Abstract
Purpose :
In the development of a retina tissue construct to act as a tissue scaffold for cells for implantation into the eye, we describe the fabrication of an ultra-thin membrane. We postulate that a thinner membrane will provide improved degradation rate with reduced degradation by-product in the retina post implantation. Also, added porosity would allow the membrane to more mimic Bruch′s membrane in facilitating transport across.
Methods :
The membrane was prepared by casting a biodegradable mixture of chloroform, polyethylene glycol (PEG) and polycaprolactone (PCL) onto a petri dish containing PEG solution (see Figure 1). This method of fabricating using a combination of phase separation and particulate leaching gave us the ability to develop nano-sized pores on the membrane, casting on PEG solution enables us to develop an ultra-thin product due to the spreading on the surface of the solution. Thickness of the product was measured using an optical profiler and pore size and distribution was determined using Scanning Electron Microscope (SEM). ARPE-19 cells (American Type Culture Collection, n=3) were used and incubated for 7 days. Live/dead staining was used to determine retina pigment epithelium (RPE) cells proliferation.
Results :
Using an optical image profiler, the thickness of the membrane was shown to be approximately 3μm, similar to Bruch′s membrane. A SEM was also done to determine that the pore size to be approximately 0.377μm (±0.031). The contact angle of the membrane was reduced by 5° compared to pure hot compressed PCL film, showing that the membrane is slightly hydrophilic which may induce better cell proliferation. This is likely due to the effect of PEG on the surface of the membrane. ARPE-19 cells were determined to be almost completely viable on the surface of the membrane after the use of live/dead staining.
Conclusions :
Using a simple Langmuir-Blodgett technique combined with particulate leaching, an ultra-thin biodegradable, porous membrane with an average pore size of 300nm can be fabricated. An ARPE-19 cell line has also been shown to survive on the surface of the membrane with minimal cell death and limited cytotoxic activity being observed. Further studies are needed to determine the effect of the cell-scaffold interaction and to determine the degradation rate of the scaffold.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.