Storage and Operational Stability of pH-Responsive Hydrogels
Hydrogels have proven their ability to respond to changes in the local environment [1-6]. While the results obtained by many researchers highlight the promising nature of hydrogels in biomedical sensors, work has yet to be done to demonstrate the ability of hydrogels to maintain a response after being stored for an extended period of time, and to demonstrate the ability to maintain a strong stimuli response after repeated cycles. Some researchers have proposed utilizing hydrogel-based sensors in implantable devices [7]. If this technology is to work, it is important to understand the duration and stability of the stimuli response. This will determine the life of a hydrogel-based sensor and the time frame in which the device will become ineffective and need to be replaced. Furthermore, devices may not be used as soon as the hydrogel has been synthesized. Therefore, it is also important to understand how long a device may remain in storage before it loses its effectiveness.
