An important determinant of cellular response to drugs and toxins is the chemical and physical nature of the extracellular matrix (ECM) to which cells are adhered to within tissues. The cell's ECM environment can drastically affect intracellular pathways, and can alter cell response in various in vitro cell-based assays. Cell-based assays are used extensively in drug discovery, in assessment of toxicity to chemical and biological agents, in research settings to understand intracellular pathway systems, and in some diagnostic and therapeutic settings.
Currently, cellular assays are most often performed in plastic culture dishes which are sometimes modified with ill-defined protein coatings. A standard reference extracellular matrix material that is sufficiently characterized, reproducible, stable, and biologically relevant would improve confidence in the biological relevance of the assay, and in assay reproducibility. Previous results collected at NIST have shown that films composed of Type I collagen fibrils induce reproducible and physiologically relevant cell behaviors similar to those observed on collagen gels, but are easier to handle, are more reproducible, can be rigorously physically characterized, and provide better optical properties for cell imaging.
Research is ongoing to assess what information is required to validate films of collagen as reference extracellular matrix. During the first portion of this work we will develop protocols for characterizing the prototype collagen reference material with various instrumental techniques to develop standard metrics to which different batches can be compared. The second segment of research will focus on determining the reproducibility of cell response on collagen fibrils. Finally, examination of the behavior of cells on fibrils handled in different ways will be used to determine the functional stability of the collagen matrices. Within the first year, and continuing into the second year of funding, we will engage a user community for this material that will provide a test group for assessing the practicality of this material.
Movies of smooth muscle cells interacting with collagen fibrils:
SMC interaction with hydrated and dehydrated collagen
High resolution SMC on hydrated fibrils
High resolution SMC on dehydrated fibrils