Disclosed are materials, devices, methods and systems for the detection of target molecules in test samples using microrobots. The target molecules may be bacterial toxins. The microrobots may include biohybrid materials such as porous spore core, a middle layer coated on the spore core for the actuation and steering in a fluid and further conjugation with a functional probe, and a sensing probe anchored onto middle layer for attaching to the targeted molecules in a fluid to respond to fluorescent tracking. A system for detecting bacterial toxin, is disclosed and comprises an intelligent motion control system based on automated fluorescent recognition and detection methods, which can propel and guide the microrobots to realize the automated motion in a pre-designed path and perform the real-time monitoring when integrating with an inverted fluorescent microscope or a fluorescent emission multi-reader.