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Here we demonstrate an efficient method to fabricate large-domain monodisperse foam scaffolds made of gelatin for 3D cell culture. We tested three distinct tissue cell types cultured in foam scaffolds composed of uniform spherical pores. The cells displayed appropriate morphological and physiological characteristics: epithelial cells formed cyst-like structures and were polarized inside pores, myoblasts adopted a tubular structure and fused into myotubes, and fibroblasts exhibited a wide variety of morphologies. Scaffolds with uniform pores can thus provide a platform for systematic study of 3D cell–matrix interactions.

We have developed an approach to prepare large array nanostructured thin films using polyethylene oxide assisted self-assembly of polystyrene nanospheres as a template. By tuning the antidot diameter in the cobalt thin films, we found a crossover behavior in the magnetization reversal process. In addition, the effective moment per cobalt atom turns out to drop with growing antidot diameter which effectively increases the surface to bulk volume fraction. Our results suggest a tendency of reduced saturation magnetization in a ferromagnet/normal metal interface, where the mixing of itinerant electrons with ferromagnetic d electrons can give rise to observable effect.

We create a novel 3D matrix with uniform and ordered pores by microfluidic technique. We can vary the pore size and the interconnection between the pores andmeasure the elastic modulus of the matrix. We culture cells inside and observe their morphology by confocal microscopy. Our matrix allows 3D cell cultures in a uniform environment.View Large Image | View Hi-Res Image | Download PowerPoint Slide

To understand cell adhesion and migration, it is crucial to have information on cellular traction stress. Most traction force microscopy only measures shear stress. Recently a few group developed develop methods to measure normal stress and mostly based on finite element method. We report our finite element-method to compute three-dimensional (3D) traction stress exerted by human mesenchymal stem cells on a two-dimensional compliant polyacrylamide substrate embedded with fluorescent nanoparticles. The images of nanoparticles are acquired by confocal microscopy. We tracked the displacement of nanoparticles and computed strain, stress and strain energy by ANSYS. We examined both experimental factors and calculation that affect the resolution of the force measurement, especially in z direction. The stress measurement of the third dimension provides complete information on traction stress.

We have created 3D ordered gelatin scaffolds with monodisperse pores and cultured 3T3 fibroblasts inside. We are interested to explore the effect of microenvironment on the cell morphologies. The morphologies of cells are observed through labeling the F-actin inside the cells with fluorescent phalloidin and imaged by a confocal microscope. We compare the cell morphologies in the following microenvironment - on a 2D hard surface, on a 2D soft gelatin surface, in a 3D collagen gel, and scaffolds of different pore sizes. We found that the cells exhibit wide range of morphologies in different microenvironment. We classified cell shapes into three categories and measured the extension of cells by fitting with an ellipsoid. From the trend of cell extensions, a cell in a large pore resembles one on 2D soft gel surface. This result suggests a crossover in length from 2D-like to 3D-like morphology for cell cultured on a curved surface.View Large Image | View Hi-Res Image | Download PowerPoint Slide