Characterizing fibroblast migration on discrete collagen threads for applications in tissue regeneration

Abstract

Collagen threads with mechanical properties and fibrillar substructure similar to native tissue have been synthesized for the repair of injured tendon and ligament. While these scaffolding materials have demonstrated the potential for inducing tissue regeneration, one limitation has been an insufficient rate of tissue ingrowth for complete regeneration. We hypothesize that the structural hierarchy and biochemical cues on the surfaces of these threads will enhance the rate of cell migration and ultimately the rate of new tissue ingrowth. We developed an in vitro assay to measure the effects of various collagen sources and crosslinking on the rate of fibroblast migration on the surfaces of collagen threads. Threads were suspended from elevated platforms and seeded with fibroblast-populated collagen lattices. Cell migration rates ranging from 0.75 to 1.25 mm/day were measured as the fibroblasts left the lattices and migrated onto various thread types. Threads self-assembled from type I collagen were found to have migration rates similar to native tendon threads while crosslinking by severe dehydration decreased the rate. This novel in vitro model system allows examination of cell migration from a wound margin onto biomaterials to determine the effects of various cell types, matrix materials, and surface biochemistries on cell-matrix interactions. Ultimately, this assay will allow us to identify design parameters that will be most effective for enhancing the rate of tissue ingrowth on fiber-based collagen scaffolds for soft tissue regeneration.

Engineering extruded collagen fibers for biomedical applications

“…Moreover, such unique features have been shown to facilitate cell attachment and fibroblast migration. 24 Detailed scanning electron microscopy of the failed ends of the fibers revealed a consistently filled interfiber space. It has been mentioned that very little free interfiber space occurs in fibers formed in vitro.…”

Development of Microfabricated Dermal Epidermal Regenerative Matrices to Evaluate the Role of Cellular Microenvironments on Epidermal Morphogenesis

“…27,28 The CI was lyophilized and resuspended at a concentration of 10 mg/mL in 5 mM HCl (Sigma Aldrich). The CI solution was then self-assembled using 5 · Dulbecco's modified Eagle's medium (DMEM; Invitrogen) with 0.22 M NaHCO 3 and 0.1 M NaOH (Sigma) and incubated at 37°C for 18 h on circular negative replicated PDMS molds to create the microfabricated portion of the mDERMs (Fig.…”

Enhanced Directional Migration of Cancer Stem Cells in 3D Aligned Collagen Matrices

“…To date, a handful of reports have been presented for fabrication of 3D microenvironments that successfully align collagen matrices in vitro including magnetic alignment (either by high-power magnets (15) or flow of magnetic beads embedded during formation of the matrix (13,16), alignment in microfluidic channels (17,18), alignment by mechanical stretching (18), or collagen fiber extrusion (19)). However, these methods may cause interference with imaging modalities (scattering from magnetic beads), introduce additional alignment cues by confinement (alignment in narrow channels), induce unwanted damage or prestress to the fibers (mechanical stretching), and overall may not be conducive to repeated benchtop production at a reasonably high throughput (e.g., alignment by ultra-highpower magnets).…”