A particularly interesting class of ionic hydrogels are nano-and microgels, whose sizes range from tens of nanometers to micrometers. Due to their size, these materials are promising candidates for numerous applications in nanotechnology 9 and nanomedicine. Unlike macroscopic hydrogels, which are electrically neutral, microgels possess a net charge due to the uneven distribution of microions between the interior and exterior of the microgel. pH-controlled charge regulation of the net charge can be harnessed as an electrostatically controlled mechanism for loading and releasing guest molecules in drug delivery applications. It is for example well-established that tumor tissues are more acidic than healthy tissues, with a pH difference of up to one unit. This insight can be leveraged for the controlled uptake and release of therapeutic molecules. Additionally, the net charge of ionic microgels can significantly alter the effective microgel-microgel interactions as compared to their neutral counterparts, leading to a rich phase behavior of microgel suspensions.