Electrosprayed fiber with controllable pore size for tissue regeneration

Abstract

Scope and Method of Study: Architecture of 3D scaffold is closely related to cell behaviors such as cell infiltration, cell attachment, cell growing and cell colonization in 3D scaffold. The influence of 3D scaffold on the cell behavior is very important to understand the nature of cells in artificial 3D structure and to design better 3D scaffold. Thus, the thin layer of nano or microsize fibers made of synthetic (polycaprolactone or PCL) and natural (gelatin) polymer are fabricated using novel electrospraying process. I designed the innovative collector plate with void gaps and developed novel process with the collector plate to fabricate large and controllable pore size. Physical (pore diameter, shape factor, and pore size), mechanical (load-extension curve), chemical (gelatin distribution on single fiber, stability test of single fiber under physiological condition) were evaluated. Using human fibroblast and the thin layers of the large and controllable new fibers, the cell cultures study was carried out in serum free media or in serum media. The multilayer of cell culture was developed using layer-by-layer assembly methods. The cell morphology was confirmed by using confocal and light microscope, SEM. The cells were stained with Alexa Fluor 546, DAPI, and CFDA-SE for morphology study and H & E staining for cell histology. The cell glued 3D scaffold with multilayer was confirmed by tailoring random area of the scaffold.

Findings and Conclusions: The novel collector plate allowed the new fiber with large pore size and the pore size to be controllable by manipulating the deposit volume and the size of the circular void gap in the collector plate. The fiber diameter is independent of the new collector plate and they are related to the electrospraying parameters such as the distance between the needle tip and the collector plate. The shape of the void gap affects the alignment of the fiber on the edge of the triangular shape but in circular and rectangular shape of the void gap, fibers were randomly oriented. While 30 day cell culture using PCL fibers and serum added media, some cells were infiltrating through large pore and other cells are attaching on the fiber, growing on or between the fibers not only horizontally but also vertically, colonizing each other, and merging three layers of the fibers into one stable 3D scaffold, finally becoming cell-glued thick 3D scaffold even after tailoring the aluminum frame since cell acts as a glue. The shape of single cell on PCL/gelatin single nanofibers in serum free media was regulated by the configuration of single fibers, not the period of cell culture from 3hr to 24 hr.