Highly Porous Electrospun Nanofibers Enhanced by Ultrasonication for Improved Cellular Infiltration

Abstract

A significant problem that affects tissue-engineered electrospun nanofibrous scaffolds is poor infiltration of cells into the three-dimensional (3D) structure. Physical manipulation can enhance cellular infiltration into electrospun scaffolds. The porosity of electrospun nanofibers was highly enlarged by ultrasonication in an aqueous solution. The porosity and related property changes on a series of nanofibers were observed to be dependent on ultrasonication time and energy. To evaluate cell infiltration into the scaffold, fibroblasts were seeded onto these nanofibers and cultured for different lengths of time. The penetration levels of these cells into the scaffold were monitored using confocal lazer scanning microscopy. The cell infiltration potential was greatly increased with regard to an increase in pore size and porosity. These 3D nanofibrous scaffolds fabricated by an ultrasonication process allowed cells to infiltrate easily into the scaffold. This approach shows great promise for design of cell permeable nanofibrous scaffolds for tissue-engineering applications.

Fabrication of bioactive polycaprolactone/hydroxyapatite scaffolds with final bilayer nano-/micro-fibrous structures for tissue engineering application

“…Electrospinning is a process that can generate a fibrous scaffold with high porosity, interconnected pores, a large surface-area-to-volume ratio and a variable fiber diameter [15]. However, the small pore size of electrospun nanofibrous scaffolds may limit cellular infiltration [16]. Pore size below cellular diameter cannot allow cell migration within the structure [17].…”

The Integration of Nanotechnology and Biology for Cell Engineering: Promises and Challenges

“…Thus, the original tissue engineering triad has now transformed into a 'tetrad' with the introduction of mechanical cues and mechanotransduction for effective tissue engineering. The field of tissue engineering continues to evolve, with more external stimuli such as ultrasound and electric impulses being explored as additional factors that can stimulate and activate cells to grow, proliferate and establish cell-cell communication for effective functioning [22]. A new paradigm in tissue engineering that has emerged in recent years is the concept of the 'living scaffold'.…”

“…The ultrasonication of electrospun nanofibres of poly(Llactic acid) at 4 o C before cell seeding has been reported to enhance the pore dimensions of the scaffold and resulted in the increased infiltration and density of the fibroblasts when compared with the untreated scaffold [22]. However, the optimization of the ultrasound frequency, power and duration may be necessary for each type of scaffold as there exists a risk of the fragmentation of the polymer fibres on exposure to ultrasound.…”

Electrospun fibers/branched-clusters as building units for tissue engineering

“…While these methods of improving template porosity are promising, they all rely on cellular infiltration from outside the template, limiting their effectiveness at greater template volumes [12,25,29]. Furthermore, because of the degree of interconnectedness of the fibers, cellular reprogramming of the template microstructure is partially dependent on the degradation rate of the polymer, and use of a synthetic polymer could slow the re-organization time to several weeks to months.…”