Incorporation of Human Recombinant Tropoelastin into Silk Fibroin Membranes with the View to Repairing Bruch's Membrane

Audra M A Shadforth; Shuko Suzuki; Raphaelle Alzonne; Grant A Edwards; Neil A Richardson; Traian V Chirila; Damien G Harkin

doi:10.3390/jfb6030946

Incorporation of Human Recombinant Tropoelastin into Silk Fibroin Membranes with the View to Repairing Bruch's Membrane

J Funct Biomater. 2015 Sep 16;6(3):946-62. doi: 10.3390/jfb6030946.

Authors

Audra M A Shadforth^{1

2}, Shuko Suzuki³, Raphaelle Alzonne⁴, Grant A Edwards⁵, Neil A Richardson^{6

7}, Traian V Chirila^{8

5

9

10

11}, Damien G Harkin^{12

13}

Affiliations

¹ Queensland Eye Institute, 140 Melbourne Street, South Brisbane, Queensland 4101, Australia. audra.shadforth@qei.org.au.
² School of Biomedical Sciences and Institute of Health & Biomedical Innovation, Queensland University of Technology, 2 George Street, Brisbane, Queensland 4001, Australia. audra.shadforth@qei.org.au.
³ Queensland Eye Institute, 140 Melbourne Street, South Brisbane, Queensland 4101, Australia. shuko.suzuki@qei.org.au.
⁴ Queensland Eye Institute, 140 Melbourne Street, South Brisbane, Queensland 4101, Australia. raphaelle.alzonne@supersonicimagine.com.
⁵ Australian Institute for Bioengineering and Nanotechnology, University of Queensland, St Lucia, Queensland 4072, Australia. g.edwards1@uq.edu.au.
⁶ Queensland Eye Institute, 140 Melbourne Street, South Brisbane, Queensland 4101, Australia. n.richardson@qut.edu.au.
⁷ School of Biomedical Sciences and Institute of Health & Biomedical Innovation, Queensland University of Technology, 2 George Street, Brisbane, Queensland 4001, Australia. n.richardson@qut.edu.au.
⁸ Queensland Eye Institute, 140 Melbourne Street, South Brisbane, Queensland 4101, Australia. g.edwards1@uq.edu.au.
⁹ Science and Engineering Faculty, Queensland University of Technology, Brisbane, Queensland 4001, Australia. g.edwards1@uq.edu.au.
¹⁰ Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston, Queensland 4029, Australia. g.edwards1@uq.edu.au.
¹¹ Faculty of Science, University of Western Australia, Crawley, Western Australia 6009, Australia. g.edwards1@uq.edu.au.
¹² Queensland Eye Institute, 140 Melbourne Street, South Brisbane, Queensland 4101, Australia. d.harkin@qut.edu.au.
¹³ School of Biomedical Sciences and Institute of Health & Biomedical Innovation, Queensland University of Technology, 2 George Street, Brisbane, Queensland 4001, Australia. d.harkin@qut.edu.au.

Abstract

Bombyx mori silk fibroin membranes provide a potential delivery vehicle for both cells and extracellular matrix (ECM) components into diseased or injured tissues. We have previously demonstrated the feasibility of growing retinal pigment epithelial cells (RPE) on fibroin membranes with the view to repairing the retina of patients afflicted with age-related macular degeneration (AMD). The goal of the present study was to investigate the feasibility of incorporating the ECM component elastin, in the form of human recombinant tropoelastin, into these same membranes. Two basic strategies were explored: (1) membranes prepared from blended solutions of fibroin and tropoelastin; and (2) layered constructs prepared from sequentially cast solutions of fibroin, tropoelastin, and fibroin. Optimal conditions for RPE attachment were achieved using a tropoelastin-fibroin blend ratio of 10 to 90 parts by weight. Retention of tropoelastin within the blend and layered constructs was confirmed by immunolabelling and Fourier-transform infrared spectroscopy (FTIR). In the layered constructs, the bulk of tropoelastin was apparently absorbed into the initially cast fibroin layer. Blend membranes displayed higher elastic modulus, percentage elongation, and tensile strength (p < 0.01) when compared to the layered constructs. RPE cell response to fibroin membranes was not affected by the presence of tropoelastin. These findings support the potential use of fibroin membranes for the co-delivery of RPE cells and tropoelastin.

Keywords: Bombyx mori; Bruch’s membrane; age-related macular degeneration; retinal pigment epithelium; silk fibroin; tropoelastin.