Assistant Professor University of Illinois at Urbana Champaign Urbana, Illinois, United States
Introduction: Targeted delivery of therapies to cancer cells is very important to reduce off target toxicity. Metabolic glycoengineering is a simple method to present Azide labels on the surface of cells by incubating them with sugar. These labels serve as targets for DBCO conjugated molecules to bind via click chemistry. As the cell membrane is dynamic the labels undergo endocytosis and the duration for which the label is present on the surface of the cell varies from cell to cell. In some cases we would like to increase the surface retention of cargo for applications like imaging. Endocytosis on the other hand will be useful if we want to design efficient cancer drug delivery. Modifying the size, binding sites and hydrophobicity of the cargo we can alter the dynamics of the azide labels.
Materials and
Methods: Poly acrylic acid was used to synthesize polymers of various Molecular weights ranging from 2k to 450k. The polymers were modified to present DBCO every 8 monomers. The polymers were also conjugated with a dye and biotin. The dye can be visible within or outside the cell and biotin allows us to conjugate avidin-FITC on the day of the analysis to selectively identify the polymer molecules that are on the surface of the cell. To get a general overview and see if there are any peculiar trends for certain cells we test it on CHO epithelial cells, 4T1 cancer cells and RAW 264.7 macrophages. Over the course of 6 days we obtain a trend for the various different cell types and how they interact with the polymers of differing molecular weight and then with polymers with different amounts of DBCO ranging from one every 4 monomer units to one every 25. Hydrophobic side groups like benzene and hexane were also conjugated to PAA and tested.
Results, Conclusions, and Discussions: MW studies show that the polymer is easily uptaken and that it can last for up to 2 days at lower MW. The higher MW polymers show immediate uptake in most cell lines and then stabilizes. The Effect of valency is currently being studied for 2k polymer and shows better uptake with higher valency which also ties in with the higher MW study. Further analysis will be done to identify trends across cell lines which could indicate traits individual to a certain type of cell. Once we have identified the trends that are preferred for specific applications we will try out those polymers with animal models.
