Cecilia Ferrantini1,2, Josè M Pioner1, Daniele Martella3,2,4, Raffaele Coppini5, Nicoletta Piroddi1, Paolo Paoli6, Martino Calamai2,4, Francesco S Pavone7,2,4, Diederik S Wiersma7,2,4,8, Chiara Tesi1, Elisabetta Cerbai5, Corrado Poggesi1,2, Leonardo Sacconi2,4, Camilla Parmeggiani3,2,4,8. 1. From the Department of Experimental and Clinical Medicine (C.F., J.M.P., N.P., C.T., C.Po.), University of Florence, Italy. 2. European Laboratory for Non-linear Spectroscopy, Sesto Fiorentino, Italy (C.F., D.M., M.C., F.S.P., D.S.W., C.Po., L.S., C.Pa.). 3. Department of Chemistry "Ugo Schiff" (D.M., C.Pa.), University of Florence, Italy. 4. National Institute of Optics, National Research Council, Sesto Fiorentino, Italy (D.M., M.C., F.S.P., D.S.W., L.S., C.Pa.). 5. Department of Neurosciences, Psychology, Drug Research and Child Health (NEUROFARBA) (R.C., E.C), University of Florence, Italy. 6. Department of Biochemical, Experimental and Clinical "Mario Serio", Italy (P.P.). 7. Department of Physics and Astronomy (F.S.P., D.S.W.), University of Florence, Italy. 8. Istituto Nazionale di Ricerca Metrologica INRiM, Turin, Italy (D.S.W., C.Pa.).
Abstract
RATIONALE: Despite major advances in cardiovascular medicine, heart disease remains a leading cause of death worldwide. However, the field of tissue engineering has been growing exponentially in the last decade and restoring heart functionality is now an affordable target; yet, new materials are still needed for effectively provide rapid and long-lasting interventions. Liquid crystalline elastomers (LCEs) are biocompatible polymers able to reversibly change shape in response to a given stimulus and generate movement. Once stimulated, LCEs can produce tension or movement like a muscle. However, so far their application in biology was limited by slow response times and a modest possibility to modulate tension levels during activation. OBJECTIVE: To develop suitable LCE-based materials to assist cardiac contraction. METHODS AND RESULTS: Thanks to a quick, simple, and versatile synthetic approach, a palette of biocompatible acrylate-based light-responsive LCEs with different molecular composition was prepared and mechanically characterized. Out of this, the more compliant one was selected. This material was able to contract for some weeks when activated with very low light intensity within a physiological environment. Its contraction was modulated in terms of light intensity, stimulation frequency, and ton/toff ratio to fit different contraction amplitude/time courses, including those of the human heart. Finally, LCE strips were mounted in parallel with cardiac trabeculae, and we demonstrated their ability to improve muscular systolic function, with no impact on diastolic properties. CONCLUSIONS: Our results indicated LCEs are promising in assisting cardiac mechanical function and developing a new generation of contraction assist devices.
RATIONALE: Despite major advances in cardiovascular medicine, heart disease remains a leading cause of death worldwide. However, the field of tissue engineering has been growing exponentially in the last decade and restoring heart functionality is now an affordable target; yet, new materials are still needed for effectively provide rapid and long-lasting interventions. Liquid crystalline elastomers (LCEs) are biocompatible polymers able to reversibly change shape in response to a given stimulus and generate movement. Once stimulated, LCEs can produce tension or movement like a muscle. However, so far their application in biology was limited by slow response times and a modest possibility to modulate tension levels during activation. OBJECTIVE: To develop suitable LCE-based materials to assist cardiac contraction. METHODS AND RESULTS: Thanks to a quick, simple, and versatile synthetic approach, a palette of biocompatible acrylate-based light-responsive LCEs with different molecular composition was prepared and mechanically characterized. Out of this, the more compliant one was selected. This material was able to contract for some weeks when activated with very low light intensity within a physiological environment. Its contraction was modulated in terms of light intensity, stimulation frequency, and ton/toff ratio to fit different contraction amplitude/time courses, including those of the human heart. Finally, LCE strips were mounted in parallel with cardiac trabeculae, and we demonstrated their ability to improve muscular systolic function, with no impact on diastolic properties. CONCLUSIONS: Our results indicated LCEs are promising in assisting cardiac mechanical function and developing a new generation of contraction assist devices.
Authors: Cedric P Ambulo; Seelay Tasmim; Suitu Wang; Mustafa K Abdelrahman; Philippe E Zimmern; Taylor H Ware Journal: J Appl Phys Date: 2020-10-08 Impact factor: 2.546
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