Photo-triggered microgel aggregation using o -nitrobenzaldehyde as aggregating power source

Abstract

In this work, cationic and anionic microgels which are mainly formed from thermal responsive polymer, poly(Nisopropylacrylamide), are prepared and mixed in water. These microgels interact with each other due to the electrostatic interaction, and aggregate voluntarily. By applying the microgel aggregating system, photo-responsive aggregating system is constructed by using o-nitrobenzaldehyde (NBA), which reacts and releases hydrogen triggered by photo stimuli. The microgel aggregates in an aqueous solution of NBA re-disperse depending on the irradiation time of UV light. In addition, by masking the UV irradiated area, the resultant shapes of microgel aggregates are controlled. The aggregated microgel shows rapid and drastic volume changes in response to heat.

Light and pH dual‐sensitive biodegradable polymeric nanoparticles for controlled release of cargos

“…Various internal and external stimuli have been investigated, based on the fact that the stimuli can induce the disassembly or morphology changes of polymeric particles . These stimuli contain pH, light, redox, specific enzymes, temperature, and so on. Among the available stimuli, light is an especially attractive one, for it can trigger release remotely in a short time and can be localized .…”

Photodegradable hydrogels for external manipulation of cellular microenvironments with real-time monitoring

“…To apply this concept, a major focus has been on light-responsive synthetic hydrogel modulated by a light beam. [43][44][45][46][47][48] Through the activation of light-triggered compound, the stiffness of such polymer networks could be controlled in the micrometer scale designedly. Therefore, light-directed activation of caged compound could be considered as a powerful technique in order to spatiotemporally modify hydrogel properties.…”

Actuation of Hydrogel Architectures Prepared by Electrophoretic Adhesion of Thermoresponsive Microgels

“…It was found that the contraction and swelling processes curved the architecture in different directions, that is, they exhibited a kinetic bending behavior with hysteresis. Previously reported gels with quick responses have not shown this type of actuation, although they showed quick response. − In this study, we fabricated hydrogels that exhibited hysteresis-type bending phenomena for the first time by layering microgels of different diameters through adhesion.…”

“…In particular, thermoresponsive polymers such as poly­( N -isopropyl­acrylamide) have attracted attention because they change their conformation significantly near biological temperatures. , For example, porous − and/or graft , gels have been reported as methods to increase the response time of hydrogels. Small gels exhibit a quick response, but the workload is small; thus, it is necessary to organize them three-dimensionally to create larger structures while maintaining a rapid response. − …”