Seamless vascularized large-diameter tubular collagen scaffolds reinforced with polymer knittings for esophageal regenerative medicine.

A clinical demand exists for alternatives to repair the esophagus in case of congenital defects, cancer, or trauma. A seamless biocompatible off-the-shelf large-diameter tubular scaffold, which is accessible for vascularization, could set the stage for regenerative medicine of the esophagus. The use of seamless scaffolds eliminates the error-prone tubularization step, which is necessary when emanating from flat scaffolds.

Characterization of polyurethane scaffold surface functionalization with diamines and heparin.

Polyurethane scaffolds (PUs) have a good biocompatibility but lack cell recognition sites. In this study, we functionalized the surface of a PU, P(D/L)LA and PCL (50:50) containing urethane segments, with heparin. The first step in this functionalization, aminolysis, lead to free amine groups on the surface of the PU.

Evaluation of methods for the construction of collagenous scaffolds with a radial pore structure for tissue engineering.

Type I collagen is used widely as a biomaterial. The structure of collagenous biomaterials, including pore sizes and general architecture, can be varied by a number of techniques. In this study, we developed a method to construct flat fibrillar type I collagen scaffolds, 6 cm in diameter and with a radially orientated pore structure, by the use of directional freezing.

Organ-specific tubular and collagen-based composite scaffolds.

The body contains a number of organs characterized by a tubular shape. In this study, we explored several methodologies for the construction of collagenous tubular scaffolds and films with defined (ultra)structure, length, diameter, orientation, and molecular composition. Standardization of molding, casting, freezing, and lyophilizing techniques using inexpensive materials and methods resulted in controllable fabrication of a wide variety of tubular and tissue-specific tubular scaffolds and films.

Urethral reconstruction of critical defects in rabbits using molecularly defined tubular type I collagen biomatrices: key issues in growth factor addition.

Tubular type I collagen biomatrices with and without growth factors (GFs) were constructed and evaluated in a rabbit model for critical urethral defects. Porous tubular biomatrices with an inner diameter of 3  mm were prepared using highly purified collagen fibrils and were crosslinked with or without heparin. Heparinized biomatrices were supplemented with the heparin-binding GFs vascular endothelial GF, fibroblast GF-2, and heparin-binding epidermal GF.