Langmuir-Schaefer film deposition onto honeycomb porous films for retinal tissue engineering

Abstract

Age-related macular degeneration (AMD) is the leading cause of vision loss in senior citizens in the developed world. The disease is characterised by the degeneration of a specific cell layer at the back of the eye -the retinal pigment epithelium (RPE), which is essential in retinal function. The most promising therapeutic option to restore the lost vision is considered to be RPE cell transplantation. This work focuses on the development of biodegradable biomaterials with similar properties to the native Bruch's membrane as carriers for RPE cells. In particular, the breath figure (BF) method was used to create semi-permeable microporous films, which were thereafter used as the substrate for the consecutive Langmuir-Schaefer (LS) deposition of highly organised layers of collagen type I and collagen type IV. The newly developed biomaterials were further characterised in terms of surface porosity, roughness, hydrophilicity, collagen distribution, diffusion properties and hydrolytic stability.Human embryonic stem cell-derived RPE cells (hESC-RPE) cultured on the biomaterials showed good adhesion, spreading and morphology, as well as the expression of specific protein markers. Cell function was additionally confirmed by the assessment of the phagocytic capacity of hESC-RPE.Throughout the study, microporous films consistently showed better results as cell culture materials for 2 hESC-RPE than dip-coated controls. This work demonstrates the potential of the BF-LS combined technologies to create biomimetic prosthetic Bruch's membranes for hESC-RPE transplantation.

Collective adhesion and displacement of retinal progenitor cells upon extracellular matrix substrates of transplantable biomaterials

“… 13 Reported advancements 14 in the survival and integration of transplanted photoreceptor progenitors have inspired dramatic innovation in contemporary transplantation strategies, including elastomeric grafts 15 and protein-coated, electrospun fibers, 16 whose properties mimic in vivo cues affecting cell fate, behavior, and response in host retina. 17 , 18 …”

Controlling the hydrophilicity and cohesion during deposition of highly oriented type I collagen films: An approach for biomedical applications

“…Based on previous work (e.g. collagen/PBS gels, collagen/hydrophobic-hydrophilic substrates [8,20,22,24,36,[40][41][42][43][44][45]), it is expected that ultra-thin film coatings (from fresh or aged (more hydrophilic) solutions) on both hydrophobic and hydrophilic substrates are feasible. It is, however, not clear whether, e.g., films exhibit still a stable and highly oriented collagen alignment when transferred to hydrophilic samples, or if collagen is transferable at all in studies without a stabilizer.…”

Coculture techniques for modeling retinal development and disease, and enabling regenerative medicine

“…126 Ex vivo Bruch's membrane from individuals with outer retinal disease may serve in coculture models of these diseases. 127 Other physical properties which have been investigated are porosity, wettability, and ion diffusion capacity in a variety of synthetic and natural explants (reviewed in detail here) 128 and using a variety of surface coating to facilitate cell adhesion 122,123,129,130 ; however, these studies have not investigated stiffness or tethering properties. Unsurprisingly, several polymers and several surface coatings containing ECM proteins such as collagens and laminins were found to be suitable for culture of hESC-derived RPE, although the identification of specific conditions which optimize RPE function have been equivocal.…”