System for portable and easy-to-use detection of analytes with mobile computing device

A system for identifying the presence, absence, and/or quantity of a molecule of interest in a sample, comprising:

• a reader;
• and
• a cartridge that fits into the reader, the cartridge configured to accept a sample collection device that fits into the cartridge,
• wherein the cartridge comprises:
• a first reservoir for storing a liquid, wherein a mixture comprising the liquid and the sample is formed in the first reservoir when the sample collected by the sample collection device is inserted into the first reservoir, and wherein the mixture further comprises a plurality of magnetic particle complexes;
• a second reservoir for storing a chemical substrate;
• an analysis channel comprising an electrochemical sensor;
• and
• valve-actuating elements for transferring the mixture from the reservoir directly into the analysis channel and the chemical substrate from the second reservoir directly into the analysis channel, wherein the mixture localized over the electrochemical sensor reacts with the chemical substrate at the electrochemical sensor in the analysis channel for detection by the electrochemical sensor, and
• wherein the reader comprises a permanent magnet adjacent to the analysis channel when the cartridge fits into the reader such that the plurality of magnetic particle complexes can be localized in the analysis channel at the electrochemical sensor within a magnetic field generated by the permanent magnet.