Barrier membrane demonstrates biosensing platform protection

Biological signaling mechanisms often involve small molecules, ions, and protons, and facile in situ monitoring of the levels of these species is vital for medical diagnostics. Even the simplest signals, such as intracellular pH level, can provide important information. Of all biosensing platforms, electrical sensors represent the best opportunity to develop implantable long-term sensing platforms because of their typically high sensitivity levels, fast response, and ease of multiplexing, signal processing, and coupling to wireless readout components. As field effect transistor (FET)-based electrical ion sensing and diagnostic platforms move into the realms of clinical use and potentially even long-term implantable applications, some of the limitations of this technology come into sharp relief, especially those related to device fouling in complex fluid environments. To solve the fouling problem, a team of Livermore scientists has developed a semipermeable lipid membrane coating that isolates the sensor surface from the solution and only allows the species of interest to reach the device sensing surface. When they integrated silicon nanoribbon FET sensors with an antifouling lipid bilayer coating that contains proton-permeable carbon nanotube porin channels, they found that the membrane makes the sensors resistant to fouling by a range of complex biological fluids without affecting sensor performance.

This work was featured on the front cover of the February 2019 issue of Nano Letters.

[X. Chen, H. Zhang, R.H. Tunuguntla, and A. Noy, Silicon Nanoribbon pH Sensors Protected by a Barrier Membrane with Carbon Nanotube Porins, Nano Letters 19 (2), 629–634 (2019), doi: 10.1021/acs.nanolett.8b02898.]