Anne Okrah

Anne Okrah

“Synthesizing 2-Step BZ Oscillating Hydrogel Beads”

Anne Okrah, Baptiste Blanc, Seth Fraden
Hampton University / Chemical Engineering
Hosted by Fraden's Lab


Blue eels rely on their nervous system, that sends electrical waves through their spinal cord, to actuate their muscle and move. In Fraden lab, people have been able to mimic the nervous system of a blue eel using the Belousov-Zhabotinsky reaction, or BZ reaction, a nonlinear chemical oscillator. The goal of my project is to design its muscle part, which is going to experience mechanical change in response to the oscillating BZ chemistry. A good candidate for this responsive actuator is a soft hydrogel functionalized with BZ chemistry.

We developed a technique to create BZ oscillating beads where the bead formation and the BZ catalyst incorporation are made in 2 separated steps. The advantage of this technique is to untangle the gel fabrication to the BZ chemistry, enabling a better understanding of the BZ gel mystery. To synthesize the beads, I used a micromolding technique, using PDMS as a template, with a specific polymer chemistry made of Acrylic Acid, Acrylamide and Bisacrylamide. Then, the EDC/NHS chemistry allows us to attach the catalyst to the gel bead via a reaction between an amine and a carboxylic function.

My preliminary results show that the size of the PDMS mold controls the gel bead size. In addition, the time the beads were reacting with the catalyst via EDC/NHS chemistry control the BZ catalyst incorporated into the bead. Also, the beads placed in the BZ solution (0.06M MA, 0.08M NaBrO3 and 0.4M H2SO4), are able to support chemical oscillation. The next step towards actuating BZ gel is to create softer gel, enabling larger volume change.