Determining extracellular analyte concentration with nanoplasmonic sensors

An imaging method for determining concentrations of an analyte, the method comprising:

• forming at least one array of functionalized plasmonic nanostructures on a localized surface plasmon resonance imaging (LSPRi) chip;
• contacting the at least one array with a fluid comprising an analyte;
• illuminating the at least one array with a visible light source causing the nanostructures to emit sensor data;
• imaging the illuminated plasmonic nanostructures of the at least one array with a camera for each of a plurality of times;
• measuring brightness intensity data of the nanostructures for each of the plurality of times using camera imagery;
• determining fractional occupancy data for the nanostructures using the brightness intensity data measured by the camera for each of the plurality of times since there is a linear relationship between intensity data from the camera and fractional occupancy;
• and
• determining concentration data of the analyte based on the fractional occupancy data using the law of mass action.