title: Evaluation of a sphere-templated polymeric scaffold as a subcutaneous implant.
abstract: OBJECTIVE
  To evaluate the performance of a sphere-templated poly(2-hydroxyethyl methacrylate) (poly[HEMA]) tissue scaffold as a subcutaneous implant by comparing it with widely used high-density porous polyethylene (HDPPE) implant material.
  
  
  METHODS
  We implanted sphere-templated porous poly-(HEMA) and HDPPE disks into the dorsal subcutis of C57BL/6 mice for 4 and 9 weeks. Excisional biopsy specimens of the implants and surrounding tissue were assessed for host inflammatory response, tissue ingrowth, and neovascularization using trichrome, picrosirius red, and anti-endothelial cell antibody staining.
  
  
  RESULTS
  The poly(HEMA) and HDPPE implants showed resistance to extrusion and elicited a minimal inflammatory response. Both implants supported cellular and collagen ingrowth, but ingrowth within the HDPPE implant was thicker owing to the larger porous structure (>100 μm) of HDPPE, whereas the poly(HEMA) implant had much thinner collagen fibrils within much smaller (40-μm) pores, suggestive of less scar-type reaction. Neovascularization was supported by both implants. Blood vessels were identified within the fibrous ingrowth of the HDPPE and within individual pores of the poly(HEMA).
  
  
  CONCLUSIONS
  Sphere-templated poly(HEMA) implanted as a subcutaneous tissue scaffold stimulates a minimal inflammatory response and supports cellular infiltration, collagen formation, and neovascularization. Because of its tightly controlled porous structure, poly-(HEMA) appears to induce less scar-type ingrowth compared with HDPPE.
authors: Department of Otolaryngology–Head and Neck Surgery, University of Washington, Seattle, WA 98195, USA. abhrany@uw.edu.
authors: Amit D
authors: AD
authors: Bhrany
authors: Colleen A
authors: CA
authors: Irvin
authors: Kenji
authors: K
authors: Fujitani
authors: Zada
authors: Z
authors: Liu
authors: Buddy D
authors: BD
authors: Ratner
mesh_terms: D000818:Animals; D002921:Cicatrix / Q000473:pathology; D005549:Foreign-Body Reaction / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018919:Neovascularization, Physiologic; D020959:Polyethylene; D011102:Polyhydroxyethyl Methacrylate; D019736:Prostheses and Implants; D040521:Subcutaneous Tissue / Q000473:pathology; D054457:Tissue Scaffolds; D014945:Wound Healing / Q000502:physiology
chemical_list: D011102:Polyhydroxyethyl Methacrylate; D020959:Polyethylene