DUAL CARDIOMYOCYTE CLUSTER ARRHYTHMIAS DETECTED BY ATOMIC FORCE MICROSCOPY

Single cardiomyocytes (CMs) present unstable beating patterns, partially compensated in a clustered syncytium. We have proposed and tested a novel biosensor utilizing two clusters of cardiomyocytes for advanced detection of cardiac arrhythmias and
subsequent drug testing.
Methods: hESC's clusters were differentiated into spherical CMs syncytium. Two such spheres were seeded on adherent plates in the vicinity and within four days spontaneously formed electrically connected syncytium resembling the human myocardium and its conductive system. Contraction of twin clustered spontaneously synchronized by day 4. The Atomic Force Microscope (AFM) vertical deflection enabled measurement and calculation of absolute cardiomyocyte contraction force [1], while lateral force measurement was tracking synchronized or independent contraction behavior of twin clusters [2]. Caffeine induced arrhythmia as a model drug [3]. After its administration subsequent beating patterns were monitored by AFM lateral force recording and calcium fluorescence imaging as a reference method for describing non-synchronized contractions of cardiomyocytes. Caffeine increased the beat rate of the syncytium. This was reflected by both the change in vertical and lateral deflection. A significant increase in standard deviation was observed immediately after caffeine injection for both the lateral and the vertical deflection.
Results: Caffeine affected the synchronization of vertical and lateral displacement of the AFM cantilever, characteristic of independent lateral and vertical deflections, interpreted as defects in signal spreading through the bridge resulting in the irregular beat of the two clusters.

[1] Pesl M., et al. Biosens. Bioelektron. 85, 2016,10.1016/j.bios.2016.05.073
[2] Pivato R et al. Anal Chim Acta. 2022 čec 11;1216:339959. doi:10.1016/j.aca.2022.339959.
[3] Voskoboinik A et al. JACC Clin Electrophys., 4 (2018), s. 425-432, 10.1016/j.jacep.2018.01.012

The work was supported by the European Regional Development Fund – Project ENOCH (No. CZ.02.1.01/0.0/0.0/16_019/0000868) and by the project National Institute for Research of Metabolic and Cardiovascular Diseases (Programme EXCELES, ID Project No. LX22NPO5104) - Funded by the European Union – Next Generation EU. Ministry of Health of the Czech Republic, grant NU20-06-00156 and CIISB, Instruct-CZ Centre of Instruct-ERIC EU consortium, funded by MEYS CR project
LM2018127, supported project and measurements at the CF Nanobiotechnology.