MicroElectroMechanical System (MEMS) devices can be fabricated completely of hydrogel materials. Such hydrogels can include polyethylene glycol with diacrylate functional groups (e.g., PEGDA), which are photopolymerizable in the presence of crosslinkers and photoinitiators. By using PEGDA monomers of different molecular weights and at different percentages, the mechanical properties of the polymerized gels and their respective permeabilities can be tuned. This spatial variation in properties and permeabilities can lead to different functionalities between different portions of the hydrogel MEMS device. Portions of the hydrogel device may be remotely actuated by applying wave energy, for example, a magnetic field, high intensity focused ultrasound, and/or infrared radiation. The remote actuation can allow the device to be actuated in vivo, for example, to allow the device to deliver a drug or other substance at a desired time and/or desired location within a patient.