Investigating Cell Adhesion via Parallel Disk Rotational Flow: A Biocompatibility Study

Abstract

The major impact of this research lies in the aspect of improved design and long term biocompatibility of materials used for implants. There are two goals in this research. The first goal is to develop a methodology to quantitatively measure cell-material adhesion. The second goal is to obtain fundamental understanding of cell-material adhesion mechanisms. A rotating parallel disk is used to measure cell adhesion. The rotational system applies a controlled shear stress to the cultured cells. The shear stress experienced by the cells varies with radial location, being highest at the edge and zero at the disk?s center. There is a critical point along the radius where the shear stress experienced by the cells equals their adhesion strength. The cells outside it are removed and the cells inside it remain attached to the surface. NIH 3T3 Swiss mouse fibroblasts and chick retina neuron cells from 6-day embryos are used in this study. The fibroblasts were cultured on poly(methyl methacrylate) (PMMA), polycarbonate (PC), and on gold coated poly(vinylidene fluoride) (Au/PVDF). The critical shear stress for fibroblasts was the lowest for PC with 5.09 dynes/cm2 and highest for PMMA with 21.0 dynes/cm2. This four-fold difference is mainly due to the chemical structure of PMMA which promotes higher cell adhesion when compared to PC. Neurons were cultured on poly-D-lysine coated glass to promote cell adhesion. The critical shear stress of neuron cells varied from 3.94 to 27.8 dynes/cm2 these values are directly proportional to the applied shear stress. The neuron adhesion plateau at ~27 dynes/cm2 which indicates the maximum adhesion strength of the neuron/poly-D-lysine coated glass pair. This thesis contains six chapters. Chapter I describes the importance of cell adhesion for biocompatibility. Chapter II describes in more detail the goals of this research and the expected results. Chapter III lists all the materials, equipment, and methods used in this study. The most significant results are summarized in Chapter IV. The observations and results obtained are explained in detail in Chapter V and Chapter VI describes the key outcomes as well as proposes questions for the advancement of this research.