Permeable guidance channels containing microfilament scaffolds enhance axon growth and maturation.

Successful peripheral nerve regeneration is still limited in artificial conduits, especially for long lesion gaps. In this study, porous poly(L-lactide-co-DL-lactide, 75:25) (PLA) conduits were manufactured with 16 poly(L-lactide) (PLLA) microfilaments aligned inside the lumen. Fourteen and 18 mm lesion gaps were created in a rat sciatic nerve lesion model.

Mechanical properties and in vitro degradation of bioresorbable fibers and expandable fiber-based stents.

Bioresorbable polymeric support devices (stents) are being developed in order to improve the biocompatibility and drug reservoir capacity of metal stents, as well as to offer a temporary alternative to permanent metallic stents. These temporary devices may be utilized for coronary, urethral, tracheal, and other applications. The present study focuses on the mechanical properties of bioresorbable fibers as well as stents developed from these fibers.

Functional repair after dorsal root rhizotomy using nerve conduits and neurotrophic molecules.

Functional recovery after large excision of dorsal roots is absent because of both the limited regeneration capacity of the transected root, and the inability of regenerating sensory fibers to traverse the dorsal root entry zone. In this study, bioresorbable guidance conduits were used to repair 6-mm dorsal root lesion gaps in rats, while neurotrophin-encoding adenoviruses were used to elicit regeneration into the spinal cord. Polyester conduits with or without microfilament bundles were implanted between the transected ends of lumbar dorsal roots.

Protein-coated poly(L-lactic acid) fibers provide a substrate for differentiation of human skeletal muscle cells.

Tissue engineering represents a potential method for repairing damaged skeletal muscle tissue. Extracellular matrix (ECM) proteins were evaluated for their ability to aid in cell attachment, whereas a poly(L-lactic acid) (PLLA) fiber scaffold was tested as a substrate for the differentiation of human skeletal muscle cells. In comparison to uncoated or gelatin-coated PLLA films, cell attachment increased significantly (p < 0.

Synergistic improvements in cell and axonal migration across sciatic nerve lesion gaps using bioresorbable filaments and heregulin-beta1.

The success of entubulation for peripheral nerve regeneration is still limited, especially with long lesion gaps. In this study, we examined if regeneration could be enhanced by constructing implants to both align axonal growth and promote Schwann cell proliferation and migration. Silicone implants were used to bridge a 1.

Technique paper for wet-spinning poly(L-lactic acid) and poly(DL-lactide-co-glycolide) monofilament fibers.

A simple and repeatable method is described for wet-spinning poly(L-lactic acid) (PLLA) and poly(DL-lactic-co-glycolic acid) (PLGA) monofilament fibers. These fibers are strong, elastic, and suitable for many applications, including use as tissue-engineering scaffolds. The PLLA wet-extruded fibers do not show additional strain-induced crystallization as a result of drawing the fibers during fabrication; however, there is an apparent increase in crystallinity late in the degradation process in saline at 37 degrees C.

Initial burst measures of release kinetics from fiber matrices.

A comprehensive axisymmetric diffusion model of drug release from a fiber is developed to account for both the initial burst (IB) phenomenon as well as the later diffusion-dominated release. This model is an enhancement over previous models in that a set of four IB parameters are calculated, which both describe the initial burst phenomenon as well as improve the fit for the diffusion-dominated release phase. This model is also an enhancement over previous models in allowing: finite dissolution volumes, finite stirring levels of the medium, and user-specified initial drug dispersion within the device.

Expandable bioresorbable endovascular stent. I. Fabrication and properties.

A bioresorbable, expandable poly(L-lactic acid) stent has been designed, based on a linear, continuous coil array principle, by which multiple furled lobes convert to a single lobe upon balloon expansion, without heating. Stent strength and compliance are sufficient to permit deployment by a conventional balloon angioplasty catheter. Several multiple lobe configurations were investigated, with expansion ratios ranging from 1.

Bioresorbable polymeric stents: current status and future promise.

Metal stents and, more recently, polymer-coated metal stents are used to stabilize dissections, eliminate vessel recoil, and guide remodeling after balloon angioplasty and other treatments for arterial disease. Bioresorbable polymeric stents are being developed to improve the biocompatibility and the drug reservoir capacity of metal stents, and to offer a transient alternative to the permanent metallic stent implant. Following a brief review of metal stent technology, the emerging class of expandable, bioresorbable polymeric stents is described, with emphasis on developments in the authors' laboratory.

Poly(L-Lactide) microfilaments enhance peripheral nerve regeneration across extended nerve lesions.

After injury, axonal regeneration occurs across short gaps in the peripheral nervous system, but regeneration across larger gaps remains a challenge. To improve regeneration across extended nerve defects, we have fabricated novel microfilaments with the capability for drug release to support cellular migration and guide axonal growth across a lesion. In this study, we examine the nerve repair parameters of non-loaded filaments.