Title : Biodegradable ultrathin nanofibrous membranes for retinal tissue engineering
Abstract:
Degenerative retinal diseases such as age-related macular degeneration (AMD) impair the function of the retinal pigment epithelium (RPE), which results in failure of photoreceptors and loss of vision. Replacement of the RPE by a transplantation of retinal cells via nanofibrous membrane is therefore considered as a therapeutic option for patients with these eye conditions. In this work, we compare two conventional culturing membranes for retinal tissue engineering made either from polyethylene terephthalate (PET) or polyimide (PI), with cell carrier based on 400-nm-thick poly(L-lactide-DL-lactide) fibres (thickness 4 µm, porosity 80%). Nanofibrous membranes were prepared by electrospinning that easily allowed an embedding of a supporting frame. Such a frame enables not only handling without irreversible folding of carrier and keeping a side-orientation of the sample while seeded with cells, but also to regain membrane’s flat shape when inserted into the subretinal space during surgery. ARPE-19 cells were seeded onto PET, PI and nanofibrous membranes (NM uncoated, NM laminin coated). Viability of ARPE-19 cells was monitored in different stages of sample preparation. Flat surface of commercial PET and PI membranes with track-etched porosity enable formation of RPE monolayer. However, lower number of pores with a manufacturer-specified pore size is not sufficient to mimic real Bruch’s membrane properties. In contrast to commercial membranes, electrospun membrane offers a 3D surrounding with large pore size which supports continuous flow of nutrients for seeded cells. PET and PI membranes could not be cut with our laser manufacturing setup because high thickness of the membranes. Cutting of NMs with a femtosecond laser is feasible. During laser ablation radicals and ions are generated in culturing medium. Seeded cells are sensitive to such a stress and are easily removed from the NMs, especially in case of laminin uncoated NMs. Laminin coated membranes showed better contact of ARPE cells with nanofibrous surface, which reflects in mechanically more stable adhesion of cells on the NMs during laser ablation and injector loading/unloading cycle.
Acknowledgments:The authors would like to thank the Technology Agency of the Czech Republic (KAPPA Programme, Project Number TO01000107) for providing financial support.
Audience Take Away:
- The novel setting for retinal carrier preparation is presented.
- Using the femtosecond laser ablation is possible to cut aseptically the ultrathin nanofibrous membrane.
- Stability of seeded RPE cell layer is possible to increase by laminin coating of NM.
