Mar 9 2016
Scientists have successfully developed a thin, water-soluble, nonpermanent adhesive gel that can be utilized in the field of biomedical applications. Developed from a naturally occurring chemical reaction, this water-soluble adhesive could be useful for drug delivery or tissue repair. The researchers from LSU and the University of Sheffield collaborated for this study, which has been reported in the scientific journal, Angewandte Chemie.
To develop the new adhesive the chemists initially examined the naturally occurring chemical process, which takes place when urea is broken down by the urease enzyme. Urea is a molecule present in urine, while urease creates carbon dioxide and ammonia.
Based on previous work, the researchers were aware of the time taken by the urease enzyme to break down urea. This urea can then be utilized to produce a chemical process known as a pH clock reaction. The combination of urease and urea was selected because it is regarded as a safe, natural clock reaction. The team added two chemicals, such as a synthetic acrylate and a sulfur-based thiol, as well as water during the urea-urease clock reaction, and eventually produced a thin adhesive gel that is soluble in water.
The study was headed by Elizabeth Jee, a doctoral candidate at LSU. In this experiment, over 20 different combinations of chemicals were tested by Jee before realizing the proposed reaction.
I was so excited. I jumped up and down and ran into the office to tell my lab mates that my experiment worked.
Elizabeth Jee, Doctoral Candidate, LSU
She will be receiving her doctorate in August from the LSU Department of Chemistry.
Ammonia is created as the urease breaks down, changing the watery solution from the acidic state to the basic state. Soon after the molecules create a polymer framework that traps water, and the solution turns into a solid gel which is similar to Jell-O.
During the experiment Jee recorded the time taken by urease to disintegrate urea, the time taken by the gel to form, the time at which the gel will convert into a basic solution, and how this basic solution reacts in containers of different sizes.
By tuning the properties of this system, we can adjust the rate of degradation, which might be desirable in a biomedical adhesive or drug carrier in your body.
Elizabeth Jee, Doctoral Candidate, LSU
Professor John Pojman, Jee’s Ph.D. advisor, has produced a range of polymer clays and adhesives that can be easily exploited through different chemical processes, for instance, by applying heat.
The new work is based on urea-urease pH clock reaction study that was previously performed by Pojman with a partner in England.