Novel biodegradable electrospun membrane: scaffold
for tissue engineering

Shanta Raj Bhattarai, Narayan Bhattarai, Ho Keun Yi, Pyong Han Hwang,
Dong Il Cha, Hak Yong Kim

http://www.eng.uq.edu.au/files/course/files/CHEE4020/Choy.pdf

This paper presents the results of using electrospun membranes as the extra-cellular matrix in tissue engineering. The study uses the copolymer PPDO/PLLA-b-PEG to fabricate a nanofibrous matrix. The electrospinning consists of a syringe, a ground electrode, and a high voltage power supply.

The copolymer solution is charged and injected through a capillary tip. Because of its charge, the solution is drawn towards the collator as a whipping jet. While the jet travels, the solvent evaporates and leaves a continuous fiber that builds up on the collector target. The design of the fiber can be controlled by the rotation and translation of the collector drum while collecting the fiber. This produces a nonwoven fibrous mat. The morphology of the electrospun membrane is examined with SEM.

The NIH 3T3 cells were seeded onto the nanofibrous scaffold as a monolayer and the cultures were allowed to incubate. The number of cells in a nanofibrous scaffold was found at certain time intervals with a cell proliferation assay. The DNA content was also assayed and used to determine the cell number in the cell culture matrices using a standard DNA digestion procedure. After incubating for 7 days, the seeded 3T3 cells reached a plateau at six times more than the original population during the 10 days of incubation. Because the cell was able to proliferate, the electrospun membrane can be determined to promote cell growth and nontoxic for cell culture.

Cell migration occurs through the pores in the electrospun membrane. The paper states that pore properties such as porosity, pore dimension and pore volume, are parameters related to how the cells accommodate. The cells use amoeboid movement to migrate through the pores. The study also shows that cells seeded on the scaffold interacted with their environment. The cells maintained a normal phenotypic shape, which shows that the cells function biologically within this structure. Because the cells adhere onto the fibers, proliferate, and pack together on the structure surface, the cells must favor the electrospun membrane. The cells also crosslink the nanofiber and integrate with the surrounding fibers to form a three-dimensional cellular network.

The architecture of the structure of the nanofibrous membrane is similar to that of the natural extra-cellular matrix, so that the scaffold of the PPDO/PLLA-b-PEG copolymer may be suitable for tissue engineering applications. The studies in the paper have not optimized the physical properties of the nanofibrous membrane that would be best for cell attachment, growth, and proliferation, but the structure of the membrane could be suitable for soft tissue such as skin.