바이오 응용을 위한 3차원 마이크로-/나노 구조물의 제작

Abstract

In this dissertation, the development of fabrication methods of three-dimensional micro-/nano-structure for bio-applications is presented and can be divided into two individual parts. In first part, wet electrospun three-dimensional nanofibrous scaffold which can be applicable to tissue engineering, is presented. In second part, the novel fabrication method of polymeric nanochannel stack array, which can be applicable to micro bio-chip fields, is demonstrated and shows good performances in the two kinds of bio-applications such as an ion concentration polarization and multiplexed one microstructure-on-one nanostructure interfacing. In the first part, the development of fabrication method for cell manipulataion of invivo approach, wet electrospun scaffold is reported. Electrospinning technology is a versatile method of fabricating a three-dimensional (3D) nanofibrous scaffold using a wide range of polymeric materials for tissue engineering and regenerative medicine. However, one of the major concerns about 3D electrospun scaffolds is that they hinder an even cellular distribution and in-depth infiltration because of the densely packed layers. Here, we described a new all-at-once method enabling scaffold fabrication and cell seeding simultaneously, in which the medium bath containing cells was rotated eccentrically at high speed (> 1500 rpm). The unstable flow of cell medium in hydrodynamic conditions allowed a skein-shaped 3D structure and enhanced an even cellular distribution and in-depth infiltration. The cellular distribution and infiltration analysis confirmed that our method was superior to either static or dynamic methods. Moreover, we showed that our method facilitated long-term (14 days) proliferation. In the second part, the development of fabrication method for cell manipulataion of invitro approach, three-dimensional polymeric nanochannel stack array is reported. Nanofabrication technologies have been a strong advocator for new scientific fundamentals that have never been described by traditional theory, and have played a seed role in ground-breaking nano-engineering applications. In this study, we fabricated ultra-high-aspect (10^5~10^6 with O(100)nm nanochannel opening and O(100)mm length) orthogonal nanochannel array using only polymeric materials. Vertically aligned nanochannel arrays in parallel can be stacked to form a dense nano-structure. Due to the flexibility and stretchability of the material, one can tune the size/elongation and shape of the nanochannels, and even roll the array stack to form a radially uniform nanochannel-array distribution. The roll can be cut at discretionary lengths for incorporation with a micro/nanofluidic device. As examples, we demonstrated ion concentration polarization with the device for Ohmic-limiting/overlimiting current–voltage characteristics and preconcentrated charged species. The density of the nanochannel array was lower than conventional nanoporous membranes, such as anodic aluminum oxide membranes. However, accurate controllability over the nanochannel array dimensions enabled multiplexed micro/nano one-on-one interfacing for valuable biological/biomedical microelectromechanical system (BioMEMS) platforms, such as nano-electroporation.