Won-Gun Koh, Ph.D., Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul, South Korea, will deliver a seminar entitled "Multiscale Micro/Macro Patterns for Biomedical Application." This seminar deals with combining different types of nanomaterials with patterning process to create multiscale biopatterns. Two different applications of resultant biopatterns such as cell patterning and cancer therapy will be introduced. First, fabrication of micropatterned nanofiber will be described. Micropatterned scaffolds were prepared by fabricating poly(ethylene glycol)(PEG) hydrogel microstructures on electrospun nanofiber matrix, and produced as free-standing and bidirectionally-porous sheets. Since the PEG hydrogel showed non-adhesiveness toward proteins and cells, cells selectively adhered and remained viable within the nanofiber region, thereby creating cellular micropatterns. We also incorporated different functionality such as biosensing or growth factor delivery into resultant scaffold. Second, we fabricated doxorubicin(DOX)-loaded PAH/dendrimer porphyrin(DP) multilayer nanocapsules (NCs) that may potentially deliver a combined cancer therapy. As a component in the layer-by-layer (LbL) assembly of the NC shell, DP served as a photosensitizing agent for PDT, and the amount of DP was controlled by changing the number of layers deposited. DOX easily permeated the multilayer shells, filling the hollow NCs and subsequent crosslinking between PAH and DP allowed us to control the release of DOX from the hollow NCs. Cell viability studies revealed that combined treatment exerted higher toxicity than either chemotherapy or PDT alone.
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