Cardiovascular diseases (CVDs) remain the leading cause of death worldwide[1] Untethered microscale robots (“microswimmers”) have emerged as a promising class of minimally invasive tools for addressing vascular pathologies. These tiny devices often magnetically actuated can navigate the bloodstream and reach sites of interest (e.g. arterial blockages) that are inaccessible by conventional instruments. Researchers note their potential to targeted drug delivery, clot removal, and even plaque debridement in arteries [2]. For example, Microswimmers can carry and release therapeutics at precise locations to improve efficacy while reducing side effects [3]. They can also be designed to mechanically clear obstructions: e.g. rotating magnetic helices could “scrape” lipid-rich plaque from vessel walls or carry clot-dissolving drugs to thrombi [1]. These and related concepts have been analyzed in recent surveys of microrobotics for biomedicine [2]. Overall, the literature highlights that while in vivo and clinical use are still emerging, microswimmers offer unique capabilities for precision intervention in the cardiovascular system [3].
Targeted Drug Delivery
One of the most explored applications of microswimmers is targeted drug delivery in the circulatory system. By encapsulating or adsorbing therapeutic agents, microswimmers can ferry drugs through complex blood flow and release them at diseased sites. Researchers summarize numerous designs of magnetic and chemical propulsion microswimmers for in vivo delivery . For example [3], Lin et al. (2024) detail advances in magnetic microrobots built with helical or needle-like structures, which can be guided by external fields to drug targets while carrying high cargo loads [4]. Biohybrid robots (e.g. cell- or enzyme-powered) also show promise for carrying payloads [2]. In general, these researchers note that microswimmers can improve spatial precision of drug delivery, but face challenges in controlling release timing and ensuring biocompatibility. For example, Bunea and Taboryski (2020) observe that many in vitro and animal studies of microswimmer drug delivery exist, yet clinical translation remains a bottleneck [3]. Similarly, recent researchers highlight the need for standardized evaluation of drug-loading and real-time tracking of microrobots in vivo [5]. Despite these hurdles, the targeted delivery potential including intracoronary or systemic delivery with reduced side effects is a major focus in recent literature[2].
Thrombus (Clot) Treatment
Microswimmer systems have been proposed to address thrombi (blood clots) in arteries and veins. researchers emphasize that vascular obstructions due to thrombus or plaque formation are major causes of stroke and heart attack [1], motivating less-invasive alternatives to surgery. In this context, microswimmers can be engineered to locate clot sites and promote thrombolysis. Zheng et al. (2024) discuss “thrombus clearance” as a key application: microrobots can carry thrombolytic agents (like tPA) to the clot, release the drug to dissolve the clot, and even physically break up or “scrub” remaining material [6]. Similarly, Doutel et al. (2021) note that microbots traveling through microvessels can remove clots and deliver drugs for antithrombic therapy [1]. The literature also suggests micro-robots might assist or replace catheter devices: e.g. chains of magnetically steered beads could be inserted by catheter and then propelled into a thrombus to retrieve it (as demonstrated in in vitro models) [7]. researchers classify this as a “mechanical removal” strategy, alongside ultrasound or laser methods [1]. In summary, microswimmers for thrombus treatment are envisioned to combine targeted drug release with mechanical clot disruption, potentially improving recanalization success while avoiding complications of open surgery.
Plaque (Atherosclerosis) Removal
A related application is atherosclerotic plaque removal in arteries. Conventional treatments (angioplasty, stenting) can damage vessel walls or leave residual debris. Microswimmers offer a conceptually novel approach: tiny robots could penetrate and clear plaque from inside the artery wall. Reviews of microswimmer capabilities note “cleaning clogged arteries” as a potential task[2]. For instance, Doutel et al.[1] describe that a microbot could use a rotary motion to “scrape” fatty deposits from arterial walls. Prototype demonstrations also exist: for example, magnetic helices that drill into gelatin models of plaque have been fabricated to mimic this concept. In the Drexel news report, helical microrobot chains are proposed to act as tiny drills to loosen and extract atheroma [8]. While reviews focus mainly on the concept rather than clinical trials, they stress that microswimmers could carry chemical “melting” agents or physically remove calcified material under magnetic control [1]. In summary, arterial plaque removal via microswimmers is an emerging idea: reviews highlight it as a future direction, noting that specialized micro-tools could complement existing angioplasty by directly addressing the occlusive material.
Challenges and Future Directions
Despite these promising visions, reviews consistently note significant challenges for cardiovascular microswimmers. The complex hemodynamics of blood flow (pulsatility, non-Newtonian viscosity) and the immune environment pose hurdles for navigation and safety. Many authors emphasize the need for biocompatible and biodegradable materials to avoid chronic implantation issues. In vivo imaging and precise control in deep tissues remain open problems. Standardized metrics for microrobot performance (speed, cargo capacity, release rate) are lacking. Nevertheless, the steadily increasing number of review articles since 2020 shows the field’s rapid growth. Recent surveys underscore that microswimmers are a fertile research area, with engineering frameworks being developed for navigation, swarm control, and intelligent actuation. Continued interdisciplinary work combining robotics, material science, and medicine is expected to bring these concepts closer to clinical reality.
References:
[1] E. Doutel, F. J. Galindo-Rosales, and L. Campo-Deaño, “Hemodynamics Challenges for the Navigation of Medical Microbots for the Treatment of CVDs,” Materials, vol. 14, no. 23, p. 7402, Dec. 2021, doi: 10.3390/ma14237402.
[2] Z. H. Shah, B. Wu, and S. Das, “Multistimuli-responsive microrobots: A comprehensive review,” Front Robot AI, vol. 9, Nov. 2022, doi: 10.3389/frobt.2022.1027415.
[3] A.-I. Bunea and R. Taboryski, “Recent Advances in Microswimmers for Biomedical Applications,” Micromachines (Basel), vol. 11, no. 12, p. 1048, Nov. 2020, doi: 10.3390/mi11121048.
[4] J. Lin, Q. Cong, and D. Zhang, “Magnetic Microrobots for In Vivo Cargo Delivery: A Review,” Micromachines (Basel), vol. 15, no. 5, p. 664, May 2024, doi: 10.3390/mi15050664.
[5] M. Anto, K. Mukherjee, and K. Mukherjee, “Nano bio-robots: a new frontier in targeted therapeutic delivery,” Front Robot AI, vol. 12, Nov. 2025, doi: 10.3389/frobt.2025.1639445.
[6] R. Xu and Q. Xu, “A Survey of Recent Developments in Magnetic Microrobots for Micro-/Nano-Manipulation,” Micromachines (Basel), vol. 15, no. 4, p. 468, Mar. 2024, doi: 10.3390/mi15040468.
[7] A. V. Pozhitkova, D. V. Kladko, D. A. Vinnik, S. V. Taskaev, and V. V. Vinogradov, “Reprogrammable Soft Swimmers for Minimally Invasive Thrombus Extraction,” ACS Appl Mater Interfaces, vol. 14, no. 20, pp. 23896–23908, May 2022, doi: 10.1021/acsami.2c04745.
[8] “Drexel’s Microscale ‘Transformer’ Robots Are Joining Forces to Break Through Blocked Arteries,” Drexel, 2015. Accessed: Nov. 17, 2025. [Online]. Available: https://drexel.edu/news/archive/2015/June/microswimmer-surgery/#:~:text=DGIST%20researchers%20are%20planning%20to,that%20is%20causing%20the%20blockage