Different Types of Scaffolds for Reconstruction of the Urinary Tract by Tissue Engineering

Abstract

Introduction: Tissue engineering is an important and expanding field in reconstructive surgery. The ideal biomaterial for urologic tissue engineering should be biodegradable and support autologous cell growth. We examined different scaffolds to select the ideal material for the reconstruction of the bladder wall by tissue engineering. Materials and Methods: We seeded mouse fibroblasts and human keratinocytes in a co-culture model on 13 different scaffolds. The cell-seeded scaffolds were fixed and processed for electron microscopy, hematoxylin and eosin stain, and immunohistochemistry. Cell density and epithelial cell layers were evaluated utilizing a computer-assisted optical measurement system. Results: Depending on the growth pattern, scaffolds were classified into the following three distinct scaffold types: carrier-type scaffolds with very small pore sizes and no ingrowth of the cells. This scaffold type induces a well-differentiated epithelium. Fleece-type scaffolds with fibers and huge pores. We found cellular growth inside the scaffold but no epithelium on top of it. Sponge-type scaffolds with pores between 20 and 40 µm. Cellular growth was observed inside the scaffold and well-differentiated epithelium on top of it. Conclusion: To our knowledge, this is the first time three distinct scaffold types have been reported. All types supported the cell growth. The structure of the scaffolds affects the pattern of cell growth.

Experimental bladder regeneration using a poly-L-lactide/silk fibroin scaffold seeded with nanoparticle-labeled allogenic bone marrow stromal cells

“…To date, decellularized natural (based on bladder or small intestine submucosa) and synthetic scaffolds have been proposed. [8][9][10] Although natural scaffolds were shown to have a therapeutic efficacy, application of synthetic scaffolds is preferential due to the possibility of producing individualized forms with defined physicochemical characteristics.…”

Bladder reconstruction: The past, present and future

“…Bladder acellular matrix may be the most extensively used scaffold in tissue engineering. It has been demonstrated that the cells have the ability to induce the ingrowth of urothelium, smooth muscle, endothelium and nerve cells (53). Perhaps the greatest advantage of the use of acellular matrices is the ability to provide a method of neovascularisation following graft insertion, promoting graft survival.…”

“…The use of nanotechnology permits the development of a graft that can be manipulated to produce characteristics with definitive properties in order to promote optimal cell proliferation and tissue differentiation (53). A previous study investigated the effect of surface roughness on the interaction with matrix proteins (81).…”

Non-invasive characterization of structure and morphology of silk fibroin biomaterials using non-linear microscopy

“…cellular proliferation [1,5], differentiation [6][7][8], deposition of new structural proteins [9,10] and ultimately the regeneration of functional tissue [4,11,12]. Traditionally, methods such as NMR, FTIR and X-Ray spectroscopy have been used to assess biomaterials at the molecular level [13][14][15][16][17], while SEM and TEM have been invaluable tools for characterizing the three dimensional morphology of biomaterial scaffolds [5,[18][19][20][21][22][23]. Histology and immunostaining as well as assays for determining the expression levels of specific proteins are often used to assess how scaffolds interact with cells as tissues develop [5,10,18,20,[22][23][24].…”

“…Traditionally, methods such as NMR, FTIR and X-Ray spectroscopy have been used to assess biomaterials at the molecular level [13][14][15][16][17], while SEM and TEM have been invaluable tools for characterizing the three dimensional morphology of biomaterial scaffolds [5,[18][19][20][21][22][23]. Histology and immunostaining as well as assays for determining the expression levels of specific proteins are often used to assess how scaffolds interact with cells as tissues develop [5,10,18,20,[22][23][24]. While all of these approaches provide sensitive and specific data, they are invasive.…”