Fluorescent starch nanocrystal and preparation method and application thereof

The present invention discloses fluorescent starch nanocrystals and preparation method and application thereof. Based on the characteristic of starch nanocrystals, having an active group, hydroxyl, on the surface, the present invention introduces, by a two-step chemical surface modification method comprising silane coupling and fluorescein electrophilic addition, fluorescein isothiocyanate to the surface of starch nanocrystals with a stable covalent bond connection, such that starch nanocrystals having a fluorescence property are prepared. The preparation process of the present invention is easy to operate, has cheap raw materials with high availability, has a low cost, and can enable starch nanocrystals having no fluorescence property to have an obvious fluorescence property without influencing properties of starch nanocrystals, thus broadening applications of the starch. In addition, the acquired fluorescent starch nanocrystals have a notable fluorescence property, high biocompatibility and bio-degradability, such that the fluorescent starch nanocrystals have application potentials in various fields, such as bio-sensor manufacturing, bio-imaging of a marker and fluorescence analysis and testing, and can be further manufactured as a novel fluorescent nanoprobe using organic nanoparticles as a matrix.