According to aspects of the invention provided are apparatus, systems and methods for monitoring the presenceabsence of syringes within a storage unit and monitoring the amount of drugs that are discharged from syringes when they are not within the storage unit. Chimeric proteins are provided that target cells in which apoptosis is to be induced. The gripper mechanism further includes at least one optically detectable indicator associated with the position and movement of the gripper fingers, and an optical sensor positioned to detect at least one of the optically detectable indicators.