Development of micropatterned supramolecular hydrogels for myocardium regeneration

Development of micropatterned supramolecular hydrogels for myocardium regeneration

S. F. Gomes^1,2, A. M. Brito^1,2, D. Caballero^1,2, D. S. Costa^1,2, S. C. Kundu^1,2, A. M. Martins^1,2, I. Pashkuleva^1,2, R. L. Reis^1,2,3, R. A. Pires^1,2,3 

¹3B's Research Group, I3Bs – Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco, Guimarães, Portugal;

²ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal;

³The Discoveries Centre for Regenerative and Precision Medicine, Headquarters at University of Minho, Avepark, 4805-017 Barco, Guimarães, Portugal

In Europe there are 3.9 million deaths/year (45% of all deaths), from which 35.000 deaths/year in Portugal (30% of all deaths) as a consequence of the prevalence of cardiovascular diseases. The existing strategies to regenerate the myocardium and restore its normal function are invasive and inefficient. As an alternative, we propose a micropatterned electroactive self-assembled nanofibrous patch that allows autonomous myocardial regeneration. An integrated interface will be able to align cells through a micropatterned surface and promote their concerted electrical coupling, in order to simulate the heartbeat.

We prepared supramolecular hydrogels composed of a network of self-assembled nanofibers offmoc-diphenylalanine (fmoc-FF) that structurally mimic the extracellular matrix (ECM) [1,2]. Fmoc-FF is an amphiphilic short peptide that might present a semi-conductive character [3,4]- an important characteristic to permits the electrical impulses propagation of cardiomyocytes[5]. We fabricated the supramolecular hydrogels by dissolving the amphiphile in DMSO followed by dilution with ultrapure water (final fmoc-FF concentrations of 5 mM, 10 mM and 20 mM and final DMSO volume proportion of 2.5%, 5.0% and 10%, respectively)[1,6].The nanofibrous structure of the developed hydrogels was confirmed by atomic force microscopy (AFM). Rheology was carried out to determine the storage modulus of the different compositions and showed an increment of modulus with the augmentation of the fmoc-FF concentration: 5mM (≈1.3 kPa); 10mM (≈5.3 kPa); and 20mM (≈22.6 kPa). The cytocompatibility of the hydrogels was confirmed by culturing L929 cells and C2C12 cells onto the material’s surface; the results showed that all the tested compositions are not toxic and higher cell density was observed for stiffer hydrogels. The micropatterning of the hydrogels with grooves of 1x1x1 μm (height, width, pitch) was also carried out using replica moulding technique. These microstructures promote cell alignment, supporting its further evaluation targeting myocardium regeneration.

References:

1.  Mahler, A., et al. Advanced Materials 2006, 18 (11), 1365-1370.

2.  Jayawarna, V., et al. Advanced Materials 2006, 18 (5), 611-614.

3.  Kholkin, A., et al. Acs Nano 2010, 4 (2), 610-614.

4.  Tao, K., et al. Science 2017, 358 (6365).

5.  Martins, A. M., et al. Biomacromolecules 2014, 15 (2), 635-643.

6.  Raeburn, J., et al. Soft Matter 2012, 8 (4), 1168-1174.

Acknowledgements:

We acknowledge the European Commission for financial support under grants 692333-CHEM2NATURE, 668983-FORECAST and 739572-THE DISCOVERIES CTR; and the Portuguese FCT for financial support under grant IF/00032/2013 (IP) and M-ERA-NET2/0001/2016-INCIPIT.