CUR - The Council on Undergraduate Research

The Impact of Hydrophobicity/Hydrophilicity on PAMAM Dendrimer-Lipid Bilayer Interactions

Lead author: Lynnie Chong Co-authors: Escarlin Perez, A.J. Liles, Joseph Giancaspro, Patrick Scollan, Juan Rosario Faculty Research Mentors – Dr. Sunghee Lee and Dr. Casey Dougherty Iona College 715 North Ave, New Rochelle, NY 10801

Biomaterials based on dendrimer, highly branched synthetic macromolecule, have been extensively studied in applications such as drug carriers, imaging agents, and gene delivery vehicles. One of the major challenges in using dendrimers in biomedical applications is understanding their cytotoxicity, cellular uptake, and cellular membrane interaction in relation to their size and surface modification. Studies of modified dendrimers interacting with controlled compositions of lipids in a model lipid bilayer were conducted in order to better understand the dendrimer cellular uptake mechanism. In this study, Generation 3-5 poly(amidoamine) (G3-5 PAMAM) dendrimers were used with amine-terminated surface functionalization and with fluorescein isothiocyanate (FITC) and poly(ethylene glycol) (PEG) modification, in order to determine how altering the degree of hydrophobicity/hydrophilicity on a macromolecule, impacts the interaction of the macromolecule with the bilayer. Water permeability, a sensitive probe for the lipid bilayer structure, was measured on the models of the biological membrane made by the Droplet Interface Bilayer method. Combined with Confocal Raman Microspectroscopic and Differential Scanning Calorimetric studies, this study provides insights on the nature and extent of the interaction between PAMAM dendrimer and cell membrane.

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