The failure of transplanted organs can occur in the days or even years after process completion and is often difficult to detect. Early signaling of transplant rejection is the focus of a new thin, flexible biosensor engineered by researchers from Northwestern University and the University of Chicago to be applied directly to the target organ where it monitors changes in temperature. A slight increase in organ temperature documented by the sensors was demonstrated to precede the utility of conventionally used blood biomarkers by as much as three weeks in revealing the onset of organ rejection.
The initial version of the sensor was tested to gauge the status of kidney transplants in rat models. The diminutive device – just 0.3 cm wide, 0.7 cm long and 220 microns thick – houses a highly sensitive thermometer, which can detect kidney temperature variations as slight as 0.004° C. The sensor is placed just beneath the fibrous renal capsule layer of the kidney where it rests snugly against the kidney. A miniature coin cell battery for power and other biocompatible plastic-wrapped electronics are included, streaming data wirelessly via Bluetooth technology to external monitors.
The device is affixed to the organ to detect rejection in real-time. Source: Northwestern University
In test animals without immunosuppressant medications, temperatures increased two or three days before biomarkers changed in blood samples. In subjects administered such medications, the temperature increased and showed additional variations as much as three weeks before creatinine and blood urea nitrogen increased.
This early warning system for organ rejection is described in the journal Science.
