Scientists develop light-driven nanomotors to achieve motion speeds for drug del

Recently, Dr. Shao Jingsun, who graduated with a Ph.D. from the research group of Professor He Qiang at Harbin Institute of Technology and is currently engaged in research at the research group of Jan C. M. van Hest at Eindhoven University of Technology in the Netherlands, and her team, have designed a photothermally driven nanomotor using polymer vesicles with a "bowl-shaped" morphology loaded with gold nanoparticles.

The maximum speed of this motor can reach 125 μm/s, achieving a new breakthrough in the speed of nanomotor motion.

Nanomotors have a wide range of application prospects in the biomedical field. Through autonomous motion, nanomotors can be used for targeted drug delivery, early diagnosis and monitoring of diseases, tissue regeneration and repair, bioimaging, gene therapy, as well as antibacterial and anti-tumor treatments.

The photothermally driven nanomotor prepared this time can be applied to the aforementioned fields by loading corresponding "cargo" such as antibacterial and anti-tumor drugs, biomarkers, growth factors, fluorescent molecules for bioimaging, and gene editing tools (CRISPR/Cas9).

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In addition, this achievement is photothermally responsive, so it can also be used for photothermal therapy and combined with the corresponding functions of the loaded "cargo" to further expand its application fields.Additionally, gold nanoparticles can also serve as contrast agents for computed tomography (CT, Computed Tomography) imaging.

Thus, the nanomotors prepared in this study are expected to be used for precise imaging, while delivering drugs, tracking the movement and enrichment of nanomotors in vivo/ex vivo.

For the relevant paper [1], the reviewer highly praised the excellent performance of this photo-driven nanomotor.

And highly appreciated the research group's approach to characterizing and analyzing the morphology of the nanomotor using cryo-transmission electron microscopy.

It is expected that this achievement will provide new ideas for the design and preparation of soft material-based nanomotors, while also providing new inspiration for the morphological characterization and exploration of the motion mechanism of nanomotors.Preparation of "Bowl-shaped" Polymer Vesicles

It is reported that polymer vesicles with controllable morphology and integrated functions are an excellent drug carrier and have a wide range of applications in the biomedical field.

Compared with spherical polymer vesicles, "bowl-shaped" polymer vesicles have additional loading space, that is, a hollow concave cavity.

In order to further explore and expand the application field of polymer vesicles, the team led by Shao Jingxin fully utilizes the loading capacity of this cavity to load "cargo" with different functions and characteristics, and applies them to various fields.

For example, they have loaded platinum nanoparticles in the inner cavity and successfully prepared a bubble-driven nanomotor based on polymer vesicles [2];And the enzyme-loaded "bowl-shaped" polymer vesicles are used to prepare enzyme-driven nanomotors [3];

And the degradable "bowl-shaped" polymer vesicles loaded with manganese dioxide nanoparticles are used for effective penetration of tumor tissue and deep drug transportation [4].

Based on previous work, the initial idea of this study is to load gold nanoparticles into the inner cavity of the "bowl-shaped" degradable polymer vesicles to prepare polymer vesicles with photothermal responsiveness, to construct a light-driven polymer nanomotor, and to use it for photothermal anti-tumor therapy.

However, inspired by surface functionalization technology, they shifted their research focus from inner cavity loading to the functionalization of gold nanoparticles on the surface of the polymer vesicles to further improve the loading efficiency.

It is also reported that they previously constructed Janus spherical polymer vesicles [5] and Janus "bowl-shaped" polymer vesicles [6] by sputtering coating method, and used them to prepare light-driven nanomotors.By precisely controlling its motion, applications such as drug delivery, intracellular delivery, and deep tissue penetration have been achieved.

It is reported that nanomotors can convert external energy into mechanical energy, thereby achieving autonomous driving motion.

Compared with traditional nano drug carriers (which do not have autonomous motion ability), nanomotors as drug delivery systems can more effectively deliver inside cells and can enter the interior of deep tissues.

Photo-driven nanomotors have attracted widespread attention due to their precise control of motion behavior in space and time.

So far, various morphologies of gold nanomaterials, such as gold nanoparticles, gold nanoshells, gold nanorods, gold nanostars, etc., have been introduced into the design and preparation of photo-driven nanomotor systems.Usually, polymer vesicles assembled from polyethylene glycol-b-polystyrene have a relatively rigid membrane structure, making it easier to construct gold-polymer hybrid polymer vesicles using sputtering coating technology.

However, polymer vesicles assembled from the biodegradable amphiphilic polymer polyethylene glycol-poly-D-lactic acid have a relatively flexible membrane structure, so sputtering coating technology is no longer applicable in this case.

Based on this, surface functionalization of polyethylene glycol-poly-D-lactic acid polymer vesicles will be more challenging.

Delivering different exogenous "cargo" to cells

It is reported that compared with other types of nanomotors (such as chemically driven motors), light-driven motors have many unique advantages.Firstly, light-driven motors can be remotely controlled without the need for direct contact, avoiding interference with motion behavior due to contact control, making them more suitable for delicate biomedical applications.

Secondly, by using near-infrared lasers, deep tissue penetration and photothermal responsive functions can be achieved.

By adjusting the intensity of the light source, wavelength, angle of incidence, and other factors, the motion behavior and direction of the nanomotors can be precisely controlled, allowing them to be applied in complex environments.

These advantages give light-driven nanomotors a broad application prospect in biomedical and other fields.

In view of this, this topic is committed to expanding the application field of "bowl-shaped" polymer vesicles, designing and preparing light-driven polymer nanomotors.As previously mentioned, inspired by the early work of the research group, the preliminary idea of this project is to load gold nanoparticles into the "bowl-shaped" polymer vesicles, preparing nano-motors driven by near-infrared laser.

However, considering the photothermal conversion efficiency, they shifted the research focus from the loading of gold nanoparticles to the functionalization of gold nanoparticles on the surface of the polymer vesicles.

Through electrostatic interactions and hydrogen bonding interactions, a large number of gold nanoparticles are decorated on the surface of the "bowl-shaped" polymer vesicles.

The results of cryo-transmission electron microscopy and low-temperature tomography characterization have confirmed the successful preparation of gold nanoparticle-decorated "bowl-shaped" polymer vesicles.

Based on the inherent asymmetric structure of the "bowl-shaped" polymer vesicles, under the irradiation of near-infrared laser, these vesicles can be transformed into light-driven nano-motors.Through single-particle tracking analysis, they discovered that "bowl-shaped" polymer vesicles decorated with gold nanoparticles exhibit ultrafast motion and precisely controllable direction.

To reveal the mechanism behind the ultrafast motion, the team conducted a detailed and in-depth analysis of the size and spatial distribution of gold nanoparticles on the surface of the nanomotors.

Combining theoretical simulation analysis, the research group found that a temperature gradient exists along the axis of the "bowl-shaped" polymer vesicles. The presence of this temperature gradient allows the nanomotors to demonstrate ultrafast motion under the excitation of near-infrared laser.

Finally, they evaluated the application of light-driven nanomotors in intracellular delivery.

The study shows that nanomotors, through autonomous motion, can quickly open the cell membrane and rapidly and effectively deliver exogenous "cargo" of various sizes into the cells.Recently, the relevant paper was published in Nature Communications under the title "Ultrafast light-activated polymeric nanomotors."

Wang Jianhong, a Ph.D. student at Eindhoven University of Technology in the Netherlands, is the first author, and Dr. Shao Juxin and Professor Jan C. M. van Hest from Eindhoven University of Technology in the Netherlands serve as co-corresponding authors.

Based on this research, they will further expand the surface-functionalized materials, such as adding cell-targeting functional groups or cell-penetrating peptides, to further enhance the biomedical functions of the light-driven nanomotors.

At the same time, they plan to load various "cargo" in the cavity of the "bowl-shaped" polymeric nanomotors and combine the functional groups on the surface to construct a synergistic system.

The nanomotors in this study mainly rely on a single driving force, and in subsequent research, they will design polymeric nanomotors with multiple driving forces to achieve more diverse and efficient applications.At the same time, the application of nanomotors in the loading and delivery of gene therapy drugs will also be further explored.