A Polymer is a long thread-like chain formed by attachment of similar molecules. Poly(methyl methacrylate) (PMMA) is one of the most widely produced polymer in the world today. It is formed by polymerizing or ‘attaching’ methylmethacrylate (MMA) and is used in household items, in paints and as a substitute for glass. PMMA is compatible with the human body so it has several biomedical applications also which includes dental bases, bone filler and intraocular lens.
Glycerol is a highly hydrophilic or ‘water-loving’ species, a byproduct obtained from the soap making process and from the biofuel industry. It is also generated by hydrolysis of coconut oil. It mainly finds its application as a sweetening agent, stabilizer in food industries and humectants in cosmetic formulations.
As part of our project we cross-linked or ‘tied up’ PMMA chains while synthesizing it using glycerol to form a 3D polymer network to encapsulate N,N-diethyl-m-toluamide (DEET), a mosquito repellant. The networks were reduced to nano size capsules prior to DEET encapsulation. When the polymer swelled in a solvent, DEET entered the porous network of the polymer and got captured. They were released slowly when the network got squeezed by changing the solvent. Instead of using chemicals to crosslink glycerol and PMMA, the group used commercially available benign enzymes as ‘biocatalyst’ to speed up the reaction and to eliminate the chance of inducing toxicity from a chemical catalyst. The concept of encapsulation and release of DEET from PMMA network is schematically represented as following:
Encapsulation and Release of DEET from the polymeric network of PMMA formed by crosslinking PMMA with glycerol
DEET is one of the most effective mosquito repellent available in the market and is available in the form of lotions, creams, gels and aerosol spray. However, these formulations utilize DEET inefficiently. Most of the DEET is lost within a few hours of application due to perspiration, rub off and other activities. To go beyond six hours the concentration of DEET needs to be increased or the repellent needs to be reapplied.With the use of our formulation where DEET remains encapsulated inside the polymeric network, slow and controlled release of DEET was observed beyond 10h. The study establishes that DEET encapsulated inside the polymeric network of PMMA gets released at a controlled rate for prolonged period and can be further studied for the development of a long lasting mosquito repellant formulation.
A copy of the article is available online at 10.1016/j.msec.2012.06.001.
Dr. Soma Chakraborty is currently an Associate Professor at the Chemistry Department of Ateneo de Manila University. She finished her PhD in Polymer Chemistry at the Polytechnic University of New York. Her research interests include biocatalytic synthesis, modification of organic and macromolecules, and polymeric vehicles as controlled release system.