Antimicrobial micro/nanorobotic materials design: From passive combat to active therapy

The rise of multidrug-resistant bacteria has emerged as one of the major threats to global public health. Moreover, many pathogenic bacteria can form stubborn biofilms to prevent antibiotic penetration and to protect them from environmental stress. Worse still, it is in dire need of developing novel antibiotics. Such circumstances call urgently for breakthrough strategies beyond traditional antibacterial treatments to fight back against the impending human health disaster. In this connection, micro/nanorobots can perform autonomous or field-driven locomotion, actively deliver therapeutic cargos, precisely implement micromanipulation, exert robust mechanical forces upon movement, and respond to internal (pH, chemical gradients, chemoattractants, etc.) or external (magnetic field, light, ultrasound, etc.) stimuli. These characteristics enable the targeted delivery of antimicrobials to infected sites and boost their deep penetration through bacterial biofilms, making the use of micro/nanorobots an attractive alternative to traditional antimicrobial treatments. In this review, we will comprehensively summarize the recent progress and future outlook for the application-oriented material designs of antimicrobial micro/nanorobots, covering broad topics from traditional antimicrobial nanomaterials to intelligent antimicrobial micro/nanorobots, from passive infection resistance to active antimicrobial therapy, and from eradicating bacteria and biofilms to eliminating bacterial toxins. Our goal is to deliver a comprehensive review that can serve as a useful reference and provide guidance for the rational design and development of novel antimicrobial micro/nanorobots and bridge the gap between traditional antimicrobial nanomaterials and active antimicrobial micro/nanorobots.