Controlled release of bioactive TGF-β1 from microspheres embedded within biodegradable hydrogels

Hydrogels for the Repair of Articular Cartilage Defects

“…228 The mechanisms of release can also be varied by manipulating interactions between encapsulated proteins and the hydrogel polymer, such as charge interactions, or by changing the degradation profiles of the hydrogels. 228,229 Another useful tool for controlling the release of growth factors is the encapsulation of growth factor-loaded microparticles, which allows delayed or tempered release profiles, [230][231][232] spatial control over delivery, 233 and greater stability and bioactivity of the encapsulated protein. 231 The controlled release of growth factors from hydrogels has been used to stimulate repair of cartilage defects by cells from the surrounding tissue, to enhance cartilage production by encapsulated chondrocytes, and to induce chondrogenesis of MSCs.…”

Response of a Preosteoblastic Cell Line to Cyclic Tensile Stress Conditioning and Growth Factors for Bone Tissue Engineering

“…17 Diverse delivery methodologies for these GFs have been developed for in vitro or in vivo bone tissue engineering research and clinical studies. [18][19][20][21][22] In vitro studies using preosteoblasts and stem cells suggest that osteoinductive GFs can induce increased cell proliferation and osteogenic differentiation. 17 Exogenous BMP-2 delivery has been shown to enhance bone regeneration, 23 and TGF-b1 can induce higher alkaline phosphate (ALP) production and proliferation in bone marrow cells.…”

Incorporation of TGF‐Beta 3 within Collagen–Hyaluronic Acid Scaffolds Improves their Chondrogenic Potential

“…There was approximately 3-fold higher (p<0.01) sGAG/DNA in the TGF-β3 loaded scaffolds than the blank scaffolds. Since it is still not clear in the literature as to the most optimal duration that TGF-β3 is required in vitro and subsequently in vivo to stimulate MSC chondrogenesis and cartilage repair [5,13,[19][20][21] , both soakloading and direct-incorporation were chosen for the in vitro analysis due to the differing release kinetics. From the results, it was evident that by day 7 there was a significantly higher COL2 gene expression in the soak-loaded scaffold group in comparison to the direct incorporation scaffold group which may be attributed to the higher initial release of TGF-β3.…”

“…However, the majority of such studies have encapsulated TGF-β within hydrogels with poor porosity or within microparticles which may impede the pore interconnectivity and porosity of the scaffolds [8][9][10][11][12] . In addition, most of the microparticles utilised hitherto have been based on synthetic materials such as poly (DL-lactideco-glycolide) (PLGA) and poly (ethylene glycol) (PEG) which may have long term deleterious effects in vivo due to their toxic degradation products [8,13] . Moreover, the encapsulation efficiency of the growth factors within such microparticles is generally very poor, leading to significant loss of the proteins during fabrication processes.…”