Multifunctional hydrogel hybrid probes. i) Conceptual illustration of the probe integrating optical, electrical, and fluidic functional fibers within a hydrogel matrix. ii) Insertion into a brain phantom: the swollen probe buckles, preventing penetration, while the dehydrated probe is stiff enough for easy insertion. iii) After implantation, the probe absorbs water from tissue, becoming compliant in its swollen state. Figure reproduced with permission from: Reprod ref.,[84]Copyright 2021, The Authors, Springer Nature;
