Tunable color hydrogel enables multistage encryption

Self-assembly, the spontaneous organization of molecules into ordered structures, has long captivated scientists with its elegance and potential. By harnessing the same principles that shape cellular membranes and crystalline materials, researchers aspire to craft advanced functional materials from the bottom up. Among the most sought-after are "smart" materials that can sense and respond to their environment, opening up applications from drug delivery to information security.