Minimally invasive abdominal surgery (laparoscopy) results in superior patient outcomes as measured by less painful recovery and an earlier return to functional health compared to conventional open surgery. However, the difficulty of manipulating traditional laparoscopic tools from outside the patient's body generally limits these benefits to patients undergoing procedures with relatively low complexity. The use of miniature in vivo robots that fit entirely inside the peritoneal cavity represents a novel approach to laparoscopic surgery. Our previous work has demonstrated that mobile and fixedbased in vivo robots can successfully operate within the abdominal cavity and provide surgical vision and task assistance. All of these robots used tethers for power and data transmission. This paper describes recent work focused on developing a modular wireless mobile platform that can be used for in vivo sensing and manipulation applications. The robot base can accommodate a variety of payloads. Details of the designs and results of ex vivo and in vivo tests of robots with biopsy grasper and physiological sensor payloads are presented. These types of self-contained surgical devices are much more transportable and much lower in cost than current robotic surgical assistants. These attributes could ultimately allow such devices to be carried and deployed by non-medical personnel at the site of an injury. A remotely located surgeon could then use these robots to provide critical first response medical intervention irrespective of the location of the patient.