This paper addresses a new insight into the properties of a tactile sensing microfinger. The tactile sensing microfinger integrates a pneumatic balloon actuator (PBA) and a liquid metal strain sensor. Integration of the actuator and sensor enables active sensing that is a sensor can approach and contact objects. This paper investigated the parameters that affect both actuator and sensor properties for the optimization of the microfinger design. It is possible to optimize the performance of actuator and sensor by controlling parameters such as bending stiffness EI. The design focuses on bending stiffness EI successfully improved the sensitivity of the liquid metal strain sensor.