Due to the complex structures of living systems, the use of microtechnology to recreate in vivo architecture has exciting potential applications. Living tissues maintain a well-organized three-dimensional (3-D) architecture, with “micro” and “nano” scale features. Microtechnologies offer the new possibility of designing and building sensors and devices in dimensional scales close to that of living tissues.1–2 However, most available microscale systems are two-dimensional, and few 3-D systems are being explored. Therefore, we have developed a versatile technique to create a 3-D microscale hierarchical system for cells and biopolymers. By taking advantage of the contraction of hydrogel matrix biopolymers, one can achieve multiple layers of cells within biopolymers using microchannels, and eventually form a hierarchical layered microstructure of cells and biopolymer. Pressure-driven microfluidics using a syringe pump (Harvard Apparatus, Model 11‘) was applied to transport cells within matrix biopolymers through the channels with controlled flow rates. Flow imaging was used to estimate the shear stress and examine the useful range of flow rates for biopolymer fluids to form the layered structure. The 3-aminopropyltriethoxysilane (APTES) — glutaraldehyde activated glass chips were found to effectively immobilize cell-matrix assemblies. Collagen or collagen-chitosan matrix biopolymers were used as constructs throughout the layers. The final structure was characterized using scanning electron microscopy (SEM). Using this approach, the “neotissue” is formed with cellular and biopolymer components engineered to model the in vivo system.
Free accessResearch articleFirst published June, 2003pp. 22-25
