Methods and systems for detecting an analyte or classifying a sample

A microfluidic system comprising

• i) at least one reservoir suitable for containing a sensor molecule,
• ii) a sensor molecule comprising a domain that binds the analyte, a chemiluminescent donor domain and an acceptor domain, wherein the separation and relative orientation of the chemiluminescent donor domain and the acceptor domain, in the presence and/or the absence of analyte, is within ±50% of the Forster distance,
• iii) a microfluidic device comprising one or more microchannels,
• iv) means for mixing the sensor molecule, the sample and a substrate of the chemiluminescent donor domain in the device,
• v) a reaction chamber for detecting binding of the analyte to the sensor molecule, and
• vi) an electro-optical sensing device,
• wherein the spatial location and/or dipole orientation of the chemiluminescent donor domain relative to the acceptor domain is altered when the analyte binds the sensor molecule, and
• wherein the sensor molecule is not fixed to the microfluidic device.

A method of classifying a sample, the method comprising

• i) flowing through a microfluidic device comprising one or more microchannels,
• a) the sample,
• b) a sensor molecule comprising a domain that binds one or more analytes, a chemiluminescent donor domain and an acceptor domain, wherein the separation and relative orientation of the chemiluminescent donor domain and the acceptor domain, in the presence and/or the absence of analyte(s), is within ±50% of the Forster distance, and wherein the sensor molecule is not fixed to the device,
• c) a substrate of the chemiluminescent donor,
• ii) mixing the sensor molecule, sample and substrate in the device,
• iii) detecting modification of the substrate by the chemiluminescent donor using an electro-optical sensing device and calculating as a ratio the energy transfer occurring between the chemiluminescent donor domain and the acceptor domain,
• iv) processing at least one signal from the electro-optical sensing device and correlating the pattern of electro-optical responses with one or more pre-determined characteristics of one or more samples of interest, and
• v) classifying the sample based on the correlation of the pattern of responses,
• wherein the spatial location and/or dipole orientation of the chemiluminescent donor domain relative to the acceptor domain is altered when the one or more analytes binds the sensor molecule.