A CRISPR set of materials CRISPR technology is best known as a gene editing tool. English et al. developed a group of stimuli-responsive hydrogels to respond to the programmable nuclease Cas12a (see the Perspective by Han et al. ). The materials undergo molecular to macroscopic changes after Cas12a-dependent cleavage of double- or single-stranded DNA integrated into the gel. The authors show controlled release of particles linked to or imprisoned within the DNA, degradation of a gel with DNA solely forming the cross-links, and permeabilization of a gel with DNA partially forming the cross-links. These tools allow for the production of materials that release encapsulated nanoparticles and cells, act as degradable fuses, and enable remote radio-frequency identification signaling. Science , this issue p. 780 ; see also p. 754