Disclosed herein are pH-dependent silk fibroin-based ionomeric compositions and colloids, and methods of making the same. The state of the silk fibroin ionomeric compositions is reversible and can transform from a gel-like colloid to a more fluid-like solution, or vice versa, upon an environmental stimulus, e.g., pH. Thus, the silk-based ionomeric compositions and colloids can be applied in various industries, ranging from electronic applications to biomedical applications, such as sensors, gel diodes, absorbent materials, drug delivery systems, tissue implants and contrast agents.
