Poly(lactic-co-glycolic acid) Microspheres as an Injectable Scaffold for Cartilage Tissue Engineering

Abstract

Injectable scaffold has raised great interest for tissue regeneration in vivo, because it allows easy filling of irregularly shaped defects and the implantation of cells through minimally invasive surgical procedures. In this study, we evaluated poly(lactic-co-glycolic acid) (PLGA) microsphere as an injectable scaffold for in vivo cartilage tissue engineering. PLGA microspheres (30-80 microm in diameter) were injectable through various gauges of needles, as the microspheres did not obstruct the needles and microsphere size exclusion was not observed at injection. The culture of chondrocytes on PLGA microspheres in vitro showed that the microspheres were permissive for chondrocyte adhesion to the microsphere surface. Rabbit chondrocytes were mixed with PLGA microspheres and injected immediately into athymic mouse subcutaneous sites. Chondrocyte transplantation without PLGA microspheres and PLGA microsphere implantation without chondrocytes served as controls. Four and 9 weeks after implantation, chondrocytes implanted with PLGA microspheres formed solid, white cartilaginous tissues, whereas no gross evidence of cartilage tissue formation was noted in the control groups. Histological analysis of the implants by hematoxylin and eosin staining showed mature and well-formed cartilage. Alcian blue/safranin O staining and Masson's trichrome staining indicated the presence of highly sulfated glycosaminoglycans and collagen, respectively, both of which are the major extracellular matrices of cartilage. Immunohistochemical analysis showed that the collagen was mainly type II, the major collagen type in cartilage. This study demonstrates the feasibility of using PLGA microspheres as an injectable scaffold for in vivo cartilage tissue engineering. This scaffold may be useful to regenerate cartilaginous tissues through minimally invasive surgical procedures in orthopedic, maxillofacial, and urologic applications.

A Novel Method for Differentiation of Human Mesenchymal Stem Cells into Smooth Muscle-Like Cells on Clinically Deliverable Thermally Induced Phase Separation Microspheres

“…3 Urethral sphincter deficiency resulting in incontinence is a condition that is also likely to benefit from this type of therapy. [4][5][6][7][8] Smooth muscle provides an important function for a number of physiological processes. This includes, for example, peristaltic movements within the gastrointestinal tract, 9 regulation of blood pressure, 10 and maintaining ventilation of the airways.…”

Nanostructured Injectable Cell Microcarriers for Tissue Regeneration

“…Cartilage formed after 9 weeks, as shown by positive GAG and type II collagen staining. By comparison, bare chondrocyte transplantation without microspheres and microsphere injection without chondrocytes led to significantly less cartilage formation [111,112]. Thus, the combination of microspheres with cells ex vivo prior to implantation can lead to enhanced tissue regeneration.…”

Nanomaterials for cartilage tissue engineering

“…The explants showed chondrocytes within lacunae in a mature cartilaginous matrix that expressed collagen type II. Rabbit chondrocytes seeded on PLGA microspheres of 30-80 μm in diameter showed good adhesion to the microsphere surface [70]. In vivo, chondrocytes mixed with these PLGA microspheres were injected into subcutaneous sites in mice, and solid white cartilaginous tissues were formed in the implantation site after 4 and 9 weeks.…”