Hemodynamics Challenges for the Navigation of Medical Microbots for the Treatment of CVDs

Abstract

Microbots have been considered powerful tools in minimally invasive medicine. In the last few years, the topic has been highly studied by researchers across the globe to further develop the capabilities of microbots in medicine. One of many applications of these devices is performing surgical procedures inside the human circulatory system. It is expected that these microdevices traveling along the microvascular system can remove clots, deliver drugs, or even look for specific cells or regions to diagnose and treat. Although many studies have been published about this subject, the experimental influence of microbot morphology in hemodynamics of specific sites of the human circulatory system is yet to be explored. There are numerical studies already considering some of human physiological conditions, however, experimental validation is vital and demands further investigations. The roles of specific hemodynamic variables, the non-Newtonian behavior of blood and its particulate nature at small scales, the flow disturbances caused by the heart cycle, and the anatomy of certain arteries (i.e., bifurcations and tortuosity of vessels of some regions) in the determination of the dynamic performance of microbots are of paramount importance. This paper presents a critical analysis of the state-of-the-art literature related to pulsatile blood flow around microbots.

Reduced rotational flows enable the translation of surface-rolling microrobots in confined spaces

“…One of the most important application areas of microrobots is a medicine; they can be used in applications such as targeted drug/gene delivery 33 , 34 thanks to their active targeting capability. Many biological media, including blood vessels, and tissues, exhibit microtopographies and confinements that are very different from microfluidic chips used in all in vitro experiments.…”

Pump-less, recirculating organ-on-a-chip (rOoC) platform

“…The PC dimensions are based on the sizes of smaller arteries in the body. 21 We use a cross-section of 1.2 × 0.8 mm 2 . To have a media-to-cell ratio comparable to standard cell culture plastics (96/48 well plates), we selected a reservoir volume of 200 μL for the inner and 300 μL for the outer circuit.…”

Pump-less, recirculating organ-on-a-chip (rOoC) platform

“…The PC dimensions are based on the sizes of smaller arteries in the body 15 . We use a cross-section of 1.2 × 0.8 mm 2 .…”

“…Text). Re out corresponds to the flow conditions that are present in smaller arteries or arterioles 27 and Re in equals values present in smaller veins. Thus, the platform can be used to model both, venous and arterial flow conditions on one device without using external pumps.…”