Research: Interfaces for controlling cell fate and function

Mechanical and chemical stimuli involved in stem cell biology (Krishanu Saha)

My focus is on understanding the mechanical and chemical stimuli involved in stem cell proliferation and development. Fundamental scientific advances in this field of stem cell biology are attractive for heart disease therapy, related to bone marrow derived stem cells, and Parkinson's and Alzheimer's disease therapy, related to neural stem cells. I work collaboratively with the Schaffer Group in the Chemical Engineering Department. For my work, I hypothesize that a combination of diffusible chemical signals and mechanical signals under certain temporal constraints are required in vitro and in vivo for the efficient proliferation and differentiation of stem cells. Hydrogels allow appropriate delivery of mechanical stimuli to stem cells, and viral delivery developed in the Schaffer group allows tunable control of temporal chemical stimuli. Bone marrow derived and neural stem cells are current cell types of interest. Engineering modeling that assigns quantitatively kinetic rates to receptor binding, signaling, and gene expression processes in a stem cell will be further developed to understand global stem cell behavior.

Swelling of thin IPN films employing a QCM-D (Beth Irwin)

The mechanical properties of our IPN thin films can affect the non-fouling nature of the surface. In order to investigate this, swelling experiments are performed employing a QCM-D in order to record both frequency and dissipation data of thin polymer films when dry and swollen. Data is interpreted with a Kelvin-Voigt viscoelastic model to obtain information about the viscosity and shear modulus of the film. The swelling ratio (Q) and molecular weight between crosslinks of the film can also be calculated.

Patterning materials to control cell function (Ray Schmidt)

In order to develop technologies for tissue engineering and bioengineering, researchers have created a variety of methodologies for generating patterned surfaces, often borrowing techniques from the MEMS and microfluidics communities. These patterned surfaces allow for more accurate replication of the complex architecture of various tissues and the examination of cell-cell and cell-substrate interactions. By controlling the areas in which cells can adhere to a substrate, cell spreading and shape can be controlled, affecting proliferation, differentiation, and gene expression.

My research involves the development and characterization of a patterning scheme the utilizes a laser with a small spot size (<100nm) to selectively attach a cell binding sequence onto a substrate via a photoactive crosslinker. With the high resolution and tunability afforded by the laser, the spatial arrangement and density of focal adhesion ligands can be explored. However, this high resolution patterning also requires a high resolution detection method to characterize it. We are currently investigating new versions of x-ray photoemission electron spectroscopy, PEEM-2 and 3, that will allow us to obtain high resolution chemical and spatial information about the surface. Using these new techniques, we hope to determine the relationships between the process parameters and the ligand density, as well as the cell-substrate interaction dependence on ligand density and spatial arrangement on a nanometer length scale.

Naomi's Research (Naomi Kohen)

Coming soon!