Polymeric waveguide biosensors with calixarene monolayer for detecting potassium ion concentration

Biophotonic sensors based on a polymer waveguide with Bragg reflection gratings are proposed in this work. For developing low-cost disposable sensors, UV curable polymer materials are utilized to demonstrate the waveguide sensors. The grating pattern is formed on the core layer of a polymer waveguide by exposing a laser interference pattern on a photoresist. To detect a small amount of analyte molecule through a specific binding, a calixarene crown molecule is immobilized on a sensing interface. Bragg reflection peak movement is observed depending on the potassium ion concentration dissolved in phosphate buffered saline solution. It has been confirmed experimentally that the sensor could detect the potassium ion concentration on the order of 1pM.