Enzyme-Powered Liquid Metal Nanobots Endowed with Multiple Biomedical Functions

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Materials Science

Background:

• Catalytically powered micro/nanobots (MNBs) show promise for biomedical applications but lack imaging capabilities and multiple therapeutic functions.
• Developing imageable MNBs powered by bioavailable fuels with diverse therapeutic functions remains a significant challenge.

Purpose of the Study:

• To develop enzyme-powered liquid metal (LM) nanobots with multiple therapeutic functions and imaging signals.
• To create a versatile nanosystem for targeted drug delivery and imaging-guided therapy.

Main Methods:

• Fabrication of LM nanobots using biocompatible liquid metal nanoparticles encapsulated by polydopamine (PDA).
• Grafting urease enzyme and cefixime trihydrate antibiotic onto the PDA shell for propulsion and therapy.
• Utilizing dual-mode ultrasonic (US) and photoacoustic (PA) imaging for nanobot tracking.
• Investigating nanobot behavior and therapeutic efficacy in microfluidic models and *in vivo* mouse bladder.

Main Results:

• The LM nanobots demonstrated urease-powered active movement and chemotaxis towards urea gradients.
• Nanobots exhibited dual-mode US and PA imaging signals, enabling tracking of their movement.
• NIR light exposure induced nanobot deformation, facilitating a transition to photothermal therapy.
• Synergistic antibacterial treatment was achieved through combined photothermal and chemotherapeutic effects.
• *In vivo* imaging visualized nanobot dynamics in a mouse bladder.

Conclusions:

• The developed LM nanobots represent a proof-of-concept for a multifunctional therapeutic nanosystem.
• These nanobots offer a feasible tool for preclinical studies and clinical trials in MNB-based imaging-guided therapy.
• The study highlights the potential of enzyme-powered LM nanobots for advanced biomedical applications.