Scalable production of magnetic fluorescent cellulose microparticles

Fluorescent and magnetic nano- and microparticles have already been used for wide range of (bio)applications. Multimodal imaging as well as simultaneous control and monitoring of intracellular movements profit from the combination of these functionalities. Accordingly, several methods have been developed for the synthesis of magnetic fluorescent particles. The majority of these methods, however, require complex modification and purification steps and result in a low yield of particles. Here, we describe a straightforward and scalable method for the magnetic modification of cellulose-based fluorescent particles. The method is based on the use of microwave-synthesized magnetite nanoparticles prepared from ferrous sulfate at high pH. Magnetic modification did not change the pH sensitivity or the optical properties of the fluorescent particles, and allowed them to be manipulated by external magnetic field. Our results demonstrate the possibility of large scale, easy production of bifunctional particles. We anticipate that our method can be expanded to include other types of particles or functionalities relevant for biomedical applications.