density, thereby establishing
the gradient porosity and mechanical strength (through buckled fibers)
in the scaffolds. In vitro studies showed that as-spun scaffolds are
cell-permeable hierarchical 3D microporous structures enabling lateral
cell seeding into multiple layers. The cell proliferation on days
6 and 9 increased 21% and 38% correspondingly on MFSs than on nanofibrous
scaffolds (NFSs) done by conventional multijets electrospinning. Remarkably,
this novel and single-step process is highly reproducible and tunable
for developing fibrous scaffolds for tissue engineering applications.