Method for detecting biomaterial using linear upconversion fluorescent property

A method for detecting a biomaterial by means of a dye having a linear upconversion fluorescent property, the method comprising:

• i) preparing a fluorophore having a linear upconversion fluorescent property;
• ii) reacting the fluorophore with the biomaterial to form a reaction complex thereof;
• iii) exciting the reaction complex using a light source with a wavelength longer than the maximum emission wavelength of the fluorophore;
• and
• iv) detecting and measuring a fluorescence signal with a wavelength shorter than the wavelength of excitation light emitted from the excited reaction complex;
• wherein the fluorophore has a Stokes' shift of <100 nm,
• in Step i), the fluorophore is loaded on or conjugated to a nanostructure, thereby forming a fluorescent nanostructure,
• in Step iii), the reaction complex is excited using a light source with a wavelength 5 to 50 nm longer than the maximum emission wavelength of the fluorophore, and
• in Step iv), the emission signal emitted from the reaction complex is an emission signal in a wavelength range 10 to 100 nm shorter than that of the excitation light.