Disclosed cannula systems can detect the tissue type within which the cannula tip is located in real time using electrodes adjacent the cannula tip. The sensing cannula system can differentiate when the cannula tip is in adipose tissue or muscle based on electrical impedance. The system can be used in fat grafting and liposuction procedures, for example. An operator can detect if the cannula tip enters muscle by watching for an indicator light or audible alarm that is automatically activated by the device based on a change in sensed impedance. The device may also stop the flow of fat through a pump halting injection into the sub-muscular space.