Biosensor based on a tethered particle

A biosensor for sensing an analyte using tethered particle motion, the biosensor comprising:

• a particle;
• a surface;
• a tether molecule bound at a first end to the particle and bound at a second end to the surface;
• a first moiety bound either to the particle or to the tether molecule;
• a second moiety bound either to the surface or to the tether molecule;
• wherein first moiety is bound to the particle and/or the second moiety is bound to the surface;
• wherein either 1) the first moiety and the second moiety have a binding affinity to each other in dependence on the presence or absence of a target analyte, or 2) the first moiety and the second moiety have a binding affinity to the target analyte;
• whereby motion characteristics of the particle change depending on the presence of the analyte, thereby allowing sensing of the analyte by measuring changes in a spatial coordinate parameter of the particle relative to the surface.

A method for sensing an analyte using tethered particle motion, the method comprising:

• providing a biosensor comprising:
• a surface;
• a tether molecule bound at a first end to the particle and bound at a second end to the surface;
• a first moiety bound either to the particle or to the tether molecule;
• a second moiety bound either to the surface or to the tether molecule;
• wherein first moiety is bound to the particle and/or the second moiety is bound to the surface;
• wherein either
• 1) the first moiety and the second moiety have a binding affinity to each other in dependence on the presence or absence of a target analyte, or
• 2) the first moiety and the second moiety have a binding affinity to the target analyte;
• and
• detecting motion characteristics of the particle that change depending on a presence of the analyte, wherein the motion characteristics comprise a spatial coordinate parameter of the particle relative to the surface.