An Experiment to Introduce Temperature-responsive Polymers for Biomedical Applications: Polymer Synthesis

As part of an ongoing effort to introduce concepts of drug delivery into the chemical engineering core curriculum, we are developing an experiment to introduce engineering students to temperature-responsive polymers for controlled release applications. Stimulus responsive polymers experience an abrupt change in physical or chemical characteristics in response to a small external change in environment. Temperature is the most commonly exploited stimulus in responsive polymer systems, and polymers that exhibit a response in water at a temperature of about 37 °C are of particular interest in biological applications. In this experiment, students produce a temperature responsive, acrylamide-based copolymer using free radical copolymerization. The copolymer composition is validated using NMR, IR, and elemental analysis, and the copolymer is then used to make a hydrogel which is also temperature sensitive. Students are challenged to design a water-soluble polymer with a controlled temperature response by tailoring the chemical composition of the copolymer. The physical and mechanical properties of the hydrogel such as swelling, density, and tensile strength are tested with and without drug loading, after exposure to different temperature environments. Finally, the drug release profiles will be analyzed in different temperature environments. In addition to learning about temperature-responsive drug delivery, students learn analytical techniques and concepts related to material properties, design of experiments, data analysis, and engineering design.