Synthesis and characterization of pH-responsive hydrogels. Application as flow control valve in microfluidic systems.

MARCELO ROMERO; RUBEN DARIO ARRUA; ÁLVAREZ IGARZABAL CECILIA; E.F. HILDER

Melbourne

Congreso; International Congress of Biosensors 2014; 2014

The conventional solid state actuators are manufactured using complex systems and require an electrical source, which limits their applications. Stimuli-sensitive hydrogels are materials that respond to environmental stimuli, such as temperature, pH or an electric field, by abruptly changing their volume and hence hold or release a large amount of water. Those hydrogels sense a change in those stimuli and expand or contract based on the stimulus. By their capability to reach a large yet reversible volume change, hydrogels have been used as novel drug delivery systems, scaffolding materials for tissue engineering and sensors and actuators for microfluidic devices. In this work, we present the synthesis and characterization of a novel hydrogel prepared from tris[(hydroxymethyl) methyl]acrylamide (NAT) and itaconic acid (ITA) as monomers and (+) N,N-diallyltartradiamide (DAT) as crosslinker. A set of hydrogels were prepared using different molar fraction of monomers and their mechanical forces, rheology, FTIR-ATR and swelling properties were studied. In order to demonstrate the application of the pH-responsive hydrogels, one of the poly(NAT-co-ITA) copolymers was incorporated into a flow control valve system to act as an actuator, testing it within a capillary system. The hydrogel was configured as a valve to control the passage of a solution according to changes in the pH that produces variations in the hydrogel swelling. The results obtained suggest that the developed hydrogel could be used as actuator to flow control of drugs in microfluidic devices.