(4al) Synthetic Micro/Nanomachines and Their Biomedical Applications

Authors: 
Gao, W., University of California, San Diego



The 1966 movie Fantastic Voyage captured the world’s imagination, portraying a tiny submarine navigating through the human bloodstream and treating life-threatening medical conditions. This poster summarizes my PhD research advances in nano/microscale machines to realize the Fantastic Voyage vision, and highlights the challenges and opportunities in translating the progresses toward practical biomedical applications. Various areas of medicine, including targeted drug delivery, precision nanosurgery, biopsy, cell sorting, or diagnostic assays, would benefit from recent developments of efficient fuel-free and fuel-driven nano/microscale machines.

Polymer-based Catalytic Microrockets. The polymer-based catalytic tubular microrocket is synthesized using a template based electrodeposition method. The oxygen bubble propelled microrocket harvests the energy from chemical fuels (such as H2O2) and displays a record-breaking speed of 1400 body lengths/s. It can serve as an ideal platform for diverse biomedical and environmental applications. For example, antibody modified microrockets can isolate circulating tumor cells (CTCs) from biological media, and lectin modified polyaniline based microrockets can be used for selective bacteria (E. Coli) isolation from food, clinical and environmental samples. Poly(3-aminophenylboronic acid)/Ni/Pt microrocket itself provides the ‘built in’ glucose recognition capability for 'On-the-fly' capture, transport and release of yeast cells.

Micromotors: Toward In Situ Fuels. Various new hydrogen bubble propelled micromotors which can be self-propelled in their natural environments without any additional chemical fuel are demonstrated. The polyaniline/zinc microrockets display effective autonomous motion in extreme acidic environments (such as the human stomach). The attractive guided cargo transport capabilities of these acid driven microrockets hold great promise for in vivobiomedical applications such as targeted drug delivery. In contrast, the new water-driven Al-Ga/Ti based Janus micromotor can be propelled by the hydrogen bubbles generated from the rapid aluminum and water reaction which is promoted through ‘liquid metal embrittlement’. The self-assembled monolayers (SAMs) of alkanethiols modified seawater-driven Mg Janus micromotors, which utilize macrogalvanic corrosion and chloride pitting corrosion processes, can be used for environmental oil remediation.

Magnetic Nanowire Swimmer. Magnetically powered nanomotors have attracted considerable attention due to their great biocompatibility. A high-speed magnetically-propelled nanowire swimmer which mimics swimming microorganisms by exploiting the flexible nanowire as artificial flagella under rotating magnetic field is illustrated. Potential applications of these cargo-towing nanoswimmers are demonstrated by the directed delivery of drug-loaded microparticles to HeLa cancer cells in biological media.

During my PhD research, I gained multidisciplinary knowledge (nanomaterials, electrochemistry, polymers and nanomedicine) and developed many novel approaches. I would like to continue my research further towards addressing the important challenges in this area: artificial nanomotors are expected to advance from current initial proof-of-concept studies into practical in vitro and in vivo biomedical applications for further evaluation.

Advisor: Joseph Wang, distinguished professor at UC San Diego.

For more information, please visit: https://sites.google.com/site/weigao2009/