Pollen‐Based Magnetic Microrobots are Mediated by Electrostatic Forces to Attract, Manipulate, and Kill Cancer Cells

Abstract

Naturally occurring micro/nanoparticles provide an incredible array of potential sources when preparing hybrid micro/nanorobots and their intrinsic properties can be exploited as multitasking functionalities of modern robotics as well as ensuring their mass production availability. Herein, magnetic biological bots (BioBots) prepared from defatted sunflower pollen microparticles by ferromagnetic metal layer evaporation on one side of its surface are described. It is demonstrated that the methodology employed introduces magnetic properties to sunflower pollen microparticles-based Bio-Bots and enable their magnetic actuation. Interestingly, as-prepared magnetic sunflower pollen-based BioBots can naturally attract cancer cells due to their opposite charges (positive and negative, respectively). Such attracted cancer cells can then be transported by microrobots. This strong attraction also allows the delivery of drugs intended to kill the cancer cells. Sunflower-based BioBots can be fabricated in large quantities, and are naturally programmable, making them promising candidates for cancer cell therapy.

Facile, High-Yield, and Freeze-and-Thaw-Assisted Approach to Fabricate Bamboo-Derived Hollow Lignocellulose Microcapsules for Controlled Drug Release

“…It could be attributed to the higher O/C value and hierarchical porous structures of LMs. As shown in Table S5, PCs show higher DLC and DLE than hollow natural pollen and unmodified polymers, such as CNC, polyurethane nano-micelles, hyaluronic acid, and mPEG-g-Dextran, probably due to the natural hollow structure and hierarchical porous structures. ,− SEM images of PCs-12@DOX reveal an intact cell structure with more compact pores in the pits, indicating that LMs preserved the structural integrity without any deterioration and DOX adsorbed and covered on the nanofiber of pits (Figure S10c,d).…”

“…Developing and manufacturing microcapsules based on renewable sources have indeed played a crucial role in removing the destructive influence of synthetic materials on the environment . Recently, numerous research efforts have been devoted to the microencapsulation of cargoes with natural polymers. − The robust exine microcapsules isolated from plant spores and pollen grains have exhibited strong potential as a delivery vehicle to replace the artificial ones for the encapsulation of vaccines, oils, pharmaceutical drugs, and contrast agents. − However, they are still limited by laborious manufacturing and high production costs. At present, low-cost microcapsules are generally dominated by synthetic materials, starting from the fabrication of core structures by the template, emulsification, or microfluidic method, followed by the initiated monomer polymerization of their outer shells and the removal of internal filling. − However, these methods suffer from a multi-step preparation process and the use of synthetic polymers would bring microplastic pollution risks to the health of all living things on Earth .…”

Advances in Finite Element Analysis of External Field‐Driven Micro/Nanorobots: A Review

“…Pollen has a natural lumen structure that holds great potential for drug encapsulation and can communicate with cells through electrostatic forces. [ 12 ] Pollen‐based MNRs hold promise for cancer therapy. A sea urchin shape based on sunflower pollen could penetrate cancer cells to achieve drug release, having a strong ability to penetrate cell membranes.…”

“…Therefore, compared with self‐driven MNRs, external field‐driven ones have become a driving mode with more potential. [ 12 ] External field‐driven MNRs aim to achieve the accurate control of motion behavior by applying the external field. They are capable of converting energy between external field energies such as magnetic energy, electric energy, light energy, and kinetic energy to achieve accurate and controllable autonomous MNR navigation.…”

Multifunctional 3D‐Printed Pollen Grain‐Inspired Hydrogel Microrobots for On‐Demand Anchoring and Cargo Delivery

“…

development and implementation of such mobile medical microrobots, including fabrication of soft robotic microdevices, [11,12] synthesis of biocompatible or responsive (adaptive) materials, [13][14][15] and strategies for locomotion inside the body. [16][17][18][19][20][21][22] A myriad of remotely controlled medical microrobots has been proposed to enable shape change, multifunctionality, and reconfiguration in response to different stimuli, such as magnetic fields, [23][24][25][26][27] temperature, [28,29] chemical, [30,31] light, [32] and ultrasound, [33,34] for diverse medical applications, such as target drug delivery, minimally invasive surgery, and remote sensing. [35,36] However, microrobot interaction with biological tissues, complex biofluidic environments, and overlap of multiple stimuli are major challenges toward their future medical applications.

…”