By: Eunice Jean Patron
Thermoresponsive polymers are molecules that undergo significant changes in their properties in response to temperature changes and are widely used in biomedicine, such as drug delivery, tissue growth, and gene transfer, as noted by researchers Ward and Georgiou in their 2011 study.
One example of a thermoresponsive polymer is poly(N-isopropylacrylamide), which is used to deliver drugs, such as calcitonin and insulin, to their target organ. According to scientist Dirk Schmaljohann, poly(N-isopropylacrylamide) keeps the drug intact as it passes through the stomach, and once it reaches the intestines, which have a different pH level, the polymer breaks down and releases the drug.
While there are already existing conventional methods to synthesize polymers, it is difficult to control how monomers—small molecules that make up polymers—connect. This leads to varying polymer chain lengths, which affect the performance of the polymers. This prompted chemists from the University of the Philippines – Diliman College of Science (UPD-CS) to identify a simple, inexpensive, and environmentally friendly approach of creating thermoresponsive polymers.
Synthesis of two different architectures of copolymers of MMA and DEGMEMA using RAFT polymerization in [HPY][PF6].
Using the Reversible Addition Fragmentation Chain Transfer (RAFT) polymerization, Ludhovik Luiz Madrid and Dr. Susan Arco from the UPD-CS Institute of Chemistry (UPD-CS IC), along with Ser John Lynon Perez of the UPD-CS Natural Sciences Research Institute (UPD-CS NSRI), successfully created thermoresponsive polymers using two monomers—di(ethylene glycol) methyl ether methacrylate (DEGMEMA) and methyl methacrylate (MMA)—in a hexylpyridinium ionic liquid, N-hexylpyridinium hexafluorophosphate ([HPY][PF6]). Both linear and hyperbranched structures were successfully synthesized, using ethylene glycol dimethacrylate (EGDMA) as the crosslinking agent for the hyperbranched copolymer. The polymers produced by the researchers were biocompatible, meaning they can interact with living body tissues without causing adverse reactions. #
