Optical real-time biosensor

An optical sensor system wearable or implantable in a living subject, comprising:

• an optical probe, comprising:
• an optical waveguide having a first end and a second end, the first end configured to receive an excitation light to be propagated through the optical waveguide and to be emitted from the second end or a middle region into a surrounding medium;
• one or more molecular switches attached to a facet or a sidewall of the second end or the middle region of the optical waveguide, wherein the one or more molecular switches are configured to change conformation upon binding to a corresponding target molecule;
• and
• one or more optical reporters, each of the one or more optical reporters attached to a respective molecular switch and configured, when exposed to the excitation light, to produce an optical signal that changes upon binding of the respective molecular switch to the corresponding target molecule in the surrounding medium, wherein the optical signal is coupled back into the optical waveguide and propagated through the optical waveguide to be emitted from the first end or second end;
• a light source configured to emit the excitation light to be coupled into the optical waveguide of the optical probe;
• and
• a detector configured to (i) receive the one or more optical signals produced by the one or more optical reporters that are transmitted through the optical waveguide, and (ii) detect changes of the one or more optical signals, thereby allowing for detection of a concentration of the corresponding target molecule.