The Use of a Green Fluorescent Protein Porcine Model to Evaluate Host Tissue Integration into Extracellular Matrix Derived Bionanocomposite Scaffolds

Abstract

When using heterogeneous extracellular matrix (ECM) derived scaffolds for soft tissue repair, current methods ofin vivoevaluation can fail to provide a clear distinction between host collagen and implanted scaffolds making it difficult to assess host tissue integration and remodeling. The purpose of this study is both to evaluate novel scaffolds conjugated with nanoparticles for host tissue integration and biocompatibility and to assess green fluorescent protein (GFP) expressing swine as a new animal model to evaluate soft tissue repair materials. Human-derived graft materials conjugated with nanoparticles were subcutaneously implanted into GFP expressing swine to be evaluated for biocompatibility and tissue integration through histological scoring and confocal imaging. Histological scoring indicates biocompatibility and remodeling of the scaffolds with and without nanoparticles at 1, 3, and 6 months. Confocal microscope images display host tissue integration into scaffolds although nonspecificity of GFP does not allow for quantification of integration. However, the confocal images do allow for spatial observation of host tissue migration into the scaffolds at different depths of penetration. The study concludes that the nanoparticle scaffolds are biocompatible and promote integration and that the use of GFP expressing swine can aid in visualizing the scaffold/host interface and host cell/tissue migration.

Fluorescence imaging preparation methods for tissue scaffolds implanted into a green fluorescent protein porcine model

“…A full study investigating the biocompatibility and tissue integration of the implanted tissue scaffolds using standard histology and the fresh frozen tissue preparation method is presented elsewhere (Smith et al 2015). Four methods of fluorescence microscopy preparation techniques were performed and assessed as methods for accurately and effectively visualizing tissue integration.…”

“…It should be noted that differences between scaffolds with and without nanoparticles are beyond detection limits of the imaging techniques used in this study therefore differences between scaffold types will not be discussed. The rationale for the use of the scaffold types are described by Smith et al (2015).…”

In vivo bone tunnel evaluation of nanoparticle‐grafts using an ACL reconstruction rabbit model

“…Grafts derived from acellular human gracilis tendon conjugated with gold nanoparticles (AuNP) and hydroxyapatite nanoparticles (nano‐Hap) have been developed for use as graft materials in ACL reconstruction. Previous studies performed by our laboratory have demonstrated enhancement of tissue remodeling using AuNPs and nano‐HAp conjugated to extracellular matrix (ECM) . Other researchers have also investigated hydroxyapatite crystals and nanofibers composed of polycaprolactone/nanohydroxyapatite/collagen .…”

“…Previous studies performed by our laboratory have demonstrated enhancement of tissue remodeling using AuNPs and nano-HAp conjugated to extracellular matrix (ECM). 11,12 Other researchers have also investigated hydroxyapatite crystals and nanofibers composed of polycaprolactone/nanohydroxyapatite/collagen. 13 By attaching the nanoparticles to the tissue using a zero-length crosslinker, light crosslinking of the tissue occurs, which may slow in vivo degradation by increasing enzymatic resistance.…”