Method for marking items for identification

摘要

A method for marking or tagging individual microparticles using a near infrared fluorophore for identification is provided. The near infrared fluorophore is included with one or more layers comprising the microparticle. Desirably, the coating layers contain colorants such as dyes and/or pigments which increases the total possible combinations that may be used to identify the marked material. There is further provided a method for marking a material using these microparticles containing a near infrared fluorophore.