(627d) Bihydrogel Particles As Free-Standing Mechanical Microsensors

We propose a new type of mechanical microsensors that are microparticles consisting of two parallel phases of crosslinked hydrogels with different sensitivity to a certain enviromental parameter. Working similarly to a bimetallic strip, this type of sensors can bend to a different degree depending on the corresponding environmental parameter and therefore was named bihydrogel microsensors. For demonstration, we have manufactured pH and temperature bihydrogel sensors that use acrylic acid and PNIPAM to form the pH and the temperature sensitive hydrogels. These microsensors were manufactured very efficiently and economically using the stop-flow lithography printing technique in PDMS microchannel. Because the bihydrogel microsensors are free-standing particles, they are particularly suitable for use in confined environment where most types of microsensors are unable to fit in. Furthermore, since the working principle of the bihydrogel microsensors is very general, the same principle can be applied for producing sensors for detecting a wide variety of environmental parameters.