Abstract: As the fight against Covid-19 pandemic continues, we have learned that the blood clotting caused by Covid-19 is the main issue making this disease much more server than any flu or pneumonia. Doctors are seeing an alarming number of COVID-19 patients with blood clots — gel-like clumps in the blood that cause serious problems: internal bleeding, heart attack and stroke [1]. Autopsies have also found blood clots not only in the lungs of these victims, but throughout their bloodstream [2]. The microscopic image in Fig.1 illustrates that as the red blood cells stack together to form clots, their surfaces are blocked, compromising their oxygen function. When the blood clots get bigger, they can block blood circulation and trigger heart attack or stroke. Dr. Kanthi et.al recently claim that sever Covid-19, same as AP Syndrome, induces antibody to attack the phospholipid in red cell membrane, triggering blood clotting [3]. These blood clots take most platelets, creating high risk for internal bleeding. Currently blood thinners are the only medicine used to reduce the blood clot formation in server Covid-19 patients. Unfortunately, blood thinner medicines do not disassemble the blood clots. Moreover, they increase the risk of bleeding, serious, or even life threatening. In fact, many patients were not saved by these medicines. Therefore, a new, safe and reliable approach to disassemble blood clots for Covid-19 patients is urgently needed.Here I am presenting our magnetorheology (MR) technology [4] to treat Covid-19 patients with thrombosis: applying a strong magnetic field along the patients’ arm. When the blood clots come to the magnetic field with blood circulation, they will be disassembled. Red cells will be freed, the blood oxygenation function will be recovered, internal bleeding can be avoided, the blood viscosity along the flow direction will be reduced, turbulence will be suppressed, and cardiovascular accident can be prevented.Blood is a liquid suspension consisting mainly of red cells in plasma. The volume fraction of red cells is 40-50%. The amount of white blood cells and platelets in the blood is very small. Therefore, blood clots are actually aggerates of red cells (Fig.1). A typical human red cell is a biconcave disk (Fig.2a), with its diameter about 7.7 μm and the thickness decreasing from 2.5 µm at its edge to 0.8–1 µm at its center. The cytoplasm of the red cell contains hemoglobin, a metalloprotein containing heme groups that temporarily bind oxygen molecules taken up from the lungs and release them throughout the body. To allow efficient diffusion of oxygen, the full surface area of the red cells need to be available. When the blood form clots such as in Fig.1, surfaces of red cells are blocked and oxygen uptake and delivery is impeded.As the hemoglobin in red cells is an iron containing protein, deoxygenated red cells are paramagnetic. We are utilizing this property to disassemble blood clots (Fig.2). Red cells are polarized in a magnetic field. Because red cell is a disk, the strongest polarization is along the diameter direction. In a strong magnetic field, red cells will tilt to make their disk surface parallel to the field. Each red cell obtains an induced magnetic dipole moment. As shown in Fig.2b, when the red blood cells stack each other as in the clots, the interaction between neighboring red cells is strongly repulsive. This force is proportional to the square of magnetic field. If the applied magnetic field stronger than one Tesla, this repulsive force is strong enough to break the toughest blood clots, rouleaux [4,5]. As blood clots are mainly aggregates of red cells, once red cells are disassembled, platelets and other components are also released; internal bleeding risk is reduced. The magnetic field will further align the released red cells to form short chains along the diameter direction (Fig.2c). In such chains, the surface of red cells is fully exposed, excellent for their normal oxygen functions. Fig.2d shows a microscopic image of such short chain. Also shown in Fig.2d, we apply the magnetic field along the blood flow direction. The short chains is parallel to the blood flow. As the chains are streamlined in the flow direction, the blood viscosity along the flow direction is considerably reduced. Meanwhile, the short chains resist any motion in the directions perpendicular to the flow. The treated blood thus suppresses turbulence or disturbed motion as any disturbed flow cannot survive without motions in the directions perpendicular to the flow [4,6]. The blood circulation and red cell function will thus be greatly improved and cardiovascular accident can be prevented. Of course, after the magnetic field is turned off, these short chains will be eventually broken and the red cells will become wholly independent, flowing inside the plasma (Fig.2e).Our lab tests [4] have confirmed that this MR technology can effectively disassemble rouleaux [6]. As the newly formed blood clots in Covid19 patients should be weaker than rouleaux, we expect that this technology can safely and effectively disassemble them and help the patients to recover. References: Z. Varga, et al , www.thelancet.com Vol 395, pp 1417-1418, May 2, 2020.2. https://www.webmd.com/lung/news/20200424/blood-clots-are-another-dangerous-covid-19-mystery3. Y. Zuo et al, Science Translational Medicine, 12. eabd3876 (2020)4, R. Tao, et al., Systems and method for reducing the viscosity of blood, suppressing turbulence n blood circulation, and curing rouleaux. PCT/US2017/059446 (https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2018085330)5. N. Abramson, BLOOD, V107, I 11, 4205-4205 (2006)6. R. Tao, K. Huang, Physical Review E 84, 011905 (2011). Images: https://s3.eu-west-1.amazonaws.com/underline.prod/uploads/markdown_image/1/image/6b64306da497c2fe6f2556b8eeaa213b.jpg Fig.1 Blood clots found in coronavirus patients’ blood. https://s3.eu-west-1.amazonaws.com/underline.prod/uploads/markdown_image/1/image/ac8be56cb6be363d3ac421eb3b6622ed.jpg Fig.2 (a) Red blood cell. (b) The strong magnetic field breaks the blood clot. (c) The released red cells form short chains along the diameter-magnetic field direction. (d) The microscopic image of a short red-cell chain. The magnetic field improves blood circulation. (e) After the magnetic field is off, the red cells will eventually become wholly independent within the plasma.