Changyong Gao

Stem Cell Membrane-Coated Nanogels for Highly Efficient In Vivo Tumor Targeted Drug Delivery.

Stem cell membrane-coated nanogels can effectively evade clearance of the immune system, enhance the tumor targeting properties and antitumor chemotherapy efficacy of gelatin nanogels loaded doxorubicin in mice.

Remote‐Controllable Explosive Polymer Multilayer Tubes for Rapid Cancer Cell Killing

Gold nanoshell-functionalized polymer multilayer tubes can be used as potent therapeutic agents for remote killing of cancer cells in a controlled manner due to the emerging pressure wave and tube fragments piercing the cell wall. The explosion is based on rapid evaporation of water inside the tubes caused by photothermal effects. The mechanism of explosion is presented in theory and experiment. The explosion of the tubes depends on the absorption coefficient and size of the gold nanoshells in the tubes, whereby the placement of the gold particles inside or outside of the tubes has no obvious effect on the explosive properties.

Light-activated Active Colloid Ribbons

We report a dynamic self-organization of self-propelled peanut-shaped hematite motors from non-equilibrium driving forces where the propulsion can be triggered by blue light. They result in one-dimensional, active colloid ribbons with a positive phototactic characteristic. The motion of colloid motors is ascribed to the diffusion-osmotic flow in a chemical gradient by the photocatalytic decomposition of hydrogen peroxide fuel. We show that self-propelled peanut-shaped colloids readily form one-dimensional, slithering ribbon structures under the out-of-equilibrium collisions. This self-organization intrinsically results from the competition among the osmotically driven motion, the phoretic attraction and the inherent magnetic moments. The giant size number fluctuation in colloid ribbons is observed above a critical point 4.1 % of the surface density of colloid motors. Such phototactic colloid ribbons may provide a model system to understand the emergence of function in biological systems and have potential to construct bioinspired active materials based on different active building blocks.

Magnetically Actuated Peanut Colloid Motors for Cell Manipulation and Patterning

We report a magnetically actuated peanut-shaped hematite colloid motor that can not only move in a rolling or wobbling mode in fluids but also perform single cell manipulation and patterning in a noncontact way. The peanut motor in a rolling mode can reach a maximal velocity of 10.6 μm s-1 under a rotating magnetic field of 130 Hz and 6.3 mT and achieve a more precisely controllable motion in predefined tracks. While in a wobbling mode, the motor reaches a maximal velocity of 14.5 μm s-1 under a conical rotating magnetic field of 80 Hz and 6.3 mT and can climb over steep slopes to adapt the motor for more complex environments. The fluid flow simulation results reveal that the difference between two movement modes mostly comes from the distribution discrepancy of the flow fields near the motors. Through the integration of the rolling and wobbling movement, these peanut motors can autonomously transport and release cells to a predefined site and thus form complex cell patterns without a physical contact. Such magnetically actuated peanut colloid motors afford a biofriendly technique for manipulation and patterning of cells, cell measurements, and intracellular communication investigations.

Noncontinuous Super-Diffusive Dynamics of a Light-Activated Nanobottle Motor

We report a carbonaceous nanobottle (CNB) motor for near infrared (NIR) light-driven jet propulsion. The bottle structure of the CNB motor is fabricated by soft-template-based polymerization. Upon illumination with NIR light, the photothermal effect of the CNB motor carbon shell causes a rapid increase in the temperature of the water inside the nanobottle and thus the ejection of the heated fluid from the open neck, which propels the CNB motor. The occurrence of an explosion, the on/off motion, and the swing behavior of the CNB motor can be modulated by adjusting the NIR light source. Moreover, we simulated the physical field distribution (temperature, fluid velocity, and pressure) of the CNB motor to demonstrate the mechanism of NIR light-driven jet propulsion. This NIR light-powered CNB motor exhibits fuel-free propulsion and control of the swimming velocity by external light and has great potential for future biomedical applications.

Bubble-Pair Propelled Colloidal Kayaker

We report a hollow dumbbell-shaped manganese dioxide (MnO2) colloidal kayaker capable of converting a pair of breathing oxygen bubbles into self-propelled movement. The bubble pair generated by catalytic decomposition of hydrogen peroxide fuel grew either synchronously or asynchronously, driving the colloidal kayaker to move along a fluctuating circle. The synchronous or asynchronous breathing mode of bubble pair is governed by the asymmetric catalytic sites of the colloidal kayakers. This imbalanced distribution of bubble propulsion force generates the driving force and the centripetal force on the colloidal kayaker. The dynamics of colloidal kayakers is well-described by the overdamped Langevin equation and fluid field simulation. Such bubble-pair propelled colloidal kayakers could advance applications of catalytic nanomotors, offering effective implementation for diverse tasks for a wide range of practical applications.

Cell Membrane-Camouflaged Colloid Motors for Biomedical Applications

Natural cell membrane–camouflaged colloid motors can not only convert the surrounding environmental energy into directed movement but also possess the functions of natural cell membranes. They can autonomously move and are guided by exogenous (e.g., chemical fuel, light, magnetic field, and ultrasound) and endogenous (i.e., chemotaxis) stimuli. These biointerfacing colloid motors with efficient drug loading/transporting capacity, prolonged blood circulation, and antibiofouling and specific targeting abilities are expected to open up opportunities for various biomedical applications and are recognized as the next‐generation therapeutic systems. In this progress report, the authors highlight the recent progress in research on cell membrane–coated colloid motors, as well as their potential for biomedical applications. The limitations and challenges of these colloid motors for in vivo applications are also addressed.

Shape-Transformable, Fusible Rodlike Swimming Liquid Metal Nanomachine

The T-1000 liquid metal terminator, which can transform and self-repair, represents a dream for decades that robots can fundamentally change our daily life. Until now, some large-scale liquid metal machines have been developed. However, there is no report on nanoscaled liquid metal machines and their biomedical applications. We describe here a shape-transformable and fusible rodlike swimming liquid metal nanomachine, based on the biocompatible and transformable liquid metal gallium. These nanomachines were prepared by a pressure-filter-template technology, and the diameter and length could be controlled by adjusting the nanoporous templates, filter time, and pressure. The as-prepared liquid gallium nanomotors display a core-shell nanorod structure composed of a liquid gallium core and solid gallium oxide shell. Upon exposure to an ultrasound field, the generated acoustic radiation force in the levitation plane can propel them to move autonomously. The liquid metal nanomachine can actively seek cancer cells and transform from a rod to a droplet after drilling into cells owing to the removal of gallium oxide layers in the acidic endosomes. These transformed nanomachines could fuse together inside cells and photothermally kill cancer cells under illumination of near-infrared light. Such acoustically propelled shape-transformable rodlike liquid metal nanomachines have great potential for biomedical applications.