Micro/nanomotor technology: A new opportunity for enhancing the oral bioavailability of bioactive substances

Background

Bioactive substances hold significant promise in nutrition and health due to their exceptional physiological regulatory functions. However, their oral bioavailability is typically low due to various gastrointestinal barriers. Although traditional nanoparticle delivery systems improve the oral stability and absorption efficiency of bioactive substances through encapsulation, they still face significant limitations, including dependence on inefficient and uncontrollable passive diffusion, vulnerability to entrapment and clearance by the viscoelastic mucus layer, and lack of effective targeting capability. Micro/Nanomotors (MNMs), microdevices that convert external energy into mechanical motion, offer distinct advantages such as autonomous movement and targeted delivery, presenting a promising solution to overcome the limitations of traditional nanoparticle systems and enhance the oral bioavailability of bioactive substances.

Scope and approach

This review systematically summarizes the major barriers to the oral delivery of bioactive substances, with a focus on the propulsive mechanisms and research progress in overcoming multiple gastrointestinal physiological barriers of various MNMs. It provides a detailed analysis of the advantages and challenges of using MNMs in oral delivery, aiming to provide theoretical foundations and innovative strategies for the precise, targeted, and efficient delivery of bioactive substances.

Key findings and conclusions

MNMs can effectively convert external energies (chemical, light, magnetic, or acoustic) into self-propulsion, enabling autonomous navigation, barrier penetration, and targeted accumulation in the complex gastrointestinal tract. Some MNMs can even harness adverse conditions like gastric acid as driving forces, achieving efficient payload delivery and synergistic therapy. With excellent penetration, targeting, and controllability, MNMs offer a promising strategy to enhance the oral bioavailability of bioactive substances.