Increasing the pore sizes of bone-mimetic electrospun scaffolds comprised of polycaprolactone, collagen I and hydroxyapatite to enhance cell infiltration

• Published in: Biomaterials Vol. 33; no. 2; pp. 524 - 534
• Main Authors: Phipps, Matthew C, Clem, William C, Grunda, Jessica M, Clines, Gregory A, Bellis, Susan L
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.01.2012
• Subjects: Advanced Basic Science; Animals; Biomimetic material; Biomimetic Materials - chemistry; Bone Substitutes - chemistry; Bone tissue engineering; Cell Adhesion; Cell Proliferation; Cellular infiltration; Collagen Type I - chemistry; Dentistry; Durapatite - chemistry; Extracellular Matrix - metabolism; Male; Mesenchymal Stromal Cells - cytology; Microscopy, Electron, Scanning; Organ culture; Polyesters - chemistry; Porosity; Rats; Rats, Sprague-Dawley; Scaffold; Tissue Engineering - methods; Tissue Scaffolds - chemistry; Cellular infiltration; Bone tissue engineering; Porosity; Scaffold; Biomimetic material; Organ culture
• ISSN: 0142-9612; 1878-5905
• DOI: 10.1016/j.biomaterials.2011.09.080

Abstract Bone-mimetic electrospun scaffolds consisting of polycaprolactone (PCL), collagen I and nanoparticulate hydroxyapatite (HA) have previously been shown to support the adhesion, integrin-related signaling and proliferation of mesenchymal stem cells (MSCs), suggesting these matrices serve as promising degradable substrates for osteoregeneration. However, the small pore sizes in electrospun scaffolds hinder cell infiltration in vitro and tissue-ingrowth into the scaffold in vivo, limiting their clinical potential. In this study, three separate techniques were evaluated for their capability to increase the pore size of the PCL/col I/nanoHA scaffolds: limited protease digestion, decreasing the fiber packing density during electrospinning, and inclusion of sacrificial fibers of the water-soluble polymer PEO. The PEO sacrificial fiber approach was found to be the most effective in increasing scaffold pore size. Furthermore, the use of sacrificial fibers promoted increased MSC infiltration into the scaffolds, as well as greater infiltration of endogenous cells within bone upon placement of scaffolds within calvarial organ cultures. These collective findings support the use of sacrificial PEO fibers as a means to increase the porosity of complex, bone-mimicking electrospun scaffolds, thereby enhancing tissue regenerative processes that depend upon cell infiltration, such as vascularization and replacement of the scaffold with native bone tissue.