Contamination Sensor may Tackle Catheter Superbugs

The lower layer is composed of poly(vinyl alcohol) (PVA), which contains a self-quenching carboxyfluorescein dye. This is capped by an upper layer of the pH-responsive polymer microgel poly(methyl methacrylate-co-methacrylic acid) (PMA-MAA).

An elevation in urinary pH dissolves the PMA-MAA layer, releasing the dye to provide a clear visual warning of impending blockage. Evaluation of prototype coatings using a clinically relevant in vitro bladder model system demonstrated that the coatings provide up to 12 hours advance warning of blockage, and are stable both in the absence of infection and in the presence of bacterial species that do not cause catheter blockage. The study was published early online of February 26, 2016, in Biosensors and Bioelectronics.

“Catheter-related infections are a serious problem, especially if the bacteria are resistant to antibiotics. We hope that with this simple to use sensor system we can ultimately make a real difference to patients' lives,” said senior author biophysical chemist Toby Jenkins, PhD, of the University of Brighton. “Our new coating works with existing catheter designs and gives a clear, early visual warning of infection before a catheter is blocked. It could dramatically reduce the number of infections resulting from bacterial blockages.”

Over time bacteria can build a biofilm layer inside the catheter tubing, eventually blocking it. The urine cannot drain and pushes back into the kidneys, where the bacteria can cause kidney failure, systemic infection, and even death. Up to half the people who use catheters suffer long-term problems with blockages caused by bacteria, but there is currently no way to detect them before they cause problems.

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