With a tiny chip-based sensor and 30 minutes of time, surgeons could evaluate a lung destined for transplantation and predict whether that donated organ is likely to fail or whether it will save a life.
In lung transplant surgery, the clock is ticking. Once surgeons remove the donor lung they have about 7 hours before it’s too damaged to be used, and transplant teams often rush the organ via helicopter to the hospital where a desperate recipient is waiting. People who need lung transplants are typically in the final stages of a lung disease such as emphysema or cystic fibrosis, and have exhausted all other treatment options.
Sometimes, despite the doctors’ best efforts, the transplanted lung begins to malfunction in the recipient’s body. This disorder, called primary graft dysfunction, is the leading cause of death for patients in the immediate aftermath of surgery.
The new sensor can predict, before transplantation, which donated lungs will malfunction. Biomedical engineer Shana Kelley and her colleagues at the University of Toronto created a tiny electrochemical device that detects several biomarkers associated with graft dysfunction, and can do so within half an hour. The researchers describe the experimental device in the journal Science.
Their technical advance is the creation of a “fractal circuit sensor,” on which nanoscale gold particles form spiky lines along a glass chip. These protrusions increase the sensor’s surface area, and produce more accurate readings. On these gold electrodes are genetic “probes,” strands of DNA that register the presense of genetic biomarkers associated with graft dysfunction. For example, one probe indicates that the lung cells are producing interleukin-6, a molecule linked to the body’s inflammatory response. When the genetic probes detect and bind to their targets, the electrodes register a tiny change in voltage.
This new tech is still far from real clinical use, but Kelley and her colleagues think it could offer a big improvement over current procedures. Today, transplant teams do basic checks of a donated lung’s viability, but they don’t have time to do sophisticated tests. Genetic tests of the lung tissue currently require “6 to 12 hours in a typical hospital workflow,” the researchers write, and they require highly trained personnel and contamination-free laboratories—which may not be available at the critical transplant moment.
The new sensor can do the same genetic testing in less than 30 minutes. In addition to preventing graft dyfunction by recognizing problematic lungs, the sensor could also be used to evaluate questionable lungs that are currently discarded out of an abundance of caution. “It is estimated that 40 percent of the discarded lungs may actually be suitable for clinical transplantation,” the researchers write. Salvaging those organs would be a great benefit, because a lung is a terrible thing to waste.