Tissue engineering bioreactor systems for applying physical and electrical stimulations to cells.

Bioreactor systems in tissue engineering applications provide various types of stimulation to mimic the tissues in vitro and in vivo. Various bioreactors have been designed to induce high cellular activities, including initial cell attachment, cell growth, and differentiation. Although cell-stimulation processes exert mostly positive effects on cellular responses, in some cases such stimulation can also have a negative effect on cultured cells.

Preparation and characterization of multi-layered poly(ε-caprolactone)/chitosan scaffolds fabricated with a combination of melt-plotting/in situ plasma treatment and a coating method for hard tissue regeneration.

Here, we propose a new combinational method supplemented with melt-plotting and in situ plasma treatment to improve the coating ability of chitosan solution. Using the proposed method, the hydrophobic surface of poly(ε-caprolactone) (PCL) was altered to a hydrophilic surface to facilitate homogeneous coating of the micro-structured PCL scaffold with chitosan of various molecular weights. The fabricated chitosan-coated PCL scaffolds were assessed in terms of not only physical properties, including tensile strength and water uptake ability, but also biological capabilities by culturing osteoblast-like cells (MG63) in the presence of coatings of chitosan of various molecular weights (1-5, 5-10, and >10 kDa).

The effect of sinusoidal AC electric stimulation of 3D PCL/CNT and PCL/β-TCP based bio-composites on cellular activities for bone tissue regeneration.

Various physical stimulations have been widely applied to tissue regenerative applications. In particular, for bone tissue regeneration, several experimental studies have reported that electric stimulation can enhance the mineral formation in cultured osteoblasts and even alter the pattern of gene expression, promoting bone tissue formation. However, to date, for rapid-prototyped polycaprolactone (PCL)-based composites of pure PCL and dispersed materials including carbon nanotubes and β-tricalcium phosphate (TCP), the effect of electric stimulation on various cellular activities has not been analyzed.

Pressure/electric-field-assisted micro/nanocasting method for replicating a lotus leaf.

An electric field-aided process was introduced for a curable casting process. As a micro/nanosized pattern mask, a lotus leaf, which has a hierarchical structure, was used. The process consists of two steps: (1) applying an electric field to a liquid polymer and solidifying the polymer for use as a negative mold, and (2) using the negative polymer mold to fabricate a replicated poly(ethylene oxide) (PEO) surface in the original shape of the lotus leaf.