Micro‐/Nanorobots at Work in Active Drug Delivery

Abstract

After the tremendous advances over the past two decades, micro‐/nanorobots can effectively convert other forms of energy into propulsion and movement, as well as be navigated to targeted locations under physiological conditions and environments. They have been demonstrated to have the potential to load, transport, and deliver therapeutic payloads directly to disease sites, thereby improving the therapeutic efficacy and reducing systemic side effects of highly toxic drugs. In this feature article, the various propulsion modalities of micro‐/nanorobots ranging from chemical/biochemical reactions to external fields, and to motile microorganisms are summarized and commented in terms of driving forces required by the automotive motion in biological media, biocompatibility, as well as the corresponding advantages and limitations in terms of biomedical applications. Then, the latest developments of in vitro and in vivo active drug delivery based on micro‐/nanorobots are discussed in detail. The challenges and future prospects are also highlighted in the end. With ever booming research enthusiasm in this field and increasing multidisciplinary cooperation, micro‐/nanorobots with intelligence and multifunctions will emerge in the near future, which would have a profound impact on the treatment of diseases.

Recent Advances in Nano‐ and Micromotors

“…[3] Alternatively, fueled nano-and micromotors translate chemical energy into locomotion typically via a catalytic conversion of fuel molecules on their surface. [4] These various concepts evolved and advanced from simple colloidal systems to approaches with potential practical relevance in different areas of biomedicine [5] including first evaluations in animal models, [6] active drug delivery, [7] or diagnostics [7] or for environmental applications. [8] In this Progress Report, an overview of the general developments in the area of nano-and micromotors in the past 24 months is provided (Scheme 1).…”

High‐Resolution SPECT Imaging of Stimuli‐Responsive Soft Microrobots

“…One of the ultimate goals of these devices is to perform biomedical tasks such as microsurgery or targeted drug delivery in confined locations of the human body . The issues of locomotion in biologically relevant fluids and the release of therapeutic payloads are currently in focus. Preliminary work with animal models has recently shown the potential of small‐scale robots in the biomedical field .…”

Thermoresponsive Polymer Brush Modulation on the Direction of Motion of Phoretically Driven Janus Micromotors

“…Self‐propelled synthetic micro‐/nanomotors have received growing attention over the past few decades . Inspired by natural micro‐/nanomotors (e.g., bacteria or kinesin) powered by spontaneously catalytic hydrolysis of adenosine triphosphate (ATP) molecules, the Au–Pt bimetallic nanorods were the first reported nanomotor in hydrogen oxide solution driven by catalytic reaction‐induced electrophoresis, resulting from ion gradients along the nanorod surface .…”