Cyborg and Bionic Systems / 2022 / Article / Fig 6

Review Article

Biohybrid Micro- and Nanorobots for Intelligent Drug Delivery

Figure 6

The representative applications of cargo delivery systems versus the size of biohybrid micro- and nanorobots. (a) DNA-based nanorobots for thrombin delivery to tumor-associated blood vessels with the aim to inhibit tumor growth by inducing intravascular thrombosis. Human breast cancer cells (MDA-MB-231) and BALB/c nude mice were used for in vivo experiments. Reproduced with permission from Reference [29]. Copyright 2018, Nature Publishing Group. (b) Enzyme-based nanorobots for transport and stimuli-responsive release of drugs ([Ru(bpy)3]Cl2 or doxorubicin DOX). In vitro experiments were conducted by using HeLa cells. Reproduced with permission from Reference [85]. Copyright 2019, American Chemical Society. (c) Erythrocyte-based microrobots for anticancer drug (i.e., DOX) delivery. Reproduced with permission from Reference [86]. Copyright 2020, American Chemical Society. (d) Microalgae (i.e., Chlamydomonas reinhardtii)-based microrobot for anticancer drug (i.e., DOX) delivery. SK-BR-3 breast cancer cells were adopted for in vitro experiments. Reproduced with permission from Reference [76]. Copyright 2020, The Authors. (e) Neutrophil-based microrobots for targeted drug delivery in the brain. Under the navigation of a rotating magnetic field, the microrobots can travel across the blood-brain barrier to inhibit the proliferation of tumor cells by releasing the drugs in targeted sites. Reproduced with permission from Reference [56]. Copyright 2016, The Authors. (f) A magnetotactic bacteria-based microrobot with conjugated nanoliposomes, which has the potential to deliver therapy drugs to hard-to-reach regions in solid tumors via the self-propulsion from the flagella and navigation of external magnetic fields. Reproduced with permission from Reference [87] Copyright 2014, American Chemical Society. (g) Sperm-based micromotors with the loading of doxorubicin hydrochloride for active drug delivery. HeLa cell tumor spheroids were used for in vitro drug delivery experiments performed in a microfluidic channel. Reproduced with permission from Reference [79]. Copyright 2017, American Chemical Society. (h) Macrophage-based magnetic microrobots loaded with docetaxel for active cancer therapy. The in vitro experiments were conducted in a microfluidic channel by using three-dimensional tumor spheroids from 4T1 breast cancer cells or CT26 colorectal carcinoma cells. Reproduced with permission from Reference [50]. Copyright 2016, The Authors. (i) Spirulina-based magnetic helical microrobot loaded with DOX for in vitro cancer therapy via controlled pH- and NIR-triggered drug release mode. The 769-P kidney cancer cells and EC109 esophageal cancer cells are used for in vitro experiments. Reproduced with permission from Reference [88]. Copyright 2019, American Chemical Society. (j) Sperm-based microrobots for heparin (i.e., a type of anticoagulant agent) transport in flowing blood, which have the potential to treat blood clots or other diseases in the circulatory system. Reproduced with permission from Reference [80]. Copyright 2020, American Chemical Society.