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Recently, the top international academic journal Advanced Materials(IF=19.791)published a cover article about the latest research by Professor Li Yigang‘s team, which showed that the cardiac patch based on superalignedcarbon nanotube sheets(SA-CNT)would have a good application in cardiac resynchronization and myocardial infarction treatment.
Professor Li Yigang and his team, from the affiliated Xinhua Hospital, collaborating with Professor Pang Huisheng, from the department of Macromolecular Science of Fudan University, haveproposed and successfully constructed a new type of cardiac patch based on superalignedcarbon nanotube material. Given the groundbreaking and significant academic value of this achievement, Advanced Materials (IF = 19.791), one of the top international academic journals, has selected it as the cover article in its latest issue.
Myocardial infarction is one of the major killers of human health. Once damaged and necrosis,myocardial cells are difficult to regenerate, which willbegraduallyreplaced by fibrous scar tissues. The newly-formed scar tissues, on the one hand, would cause ventricular remodeling. On the other hand, unlike normal myocardium, thefibrous scarsare lack of good electrical conductivity, whichwill slow down the electrical conduction of impaired heart and thus increase the heterogeneity ofthe conduction direction, resulting in increased heterogeneity of electrophysiological characteristics of infarct areas andaggravating heart failure caused by unsynchronized cardiac contractions, and finally inducing fatal malignant arrhythmia or even sudden death. Treatmentscurrently used in clinic(including drugs, thrombolytic therapy, interventional therapy, coronary artery bypass surgery) can delay ventricular remodeling and improve cardiac function, but cannot fundamentally repair the progress of the impaired myocardial block, which eventually lead to heart failure and malignant arrhythmias. Heart transplantation remains the only treatment for most patients with end-stage heart failure, but people are struggling to find new treatments because of limited sources of donor and immune rejection, which are far from meeting the actual clinical needs.
Cardiac tissue engineering is a promising method of repairing infarcted myocardium. By culturing myocardial tissuein vitro, the damaged parts can be replanted to restore the heart structure and function. However, the current cardiac patch is still difficult to completely simulate the orientation of natural myocardium, as well as the rapid conduction of electrical signals and myocardial synchronous contraction. Carbon Nanotubes (CNTs) is a kind of one-dimensional quantum material with special structure (the radial size is in the nanometers level, while the axial size is in the micrometer range and the tube end is sealed), andis also a coaxial tubewith several layers todozens of layersthat is mainly made up of the hexagon-arrangedcarbon atoms. Studies have shown that CNTs can interact with excitable cells, promote cell proliferation and growth and induct stem cell differentiation. CNTs powders have shown good performance as an additive in in-vitro-cultured cell scaffolds. The research team boldly assumes that if each CNT is aligned in one dimension, it will be more conducive to take advantage of its unique properties of the nanotubes’ tubular structure and to simulating the myocardial alignment. In this study, Super-aligned Carbon Nanotube Sheets (SA-CNTs) prepared by dry-spinning technology have the properties of light weight, good flexibility, self-supporting, porous and rough surface, excellent conductivity and regulatability on the nanoscale. In vitro culture of cardiomyocytes with SA-CNTs can not only induce the cardiomyocytes to grow in one orientation, but also provide an effective signal transduction pathway for isolated cardiomyocyte clusters. At the same time, with the help of electrical stimulation, the expression of connexin CX43 among the number of adjacent cardiomyocytes will be increased, whichimproves the signal transduction between cells and achieve synchronous contraction of cardiomyocytes on SA-CNTs. In addition, SA-CNTs can reduce the repolarization dispersion between different beats and different cardiomyocytes in a single cardiomyocyte, which is crucial for normal pulsatile rhythms of engineered myocardium and has the potential to reduce the incidence of arrhythmia associated with myocardial infarction.
Finally, the research team further built a monolithic flexible electrode based on oriented SA-CNTs and demonstrated its functionof multipoint synchronized pacing. The results showed that the cardiac patch based on oriented SA-CNTs hada promising application in cardiac resynchronization therapy, especially for patients with post-MI heart failure.