Multifunctional protein microparticles for medical applications

Micro- and nano-scale intelligent devices can revolutionize the medical field. Although proteins are promising materials for creating biocompatible miniature medical devices with biological functions, construction of complicated solid-state architectures, using inherently vulnerable proteins, remains challenging. Here, I present a sophisticated strategy for constructing a multifunctional microparticle for medical applications using multiple proteins; this strategy achieved the retention of function, increased stability, and orientation control of the proteins in the fabricated particle. As proof-of-concept, the particle, designed to cope with excess reactive oxygen species (ROS) involved in many diseases, was constructed by combining three proteins with different functions. The body of the particle was fabricated using albumin and superoxide dismutase (SOD), and the antibody was incorporated into the surface of the particle in an orientation-controlled manner. The constructed protein microparticle exhibited coordinated activities for coping with ROS, such as capture of the ROS-secreting cells by the incorporated antibody, followed by the elimination of 70% ROS, secreted from the captured cells, by the SOD in the particle. Additionally, diapocynin, loaded to the particle via the drug-binding ability of albumin, was released from the particle, preventing ROS production in the cells. This multifunctional microparticle, constructed from proteins, will profoundly impact the development of intelligent protein-based miniature devices used in medical fields. (C) 2017 Elsevier Ltd. All rights reserved.